Opel Manta Turbo Ecotec Build

[Later-A-body]

I’m really excited to start my new project.This is a 1974 Opel Manta. GM imported the Manta from Opel in Germany and sold them through Buick dealers from 1971-1975. My friend and I traveled up to Northern California to get the car after his brother-in-law told him he would not be able to do anything with the car. My buddy owns two Manta’s, and he knows that I really like these cars, so he asked me if I was interested. His brother got the car about 5 years ago, but never started on it. He said he didn’t need any money for it, so for the price of gas to drive from Southern California to Sacramento and back ($275.00), the car is mine. It sat outside under a tree and greenery and was pretty dirty inside and out. After getting it home I realized the car was only registered once. I tracked down the original owner and spoke with him on the phone. He explained he bought the car in 1975 at age 26 for a cash price of around $3,000.00 at San Rafael Buick. The car had been on the lot for over 1 year. He originally wanted an Opel GT, but that model was discontinued. The dealer explained that the Manta was highly discounted to sell. The reason the Buick dealer couldn’t sell the car was the color. Nobody wanted a lime green Manta. Well he bought it, and drove it until 1986 when the head cracked at 133,000 miles. He was a high school auto shop teacher, so he parked the car at the high school for the next 15 years. Apparently during that time, a student that received an F in auto shop decided to vandalize the car which explains the busted windshield and some dings and dents. He sold it to an Opel enthusiast who never touched the car, and then it was sold to my friend’s brother. No other buyer ever registered the car in their name, and the original owners name is still on the pink slip which is how I found him. After speaking with the original owner, he agreed to send me some old photographs of the car. This poor little green car deserves a break. 157741157740157742157743

[Later-A-body]

After doing a full cleaning of the inside and out, I found the car to be in surprisingly good condition. There is no rust in the car. All the floorboards, trunk area, doors are shiny green underneath. There is some minor surface rust that comes off with scotch-bright. So my plan is to leave the patina and restore all the mechanical's of the car, while updating the drivetrain. Honestly, I would not have picked this color, but everyone that sees it thinks it’s a great color, so I guess when it’s time to paint the car, it will stay lime green. The mechanical's include swapping in a GM Ecotec LTG 2.0 Turbo motor from a 2016 Camaro. I purchased locally from a auto recycler. The motor has only 14,000 miles on it. Price was $1200.00. I also bought a brand new GM/Aisan 5-Speed manual transmission for a 2007-2009 Solstice/Sky for $600.00. The largest hurdle is the front cross-member and the oil pan. I have spoken with someone that did an Ecotec swap, and that was the biggest obstacle. I’m looking at doing a 15” or 16” wheel, a disc brake set up on the rear, and some larger disc brakes up front. The car already has rack and pinion up front and a 3-link panhard bar set up in the rear. Some modern seats will be added as well. I am not turning this car into a hacked up race car. I would like to have fun with the car and be able to autocross and road race it occasionally. The body is not perfect. There are a number of dings and dents that need to be addressed, but for the most part, I am leaving it alone. And since it has the original paint, I know it has no body filler. I hope to get it running and driving by the end of 2019. 157744157745

[Later-A-body]

After cleaning out the car I was happy with what I didn't find. No rust. Everything underneath all the dirt was well preserved. There was some surface rust on the drivers side floor, but it lifted off with some 100 grit sandpaper. 157746157747157748

[slimjim]

great project and a stylish little car. I saw one for sale near me recently(NC) and was thinking how good it could look with a few minor changes. the ecotec will be badass

[ryeguy2006a]

That is an awesome project, and pretty cool you are using a modern driveline. I wonder how many of those dents could be removed by an experienced PDR specialist?

[andrewb70]

Fantastic project!!!

Andrew

[SonomaZ]

My brother had an Opel GT way back when. Fun little car.
I would be willing to bet the German/Euro version of the bumpers would be an easy styling makeover assuming they can be sourced.
US market 5 mph bumpers were the worst thing to happen stylistically to every vehicle they were hung on.
Love your engine choice.

[cornfedbill]

Nice project. This is a very good platform for the LTG. It is just the right size. The power to weight ratio should be great.

[Michaels 69]

This should be fun!

[Bugzilla]

Sweet, another Ecotec powered project going on here!

[Later-A-body]

My brother had an Opel GT way back when. Fun little car.
I would be willing to bet the German/Euro version of the bumpers would be an easy styling makeover assuming they can be sourced.
US market 5 mph bumpers were the worst thing to happen stylistically to every vehicle they were hung on.
Love your engine choice.

Yes, the big ugly bumpers are coming off. I will be replacing them with the 71-73 small bumpers. There are a few things I have in mind as far as subtle changes. The rear licence plate lights are way too big. I think if I recess the license plate, I can eliminate the lights and incorporate a hidden light above.

[Later-A-body]

That is an awesome project, and pretty cool you are using a modern driveline. I wonder how many of those dents could be removed by an experienced PDR specialist?

I was thinking the same thing. I will have a dent guy come over to get an idea if they can be worked out of the metal. The metal on the Manta isn't as thin and tinny as a like year Japanese car, but still thinner than US cars.

[Later-A-body]

Nice project. This is a very good platform for the LTG. It is just the right size. The power to weight ratio should be great.

It for sure will have a favorable power to weight ratio. I actually didn't want to use the LTG motor simply because the standard N/A Ecotec's are making between 180-230 HP with a stand alone harness and proper tune which I think is plenty. The problem I ran into was the N/A motors are all priced way too high for a low mileage version. I consistently found the turbo ones cheaper which seems odd to me. So I said fine, get the turbo. It will require a roll bar just to keep the car from twisting. I won't be installing a front section, just a center bar and a rear section, but will retain the back seat. Not a race car!! These Ecotec motors are some of the best 4-cylinder platforms available. The amount of engineering GM has in these are incredible. Since this is a GM car, I wanted to keep it GM under the hood. I know there will be quite a lot of work and fabrication needed to get this motor, turbo plumbing, intercooler, etc. to fit properly, but I always take my time when it comes to the details. One area I will not leave the patina is the engine compartment. After finishing all of the fab work, I will paint the engine compartment the lime green to look new, as well as the engine will be detailed .

