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[Z06] Disappointing dyno today

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Old May 8, 2004 | 01:23 PM
  #21  
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Default Re: Disappointing dyno today (Y2K253SS)

On the dyno it's the gears, but I bet it feel like you have more when you're on the street. :yesnod:
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Old May 8, 2004 | 09:00 PM
  #22  
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Default Re: Disappointing dyno today (lager99)

Pumba... I am not sure about how it works, but i am pretty sure it has very little to do with friction... you would be better off to pm julio, lou, or any other tuners that do work with them to get a really good answer :cheers:
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Old May 9, 2004 | 08:34 AM
  #23  
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Default Re: Disappointing dyno today (Y2K253SS)

You will lose power going to the bigger (numerically) gears due to increased friction loss, I have seen 10 RWHP loss on the same dyno (and operator) going from 3.42 to 3.90. So add in different dyno, different weather, different operator and 4.10 gears and your reduction is not surprising IMO.

Dyno's are for tuning, comparing all the variables above is an exercise in frustration. Go drive and enjoy the car. The track is the only place to measure before and after performance.

Les
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Old May 9, 2004 | 11:11 PM
  #24  
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Default Re: Disappointing dyno today (ZO6Les)

You will lose power going to the bigger (numerically) gears due to increased friction loss, I have seen 10 RWHP loss on the same dyno (and operator) going from 3.42 to 3.90. So add in different dyno, different weather, different operator and 4.10 gears and your reduction is not surprising IMO.

Dyno's are for tuning, comparing all the variables above is an exercise in frustration. Go drive and enjoy the car. The track is the only place to measure before and after performance.

Les

No, it is not friction. Horse power is calculated as torque * RPM divided by 5252. Gears will change the RPM vs. torque relationship - e.g. it will move max torque to lower RPM, thus you run out of usable portion of RPM range. Plain and simple.
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Old May 10, 2004 | 02:56 PM
  #25  
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Default Re: Disappointing dyno today (Y2K253SS)

Which gear did they do the dyno reading with. When I got mine dyno'ed, Andy used 4th to redline. He was saying because the gear ratio is 1:1. If you differ from the 1:1 ratio you'll get incorrect readings. Does anybody know what gear is 1:1 when you have 4.10 rear end?
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Old May 10, 2004 | 03:07 PM
  #26  
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Default Re: Disappointing dyno today (robz)

Its the gears. I lost 19 hp with the gear swap and others have lost close to 20 as well. Dont sweat the dyno numbers. Your car will run alot faster now provided you get traction to the tires. Trust me, get some et streets and hit the track.
:iagree: :iagree: :iagree: :iagree:
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Old May 10, 2004 | 07:37 PM
  #27  
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Default Re: Disappointing dyno today (Gonzo)

Here's my opinion, Those are inertia dyno's, they measure hp, by how fast that heavy drum spin's up. But your engine now has to spin up faster than it did before, just to make the same hp, and there's limit to how fast an engine will spin up, it's the same reason that a lighter flywheel makes more hp on a chassis dyno.

If you dyno'd in a higher gear, I'd bet some of your "missing" hp showed back up.
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Old May 11, 2004 | 05:14 PM
  #28  
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Default Re: Disappointing dyno today (Y2K253SS)

Thanks guys for the continued discussion on wears my HP :D
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