Pro touring Nova - Rear suspension question

[maverick3316]

Hey guys, trying to figure something out, but there are no real straight answers.

I am building a 1970 Nova - 4 door... I know - I am going pro touring style. I wanna do something unique with the rear suspension. I have access to a 2003 BMW 325i. The entire rear, differential, axles, shocks, springs, brakes cage... everything for what seems like a good price. Will this be a good choice, or are they not that good to use?

1970 Nova 4 door
20x10 rear wheels
20x8 front wheels
building a 427 big block
currently an automatic, plan to change to a 6 speed.




I dont have to use this rear, it is just a thought. I have full access to a fab shop, I know it is not a bolt in installation. My skills are about a 7 out of 10.

If this rear would not be good, what do you all suggest?
If I didnt give enough info let me know.

[jakespeeds]

Well you have a Nova with a curb weight of about 3100ish lbs. compared to 3200ish of the BMW so you are looking pretty good there. The Nova has a track width of about 59" compared to the BMW of 58.8. So again a real good match. The only issue I can think of is that the BMW uses a rear McPherson strut suspension. That means you are going to have to do a lot of fabrication to the Nova to build proper mounting locations. Or create an elaborate mechanism that changes it to coil overs mounted inboard and horizontal. It can be done. If that amount of work does not bother you than do it. The suspension once in should work well. I can't remember if the 03 BMW had an electronic diff though of if it was an option. But that is another thing that is adaptable.

Jake

[csouth]

I'd weigh the cost to end result ratio. I know you said the BMW is a good price and that you have fab skills plus access to a shop, but you can't put a price on your time and labor. For me it would be if being unique would also yield a different result in performance over a bolt on solution. I think the 427 and 6 speed will be awesome! As far as the wheels, I think 20" are big for a Nova. FYI I'm not one of those guys that think 20" wheels should never go on a mucsle car, just not on a Nova.

[cornfedbill]

While the front is McPherson strut, the rear is semi-trailing arms. With the exception of the shocks, everything else, including the springs sets relatively low in the car.

There is some camber change as the suspension moves. This means that lowering it takes a lot of forethought. It can also be difficult to fit wide tires around the lower control arms. Do some research on BMW forums.

It would be interesting. I am not sure it is what I would do. Although I owned a 1988 BMW 325is and really loved it. It had very neutral handling and was a blast to drive.

[BMR Sales]

I'm mixed on this one!

Having access to a Fab Shop is different than living there. Don't know what it is going to take, but is 7 out of 10 on the scale going to be able to do it?

But it's interesting so I'll watch!

[TheJDMan]

In addition to the above installation questions, I would ask what the gear ratio is and if it is compatible with your intended use for the car. I assume the BMW had an OD transmission which may mean the rear gear will be problematic with a direct drive trans.

[Ben@SpeedTech]

What are you going to do with the car? Street drive? Track? Only occasional track? What is your driving style?

[maverick3316]

I'd weigh the cost to end result ratio. I know you said the BMW is a good price and that you have fab skills plus access to a shop, but you can't put a price on your time and labor. For me it would be if being unique would also yield a different result in performance over a bolt on solution. I think the 427 and 6 speed will be awesome! As far as the wheels, I think 20" are big for a Nova. FYI I'm not one of those guys that think 20" wheels should never go on a mucsle car, just not on a Nova.

Im not a fan of 20" wheels either, but a friend had them laying around so I gave him $100 for all 4 with tires, lugnuts, everything. So thats why the 20" wheels, I would have went with 18"... maybe down the road.

[maverick3316]

Well you have a Nova with a curb weight of about 3100ish lbs. compared to 3200ish of the BMW so you are looking pretty good there. The Nova has a track width of about 59" compared to the BMW of 58.8. So again a real good match. The only issue I can think of is that the BMW uses a rear McPherson strut suspension. That means you are going to have to do a lot of fabrication to the Nova to build proper mounting locations. Or create an elaborate mechanism that changes it to coil overs mounted inboard and horizontal. It can be done. If that amount of work does not bother you than do it. The suspension once in should work well. I can't remember if the 03 BMW had an electronic diff though of if it was an option. But that is another thing that is adaptable.

Jake

I tried to find all this type of info, but couldn't. Maybe I am not google'ing correctly. lol. The fab work does not bother me. I like to be challenged.

[maverick3316]

Sorry guys, Didn't know I got so many responses. So now Ill go through my replies in one reply.

I'm mixed on this one!

Having access to a Fab Shop is different than living there. Don't know what it is going to take, but is 7 out of 10 on the scale going to be able to do it?

But it's interesting so I'll watch!

I actually own the fab shop and live here most of the time anyways. Might as well make it fun. I might be under rating my self, but it is hard to judge. I have built my own motorcycle from the ground up, My own english wheel, planishing hammer etc... the list goes on and on. While I am no Jesse James, I am trying to attain that level of ability. Maybe that can shed some light on my abilities.

There is some camber change as the suspension moves. This means that lowering it takes a lot of forethought. It can also be difficult to fit wide tires around the lower control arms. Do some research on BMW forums.

I never thought about this. Maybe I will take a wheel with me before pulling it out of the car...What are you going to do with the car? Street drive? Track? Only occasional track? What is your driving style?

The real reason for the car is to take cruises with my family (wife+2 kids) and go to shows and event. All street. I don't plan on taking it to the track, but I might get the urge. The goal is to build a solid reliable car to be able to drive anywhere I want to go. I live in Florida, so we can take trip all year long. What kind of driver.... well I have calmed down A LOT, to the floor every time I took off used to be my style and a stack of tickets to prove it, now.. well I drive fairly calm and relaxed. I do like to get into it every now and then.