[Later-A-body]

This picture is of a Manta GTE. This was the top of the line sporty version that was available. In the future when the car does get painted, this is what I want the car to look like. The blue car has 15" wheels, which I will be doing now. I will be replacing the big bumpers, and incorporating the front spoiler as pictured.
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[cornfedbill]

It for sure will have a favorable power to weight ratio. I actually didn't want to use the LTG motor simply because the standard N/A Ecotec's are making between 180-230 HP with a stand alone harness and proper tune which I think is plenty. The problem I ran into was the N/A motors are all priced way too high for a low mileage version. I consistently found the turbo ones cheaper which seems odd to me. So I said fine, get the turbo. It will require a roll bar just to keep the car from twisting. I won't be installing a front section, just a center bar and a rear section, but will retain the back seat. Not a race car!! These Ecotec motors are some of the best 4-cylinder platforms available. The amount of engineering GM has in these are incredible. Since this is a GM car, I wanted to keep it GM under the hood. I know there will be quite a lot of work and fabrication needed to get this motor, turbo plumbing, intercooler, etc. to fit properly, but I always take my time when it comes to the details. One area I will not leave the patina is the engine compartment. After finishing all of the fab work, I will paint the engine compartment the lime green to look new, as well as the engine will be detailed .

My son and I ran a tuned HHR SS with an LNF in the Sandhills Open Road Challenge. We used a tune from ZZ Performance in Grand Rapids, MI and made a few small tweaks. The only hardware we changed were two MAP sensors. It ran pretty strong. The smaller lighter Manta will be a rocket.

[Later-A-body]

I have done a lot of research on the Ecotec regarding stand alone wiring harnesses and ECU tuning. ZZ-Performance is one of the companies I am aware of, but I have tried to contact them a few times and I get no answer on the phone. CBM Motorsports here in California does not support the LTG. I have spoken with Alpha Fab in Michigan and I am real comfortable with them. They seem to have all the knowledge and components I need to do the swap. They do a lot of Ecotec swaps and builds for off-road applications. They offer a nice harness/ECU package. They also can wire in the GM flex fuel sensor so I have the option to run E-85 which I want to do.

[Bugzilla]

CBM is working on the LTG ecu/harness. They should have a system out early next year. They just completed the LFX system (which was the holdup) and are now moving on to the LTG. Dont ask how I know haha.

[cornfedbill]

I have done a lot of research on the Ecotec regarding stand alone wiring harnesses and ECU tuning. ZZ-Performance is one of the companies I am aware of, but I have tried to contact them a few times and I get no answer on the phone. CBM Motorsports here in California does not support the LTG. I have spoken with Alpha Fab in Michigan and I am real comfortable with them. They seem to have all the knowledge and components I need to do the swap. They do a lot of Ecotec swaps and builds for off-road applications. They offer a nice harness/ECU package. They also can wire in the GM flex fuel sensor so I have the option to run E-85 which I want to do.

It's been done. See this clean Vega. http://gearheadnextdoor.com/blog/2017/06/05/de-la-vega-protouring-1973-chevy-vega/

[Boosted Falcon]

Fun build, we have a couple of 17 RS Camaro's with the Turbo Ecotec engines. The engine is impressive and in a car 1000lb less should be really fun.

[wfo guy]

I'll be watching. :)

[RMMiller]

This picture is of a Manta GTE. This was the top of the line sporty version that was available. In the future when the car does get painted, this is what I want the car to look like. The blue car has 15" wheels, which I will be doing now. I will be replacing the big bumpers, and incorporating the front spoiler as pictured.
157765

I like that! The front end has a look that makes me think late 60's Corvair, wonder if one of those bumpers could be used.

[Peanut1959]

Love it! Can't wait to see the progress on this project.

[Later-A-body]

After looking for the right engine for the last few months, I was able to locate a nice one locally. It is an Ecotec LTG 2.0 Turbo. This is the latest version of the 2.0 turbo. The engine I bought is from a 2016 Camaro. It has 14,000 miles. The transmission I bought last month is an Aisin AR-5 5-speed manual. It is a brand new unit. This is the same trans installed in many cars including the 2007-2009 Pontiac Solstice and Saturn Sky which bolts up to the Ecotec.
157842157843157844157845157846

[andrewb70]

Good stuff. I would love to do a build with one of these engines!

Andrew

[Later-A-body]

Good stuff. I would love to do a build with one of these engines!

Andrew

Yeah Andrew, I've been really wanting a small 4 cylinder car that I could build for a long, long time. Because I live in California, it had to be pre-1976 so I wouldn't have to smog it. After finishing the GA, I realized that the car is everything I wanted it to be with the exception of two things, 1: It's big 2: It's too nice to mess up. I really wanted to autocross and track the GA.....which I will, but not as often as I thought. So that is where the Manta comes in. I'm leaving the patina, and perfecting the drivetrain. Rock chip, no big deal. I like the JDM stuff, but everyone thinks that stuff is worth a fortune. The Opel is super rare. I already have a rare car in the GA which I like. The Opel is probably more obscure. I really like stuff that nobody has.

[Later-A-body]

Going forward, I will be trying to make more room for the Ecotec. Ecotec's have been installed in them before, but the problem is the cross member is directly in the way of the oil pan. The two swaps I have seen both had to modify the oil pans. I am not going that way. There are two things that I will do. The first is to cut back the firewall in the center. There is approximately 8" of room to cut back the firewall. This will also allow me to get the engine further back to redistribute the weight behind the front wheels. You can see on the picture that I will need to remove the hood latch and some of the firewall components. I will keep the areas located on each side of the firewall for the structural integrity. The DS is where the battery was located, but I plan to relocate the battery to the PS to better distribute the weight. Plus the starter on the LTG is located on the PS. The ECU will be located on the DS of the firewall. I will weld in tabs on each fender to accept a pair of AeroCatch Flush Mount hood pins. These are real nice and sit flush.157847157848

[Paraman1]

Very nice! A bunch of my friends and I ran Opel Mantas in AutoX in the early 90's. A popular swap back the was the GT motor and European heads but this should make a crapload more power than those old boat anchors.

