HELP! turbo setup sucks
I got a leaking oil return line anyway lol, going to pull the motor and weld in a bung instead of a brass fitting when I get back and install a PCV system that is much required and not yet installed. but I wipe it down under there religiously
For starters mustang dyno 's read a little low?
Second if you are trying to make 1000rwhp, why did you stop at 10psi.??
It will take you appx. 20-25psi. to get 1000rwhp, depending on the setup. Your 10psi. rwhp I would not even be bothered with. Your setup is obviously not in its efficienty range yet, so the #'s will not be good until you get it there. Turn the boost up and see what happens. You will be surprised.The turbo may be a little small for the amount of power you are wanting to make ,maybe, you will get close though.
Also, 2.5 in. charge pipe is plenty. They run 7's with that size!
Second if you are trying to make 1000rwhp, why did you stop at 10psi.??
It will take you appx. 20-25psi. to get 1000rwhp, depending on the setup. Your 10psi. rwhp I would not even be bothered with. Your setup is obviously not in its efficienty range yet, so the #'s will not be good until you get it there. Turn the boost up and see what happens. You will be surprised.The turbo may be a little small for the amount of power you are wanting to make ,maybe, you will get close though.
Also, 2.5 in. charge pipe is plenty. They run 7's with that size!
Goood luck.
precision has always told me a 408 was too big for that PT88, which is actually quite a small turbo, Im thinking the biggest issues I have is running a 3" DP in a 4" outlet, and the T4 flange.
Veee 8 name a price man might take me a few months to save up but if you still running it and willing to sell, im still willing to buy
Veee 8 name a price man might take me a few months to save up but if you still running it and willing to sell, im still willing to buy
8s @ 158 with an 88 on the back.No way that turbo is too big.
update...okay While on R&R I got the car to the track, shortened the 3" DP to a 15" long piece, did a new plug wire setup (was burning LS1 wires left and right reguardless of insulation) Got the Trans went through did a bunch of maintnance things.. The car would not make any more than 11 psi with the boost signal hose disconnected from the turbo... Ran 10.82 @ 129.. HA at least Im faster !! lol ... The Two step made all the difference putting the car back into the 1.4s 60' wise.. Untill of course the 9" let go everywhere and caused a giant mess.
Intake temps were also horrifying, 160 is as cold as they would get with the puny A2W from PTK.....
Now that I have a good baseline of where to go, I will build a 4" DP for the setup, as well as a 3 1/2" Aluminum Cold side and install a PT3000 A2W I bought in the back seat. Hopefully reducing backpressure by NOT having a 3 pipe in a 4" outlet with no transition, and having a free-er flowing cold side, as well as an intercooler with 120 degree cooler air intake temps will liven her up and maybe alow me to run more than 11psi... Ill also be installing my 40"spline stuff I bought and new center section with 3.90 gears. After its all figured out completely... I have a PT101 sitting in waiting and modify the kit some more too install her. Plus my ignition timing curve is rediculously conservative. much more to gain there.. The car is going to be a rocket soon! 3 months left of Iraq and Ill be back to work :-D
Intake temps were also horrifying, 160 is as cold as they would get with the puny A2W from PTK.....
Now that I have a good baseline of where to go, I will build a 4" DP for the setup, as well as a 3 1/2" Aluminum Cold side and install a PT3000 A2W I bought in the back seat. Hopefully reducing backpressure by NOT having a 3 pipe in a 4" outlet with no transition, and having a free-er flowing cold side, as well as an intercooler with 120 degree cooler air intake temps will liven her up and maybe alow me to run more than 11psi... Ill also be installing my 40"spline stuff I bought and new center section with 3.90 gears. After its all figured out completely... I have a PT101 sitting in waiting and modify the kit some more too install her. Plus my ignition timing curve is rediculously conservative. much more to gain there.. The car is going to be a rocket soon! 3 months left of Iraq and Ill be back to work :-D
Joined: Nov 2001
Posts: 8,484
Likes: 0
From: Cecil County Raceway!!!
