Sc400 turbo Vs 2jz 350z, C5 corvette , and 06 WRX

[BoostedV8]

Some fun runs with a few friends. My car is a 97 sc400 with the stock 1uz on 9lbs of boost. Numbers are 350/350 rwhp and tq. Stock fuel other then the walbro 400. Car is maxed out on fuel and has 150 pis in cylinder number one. (Bad ring)

1st run was against this 07 350z with a twin turbo 2jz swap. Owner claims 10lbs of boost on the stock twins. No numbers on the car only that he said it was faster now then when it had the VQ running 13.3s.

The run is from a 40 roll. I stretched him pretty bad. He says 3 to 4 cars idk I wasn't looking behind me.
http://m.youtube.com/watch?v=yWx82HTUf5s

2nd run was against this 06 WRX. Mods as follows:
exhaust , sti intercooler, headers, intake, tune, stock turbo @19psi, and race gas. 300 plus awhp

The run is from a 40 roll per WRX request.
http://m.youtube.com/watch?v=vKddemvRjEs

3rd run was against this C5 corvette. Mods are zo6 heads and cam, intake, headers, exhaust , gears and tune.

The runs. 60 roll per corvette request. 1st vid is from his gopro and the second vid is from my gopro with a rematch in the last run. I made a small video with my gopro vids.

His gopro my runs @ 1 min 42sec into the vid.

http://m.youtube.com/watch?v=RPXF56osMeI

My vid I did with my gopro.

http://m.youtube.com/watch?v=hqkxBjrVZzo

 

[stevechumo]

Those are the very nice runs. I like that. I'm sure when the boost kicks in, that's where the fun starts.

It seems like you have a turbo lag issue. You should have pulled ahead of the 350Z before the 2JZ in that 350Z kick in. Although you're on the roll, it still lags, which it shouldn't due to the V8 and 4.0L size. I'd guess it's even worse on the streets. I reread your other post about this car, and you stated it's T76 turbo. That's a giant turbo for only 9 lbs of boost and non-internal preparation. For street driving, the max turbo size is T70, but the best practical size is either T60 or T62 max. You can still achieve over 450 wrhp with T60 or T62.

There're still ways to minimize the lag, if you stay with that T76, is by reducing the intake pipe with less pipe length.

 

[BoostedV8]

Those are the very nice runs. I like that. I'm sure when the boost kicks in, that's where the fun starts.

It seems like you have a turbo lag issue. You should have pulled ahead of the 350Z before the 2JZ in that 350Z kick in. Although you're on the roll, it still lags, which it shouldn't due to the V8 and 4.0L size. I'd guess it's even worse on the streets. I reread your other post about this car, and you stated it's T76 turbo. That's a giant turbo for only 9 lbs of boost and non-internal preparation. For street driving, the max turbo size is T70, but the best practical size is either T60 or T62 max. You can still achieve over 450 wrhp with T60 or T62.

There're still ways to minimize the lag, if you stay with that T76, is by reducing the intake pipe with less pipe length.

Car came with this turbo. I want to swap it to a s366. But right now I have a few things going against me. 1. Low compression (150) in cylinder one isn't helping. 2. Trans doesn't seem to down shift . 3. Stock injectors. If I could down shift I wouldn't need to manually shift to 2nd and drive. They wanted 40 rolls and that's not a good mph to get out in. If we went from a 55 60 I would have instantly pulled and walked away.

 

[stevechumo]

Car came with this turbo. I want to swap it to a s366. But right now I have a few things going against me. 1. Low compression (150) in cylinder one isn't helping. 2. Trans doesn't seem to down shift . 3. Stock injectors. If I could down shift I wouldn't need to manually shift to 2nd and drive. They wanted 40 rolls and that's not a good mph to get out in. If we went from a 55 60 I would have instantly pulled and walked away.

Yes. Those are the things that can certainly slow you down. But a correct sizing turbo will improve the response big time. There're other factors such as manifold & pipe designs all affect turbo response time. A good turbo setup can launch the car quickly right off the stop. My SC starts boosting at 1000 RPM (almost instant) and in a split of a second, it has full boost at 3000 RPM.

 

[BoostedV8]

From a dig the car moves out nicely but I was told not to do that anymore until I do some work to the trans. 1st to 2nd shift sprang break with 300 plus hp. So I don't dig the car anymore. I get mixed advise. I know going to a smaller turbo would be more fun but I plane to make power with this car. So some say keep the turbo I have and some say swap it out. Right now I'm just enjoying the car as is. I can't really do to much with it until I buy a house. After that its build time.

 

[poorsupra]

damn! all that goodness and a auto tranny!?!?! im so excited to throw my holset on my sc4, r154 w/lsd..... should be a great freeway flyerrr. car pulls hard! even with the issues you have now. good job! is it possible to snap a pic of the engine bay? specifically the turbo manifold/wastegate piping. im intrigued.

 

[stevechumo]

I read somewhere that someone stated the sprang break after 300 hp, too. But I personally don't agree. Mine has been running fine with 400 torques, even torque is what kills things. There're many factors that are involved. I like launching at a stop, but I don't do break-torque. Break-torque creates a very hard sudden surge and that's more likely the cause to break it. Nothing lasts forever, but you'll need to do that a lot to break it.

 

[BoostedV8]

damn! all that goodness and a auto tranny!?!?! im so excited to throw my holset on my sc4, r154 w/lsd..... should be a great freeway flyerrr. car pulls hard! even with the issues you have now. good job! is it possible to snap a pic of the engine bay? specifically the turbo manifold/wastegate piping. im intrigued.

http://www.lextreme.com/forums/showthread.php?t=16245