Chassis dyno vs Engine dyno

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On 2007-05-04 22:08, MauriSSio wrote:
ok but to just say "its just a tuning tool" and brush the issue aside wont resolve the REAL issue, how to properly calculate or understand how drivetrain lossed even occur. Dont sell yourselves short
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I don't think you can look at it any other way other than a tuning tool and I think that Silverliner pretty much summed it up - "At the end of the day the chassis dyno or engine dyno are great tuning tools but trying make comparisions between different machines with different operators is futile."

There are a number of engine and chassis dyno's out there that are well known to (shall we say) optimistic. Thats just the dyno's themselves without even getting into setups, correction factors and the operators themselves (don't take that the wrong way).
Hey, just over-inflating tires or doing the pull in a different gear will effect a chassis dyno and are your initial engine dyno figures that you are trying to compare to... inflated or overstated?? There are numerous accounts of figures on the forums that don't compute with actual performance figures...so is it the setup or was the hp never really there??

i know but you guys are changing the subject from THEORETICAL DRIVETRAIN LOSSES and how or why an engine loses power, to dynojets. THATS what i was talking about.

Originally Posted by Silverliner

So, I may have some additional data for this in a week or so as I'm taking out the AOD and putting the T56 back in the car. The motor will be untouched and I'll be back on the same chassis dyno. according to just about every theory out there we should see more RWHP through the clutch and stick vs. the converter and automatic.

This will precede a carb to efi swap using an identical manifold and a 4500 style throttle body vs. the dominator carb so that will be interesting as well.

This doesn't address MauriSSip's question but I'm not sure I can. Based on two cars I know well this particular Mustang chassis dyno seems to tkae 37-39% driveline loss.

For comparison the GTO saw 1000 rpm slippage on the dyno ves. 500-600 typically at the track again using stnadrad formulas. On the dyno we had crank speed measured optically compared to wheel speed on the rollers in 3rd gear so we know what difference is with the way the dyno loads the car. We'd need a wheel speed sensor and data logging to have actual track data which neither of us have currently. I will be able to add that soon with the Innovate LM-1. More quater mile lap= more data. Eventullay I may actually learn something.
[addsig]

its been almost a year but im still interested in the results.This thread may be old, but this discussion is definately not over