[Later-A-body]

Very nice! A bunch of my friends and I ran Opel Mantas in AutoX in the early 90's. A popular swap back the was the GT motor and European heads but this should make a crapload more power than those old boat anchors.

Any information that you could give me on your experience with the Manta would be very appreciated.

[JayinMI]

Was picturing it with modded 1st gen camaro (or maybe Firebird?) bumpers. Wonder if that would work.
Can't wait to see this get underway!

Jay

[cornfedbill]

The 1971 Opel Manta has small bumpers. A swap is likely not difficult.

157965

[OLDFLM]

There was a wide bodied Manta featured in a German movie when I was stationed there in the early 90s... Manta Manta

[JayinMI]

The 1971 Opel Manta has small bumpers. A swap is likely not difficult.

157965

Not sure if this was directed at me or not, but my thought was that if Camaro-ish bumpers would fit they'd be easier to find here in the US than Opel Manta bumpers since they are more likely reproduced.

Jay

[Later-A-body]

Yes the 71-73 Manta's had the smaller bumpers pictured above. I have a source for them and will be swapping out the smaller ones. I'm excited to have as much enthusiasm for this project as I have received. I know most projects on ProTouring revolve around domestics. This is my first non-domestic car project. So thanks for the support. This will be a very fun build.

[Paraman1]

I wish I could remember a lot more about the Opel AutoX days than I do. A lot of beer has flowed since then but here is what I remember the most about it... We were a bunch of broke 19-20 year old kids when our buddy showed up with an Opel Manta (my mom drove a GT when I was a kid so I was vaguely familiar with the brand) that was painted flat black , had 14 inch mag wheels and a straight exhaust with no mufflers. He was known for driving the odd ball stuff and still has an Opel he races today in stock form. Later he built a ground effects kit out of rain gutters for it which as hokey as it sounds looked pretty darn cool and before long a few others of us had bought Opels as daily beaters and then we started searching for ways to modify them. The easiest thing to do was put the GT motor in them and I vaguely remember something about a European cylinder head. We would go to the local AutoX events which at the time were comprised largely of old men driving meticulously maintained sports cars. We were young, brash and bold with nothing to lose and we started beating a few of these guys driving much more expensive cars and when they came and asked us "whatcha got in that thing?" the standard answer was , "About 400 bucks". I am pretty sure we coined the phrase,"Drive it like you ain't got a dime in it!" about the same time.

I know this probably doesn't help much in technical terms but I think your build really embodies what we loved about the little Mantas back in the day. Cheap, fun and completely different.

[andrewb70]

Looks like CBM makes an aluminum fabricated pan, but I am not sure that it will help. ARE also makes a dry sump pan...

Andrew

[Later-A-body]

I wish I could remember a lot more about the Opel AutoX days than I do. A lot of beer has flowed since then but here is what I remember the most about it... We were a bunch of broke 19-20 year old kids when our buddy showed up with an Opel Manta (my mom drove a GT when I was a kid so I was vaguely familiar with the brand) that was painted flat black , had 14 inch mag wheels and a straight exhaust with no mufflers. He was known for driving the odd ball stuff and still has an Opel he races today in stock form. Later he built a ground effects kit out of rain gutters for it which as hokey as it sounds looked pretty darn cool and before long a few others of us had bought Opels as daily beaters and then we started searching for ways to modify them. The easiest thing to do was put the GT motor in them and I vaguely remember something about a European cylinder head. We would go to the local AutoX events which at the time were comprised largely of old men driving meticulously maintained sports cars. We were young, brash and bold with nothing to lose and we started beating a few of these guys driving much more expensive cars and when they came and asked us "whatcha got in that thing?" the standard answer was , "About 400 bucks". I am pretty sure we coined the phrase,"Drive it like you ain't got a dime in it!" about the same time.

I know this probably doesn't help much in technical terms but I think your build really embodies what we loved about the little Mantas back in the day. Cheap, fun and completely different.
It's a great story. I love the "about $400 bucks". With exception of a set of wheels, this car on the outside will look to be worth about $400 bucks as well. LOL.

[Later-A-body]

Looks like CBM makes an aluminum fabricated pan, but I am not sure that it will help. ARE also makes a dry sump pan...

Andrew

Yeah I saw the CBM set up. I want to try and keep it on the cheap if possible. The biggest problem seems to be the oil pan vs cross-member clearance, but it seem as though nobody has taken the time to slide the motor back. I know it requires fabrication, but this isn't a real big problem, plus it makes more sense considering the weight bias on the front end. I am wrapping up school in December. I plan to start with the firewall fabrication soon after. This is a picture of the blue car I posted earlier in the thread. It has the previous generation turbo Ecotec, but they are dimensionally similar. You can see that there is a lot of room for the motor to slide back. I have measured the oil pan in relation to the cross-member, and it appears that an eight inch rear placement will allow the pan to clear. I will have a better idea when I get more time to actually hoist the engine in to take real measurements.
158011158010

[SRD art]

Paraman- great story! Somebody should write a book with all of our old build and race stories, it'd be a best seller.

