to big of turbo?
10-12-2014, 10:48 AM
#1
Staging Lane
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to big of turbo? Well i ran my car and its pretty slow 12.0 at 117. Its a 5.3 with a 91.5mm turbo with a 1.39 ar exhuast. My question is am i better off to try to sell the turbo and get something small or put a smaller exhaust housing in it something like a .98 or 1.00 and change the rear end from 3.73 gears to like 3.05 gears or will that make the car even slower?
10-12-2014, 08:25 PM
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Staging Lane
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Thanks for the ideas guy I'm open to more input
No its a open housing. I think changing the housing to a divided one and getting a spool valve would cost more then say a s471 1.00 t4 and redoing the turbo kit. The turbo i have with the 1.39ar just don't come alive tell 2nd gear and by then its to late in the run to get a good time. I do have a trans brake but i still don't think it would help spool something this big
No its a open housing. I think changing the housing to a divided one and getting a spool valve would cost more then say a s471 1.00 t4 and redoing the turbo kit. The turbo i have with the 1.39ar just don't come alive tell 2nd gear and by then its to late in the run to get a good time. I do have a trans brake but i still don't think it would help spool something this big
10-12-2014, 08:50 PM
#7
Thanks for the ideas guy I'm open to more input
No its a open housing. I think changing the housing to a divided one and getting a spool valve would cost more then say a s471 1.00 t4 and redoing the turbo kit. The turbo i have with the 1.39ar just don't come alive tell 2nd gear and by then its to late in the run to get a good time. I do have a trans brake but i still don't think it would help spool something this big
No its a open housing. I think changing the housing to a divided one and getting a spool valve would cost more then say a s471 1.00 t4 and redoing the turbo kit. The turbo i have with the 1.39ar just don't come alive tell 2nd gear and by then its to late in the run to get a good time. I do have a trans brake but i still don't think it would help spool something this big
cam?
heads?
boost?
gears?
trans?
Trans brake?
Converter?
hotside piping diameter?
If it's a drag car, a little nitrous goes a long way. Personally I'd hit it with a 100 shot and turn the nitrous off after it starts to make boost on it's own.
I had mine set to come on at 3000 rpm and off by 4200. Engine made boost on it's own at that point. Your turbo is on the big side, but a 100 shot off the line will get it spooled very easily.
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10-13-2014, 10:30 AM
#9
On The Tree
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What is your 1/8 mph and et? How much boost are you running? I agree that you would be happier with a smaller turbo, but your mph isn't that high either. Look at how some of those supras run 11's at like 140mph. Yes your spoolup is slow with that turbo but your HP has to be pretty low as well.
10-13-2014, 10:31 AM
#10
All in all I think you will be much happier with a smaller turbo with a smaller turbine housing. S400 series T4 if you want to change the hot pipes. S400 T6 if you want to stay with the hot pipes you have. A T6 S475 or S476 with the standard divided turbine housing and a 92mm turbine wheel would be much nicer and spool much better. And has made the beans to get you into the 9's in other cars.
10-13-2014, 10:56 AM
#11
Staging Lane
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1/8 7.915 @ 93.67 11pounds of boost but I'm guess it at low 400 whp
What is your 1/8 mph and et? How much boost are you running? I agree that you would be happier with a smaller turbo, but your mph isn't that high either. Look at how some of those supras run 11's at like 140mph. Yes your spoolup is slow with that turbo but your HP has to be pretty low as well.
10-13-2014, 11:01 AM
#12
Turn the boost up to 20 minimum, then hit it with a 80-100hp worth of nitrous from 3000-4600 or so on the trans brake. (then shut nitrous off) Boost will come up fast and stay up.
Last edited by Forcefed86; 10-13-2014 at 11:52 AM.
10-13-2014, 11:24 AM
#13
Staging Lane
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All in all I think you will be much happier with a smaller turbo with a smaller turbine housing. S400 series T4 if you want to change the hot pipes. S400 T6 if you want to stay with the hot pipes you have. A T6 S475 or S476 with the standard divided turbine housing and a 92mm turbine wheel would be much nicer and spool much better. And has made the beans to get you into the 9's in other cars.
10-13-2014, 12:45 PM
#14
Totally depends what you are using the car for. If you only need/want it to be responsive at the track, nitrous will easily spool that turbo. This will allow you to run larger cam, make low back pressure and more power up top. It's a win-win, nothing bandaid about it. If you want a snappy quick spooling street setup, then as said... thats turbo isn't sized properly. How much power do you want?
10-13-2014, 01:05 PM
#15
Staging Lane
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I want good track times and a car that is still street able like able to drive to diner im not into street racing so i don't Care if it spools fast on the street. I would like the car to run high 9s don't really have a whp goal just a time goal
Totally depends what you are using the car for. If you only need/want it to be responsive at the track, nitrous will easily spool that turbo. This will allow you to run larger cam, make low back pressure and more power up top. It's a win-win, nothing bandaid about it. If you want a snappy quick spooling street setup, then as said... thats turbo isn't sized properly. How much power do you want?
10-13-2014, 01:12 PM
#16
Launching!
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You really need a horsepower goal to properly size a turbo. With that 90mm+ size, even the worst turbos should be able to make 1500+. For high 9s in a decently set up fbody at normal weight it should take no more than 750whp. You'd be much better off with something in the 72mm range.
Jack
Jack
10-13-2014, 04:17 PM
#17
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You really need a horsepower goal to properly size a turbo. With that 90mm+ size, even the worst turbos should be able to make 1500+. For high 9s in a decently set up fbody at normal weight it should take no more than 750whp. You'd be much better off with something in the 72mm range.
Jack
Jack
10-14-2014, 09:31 AM
#20
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That's a bit small then for 850. A BMW476 would do the job, or a cast S480. An 83mm TW with a 1.10 housing would be ideal, and would spool dramatically better than a 96mm TW in a 1.39.
Honestly though, you wont need 850whp to go 9s unless the car itself is set up VERY poorly.
Jack