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gmachinz
10-05-2004, 05:36 AM
I'm picking up an '86 Monte Carlo SS right after Halloween and I plan on getting started on it in the spring. As for the engine I have some questions about designing a motor specifically for a turbo application so therefore I did not post this in the power adder section. It will be a TT setup BUT-if the turbos generate power from the exhaust gasses which is better to build, a quick,high-revving SB or a stroker? I know the basics in turbo technology-well, enough to get myself started anyway but I want to get about 800-1000 (yeah, I know-this "1000" HP number is getting overused :barf: ) at the crank but with very minimal lag time. I plan to use a 4L80E transmission (not sure I want to use a T56 in this car....) built by a local specialist here in town and I'll have 4.10 gears inside a braced 8.5 rear diff. I'm going with advice from people who are in the business of making the most from factory offerings. I can make a reliable 10-bolt live behind a 1000/hp motor so we'll see. The guy who'll be building it builds rear ends for top fuel cars so I assume he knows his stuff. Okay, back to the motor. I'm thinking along the lines of a 377, keeping comp. to around 8.5:1 and running 28-32 total lbs. of boost. The block will be o-ringed with main studs, tray, head studs and re-worked Vortec heads. If velocity is important to a naturally aspirated engine, it must be exponentially important with a turbo application, right? For this reason I'm thinking about the Vortecs but may end up with Fast Burn heads instead-(I can get a great deal on them new from the dealer!) Finally, should I route the gasses through a dual system or through a monster single exhaust like say, 4-4.5" or so? And, from those of you who are tuning your turbo motors right now, what is more tuneable in terms of engine management-obviously I'm looking at a fuel injection system at this point. I'm just getting ideas together so please give me your insight. Thanks, Jabin.

KendallF
10-05-2004, 04:30 PM
BUT-if the turbos generate power from the exhaust gasses which is better to build, a quick,high-revving SB or a stroker? I know the basics in turbo technology-well, enough to get myself started anyway but I want to get about 800-1000 (yeah, I know-this "1000" HP number is getting overused :barf: ) at the crank but with very minimal lag time.
SNIP>>Okay, back to the motor. I'm thinking along the lines of a 377, keeping comp. to around 8.5:1 and running 28-32 total lbs. of boost. The block will be o-ringed with main studs, tray, head studs and re-worked Vortec heads. If velocity is important to a naturally aspirated engine, it must be exponentially important with a turbo application, right? For this reason I'm thinking about the Vortecs but may end up with Fast Burn heads instead-(I can get a great deal on them new from the dealer!) Finally, should I route the gasses through a dual system or through a monster single exhaust like say, 4-4.5" or so? And, from those of you who are tuning your turbo motors right now, what is more tuneable in terms of engine management-obviously I'm looking at a fuel injection system at this point. I'm just getting ideas together so please give me your insight. Thanks, Jabin.

If this is going to be a street motor, I would build a stroker and keep the revs down, especially if you plan to use inexpensive heads like the Vortec heads, which will not flow enough to take advantage of the bigger bore. A big bore 377 with appropriate heads and rev range would probably make more power but will require some bigger (i.e., less streetable) parts. Buy some decent H-beam rods and a forged crank at this power level.

You won't be able to run 28-32 psi on pump gas, and on race gas, I would expect more power than 1k HP at that boost level. I watched one of Granatelli's single turbo 347 street motors make 800+ HP at Duttweiler's last year on 24 psi; I have done a couple of 235" V6s making 500+ RWHP (600+ at the crank) on ~25 psi also. I hope my personal itty bitty 280" motor makes 1k HP..or blows up spectacularly! :hammer:

The compression ratio you're targeting will probably allow 15-18 psi on 93 octane with intercooling and good engine management, and I would expect it to make 700-800 HP. Keep the cam mild, use something like a couple of PT52s, and it will make a nice idling street motor with more power than you can hook up in a pro-touring car. :)

Engine management..FAST probably has the biggest turbo user base, with ACCEL Gen 7 second. PT&E is starting to sell quite a few Big Stuff 3 systems so that might be a choice also. A wide band O2 and data logging are very nice things to have with a turbo motor that can self destruct in a few seconds if the tune is off!

Good luck,

shmoov69
10-05-2004, 07:18 PM
I agree with kendall on all of it also. At that power level though, I would DEFINATELY get some good heads, you will be limited with the vortecs.
Just my .02 though!
Jimmy

TurboLark
10-05-2004, 07:28 PM
Dont use the 4.10's. You Could do well with 3.55's or higher. Turbos like the load of an auto with highgears.
For your power desires, good heads(afr, tfs,etc) will be helpfull. Get a custom cam(cam motion does well with turbo cams). Velocity isnt as critical when in boost, but for off boost drivability it helps.
Use twins or a big single(t88 or so), either way, it can spool quick if built corrrectly. Single 4-4.5 or dual 3", whatever you can find room for, also depends on twins/single turbo.
Oh, and good luck with that 10 bolt.

Paul69camaro
11-02-2004, 07:01 PM
Gotta agree with turbolark about the gears, i've seen a lot of turbo cars slow down when they swap to taller gears, this is why most of the Grand National guys run the stock 3.42's

gmachinz
11-04-2004, 08:12 PM
Okay, so I'm leaning on a 4L80E with 3.55's. I might look into a reverse pattern manual valve body modification if I go down this road with it. Anyway, the car was dropped off last night-it'll need put together before anything else happens...like a quarter, two rockers and a new rear spoiler/front nose. It wasn't hit, but there was a little rust so the previous owner bought a donor Monte and cut full quarters and rockers out of it for the SS. Time to do some diggin' on a turbo'd 406 SB. -Jabin

TurboLark
11-05-2004, 07:16 AM
Okay, so I'm leaning on a 4L80E with 3.55's. I might look into a reverse pattern manual valve body modification if I go down this road with it. Anyway, the car was dropped off last night-it'll need put together before anything else happens...like a quarter, two rockers and a new rear spoiler/front nose. It wasn't hit, but there was a little rust so the previous owner bought a donor Monte and cut full quarters and rockers out of it for the SS. Time to do some diggin' on a turbo'd 406 SB. -Jabin
Cool, nice to get everything straightened out. If you have more turbo questions, a great place to look and get info is www.turbomustangs.com they have forums for general, GM, Mopar, Carb, and homebuilt. If you cant find it there, you aint lookin hard enough.