Hot-air downpipes?

[camaro75racer]

Anyone tell me a good place to get a bigger downpipe for my 85 GN? Also at about what psi does the stock turbo become ineffective? Im about ready to start modding here and think downpipe, Hooker exhaust,scanmaster, and 86/87 computer with chip will be my starting point. Any info appreciated. Thanks

 

[85 ttypewh1]

The only place to get a 3 inch downpipe unless you buy used is from Kieth Mease, he is a little slow on his product but he will let you know that upfront. His quality is second to none, people bash him on here when there product is late, then praise him when they get it and say it is worth the wait. The cheapest place i found for the hooker cat back is Summit. Before you mod anything else i would start with a walbro 340 fp and hot wire, i got mine from Racetronix, then get a adjustable fuel psi reg. shop around i think a vender has one on sale right now so look in the vendor special section. Yes a 86-87 ecm swap with scanmaster is also a great tool. Kieth is making me a dp right know. if you want his # then pm me. Good luck let us know what you do. Greg

 

[highboost]

esp perfomance products sell a 3" D/P for 190bucks

www.espperformance.com/exhaust.html

 

[85 ttypewh1]

That is true but it is a replacement pipe, which means it just replace the stock pipe. You would still use the stock elbow and wastegate. There is a decent restriction in the stock elbow. But esp is an option. The Mease pipe is stainless with a ceramic coating and has the elbow in the pipe with a wastegate puck all just a bolt on to the 84-85 turbo. Now you have 2 choices.

 

[Bryan C.]

The stock turbo seems to be dead at approximately 20 psi.

 

[BRAD_PADGETT]

Bryan C - You are correct- My max was 18lbs with alot of knock. The max boost for me now is 10.5 lbs with no knock. My new walbro fuel pump came with a hot wire kit which I do not need. If you need one it is a Racetronix and let me know. Thanks, Brad

 

[Bryan C.]

Beyond 20 psi the turbo is just generating excess heat.

 

[racemybuick]

from what I hear, 18 psi or 17 is the highest power yielding range. After that, the turbo is too small to make any more juice! If you upgrade that bad boy, you can go 30 PSI with some models, so long as you have all the mods to compliment that power.

Stock turbo has a great power band from what i have seen at around 15-16 ish. Get good injectors (36's) and a decent chip with the adj fpr, and of course, good octane fuel. if you crank up that boost, you gotta make sure you got the right juice!!!!


Yeah



john

 

[85 ttypewh1]

Hey Brian, i dont mean to highjack the thread but my turbo seems dead after 6-7 psi what i mean is the car just does not pull anymore after that. I have a thermocouple in the intake and after about 150 degrees which is at 6-7 psi the car falls flat any advice, mods are in my sig but the i/c is not hooked up yet. Motor has 206k but burns no oil the only thing done on the motor is the stock turbo rebuild about 80k ago,still has orig valve spring t chain and injectors. The turbo will build boost fine i have done it to 15-17 psi b4 but no pull after 6-7. Any ideas.

 

[Bryan C.]

Are you getting any knock? Is your ECM pulling timing out? How much timing is in your chip? Having the original valve springs will not allow the engine to rev like it should, that may have an adverse affect on your once the boost gets to a certain level.

 

[85 ttypewh1]

I have the stock 85 ecm in it but have the iat and wiring in for the 87 plus i have the 87 ecm but no chip to run it because i wanted to get a chip last whenn all my mods are done. I have a xray auto link hooked to it now and yes i get knock under boost but i cant tell how much knock with the xray. I guess i need to just do the valve springs tchain and orig oil pump i was just wanting to do everything at once when i upgrade to a ta49, 60 lb, and my 3 inch dp. I am getting knock but i dont know if it is false or not i do have a few rattles in the eng. compartment that i cant find.