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Thank you. It is a 3.5" downpipe to a single 3.5" catalytic converter after that it Y's into my factory dual 2.5" exhaust. It has supported +10 psi runs without a drop off in boost. My wastegate hose fitting came loose a few weeks ago.
The whole thing is a system. Results are going to be better when everything is designed to work together. I cringe when missmatched components are put together in the name of "room to grow".
Over the winter I installed a McLeod RST twin disc clutch along with an anti-hop GeForce axle and LS7 card style MAF. With a capable clutch in place its finally dyno time:
457rwhp/503rwtq
On the dyno boost began at @2100 RPM and I hit my 7psi by 3500 RPM. From there boost stayed very flat (149-153kPa) all the way through to redline.
Congrats on the numbers! That's awesome you were able to hit full boost by 3500 rpm. I still come back to veg out and read the thread. Any thoughts about pushing it to 10psi? Any reason you wouldn't?
Thank you. Lots of torque. Yeah, it would be easy to turn up the boost. My current problem is traction. For the time being I have a very fast and reliable street car that I'm enjoying.
any idea why it choked up past 5000 rpm? is it the stock cam running out of breath or is 69mm too small for an ls2? planning my own diy turbo build a lot like this one, just seen two other builds very similar to this and they all choked past 5k and dont wanna have the same issues
The horsepower and boost stayed flat all the way to the end so I don't think the compressor was too small. If you can find a 72-74mm compressor with a similar 84mm turbine it would be more ideal at the top end.
Torque fall off at upper RPM: My tune was very conservative for that run. Lots of fuel and not much timing. Stock exhaust after a single 3.5" Cat.
What are your goals? Traction continues to be a problem on the street. I am mini-tubbed now with sticky 285 Hankook R-S3's. Car continues to be reliable, quiet, decent gas mileage and pretty fast. I love hanging with obnoxiously loud Mustangs giving it their all while I look like I'm on a Sunday drive.
Thanks for the response! My goals are a 500-600 whp turbo gto with stock like reliability and a budget of $3000. Sounds like ill be going for the Deatschwerks since youve had it so long with no reliability issues. Reliability is my main priority, want to take this car on a few 2,000+ mile roadtrips so cant risk vaporlock and would like the mileage to stay reasonable. Anything i should look out for on a budget build?
600 is pushing the reliability based on the database on LS1GTO. 12psi seems to be where stock blocks start letting go. I have a buddy that built his hot side out of parts store compression bends. Not pretty, but he makes more power than I do. Stock GTO is about 340 rwhp. Doubling that to 600 is pushing everything. I'd say don't get greedy and stay closer to 500 rwhp. You'll enjoy the car more.
600 is pushing the reliability based on the database on LS1GTO. 12psi seems to be where stock blocks start letting go. I have a buddy that built his hot side out of parts store compression bends. Not pretty, but he makes more power than I do. Stock GTO is about 340 rwhp. Doubling that to 600 is pushing everything. I'd say don't get greedy and stay closer to 500 rwhp. You'll enjoy the car more.
Man, that makes this decision even harder than it was to begin with! Would only 500 wheel be worth installing a turbo for? Should i try to do it NA? cheapest sc system ive seen was the maggie for +-6k, which i might as well just turbo. But from my reading, there seems to be a huge jump from 450 NA to 500 NA, so should i turbo regardless? If i stick to 500w for reliabilities sake, turbo still seems the way to go, but since im only using a fraction of turbo ls potential i would want a torque curve flatter than the texas panhandle to justify it. idially at such low boost positive kpa at around 2100 rpm would be nice? Ill have to do more research on turbo size optimization for that.. How do you like EFI live and would you recommend it over a professional tune? obviously a professional would be better suited, but thats $500 and no day to day data logging.
Absolutely worth it. Turbos make torque. I drove my car this morning typically shifting at about 3800 RPM leaving everyone one else way behind. Max boost I saw was 5psi. That buddy that made more peak power than me didn't have my torque curve. He can keep his extra horsepower. The more fun you can have at lower RPMs the durability increase is substantial. If you talk to some serious street drivers, they will tell you after 600hp you are just chasing a number. There is no way to put it to the ground. Like the Hellcats with their giant HP numbers, the engine and transmission de-tuning doesn't let that power ever actually make it to the pavement.
