turbo LA1 3400

[patgizz]

ok the parts are all here or on their way for the most part.

engine: uber-low-mile LA1 roller 3400, gone through and all is mint.

transmission: getrag hm282 5 speed

turbo: air research t3/t4 hybrid w/ "super 60" compressor

car: 94 lumina 3.1

i would like to run one of the TGP based 5 speed codes for ease of programming(god910 or mick, you got any insight here?). i have a set of 23# injectors(are they big enough?)

i need to know the following:

1: my turbo has no internal wastegate. how is an external wastegate controlled? i'd like to use a manually adjustable controller.

2: is there a good off the shelf air/air intercooler that is good enough to use with this setup and has both outlets straight out of one end?

3: what harness modifications are necessary from a 3.1L MPFI wiring harness configured for a 4t60-E, to turbo with TGP code and to convert to 5 speed.(i'd like to keep my AC if possible because its a summer only car)

4: what ECM is needed? will the current 9396 work or do i need a pre electronic trans ECM?

5: vacuum accessories, power brakes, AC controls, cruise diaphragm, how are those affected by positive manifold pressure?


i think that is all for now. i need some answers so i can start collecting the parts. plumbing is not a problem, set up with a mig, plasma cutter, mandrel bender, chop saws, etc...

[brian89gp]

1. it is controled the same way, via air pressure. There is a exhaust tube before and after the turbo, the vacuum line hooks up the same as an internal wastegate

2. might look into the Saab 900 Blackstone IC

3. Cut out the 4t60e stuff, wire VSS and reverse lights different. Not sure about the 3.1 -> 3400 differences though

4. 9396 will work fine

5. The vacuum canister stores up enough to keep the accesories working properly most the time There is a checkvalve that should prohibit positive pressure to the vacuum canister. The brakes will suck especially after some boost because the vacuum will bleed out.

[Mechanic]

We now have a patch file available for the TGP code that converts it for use with a 5-spd manual trans, located in the GMPCM website download area.

Luckily I have never encountered problems with brake vacuum on my Fiero 3100 turbo transplant, perhaps the Fiero brake booster check valves are superior to those GM used on other vehicles? I found that the little windshield washer pump check valves are perfect for areas like the CCP and cruise control vacuum.

I also have an LA1 sitting in my garage waiting for its turbo build and a transplant vehicle. Turbocharged GEN III's obviously have side effects that can be addictive.

[patgizz]

excellent guys. mick, i d/l the trial version of your program a long time ago. ive gotta get and register the new one, and buy some chip tools. i have lots of booster check valves to try, and i have a vacuum reserve canister that i could install. washer pump check valves!!!! great idea! i have a box full of those, i bet i could ebay them to honda boys for $20 each

any idea what # injectors i should use, and how much boost i could safely run on pump gas(dont mind paying for 91 or 93)?

[Mechanic]

You should base injector sizing on your anticipated crank horsepower. But, reality does not always follow theory, so some trial and error may also be required.

One should consider the fact that the TGP used a 22 lb/hr injector for its 3.1 L displacement, and rather conservative peak HP.
IOW, a 23 lb/hr injector will likely be an extreme limitation for a boosted 3400, as the stock normally aspirated 3400's rating of ~190 hp is already pretty close to the 205 hp offered by the TGP.

Static compression ratio of the stock GEN III is a limiting factor, but if you lower the cr you can obtain some pretty decent boost levels. Once you increase boost beyond the stock levels, injector flowrate demands change quite drastically. For instance, I currently run 36 lb/hr injectors at 14 PSIG boost on a 3100 in batch fire mode (TGP code). Injector duty cycle is optimal at WOT with the 36 lb/hr units, but with the 30 lb/hr injectors I used initially (based on anticipated hp) it was quite marginal.

You should give much thought to the choice and budget for the clutch used on a manual trans boosted 3400. I went through a $300 RAM kevlar clutch like it was butter (< 4000 miles). I use a Spec stage III now, and it seems to be holding up quite well.