Later-A- Subscribed, this is a cool build!! Although I grew up building Novas and now G-bodies I'm a huge fan of little cars. I've always liked the Opel Kadett for it's cute almost Nova like look and super compact size. When I went to college I picked up an 84 Chevette for super cheap to save on gas and I ended up lowering it and putting on 17" wheels. It had sloth like acceleration but handled like a go kart and was a blast to drive. Plans escalated to do a full pro-touring car with 315s out back but the G-body project took precedence and I ended up selling it. There was another guy I was following that was building a Chevette with a 2.0 T motor but unfortunately it suddenly came to a stop and disappeared. I recently picked up a '78 Monza wagon to touch base with my little car addiction, it's on the back burner so it's still up in the air what to do with that one. A couple pics and renderings I did for them below, I did the Opel as a dual purpose car, daily Pro Touring and autoX fun while a change of wheels and tires made a fun 1/4 mile machine. The Chevette has some subtle body mods and would've had an aluminum LS1 for power.

Back to your ride, I'm anxious to see this unfold. That Manta has some great body lines, it has a mean look with the low eyebrow hood and overall smooth form. I like the fact that you're using a unique drive train too. David Carroll has had some great Success with that set up in his Vega, it makes some decent power. That plus a light weight car should make for a bunch of fun. When you get to that point, if you need help working out the visuals and consider a rendering hit me up for a bid, I enjoy drawing Camaros and Chevelles but I particularily enjoy doing the dare to be different projects! Looking forward to watching for more progress on this one, good luck with it!

https://static1.pt-content.com/images/pt/2018/11/2jgJoLx-1.jpg

https://static1.pt-content.com/images/pt/2018/11/sC7yUv8-1.jpg

[SRD art]

Another idea I thought I'd throw out for inspiration or food for thought to overcome your cross member dilemma- Monzas/ Vegas have a whacky sheetmetal front suspension system that doesn't really have an actual frame but rather everything is pretty flimsy and integrated into the fenderwells for support, plus aftermarket handling parts for GM's H body platform are extremely limited. S10s are really narrow, both track width and overall body width, and the same width almost exactly the same as a Vega/ Monza. I've been considering grafting in the front frame clip of an S10 to get a stronger frame, 5 lug conversion with pretty much unlimited brake options, and S10s and G-bodies share the same suspension components so there's plenty of aftermarket support to correct geometry and make a decent handling front suspension. In your case you'd lose the R&P steering but a quick ratio box would do the same. Not sure what suspension support for the Opels is but the S10 clip might be something to at least look into before you get too far along.

A 2 wheel drive S10 Axle is about 54" wide wheel mount surface to wheel mount surface.

https://static1.pt-content.com/images/pt/2018/11/S6Tu2SK-1.jpg

[Later-A-body]

Paraman- great story! Somebody should write a book with all of our old build and race stories, it'd be a best seller.

Later-A- Subscribed, this is a cool build!! Although I grew up building Novas and now G-bodies I'm a huge fan of little cars. I've always liked the Opel Kadett for it's cute almost Nova like look and super compact size. When I went to college I picked up an 84 Chevette for super cheap to save on gas and I ended up lowering it and putting on 17" wheels. It had sloth like acceleration but handled like a go kart and was a blast to drive. Plans escalated to do a full pro-touring car with 315s out back but the G-body project took precedence and I ended up selling it. There was another guy I was following that was building a Chevette with a 2.0 T motor but unfortunately it suddenly came to a stop and disappeared. I recently picked up a '78 Monza wagon to touch base with my little car addiction, it's on the back burner so it's still up in the air what to do with that one. A couple pics and renderings I did for them below, I did the Opel as a dual purpose car, daily Pro Touring and autoX fun while a change of wheels and tires made a fun 1/4 mile machine. The Chevette has some subtle body mods and would've had an aluminum LS1 for power.

Back to your ride, I'm anxious to see this unfold. That Manta has some great body lines, it has a mean look with the low eyebrow hood and overall smooth form. I like the fact that you're using a unique drive train too. David Carroll has had some great Success with that set up in his Vega, it makes some decent power. That plus a light weight car should make for a bunch of fun. When you get to that point, if you need help working out the visuals and consider a rendering hit me up for a bid, I enjoy drawing Camaros and Chevelles but I particularily enjoy doing the dare to be different projects! Looking forward to watching for more progress on this one, good luck with it!

https://static1.pt-content.com/images/pt/2018/11/2jgJoLx-1.jpg

https://static1.pt-content.com/images/pt/2018/11/sC7yUv8-1.jpg

Ben,
That is cool that you posted the Chevette rendering. I saw that rendering a while back and loved the concept. I actually had the intention of buying a Chevette based on your work. I have the rendering of the orange Chevette on my phone, and was able to change the color to a blue version, and a yellow version of the car. I really like your work. I would like to have a rendering done in the future if I can swing that financially. I have decided to stay very close to the blue Manta GTE I posted, but am open to different ideas. I thought I would change the color down the road, but have decided the green is going to stay.

[Later-A-body]

Interesting idea regarding the S-10 front clip. There is an alternative I was going to bring up later in the build but it seems like a good point to post it. I have been discussing the idea of a C4 Corvette front cradle and suspension set up for the Manta. These are available as new units in various widths, and retain the factory GM suspension pieces. The '84-'87 Corvette's incorporated an 11" front brake rotor as opposed to the '88-'96 cars 12" set up. I think the 11' is plenty for a 2100-2300 pound car, and allows the use of a 15" wheel if that is what I decide on. People have been hanging these C4 set ups on street rods for years so I know they are a good alternative if the original cross-member becomes an issue.I have been in contact with a few different companies that produce these kits. It appears initially that the concept will work, but I need to have more time to do all the measuring.

[cornfedbill]

I thought I would change the color down the road, but have decided the green is going to stay.

I like the green too. It stands out.

[SRD art]

The C4 set up would be a great alternative. That base geometry would be way better than the S10's.

Thanks for the compliments on the 'Vette. I was pretty bummed to let it go, I owned it for 9 years and put over 70,000 miles on it, but I had to make a choice between projects and that would need the most amount of fab work so the G-body stuck around. I've watched for buying another over the years but they're getting so rare and the prices have been more than I see as a good value. Most I see are nice running cars whereas I prefer to pick up a cheaper beater with a decent body to start with. I figure it hurts less to cut up something that isn't nice, lol. I picked up the Monza a little rough and no drive train super cheap and as a wagon fan it fit the bill even better. Funny you mentioned color changes on the 'Vette, here's a copy of the alternative colors I explored, I guess we think alike. :D In the end I'm a big fan of orange so that won out.