160F is definately HOT...
what kinda timing did you run?
4" should be a big step in the right direction...I ran 7.99 with my little 4" downpipe...I'm upgrading to 5" now
what kinda timing did you run?
4" should be a big step in the right direction...I ran 7.99 with my little 4" downpipe...I'm upgrading to 5" now
Last edited by Fireball; Sep 28, 2009 at 11:06 AM.
Think I was in the neighborhood of 16 degrees by 5,000 at a slow ramp up my friend casey is doing the computer tuning, that was just my break-in tune. He knows what he's doing though, has what is most likely the worlds fastest rear mount turbo full weight street chevy truck, I would guess 5,500 lbs and running 9.40s with a similiar 408 motor and an S91 @ 22 PSI I think. I might be wrong on a few numbers except the 9.40 unless hes been faster in the past month!
Just an idea of what the future will soon hold! But not before finding the true potential of the T4 PT88 Im thinking Ill run 9.40s or so with her before swapping to the 101.
Just an idea of what the future will soon hold! But not before finding the true potential of the T4 PT88 Im thinking Ill run 9.40s or so with her before swapping to the 101.
Last edited by z28boysteve; Sep 28, 2009 at 04:21 PM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
I need some help. I built my own turbo kit from a PT88 on a 402 LQ9.... and it SUCKS it only made 557 Rwhp on a mustang dyno at 10 psi....... I spent $40,000 trying to build an 8 second street car, and Im going to have to do something very different with the turbo kit but I dont know what my problem is!
I have 1 5/8 header primaries, and 2 1/2" collectors, and crossover pipes with a T4 flange PT88 and a 3" downpipe, the charge pipes are 2.5" I know these are horrible dimensions but what stuff do I need to make 1000 rwhp with this 402? I can boost up to 25 psi with it and I built it from the ground up as a turbo motor so it will easily handle the task.
Im thinking I should start from a set of header flanges, and a pile of stainless
1 3/4" primaries on the headers with 3" collectors and crossover, into a T6 flange, 5" downpipe, and like a turbonetics thumper 101.. then, 4" charge pipe all around ... and the biggest A2W I can fit..... Inside the car this time.
Should I go ahead with this? or stick to what I have, make a 4" DP, and 4" charge pipes and hope for the best?
I have 1 5/8 header primaries, and 2 1/2" collectors, and crossover pipes with a T4 flange PT88 and a 3" downpipe, the charge pipes are 2.5" I know these are horrible dimensions but what stuff do I need to make 1000 rwhp with this 402? I can boost up to 25 psi with it and I built it from the ground up as a turbo motor so it will easily handle the task.
Im thinking I should start from a set of header flanges, and a pile of stainless
1 3/4" primaries on the headers with 3" collectors and crossover, into a T6 flange, 5" downpipe, and like a turbonetics thumper 101.. then, 4" charge pipe all around ... and the biggest A2W I can fit..... Inside the car this time.
Should I go ahead with this? or stick to what I have, make a 4" DP, and 4" charge pipes and hope for the best?
2.5" crossover is fine
You need a 4" Exhaust at a mininum
Are the wastegates dumped to the atmosphere? If not move them, the backpressure after the turbo is what kills performance.
I've made WELL OVER 1500hp with 1 3/4" headers and a 2.5" crossover, **** I've been multiple trips in the 157-159mph to the 1/8 mile and one hit at 162 where the boost got up on us. The headers/crossover is not your problem. Any pics of the system?
You definetly have a problem somewhere. Either a boost leak, a major exhaust leak or a problem with that turbo. My bone stock LQ9 longblock (stock everything inside except pushrods) made 17 psi once I found my boost leak and had alot left in it. That was thru truck manifolds and 2 2.5" pipes feeding the T4 flange. I went 6.32@109.5 in the 1/8, lost a plug and coasted to a 10.03@124 with a 1.38 60' on mine. Put a rod out the side on the next pass but it CAN be done LOL.