From your other post: Twin turbos are sexy and can package better. 2 3" downpipes can be easier to route than one 3.5" I'll give you that. I have never seen a test where somebody swapped a big single for a smaller twin set up. That would be something. Sizing goal would have to be a target RPM to start seeing boost. I am an automotive mechanisms designer with a dozen patents. Whenever you can accomplish something with one thing instead of two things, its always better. Remember those twins are only getting half the exhaust albeit one side slightly more efficiently.
N/A: RPMs increase engine stress exponentially. To get into that power region you are going to loose low end torque sacrificing fuel economy and driveability. Even before my turbo is making "boost" (1800RPM lets say), it is already packing more air into the motor than a N/A engine is sucking in at a higher vacuum.
Blowers use a lot of power to make power. Car Craft a couple months ago did a boosted 5.3L. Threw 3 different cams at it and eventually cranked the boost up to 29psi to hit 1K hp. Optomized cam and tuning for the (whipple?) blower. Exact same motor with a turbo and turbo cam made slightly more power on 19psi (and that with too small a turbine selection in my opinion). All that extra boost was powering the blower, sucking down gas and beating up the motor.
I like EFI-Live. The black box tuning, gauge display, serial WO2 interface. Can't get your fuel economy to display correctly or swap in a 4L80E with HPT. It is better. Worth the extra money?... My car is my hobby. I much rather spend months getting 85-90% the power a professional would get in an afternoon by learning and doing it myself. I dare say my economy and driveability is better than what a pro could get in a couple hours.
I was looking up this thread to remember how long ago I went turbo. I am still enjoying this car if anyone is benchmarking a daily driver. Everything still works though the car was fitted with an aluminum radiator this past summer. Nothing has melted except my hood liner.
Man, that makes this decision even harder than it was to begin with! Would only 500 wheel be worth installing a turbo for? Should i try to do it NA? cheapest sc system ive seen was the maggie for +-6k, which i might as well just turbo. But from my reading, there seems to be a huge jump from 450 NA to 500 NA, so should i turbo regardless? If i stick to 500w for reliabilities sake, turbo still seems the way to go, but since im only using a fraction of turbo ls potential i would want a torque curve flatter than the texas panhandle to justify it. idially at such low boost positive kpa at around 2100 rpm would be nice? Ill have to do more research on turbo size optimization for that.. How do you like EFI live and would you recommend it over a professional tune? obviously a professional would be better suited, but thats $500 and no day to day data logging.
Going FI will give you room to grow and getting to 500hp NA is NOT street friendly with stock cubes....but there are plenty of people who are 600+rwhp and its living if its tuned right. A used blower setup will be less cluttered under the hood and give a more linear powerband, read better traction, and still make a ton of hp/tq. Typically the lowend torque on a turbo is what tends to break stuff at higher power levels. Higher cylinder pressures at lower RPM's is what does it.
I like to read this thread every once in a while. This was main inspiration for my car. I remember when I first bought my gto, I was laying on the rug in my living room reading turbo builds on this car and I read this one too. I was intrigued but then quickly felt over whelmed by the amount of work that needed to be done. I ended up giving up on the turbo idea for a while and tried to make the car run mid 11's with the stock bottom end, bolt ons, heads and cam and I didnt get there. I raced a turbo v6 trans am at the track and got my *** handed to me. That was it. I made the decision then it was time........and I forged ahead until it was done. My build took me around two months and has been stone reliable like this one. Couple weeks after getting it done I took a next state over road trip to a major car show. got 20mpg and was stuck in major traffic with not one issue. thanks to the OP for giving me inspiration and advice along the way! Now i'm turbo hooked!
2-1/2" Short Radius 90 degree SCH40 0.203" mild steel wall. I purchased is from ACE Stainless Supply for $45 with shipping. Shipping being half the cost. This was a few years ago. I don't see a listing for it on their site currently.
Update: Still have the car. I put it away for the winter a couple weeks ago with about 22K miles since the turbo install. Still running strong with no repairs needed.
It has been the culmination of my turbo dreams that started with an unresolved GN infatuation. I have been toying with the idea of forged pistons and a cam for no apparent reason. I am building a hidden wing for the car currently. If it ever quits raining here in Michigan I might even drive it some more...
It has been the culmination of my turbo dreams that started with an unresolved GN infatuation. I have been toying with the idea of forged pistons and a cam for no apparent reason. I am building a hidden wing for the car currently. If it ever quits raining here in Michigan I might even drive it some more...
GN as in grand national? If so, I was talking about that today. I want one. Eventually I’ll have one. But I’d rather have a turbo v8 in it than the v6.
10-18-2013, 12:06 PM