In addition to the above installation questions, I would ask what the gear ratio is and if it is compatible with your intended use for the car. I assume the BMW had an OD transmission which may mean the rear gear will be problematic with a direct drive trans.

I am trying to find all of that out. I am awaiting some photos and such to try and determine exactly what it is. What do you mean by "problematic with a direct drive trans?

Thanks for all the interest and thoughts guys. I was/am still scratching my head on this one. If you all were looking for a specific rear, what would it be. (budget friendly).
BTW: This is my first pro touring build.
Prior build include a street rod with a 455 pontiac superduty and roll cage, 1977 trans am 400, 1971 chevelle pro street 396 for fun 383 for race, 1986 chevy c10 stepside blown 355, 1989 transam gta, 1982 ford pinto, and many many other.

[Ben@SpeedTech]

After hearing autox wasn't in the mix I say go for it. BMW has a history of well engineered machines and good handling so it would probably make a great cruiser.

My first fast car I built was a 73 4 door Nova, built it back in '92 and ran 11.80s right off the street with slicks. I used to race it at Moroso out in West Palm Beach, and would cruise it around Lake Worth beach smoking a lot of unsuspecting Camaros, Mustangs, Corvettes, light to light. I miss the year round cruising. The track would shut down in Jan for 2 weeks for repairs and cleaning, and then start up again. That was nice.

Good luck, I'll watch along. Let me know if you have any questions about any of our front suspension components or Novas in general.

[Stilettoman]

There are some good choices, certainly including the BMW rear suspension. As I see it, there are two major considerations that would affect your choice-- 1. Ease of installation 2. Ability to handle the torque and horsepower, depending on how you will drive it.

I personally favor the Nissan rear suspensions because they are built as an assembly, mounted on a cradle that attaches to the frame with four bolts, using rubber shock isolators. I believe some of the Thunderbirds used a similar arrangement. I used a Skyline unit in my 48 Studebaker, which is described elsewhere on this forum here

https://www.pro-touring.com/threads/...-coupe-project

The Infiniti J30 rear suspension is now becoming readily available in the salvage yards, as is the Q45. The JDM tuners guys say these are good for at least 400 hp, but I realize you may be going for more than that. The J30 unit is a 3.9 viscous LSD, and I think the Q45 is about 3.5, also 2 or 3 inches wider. We are just finishing the installation of a J30 rear suspension into a 68 Mustang we are upgrading. We paid $250 for the whole thing, LSD, brakes, and all.

Some of the Toyota units are also cradle mounted, but there is a lot more variation between models. The Supra differentials can handle a lot more power than the stock Nissan units - those are the differential of choice for the JDM drag racers. Of course you probably won't find one for a cheap price.

Some of the other choices will require locating pivot points on the chassis, which may be more difficult. I have no idea what kind of power the BMW diff will handle, but some of the V8 models should be pretty stout.

[maverick3316]

After hearing autox wasn't in the mix I say go for it. BMW has a history of well engineered machines and good handling so it would probably make a great cruiser.

My first fast car I built was a 73 4 door Nova, built it back in '92 and ran 11.80s right off the street with slicks. I used to race it at Moroso out in West Palm Beach, and would cruise it around Lake Worth beach smoking a lot of unsuspecting Camaros, Mustangs, Corvettes, light to light. I miss the year round cruising. The track would shut down in Jan for 2 weeks for repairs and cleaning, and then start up again. That was nice.

Good luck, I'll watch along. Let me know if you have any questions about any of our front suspension components or Novas in general.

I had the same feeling about BMW as far as engineering, just a little worried about the torque from a big block. I know some V-8 BMW's make good horsepower, but not as much torque.


Thanks for the info.

[maverick3316]

Im not too worried about ease of installation. I bought the car to test my abilities. I am in no rush to finish it. I want to do it right, that why I am doing as much research as possible. I am currently doing the body work on it. Ill get it to primer, then start on the suspension. My biggest concern is the torque. American big blocks put down alot of torque. I went through 14 rear ends in my 71 chevelle. Granted I was young, but dumping the clutch at 6500 left girls with huge smiles wink wink.
The BMW rear would be in a cradle, that I am assuming would have to be highly modified to fit the nova. I doubt highly that any of the mounts are near the same. I can get the entire cradle brakes axles etc for $150. That's why in interests me. I just don't want to go through all the fab work to blow the rear after 1000 miles.

[QUOTE=Stilettoman;1099147]There are some good choices, certainly including the BMW rear suspension. As I see it, there are two major considerations that would affect your choice-- 1. Ease of installation 2. Ability to handle the torque and horsepower, depending on how you will drive it.

I personally favor the Nissan rear suspensions because they are built as an assembly, mounted on a cradle that attaches to the frame with four bolts, using rubber shock isolators. I believe some of the Thunderbirds used a similar arrangement. I used a Skyline unit in my 48 Studebaker, which is described elsewhere on this forum here

https://www.pro-touring.com/threads/...-coupe-project

The Infiniti J30 rear suspension is now becoming readily available in the salvage yards, as is the Q45. The JDM tuners guys say these are good for at least 400 hp, but I realize you may be going for more than that. The J30 unit is a 3.9 viscous LSD, and I think the Q45 is about 3.5, also 2 or 3 inches wider. We are just finishing the installation of a J30 rear suspension into a 68 Mustang we are upgrading. We paid $250 for the whole thing, LSD, brakes, and all.

Some of the Toyota units are also cradle mounted, but there is a lot more variation between models. The Supra differentials can handle a lot more power than the stock Nissan units - those are the differential of choice for the JDM drag racers. Of course you probably won't find one for a cheap price.

Some of the other choices will require locating pivot points on the chassis, which may be more difficult. I have no idea what kind of power the BMW diff will handle, but some of the V8 models should be pretty stout.