Forced induction power differences

[gqneon]

Am I the only one confused how all the different blower and TT kits put down such wildly different power numbers? Procharger stage 2 boxes tune about 600 / 500. Hellion at under 8psi, 700 / 600?

Then mine, which at over 10 psi makes on race gas 600 /486.

I guess I don't get it. Maybe someone can walk me through what I'm missing. My cars getting better but should have been awesome at stock psi right around 10 on pump gas.

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[Reds197]

100% the tune and fuel type for peak numbers with same power adder.

Auto vs stick will show up on the dyno. At the track the auto will win.

 

[gqneon]

I'd hate to think that Lund is the weak link in all these tuner kits. Everyone raves about his work and says he's the best in the business. But stock kit tunes are laying waste to those claims on paper everyday. By a lot in some cases.

Psi on these cars gets measured directly from manifold itself, right? So if it makes boost numbers, that must mean the hardware install is correct to get that much cfm into the intake to make that boost. So if the airs there, and the fuel AFR wideband trim shows high 10-low 11, the fuels there too. Is all that's left going to be timing? How much timing do you need to run 700 hp on 8psi stock kits?

Still baffled.



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[Super Werty]

don't get caught up in psi numbers. It's all about CFM

different set ups can flow more or less at the same boost levels which is why you see different dyno numbers. If you really want to know what a car is made of look at quarter mile trap speeds

 

[Barrel]

The only difference between my car and yours is headers and a tune (I'm not convinced that the SW system isn't holding me back) and of course 100rwhp and 70rwtq and 2 PSI. Sounds right to me.

 

[Glenn G]

Super chargers use crank hp to compress air. Turbochargers use waste heat to do it. So for a given cfm a turbo system will make more power.

 

[gqneon]

The only difference between my car and yours is headers and a tune (I'm not convinced that the SW system isn't holding me back) and of course 100rwhp and 70rwtq and 2 PSI. Sounds right to me.

I agree and I've learned boost is a measure of restriction not output.

I guess I just thought that with a stage 2 kit with injectors and a pump booster and a D1SC that I would be starting with AT LEAST as much power as a stock HO or Stage 2 kit makes with the canned tune, since they make that on 91 and I can't get that power even with race gas. And they're making those pulls in KS where it's 95 degrees in the summer, about the same as here. So it's not a winter vs summer uncorrected comparison.

I'd sure love to have your 100 hp and 70 torque! I'd literally hang up my hat and call it good. I'd hate to pay another tuner another $500 to do me a completely different tune, since I've got $700 in dynos and tuning already. Maybe that's what I need to do, though, and then I'll have a definite answer on whether it's tune related or something else.

 

[RoushCharged]

Is there an intake restriction? Like a the intake hose collapsing at boost?

 

[gqneon]

Replaced the whole inlet system yesterday.

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[RoushCharged]

I'd look at the dyno curve for a normal distribution, see what the timing looks like under boost, a/f ratios, etc. Could also be Trans\driveline related (although this is new so unlikely).

 

[908ssp]

I read an article where the magazine took a stock GT500 to half dozen dynos over a one week period and everyone gave him different numbers and the highest to lowest spread was something like 70 rwhp. You cannot believe dyno numbers and you most certainly can't believe numbers spewed out by vendors.

 

[Reds197]

I read an article where the magazine took a stock GT500 to half dozen dynos over a one week period and everyone gave him different numbers and the highest to lowest spread was something like 70 rwhp. You cannot believe dyno numbers and you most certainly can't believe numbers spewed out by vendors.

THIS EXACTLY. Track numbers don't lie.

 

[gqneon]

Trap speed with my car and stock tires was 124, stock was 112. Times were similar because I spun some stock and I spun TONS with the blower.

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[olaosunt]

Trap speed with my car and stock tires was 124, stock was 112. Times were similar because I spun some stock and I spun TONS with the blower.

Tapatalk spelling errors inside!

I am no expert but I would think you would trap higher than that with 612 rwhp.
My 12 with a TVS/69 mm pulley/JLT stock block making 620 rwhp through the MT 82 trapped 128-129 mph(ET 10.9).
Based on your trap speed you are probably making mid to high 500's.
Think about it ..... you only trapped 12 mph more than stock.(I trapped the same with a tune and I suspect I am making just shy of 400 rwhp)

 

[gqneon]

I am no expert but I would think you would trap higher than that with 612 rwhp.
My 12 with a TVS/69 mm pulley/JLT stock block making 620 rwhp through the MT 82 trapped 128-129 mph(ET 10.9).
Based on your trap speed you are probably making mid to high 500's.
Think about..... you only trapped 12 mph more than stock.(I trapped the same with a tune and I suspect I am making just shy of 400 rwhp)

True. I also made my first pass in standard driving mode with traction control on as a baseline. Then it rained before I could make a second pass, so I actually might have been better or worse. It may have been pulling out significant timing to keep the wheels down, because on the street with TC off 1st is useless past 3500, 2nd breaks loose almost enough to point the car a different way at about 4500-5000, and third towards top end you can feel the tires walking a little. Fourth is all go.

So basically I need to run it without TC to give a better answer - or slap tires on it - or both.

Dyno's lie is what I'm learning - or at least foster misconceptions. If I convert from the mustang dyno to dynojet, on race gas with race tune I'm at about 640 / 510 at the wheels. This trap speed doesn't support that number.

So I think TC was waylaying the real number some.

I ran it 12.9 @ 112 on stock tires, with just a catback before the blower.

With the blower, it was 12.6 @ 124. Spin, timing retard, spin, timing retard. Spin, timing retard. Then 4th gear pulled hard to make up for the first eighth mile lol

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