One of the things I do with clients is explore different ideas, so if we got together we could do both a green and blue version, and of course play with stripes and wheels, flares or not, body mods, etc. should you want to explore those type things. Just hit me up when you get close to being ready for the rendering and we'll go over the process, I'd love to help out. Till then I'll keep an eye out for more project progress. :headbang:

https://static1.pt-content.com/images/pt/2018/11/ZzhBf9j-1.jpg

[Later-A-body]

Yes Ben, I will definitely keep you in the loop if I can swing the rendering.

[68Formula]

Love the early Mantas. And the drivetrain combo is a brilliant idea. Can't wait to see the finished product. Any ideas on the suspension upgrades?

[Later-A-body]

Looking at the possibility of a Corvette C4 front suspension if the original set up is an issue with the engine oil pan. The rear end has a factory 3-link with a panhard rod, so I would like to keep that in place by fabricating all the brackets and transferring that set up to a stronger rear diff such as a GM 8.5" 10 bolt, a Ford 8.0 or 8.8". I want a rear diff that is not too heavy though.I will narrow whatever rear end that I choose so I can fit a decent rear tire under the back.

[andrewb70]

Mustang guys use Explorer rear ends. One of the sides is shorter than the other, so they shorten the long side to match the short side and grab another short axle. They are 31 spline and would be indestructible in this application. I wouldn't use the Explorer brakes, but get some lightweight Wilwoods instead.

Andrew

[Cassius]

Lovely project! I had a -71 SR for a couple of years, sold it maybe 2 years ago to Poland (I live in Sweden) for ~8000€ :) https://www1.garaget.org/archive/4/3374/278547/278547-2618982.jpg

Here in Europe these cars rarely get that much swapped in the front suspension, the original geometry is actually pretty damn good from the start! I even heard of a Porsche 911 that swaped in a Manta A front suspension since he felt it was better suited than the stock one. (An early 911). It's pretty easy to install a coilover instead of the stock spring/damper setup, they do get quite short with limited travel thou if one does not reconstruct the top of the crossmember to allow a longer unit. Lower control arms needs strengthening (boxing them usually is enough). Many install an extra swaybar to stiffen the front end since the original is part of the lower control arm.

The most common brake swap, atleast here in Sweden, is calipers and discs from Opel Rekord E 2.2. They are about 10" and vented, others use Volvo 240 hubs with custom steel bushings for the wheel bearings and the Volvo 4 pot front calipers mated to ~265mm vented discs. It also quite easy to use the Opel Omega 3000 front brakes which come in both 280 and 298mm diameter, the discs needs some machine work to fit while the calipers are bolt on.
For the rear end most use the Volvo 240 rear axle if they are going to push more than 300hp, otherwise the stock one will hold up fine. (The stock one can take 400+ as long as you stay away from hard launches with sticky tires).

However, all these parts are common "here" in Europe, stateside I'm guessing they will be quite hard to source.. :) Corvette parts sound like good alternative. Rear axle wise, the Volvo 240 was fairly common in the states aswell and had a Dana 33 rear axle, they came in two variants "1030" and "1031", the later has a bigger ring gear and is usually considered stronger. Both models have a a lot of options for gearing and limited slip differentials. I believe that the Cherokee used the same differentials as the Volvo axle so spares and parts should be easy enough to find stateside. They are maybe an inch wider than the stock axle so it a pretty good fit. Here in Sweden, the ones doing a lot of dragracing tend to put bigger things in when going past 6-650hp since they need to swap warped driveshafts every now and then when they reach those power levels.

If there is One thing I regret when fixing my car up it was that I didn't enlarge the wheel arches.. They are really small and sit pretty low on the Manta A. I had planned to use Ascona/Manta B arches all around but didn't take the time to do it. Just raising them a bit does a huge impact on how the car looks! Stock it resembles a toy car, with bigger, raised arches it actually starts to look like a sports car. Here's an example:

https://static1.pt-content.com/images/pt/2018/11/5C82D9B4BFB04206909600B2BA3780A3_zpstgri-1.jpg

More on the "rat manta": https://www.opelgt.com/forums/member-projects/59034-1974-manta-low-n-slow-2.html

They also look stellar with the ducktail enlarged and more defined. Think BMW E46 CSL rear wing style. Another thing I started to investigate was putting recessed Camaro Gen 2 or Charger -68 tail lights on it, thats something I belive could really lift the rear end of the car.

Another easy thing that really made a difference on my car was the front lip from a VW Golf GT1 Mk1 (not present on the pic above), the larger one that is in two pieces.

[Later-A-body]

Lovely project! I had a -71 SR for a couple of years, sold it maybe 2 years ago to Poland (I live in Sweden) for ~8000€ :) https://www1.garaget.org/archive/4/3374/278547/278547-2618982.jpg

Here in Europe these cars rarely get that much swapped in the front suspension, the original geometry is actually pretty damn good from the start! I even heard of a Porsche 911 that swaped in a Manta A front suspension since he felt it was better suited than the stock one. (An early 911). It's pretty easy to install a coilover instead of the stock spring/damper setup, they do get quite short with limited travel thou if one does not reconstruct the top of the crossmember to allow a longer unit. Lower control arms needs strengthening (boxing them usually is enough). Many install an extra swaybar to stiffen the front end since the original is part of the lower control arm.

