Specifically, they get *unrealistically* high based on the fans commonly used, and assuming the loading is within reason of an accurate street pull (ie length of time).

At least, that's been my experience.

Now that, as one might imagine, could affect peak power...

that said, I've observed similar (peak power) results between running 3rd/4th gears. I have also seen the power difference in the onset of boost that Tony describes. It looks like lag, but I think it's actually the opposite - that is, I believe boost is taking about the same time to spool, but in the taller gear (4th), that time passes when less RPMs are past (ie 4th shows more power at lower RPMs).

Somewhere I have some of this data, but it doesn't appear to be online - I'll look tonight...


Regarding IATs, here's "sj6sp"'s log of IAT at the recent AWE Dyno Day (10/7). They gain 60F across a 4th gear pull:
http://forums.audiworld.com/s4/msgs/2494477.phtml


Here's my logs from 1 day earlier on the street. This shows only a 20F increase, though it's 3rd gear:


And here's a full 1st-4th drag pass which only shows about 35F increase (red):


I know those aren't perfect comparisons (temps, ICs, boost, etc could be different), but it's pointing to what I've seen with one specific car when the only change is gear choice on the dyno.

Mark P


Dyno: 469wHP / 451wTQ
93 oct - best 60':1.734 | best 1/4ET:12.239 | best 1/4mph:116.58
100+oct - best 60':1.698 | best 1/4ET:11.762 | best 1/4mph:121.72



ECUx template version 11.16 (3/12/07)
AWD Dynos by State - Race Gas in New England - B5S4 100k+ mile post

Current:
'02 Audi S4 Avant, Imola Yellow, APR Stg3 - imolavant website - 185k miles
'01.5 VW Golf 4dr 1.8T, Satin Silver, GT28R, EPL-tuned - 14.8 | 101mph - 195k miles
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'00 Audi A4 1.8T, Silver - Quattrobonium website