Twin turbo on a 327 Engine... help needed

[nicke]

Hey Guys,
I would like to do a budget twin turbo setup on a first gen 327 chevy engine for an upcoming project. Ideally I would like to get 500+HP, and have it be decently streetable. I also want reliability. I would also like it to be carburated. I would like advise on what cam, heads, pistons, and other internal parts would be best suited for this. I plan on using a 4 bolt block, and a steel crank.
My choice on 327 vs a 350 or 383 is that I like the fact that they seem to like the RPM's and for the cool factor.

Looking for opinions on this, or to be pointed in the right direction for reference material. My plan would be to buy a cheap kit for the plumbing, then upgrade the turbos down the road.
Thanks

[DButler]

Go to the turboforums because there is a wealth of knowledge on that site. I went carbuerated and I wouldn't recommend it. It was disater and I switched to holley hp efi. That is my biggest suggestion is to fo EFi in the first place. less headaches and will save you in long run. Go on that site and you will find all info one could need.

[Chevelle598bb]

There is not such a thing as a "budget build" turbo set up. Especially a twin set up. Not only does the motor need to be built for boost but so does the fuel system, trans, rear end, specialty carb, ignition system and other things. Your can put together a less expensive turbo set up but you get what you pay for and reliabilty can be a problem with cheaper turbo parts. High revving motors are cool but when you are using forced induction keeping the rpm down with substantially increase not only the life of the motor but also the turbo system. You could use a carb set up but the forced induction set ups I have messed with were a pain to deal with and tune. Efi makes forced induction infinitely easier.

What is your budget? For the motor? For the turbo set up? Fuel system? Trans you are using? With this info well can tell you of it is going to be possible or not.

[shep]

Look up Jimmy Spears (shmoov69) on here he has a carbed turbo small block in his camaro.

[shmoov69]

Thanks Shep. LOL!
Contrary to popular belief, it CAN be done on a budget if you're not trying to kill it on power. I was told "it can't be done" by alot of people in '99-2000 and I thought I'd try anyway since "it can't be done". Well, my first engine lasted 17,000+ miles and a couple years of constant beatings!! It would've lasted longer but it was a total cheapie build with a LOOSE bore block that was a hone only with the cheapest hyper pistons I could find....Badger brand factory replacement Junkers that ended up knocking off about half of the skirts, which ended up splitting the cyl wall! LOL! It was a stock 2 bolt block with a cast crank, factory rods (and bolts!) and some junk smogger heads with a Victor Jr intake and Holley 650 puddle dumper. The pump was a Holley black and the timing was locked at 24*. Pretty basic combo that pulled 550rwhp/650rwtq and ran a best of 11.20@124 with a 3.00 gear 9" rear and th350.

Anyway, A couple of TurboCoupe or GN T-3's from eBay or wherever on a 350 or 327 will fit the bill just fine. If you have pockets or want big power then definately buy some good parts for the inside of the engine and everything else, but I had about $2,000 in the setup since I had the engine already. When it puked, I did put some better parts inside the next 350. Also, a good intercooler will be helpful to keep things "safe" and with less chance of detonation.

As said, check out. http://www.theturboforums.com/
Or a guy that said it "can be done" was
http://toohighpsi.com/

Good luck and read aLOT and plan for problems!! LOL!

[DButler]

Jimmy is right plan for problems. I am not saying that carbs can't be made to run correct on turbos, but it takes ALOT of time to get them tuned in. There are planty of guys on forums that run carb setups and run great. I had a setup on mine that ran a "crutch" style setup. Look up "crutch" on turboforums it is a neat setup. I had it running pretty good, but was still not as consistent as I wanted for street driving. Thats why I bit the bullet and decided on EFI. There are only a hand full of guys that can tune a blow thorugh carb lots of people can tune EFI. This is if you can't tune it. Never build something not many people can tune lol Just remember it can be done but it is not as simple as just bolting it on and going. Alot of people think this and this is where they are BADLY mistaking. Also a budget turbo setup is somewhat possible. Just depends on what you are calling a budget.

[nicke]

To be more specific, I am hoping to spend less than 10k total on engine/turbo setup. (I have the 4 bolt block already) I see company's selling complete turn key setups for SBC's with tags into the 30k range but I am hoping it can be done less than that and still be reliable. I'm not looking for chrome or flash either, just powerful and reliable.

I don't have my heart set on carbed. I am new to EFI, so what would be the best direction to go down given the described setup?
I haven't given much thought to the fuel system yet, but trans will be a built th400, rear is a built 12 bolt. Aside from the fuel system, I know what the car needs to handle the power, just looking for a good recipe for the build.