The most common brake swap, atleast here in Sweden, is calipers and discs from Opel Rekord E 2.2. They are about 10" and vented, others use Volvo 240 hubs with custom steel bushings for the wheel bearings and the Volvo 4 pot front calipers mated to ~265mm vented discs. It also quite easy to use the Opel Omega 3000 front brakes which come in both 280 and 298mm diameter, the discs needs some machine work to fit while the calipers are bolt on.
For the rear end most use the Volvo 240 rear axle if they are going to push more than 300hp, otherwise the stock one will hold up fine. (The stock one can take 400+ as long as you stay away from hard launches with sticky tires).

However, all these parts are common "here" in Europe, stateside I'm guessing they will be quite hard to source.. :) Corvette parts sound like good alternative. Rear axle wise, the Volvo 240 was fairly common in the states aswell and had a Dana 33 rear axle, they came in two variants "1030" and "1031", the later has a bigger ring gear and is usually considered stronger. Both models have a a lot of options for gearing and limited slip differentials. I believe that the Cherokee used the same differentials as the Volvo axle so spares and parts should be easy enough to find stateside. They are maybe an inch wider than the stock axle so it a pretty good fit. Here in Sweden, the ones doing a lot of dragracing tend to put bigger things in when going past 6-650hp since they need to swap warped driveshafts every now and then when they reach those power levels.

If there is One thing I regret when fixing my car up it was that I didn't enlarge the wheel arches.. They are really small and sit pretty low on the Manta A. I had planned to use Ascona/Manta B arches all around but didn't take the time to do it. Just raising them a bit does a huge impact on how the car looks! Stock it resembles a toy car, with bigger, raised arches it actually starts to look like a sports car. Here's an example:

https://static1.pt-content.com/images/pt/2018/11/5C82D9B4BFB04206909600B2BA3780A3_zpstgri-1.jpg

More on the "rat manta": https://www.opelgt.com/forums/member-projects/59034-1974-manta-low-n-slow-2.html

They also look stellar with the ducktail enlarged and more defined. Think BMW E46 CSL rear wing style. Another thing I started to investigate was putting recessed Camaro Gen 2 or Charger -68 tail lights on it, thats something I belive could really lift the rear end of the car.

Another easy thing that really made a difference on my car was the front lip from a VW Golf GT1 Mk1 (not present on the pic above), the larger one that is in two pieces.

Cassius
Thank you for all the information on the Manta. I have seen some threads on people using the Volvo 240 rear axles in these cars as well. I do also agree with you on the wheel openings. It would be nice to open them up a little, but I am not a fan of fender flares. Maybe just a little bit raised would help. I was looking at the idea of '70-'81 Camaro tail lights, but I may be able to get a set of NOS Manta parts so I will see. I do admit I would rather stick with the original suspension and fabricate a coil-over set up. It will depend on cost, modified stock vs C4. The Corvette set up would make the brake equation much easier. I see you modified the front bumper and pulled it in. I do plan to follow that idea on both front and rear bumpers. Thanks again for the tips.

[Cassius]

The front bumper on my car was actually stock, not modified :) It does look quite flush in that pic thou.

Flares aren't needed, some cars rock them, other don't :) It was just the best pic I could find ;) The wheel openings on Ascona B and Manta B have a slightly different shape and are a tad bigger. I believe they would fit perfectly! But they will surely be difficult to source in the states. In europe there is replacement parts for the rears, the front you would need to source the whole front fenders.. They have the same type of design as the originals so it's likely only true purists would notice the difference! I'm sure there are other cars that could work as donors for these aswell. I once did a photoshop with those flares.. just can't find it now :/

[JJK]

……...a stronger rear diff such as a GM 8.5" 10 bolt, a Ford 8.0 or 8.8". I want a rear diff that is not too heavy though.I will narrow whatever rear end that I choose so I can fit a decent rear tire under the back.

If you really want to get outside the box, here's a little known donor candidate. A DJ-5 Jeep (that's a 2wd postal Jeep), circa 1970, has a Dana 44 with 3.73 gears and Trac-Lok, and it's 49" flange to flange. That's what a supremely-qualified builder put behind a Honda S2000 engine & 6 speed in a '66 Sunbeam on another forum.

[andrewb70]

If you really want to get outside the box, here's a little known donor candidate. A DJ-5 Jeep (that's a 2wd postal Jeep), circa 1970, has a Dana 44 with 3.73 gears and Trac-Lok, and it's 49" flange to flange. That's what a supremely-qualified builder put behind a Honda S2000 engine & 6 speed in a '66 Sunbeam on another forum.

A Dana 44 would be plenty strong!!!

I just did a search on car-parts.com and there are a total of three rear ends listed. Two of them are in California, at this place:

http://www.jwjeep.com

Their inventory numbers, 7M1382 and 2E0058, one has 48k miles, the other 56k miles, both at $550. The first one shows a 3.73 gear and the other shows 4.89 gear.

Andrew

[langleylad]

Mustang guys use Explorer rear ends. One of the sides is shorter than the other, so they shorten the long side to match the short side and grab another short axle. They are 31 spline and would be indestructible in this application. I wouldn't use the Explorer brakes, but get some lightweight Wilwoods instead.

Andrew

I wasn't able to find a aftermarket performance brake kit that bolts to an Explorer 8.8 . I went with Powerstop brake pieces for my build.

[Later-A-body]

A Dana 44 would be plenty strong!!!

I just did a search on car-parts.com and there are a total of three rear ends listed. Two of them are in California, at this place:

http://www.jwjeep.com

Their inventory numbers, 7M1382 and 2E0058, one has 48k miles, the other 56k miles, both at $550. The first one shows a 3.73 gear and the other shows 4.89 gear.

Andrew

Damn...we were just up there to pick up the Manta. I will look into it. Thanks Andrew. It sounds like a great swap candidate. I wonder though if there is a rear disc brake kit available for that rear diff? If so let me know, As for the gears, I would take the 3.73, but I wasn't planning on that steep of a gear ratio. Since the car will make at least 300 hp, and weighs 2150-2300 pounds, I figured I won't need more than a 3.42 gear. Plus the tire diameter dictates this since they probably will be around 24". I'd like to keep the revs down on the freeway. The trans I have has a .73 OD 5th gear.

