GT Motorsports: 370Z Supercharger system development

rackley · 02-18-2010, 09:21 AM

Quote:

Originally Posted by RCZ

344 @ 5psi in the charts.
400 @ 4.5psi in the video.

If its flowing higher, that just means it doesnt need to spin as fast to produce the same boost. Just because a turbo is bigger, doesnt mean theres more air in 5psi than there would be with a small turbo. Less stress on the turbo yes, more psi in the psi, no.

So "obviously" that's not why. I think the numbers that were throw out there by Z eliminator are pure speculation. I dont think it made GTM look good either. Stage 3 @ 10psi only making low 400 when their actual stage 1 kit is already making 350 @ 5psi.

Wtf is going on here folks? I'm not hating here, but these things aren't making GTM look good for me. I know they are a good company, this isn't necessary or needed.

I don't really know anyone who quotes flywheel HP except perhaps the manufacturer... It's rather misleading.

But yes you're right. Thanks for the "flowing" debunk. Assuming you don't have a closed throttle plate in one of the I/C tubes and you're pumping into the same engine, 5psi is 5psi is 5psi. It's putting the same number of oxygen molecules into the chamber.

With regards to sizing, a smaller SC or turbo has to work harder (spin faster) to make it, which would cause more parasitic losses, but the same amount of air is going past the intake valves into the combustion chamber. The whole "flowing more" is really misleading because the air isn't "flowing" any faster or harder.

Silo · 02-18-2010, 09:46 AM

Quote:

Originally Posted by rackley

But yes you're right. Thanks for the "flowing" debunk. Assuming you don't have a closed throttle plate in one of the I/C tubes and you're pumping into the same engine, 5psi is 5psi is 5psi. It's putting the same number of oxygen molecules into the chamber.

No, it's NOT dude... 5 psi might be harder to imagine, so lets go to 20 psi. A GT25 at 20 psi is far less "efficient" then a GT35 at the same psi. Efficient means, that on the same engine the GT25 has too spin a lot faster then the GT35 to produce 20psi of pressure causing the compressed air produced by the GT25 to be much hotter compared to that of the GT35, which in turn means that there will NOT be the same number of oxygen molecules in that chamber!

rackley · 02-18-2010, 02:34 PM

Quote:

Originally Posted by Silo

No, it's NOT dude... 5 psi might be harder to imagine, so lets go to 20 psi. A GT25 at 20 psi is far less "efficient" then a GT35 at the same psi. Efficient means, that on the same engine the GT25 has too spin a lot faster then the GT35 to produce 20psi of pressure causing the compressed air produced by the GT25 to be much hotter compared to that of the GT35, which in turn means that there will NOT be the same number of oxygen molecules in that chamber!

Yes, temperature is a factor too, but I was assuming a system with an adequately sized intercooler and boost measured post-IC, which is usually is, as it is in the GTM system.

Quote:

Conclusion: If intake temps, backpressure, boost and RPM are held constant for both setups the larger turbo will make more power because volumetric efficiency has increased due to the greater flow of the larger compressor wheel at 10PSI.

Exactly (with the exception that we're not talking about turbos or backpressure here). Volumetric efficiency of the compressor wheel. More efficient = less energy wasted = more power for the whole system. That much is very obvious. But it's not what I was talking about. I was talking about the amount of air entering through the throttle body into the combustion chamber at 5psi (at a fixed temperature). Small picture, not big picture.

Buddy Revell · 02-18-2010, 10:04 AM

Quote:

Originally Posted by rackley

I don't really know anyone who quotes flywheel HP except perhaps the manufacturer... It's rather misleading.

If I'm not mistaken, all of Vortech's hp figures for their sc kits on their website are at the flywheel.

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