Thanks for the advise so far!

[DButler]

10,000 should be plenty of money. i would go with a 6.0 block because it is already low compression. I would run an A1000 fuel pump with the fuel psi regulator. You will need a return style tank. I would then go with a mild cam and small turbos to match. Put an ls6 intake on the 6.0. The 6.0 block will take all you are wanting stock. if you inist on going sbc (thats what i have because everything was already fabbed for it) then I would run a Holley hp efi or fast uel injection and still use the same fuel system. With 10k budget you should be fine and not have to cut many corners anywhere.

[opnwide]

How about a twin turbo LS5.3? Thats about 327 cubic inches and they come with fuel injection. You could build this for $10K easy if you pick up a low mileage used engine.
Super Chevy had their 5.3 turbo pumping out crazy #s. Just follow their blueprint.
This is the route I'm going when I build my '72 vette in a couple years.

[SR71]

some may say that I'm crazy, but this is just my opinion formed by my personal experience with turbos and v8's....

a high rpm oriented turbo engine will be miserable on the street (and a 327 is already soggy on the bottom end to begin with). turbos are like camshafts, they have a 3000-4000 rpm usable powerband. if you want to spin the engine to 8k, don't expect full boost from a properly sized system until 4k. the sooner the turbo makes boost, the sooner it will choke out up top and vice versa.

I would set up a nice, street friendly combo and let the snails work their magic instead of winding it tight.

[MonzaRacer]

OK so here is what Im looking at building. 283 .040 OR 283 .125 (302) twin turbo headers off Ebay, T3/T4 adapters to T28 mount 2) GT2871/GT2872 Ebay turbos, prerequisit wastegates, blow off valves.
My plan is 61 283 block 0.040, forged pistons, 5.7 I beam rods, steel crank, main studs, mild cam, double humps 202/160 screw instuds, guide plates, swirl polished valves, Z springs
OR
61 283 0.125 over forged 350 pistons with mods, 6 in I beams, steel crank, main studs, same cam (looking at Comp 268H) same heads
THEN us a modified LT1 intake, my own design DIS set up, Megasquirt/Microsquirt depending on if I try to run sequential injection. probably use ebay 60# injectors to start then later up grade to Injector Dynamics.
If you look up "The Grenade" you get my idea and plans except Iknow the GN turbos are a tad too small and it over speeds them. So using this one matching program (http://www.turbofast.com.au/TFmatch.html) remember to use CC of engine over CI and dont get greedy a 5000cc engine ie 5.0 l with twins, intercooler and 10 psi 6400rpm comes in at 599hp. And since this combo (either should be a ble to turn 7500-9000 rpm easy, BUT turbos make uber torque (ie the Grenade car is an over 3000lb firebird with 3.00 to 1 rear gears running 9s ! in quartermile) my 3000lb Monza should be nearly as quick if Ican hook it up
And oddly using same calculator I checked out if I wanted to "twin out" my 454 and it said to use same turbos, even the .63 turbine A/R using same turbos, but a GT2871R comes either with .64 A/R OR .86 A/R (which if I run boost way up Iwould need) .
Figuring both my set ups are on the cheap, as the 454 is completely stock I was figuring stayin at 5 psi or less and was looking at over 700 hp and the 302 clocked 599hp
Yeah and if you can get a decent carb such a using a "crutch" carb (search over on theturboforums.com. They do work and a good wideband o2 sensor and some tuning and your good.

[MonzaRacer]

Oh yeah and small engines with smaller turbos in twin would really work better than big engine with a big turbo. IE spools lower and if you use common sense it would work great and be low cost.

[Spiked]

An LS motor will be your simplest/cheapest build.Get a used 4.8,5.3 or 6.0 with a harness.They are tough motors and will run low 11s with stock internals as long as you get the tune right.This site has a lot of good tips.
Good luck.
http://www.junkyardturbos.com/

[mnm99]

No problems with V8's and twin turbos.I'm running twins on a stock 350 crate motor with 5lbs of boost using a CARB. Runs perfect on the street and has tons of power from the stock motor. Right now I'm at full boost around 3000 rpm. My stall is at around 2800 so boost comes on even quicker. As of now it's 5 pounds because of the internals. I would never push it past 5lbs. I'm building a 406 now that will have between 15-18lbs at around 950hp. It will also drive very street friendly. I'll be in full boost at around 4000 rpm and be in it until my 6500 redline.

some may say that I'm crazy, but this is just my opinion formed by my personal experience with turbos and v8's....

a high rpm oriented turbo engine will be miserable on the street (and a 327 is already soggy on the bottom end to begin with). turbos are like camshafts, they have a 3000-4000 rpm usable powerband. if you want to spin the engine to 8k, don't expect full boost from a properly sized system until 4k. the sooner the turbo makes boost, the sooner it will choke out up top and vice versa.