[JJK]

Per the aforementioned forum (where the engine/trans were from an S2000): ".....I had the axles reworked at Dutchman's to fit the S2000 rotors. They are 5x4.5" and just happen to be the same pattern as the wheels you may have noticed in some of the previous pics. While at Dutchman's I had new bearings and retainers pressed on."

[Later-A-body]

I haven't had too much going on with the Manta lately, but was able to pick up some seats for the car. I decided to go to one of the local Pick-Your-Part yards. I found a 2008 Mazda RX-8 with some really nice seats. This car was on my list of potential donor cars because I like the seats they have. I think I may have ruined somebody's day because both seats were already unbolted as if someone was coming back for them. I literally lifted them out without using a wrench. They are manual seats, fairly lightweight with black / grey leather. I had to measure them to see if they would work, and luckily they fit great. I will need to cut out a small box located on each side of the floor to allow the seats to sit flat. This allows me to keep this project on a budget. I will eventually reupholster them and add some more bolstering, but these are are in real good condition for where I'm at with the car now. Total cost was $103.00.
158751158750158749158748

[andrewb70]

The seats look great!

Andrew

[SRD art]

Congrats on the seats! I also grabbed some Mazda seats for my car, from a '99 MX-3. I've had them in the car for several years and they're very supportive and comfortable. Even having driven the distance from Utah to Georgia twice no complaints on feeling stiff or uncomfortable. I spoke to a custom upholsterer once and he said factory seats tend to be better than aftermarket- they're engineered better, are stronger, longer lasting, and overall feel better than even the major popular seats that a lot of Pro Touring guys use. My son bought after market seats for his car and my opinion mine feel much more comfortable. I'd say you got a good score there.

Good luck with axle hunting!

[Later-A-body]

Congrats on the seats! I also grabbed some Mazda seats for my car, from a '99 MX-3. I've had them in the car for several years and they're very supportive and comfortable. Even having driven the distance from Utah to Georgia twice no complaints on feeling stiff or uncomfortable. I spoke to a custom upholsterer once and he said factory seats tend to be better than aftermarket- they're engineered better, are stronger, longer lasting, and overall feel better than even the major popular seats that a lot of Pro Touring guys use. My son bought after market seats for his car and my opinion mine feel much more comfortable. I'd say you got a good score there.

Good luck with axle hunting!

Very much in agreement. I have tried some aftermarket seats and found them to be uncomfortable or not well constructed unless your spending Recaro money. I have 2011 Honda CRZ seats in my Grand Am, and my fathers '65 GTO has Saab seats, (both from the junkyard and redone).

[Later-A-body]

It has been a few months since I posted on the Manta build, and that is because I have done absolutely nothing since then. It would be great to report that I have been working day and night on this project, but not the case. I have been able to purchase a lot of parts needed in anticipation of the disassembly process. I was able to buy a new windshield, NOS weatherstripping and trim, a complete front and rear suspension parts set up including HD ball joints, tie rods, control arm bushings, etc. After doing more research on the car, I realized these cars have an excellent reputation for having a well designed front and rear suspension, so I will be staying with the factory set up and upgrading components such as custom made front and rear coil springs, or possibly a coil-over set up in the front. One area I have decided not to spend money on is the factory rear differential. I understand these can handle up to 250 HP if built, but not much more. So I am looking at swapping in a Ford 8". And there is a good reason I want an 8" Ford. They are lightweight and can handle much more power than this car will produce. The Ford 9" and 8.8 are way too heavy, at least 50-75 pounds more than the 8", and will add unnecessary weight to the car. Plus it's overkill. I would rather spend the money on the Ford than invest in the Opel diff and possibly have a failure. The 8" can easily handle 450 HP. The Opel will not make more than 325 HP. I also get to pick whatever rear disc brake kit I want. Gears, posi, all easy to get. I will need to swap the rear trailing arms over to the new diff. The Manta has a 3.44 rear gear ratio. I plan to leave the stock rear end in the car for now in order to see what I think of the 3.44's. The car is so light, I feel that I will not need a higher numerical ratio since the 5-speed trans ratios are fairly steep....3.75 1st gear, and the power level vs a 2200 pound car. Probably looking at a 3.25 or 3.40 ring and pinion when swapped. I also want to find rear disc set up that uses a small rotor diameter such as 9.5-10" rotor for the rear. I am planning an 11" rotor set up up front. Wheel size will be 15" so big rotors are not needed and wont fit anyway. I am open to suggestions as always. Hopefully I will have more updates to post soon.

[SRD art]

Thumbs up!

[andrewb70]

Sounds like a solid plan!

Andrew

[Autobahn-Outlaw]

Hi,

this is a nice project ! I had also a Manta A in limegreen, over 30 years ago......
It was and is a very nice colour and you see the colour on a 70s Challenger or other Mopars.
A very nice car from the beginning, you need only to change the US bumpers, they are junk.
The A Manta was a very good racecar in its days and even Walter Röhrl drove 24h races with it.
For me one of the best racecar drivers ever !

You get mostly everything for this car, it is an icon !

https://www.fotocommunity.de/photo/manta-a-irmscher-heiko-alexander/23395193




.

[Autobahn-Outlaw]

I have found another nice pic:

http://www.fahrzeugbilder.de/bild/pkw-oldtimer~opel~manta-a-1970-1975/114352/opel-manta-a-gte-mit-zastrowumbau.html

http://www.fahrzeugbilder.de/name/galerie/kategorie/pkw-oldtimer~opel~manta-a-1970-1975.html

Most of the racecars here in Europe/Germany have flares.....

