Shift_Munky

I was wondering what ideal torque and horsepower curves should look like for a turbo roadracing car. I am rebuilding my redtop and discovered that my stock T25 has too much tangential shaft play, and now I have to pick another turbo. I considered the GTi-R turbo, but was unsure about whether this would be a good choice or not. Topend power with this turbo would be nice, but I wondered how good a fit it is for roadracing, based on when it spools and whatever other concerns there may be.

Ideally you would want a torque curve that plateaus early and stays there right? That way you have plenty of room under the curve.

TIA,
Andy

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FastNX

I would think that something with a small turbine is something you would want to stay away from on a road course unless you keep the boost quite low.

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Jim #98NX

Jeff's SRX car uses the GT3037, which is pretty big, and some feel he could even go bigger. The exhaust is about 3 feet long and offers almost no backpressure, so it spools pretty quickly. The SR20 really likes free flowing exhausts and given a turbo it will be happy to flow lots of air.

Is the GTi-R turbo ball bearing? I'm not up on my turbos.

It also, like all things racing, depends on your budget.

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SE-Rawkus

No. The only Nissan ball-bearing turbo is the T25 that comes off the W11.

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Driven97

The T25 falls off high in the powerband, as it loses efficency. The powerband is very, very flat though, and it spools smoother than the one t28 car I drove. We were able to do the closest course to us completely in 3rd gear. The 350z I drove that day had to shifted between 3rd-4th several times.

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Matt
97 SE-R - Daily driver - winter beater - autox - track slut - drag car - summer cruiser
First touched the keys @ 16 miles, now 150,000+
Boosted as of 11/15/05
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Jim #98NX

It depends on who you talk to, but ideally you should hit your HP peak at redline and then when you hit the next gear you're at your torque peak. This way all the driving us done between the torque and hp peak which usually maximizes the sum of area under both those curves. But the only real way is to do lots of math.

coolblackser

What about the disco potato turbo..that spools up insanely quick. Not sure about the torque and hp peak separation or area under the curve at that point.

you can use the math you need to figure out the length of the exhaust and tune it too. Say maximum RAM effect at 6000 to add to the area under the curve.

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