I would set up a nice, street friendly combo and let the snails work their magic instead of winding it tight.

[Supervette]

I just went to fuel injection from my blow through carb set up last summer. My 750 holley double pumper built professionally worked great under wide open throttle but I had some slight tuning issues with it for part load throttle (slightly lean). This carb was designed around E85 and helped me out when I needed to get it running. Its viable but expect to tune a carb and a little dyno time. Its jets, squirters, and pump cams. If you can afford a Holley EFI HP kit I recommend them! The self learning capabilities and how easy it is to transfer to base is amazing. Have someone that knows what they are doing set up your base timing table on the dyno. Theres a lot more timing than you would think going into an engine under light load. The AFR table is important to for drivability. but if you need a carb for inexpensive to get you by for a while until PM me. The carb made the same power as the EFI system did. I just gained better part load and driveability. I actually lost torque but that was because I did not port match the Holley intake. Im thinking that was the reason...

[uxojerry]

It is easiest with an older car to think of turbos and motor completely separate. The turbo system does not care which motor it is boosting. An older car requires custom fab work for an air to air, piping, etc. There is no kit you can buy only components. If you price all of the components, how much fab work can you do yourself? The cost of a turbo is in the fab work.

If your car has a running 327 installed, it would make sense to use it. The cheapest way is a blow thru carb but tuning can be tricky. An NA gen 1 327 could probably handle 5lbs of boost and hit your 500hp goal. If you do not have a running gen 1 327 installed, then it would be cheaper to go with a pull out ls motor. Dont do anything to the motor and you can boost it to 8lbs and be 100hp over your goals.

The cheapest way to hit 500hp is stay NA. If you have a gen 1 block, look at some postings by Chris Straub on the corvette C3 forum. In the old days there were a lot of 377ci racing motors. Smaller cranks, more piston, but higher revving than the current popular 383. He thinks the 377 ought to be revived. A high revving gen 1 377 might be fun and something different. If it was built properly you could boost it later by changing the cam and adding blow thru carb. Just food for thought, and something different I recently came across.

Im no expert but do read a lot, lol.

[madmax]

Before the project got shelved, my '69 Camaro was going to get a TT 377. I'm planning on doing a TT 388 (or a bored out LS2/destroked LS7) for my '05 GTO. A lot of guys say cubes are the way to go.... different strokes

[Supervette]

I wanted turbos too but just because of all the costs I went with a nice procharger set up. They bolt on easy and if you run E85 you do not need an intercooler. By far a efficient way to do a build. No complicated exhaust work or an oil line. What you will put into cylinder head work you could have a blower at your door step! A P1SC should do you some justice. Superchargers 4 less has good pricing. Do you have E85 in your area? The P1SC is even up gradable to the D1SC I believe. I think its just an impeller change. They also have an upgrade program they release from time to time. Buy the biggest rib belt you can get with the set up.

[Mr_Roboto]

10K is a pretty decent budget. I'd do an EFI fuel system with one of the new Walbro pumps. some 60lb/hr injectors and a Microsquirt probably. There's a pretty steep learning curve to it so be prepared for that. Hard to beat for the price though. Besides that I would consider a wide band mandatory stuff if you do a carb or EFI, if you do carb don't forget the data logger is an extra expense. 14point7.com sells a really small "OEM" unit that I'd use if I was doing a regular MS-II. In regards to your Impy I would see if a late model 9C1/Impala SS tank would bolt in. I know that they can be put into A-bodies with some work not sure what the changes are on the B-cars. They would also take the previously mentioned Walbro pump. Some 3/8 or -6 line would get you where you need to be for 500hp as well. Buick guys can make that with the stock feed line which is 3/8.

In regards to the turbo system, if you can get some decent used GN turbos they'll get you there or a set of HY35s off Dodge trucks. There are several variants of the latter made so be sure you get the same ones. I'd do a mild to moderate cam and some mild head work and get into the high 200hp low 300 HP range then run a decent set of rods/pistons on a production forged crank and go from there. By keeping the RPMs low you could even probably even go with a stockish replacement like SIRs.

Lastly a turbo IS like a cam. That's for better or worse. You put a set of turbos on a 396 BBC then put them on a 502 BBC and the RPMs they come in at and top out at will go down. If you stick a set of huge turbos on a 302 CID engine you've basically done the same thing as sticking a 244/[email protected] cam in it. You're going to have to wind it up to make the power and it may be a bit lacking in subtlety.