[Later-A-body]

Well after it finally stopped raining out here in sunny southern Ca., I decided to get the Manta out of the garage and attack the rest of the factory installed asphalt sheet insulation. I really needed to remove all of it to make sure I was not dealing with any hidden rust. So it was about 80 degrees last weekend, and because I left the car sitting outside a few hours, the insulation came up super easy after it warmed up. Luckily, I did not find any other rust. A few months ago I found a very small area under the drivers left foot that turned out to be just surface rust. I took the grinder to it, and it is lifted quite easily.
162620162621162622

[Later-A-body]

The other work I performed was to remove the large front and rear 5 MPH bumpers front and rear. I did purchase a used rear bumper from the '71-'73 Manta. It is in one of the pictures just hanging but not installed yet. Big improvement. I have not weighed the bumpers yet, but I am guessing they are approximately 30 pounds each. That will play well into more weight reduction. I also had to buy a front grille. I will be buying a front bumper soon, but am saving the money right now.
162623162624

[Later-A-body]

Last thing to talk about are wheels. I have been researching wheels for the Manta for months. I'm confident that I am now an expert on ALL 4x100 15/16/17" wheels. I have looked at every available option, and have learned quite a lot. For one thing, the Manta uses the same 4x100 bolt pattern as the Mazda Miata. And the information that I learned about the Miata has given me a lot of help choosing wheels. Because the Miata is a lightweight car with limited power, heavy cast wheels are a big negative for handling and performance. Since Miata's are probably the most popular model used for road racing and autocross, there are many very high quality lightweight 15 and 16 inch wheels available. Also I really don't want to completely blow the hell out of my budget by buying very expensive wheels that would probably wind up being too heavy, and negatively effect handling. I have narrowed my choice down to Konig Dekagram's. Konig makes very high quality wheels that are very popular in the tuner market. The best part is that they are not a cast wheel, the are Flow Formed. A few companies have this technology which allows them to create a very light wheel that is much stronger than a cast wheel. As an example, the 15x7.5 Dekagram weighs approximately 11.5 pounds!! This will allow excellent suspension movement and not add unnecessary rolling mass. They are only offered in a black and bronze. I always liked bronze wheels, so I am getting the bronze. I think the bronze will look good against the lime green. These wheels are only $139-$159 each due to the smaller diameter. I will for sure install the 15x7.5" (+35 offset) on the front with a 205/50/15. I am considering a 16x8" (+35 offset) for the rear in order to get a little taller tire (23.9") and a little tuck in the fender. The 16" would be a 225/45/16. 17" wheel are not an option. I have seen them on this car, and it looks like a clown car. Here is a picture of both the 15" and 16" side by side.162625

[Later-A-body]

Thought I would throw this picture up just because it's such a clean example of the Manta.
162626

[jpplageman]

Very interested in following your build. Looks like you're quite a few steps ahead of me. I picked up a 1972 Manta Rallye a few weeks ago and am strongly considering going the same route with the ecotec. Is there a reason you went for the turbo 2.0 vs. the n/a 2.4? Assuming space was a constraint?

[tonykim]

Wonderful thread that I am going to follow. I have been around Opels all my life. The small bumper conversion requires holes to be cut in the quarter panels and fenders for side mounting provisions. The gigantic 74-75 bumpers mounted
just to the straight out braces. I love the Miata wheels. One catch on those is finding a center cap that will cover the front hubs. A lot of folks run without caps. Relocation of the heater box and the battery tray to make more room makes a ton of sense. the heater boxes fall apart and the battery trays rust out so nothing lost there.

[Later-A-body]

I haven't been paying attention to the thread for a few months so sorry for the delay in response. First thing to state is this project has not been abandoned! I am going forward on the build but have been sidetracked the last few months. The major hold up has been wheel choice. Because I planned to have a custom brake set up built for Manta, that required me to know exactly what wheel I was running. Specifics such as bolt pattern, width, diameter, offset are all needed up front so the custom brackets, caliper size, rotor size were needed for measurements and fit. Todd at TCE Performance in Arizona will be building the brakes kit. We will be using Wilwood components. Two piece rotors will be used most likely in the 11.75" range for the front. A 4 piston caliper such as a Dynapro is being looked at. The car does not need a overly large rotor due to the 2150 lbs. the car weighs. So I finally picked wheels. I honestly was sick at looking at wheels. I really wanted 16" wheels. 15's would work, but 16's appealed to me more. So instead of a modern wheel, I got very lucky and found a set of vintage AC Schnitzer Type 1 wheels in a 16x7.5, et25. 16's are very hard to find. 15's and 17's are easy to find. 17's are too big for this car. I will be running Toyo r888r tires in a 205/45/16 front, and 225/45/16 rear stagger. The AC's will really keep this looking vintage. I always loved these wheels so I am glad I didn't have to settle. They are so simple and classic. They will need to be restored. I am looking at doing a subtle medium hyper silver color. German car....German wheels.
167906167907167908

[Later-A-body]

Very interested in following your build. Looks like you're quite a few steps ahead of me. I picked up a 1972 Manta Rallye a few weeks ago and am strongly considering going the same route with the ecotec. Is there a reason you went for the turbo 2.0 vs. the n/a 2.4? Assuming space was a constraint?

Honestly I was looking for a late model N/A Ecotec motor but they were way overpriced. I kept seeing the turbo
LTG Ecotec engines for reasonable prices. I couldn't pass up a 2016 motor with 14,000 miles for the price I paid. Space was not a factor. All the Ecotecs are fairly large so the only issue will be intercooler placement.

[Later-A-body]

There are a few details I am considering for the Manta. One idea I have is to remove the gas tank and replace it with a fuel cell. A few reasons for this are the tank would have to be restored which will cost at least $250-$300. Another reason is that I want to build a very conservative rear diffuser style panel with dual tips, see picture. There is no room to run exhaust on the passenger side with the stock tank in place. I also have a buddy who is a fabricater who builds fuel cells. He can build one in any shape I want. I would like something more rectangular and low profile that will not sit very low under the car. I would like to see it sit half way in and out of the trunk floor. I think 12 gallons is about right.167909

[68Formula]

Updates? I love Manta As. Very cool build.