I'm building a forged LQ9 (stock crank) right now. It will get a set of AFR225's and a meaty cam. Putting the PT88 kit right back on the way it was and am shooting for 8.90's @ 155+ MPH. Race weight is about 3700.
I'm building a forged LQ9 (stock crank) right now. It will get a set of AFR225's and a meaty cam. Putting the PT88 kit right back on the way it was and am shooting for 8.90's @ 155+ MPH. Race weight is about 3700.
I chased down a leak in my setup that had me so mad that I let the car sit for 2 weeks at one point. Turns out that my intake had a hair line split. Same thing, only about 10-11 psi of boost.
I had the same problem a couple years back. Put a 76 t4 on a 402 and made no power. I would only see 15psi with the waste gate hose off. The problem was the turbo. You didn't say what exhaust AR you have. I was running a 1.00 wich was too small. Also t4 is too small for the airflow a 402 needs. The charge side is also too small for your needs. I redesigned mine with 2.5" hot side piping, a t6 s88 from Forced Inductions, and a 5" down pipe to a 4" over the K-member. The difference was night and day! I am really surprised yours is running as well as it is now.
I realize a 3" DP and a PT88 people CAN run in the 8s with but don't they have much smaller cubic inch motors and lighter cars? Im 3800 lbs with a 402 cube motor. I should have built a 366 
Im thinking what I got is way too restrictive FOR MY CUBIC INCHES... Ive got a .649/.651 224/230 117 or something of the sort, really dont think I have any boost leaks. Just guessing that the 160 of basically NOT Intercooled air and jacked up pressure ratios are doing all the damage here?
Im thinking what I got is way too restrictive FOR MY CUBIC INCHES... Ive got a .649/.651 224/230 117 or something of the sort, really dont think I have any boost leaks. Just guessing that the 160 of basically NOT Intercooled air and jacked up pressure ratios are doing all the damage here? 
why dont you give us some pics of the setup? a picture is worth a thousand words, and whats going on could be something strange that you might not have thought of.
i really think you should try and fix what you have, see what works out. if it doesnt, then you know. try hooking up a pressure gauge and measuring back pressure. try actually fixing the problem instead of re working it.
for all you know, you'll do all this ******* work to find out you had a simple problem. wouldnt you be alittle pissed?
i really think you should try and fix what you have, see what works out. if it doesnt, then you know. try hooking up a pressure gauge and measuring back pressure. try actually fixing the problem instead of re working it.
for all you know, you'll do all this ******* work to find out you had a simple problem. wouldnt you be alittle pissed?
I had a 408 and the t4 pte 88...one time I was working on the car and forgot the wastegate reference and the car made 44 psi of boost. That turbo is not too small to provide the motor with more boost.
www.cardomain.com/id/z28boysteve Those are all the pics I have of the turbo setup which you can't really tell what's going where
Next time I go to dyno, I should put a balloon on the waste gate outlet and see if it blows up when I hit peak boost, with the signal hose off......
maybe I have a really high backpressure and its popping the wastegate early? is that possible? the 3" DP in a 4" outlet could that cause enormous backpressure? or what about the 2.5" cold side could that cause too much restriction on the compressor or something crazy? I can't seem to find a real problem other than a crappy setup. Going to re-vamp the cold side with the PT3000 and 3 1/2" aluminum charge pipe, and this time use t bolt clamps on all the silicone, hopefully I see some different results, I want the thing running right before I set my eyes on KILL with the 101
maybe I have a really high backpressure and its popping the wastegate early? is that possible? the 3" DP in a 4" outlet could that cause enormous backpressure? or what about the 2.5" cold side could that cause too much restriction on the compressor or something crazy? I can't seem to find a real problem other than a crappy setup. Going to re-vamp the cold side with the PT3000 and 3 1/2" aluminum charge pipe, and this time use t bolt clamps on all the silicone, hopefully I see some different results, I want the thing running right before I set my eyes on KILL with the 101