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      07-22-2008, 09:39 PM   #12
lucid
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Drives: E30 M3; Expedition
Join Date: Apr 2007
Location: USA

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Quote:
Originally Posted by IWC Doppel View Post
Not sure I follow you here. I would expect any increase in power for a pulley system to be in relation to engine rpm, either linear or otherwise.
The equation that relates power to torque is simple:

Hp = ( Tq x rpm ) / 5252 as long as Tq is measured in lb x ft

So if the tq gains decrease, but the rpms increase, the power gains can be relatively stable, which is what is happening at higher rpms.

At the low rpms, the same torque gain will yield less power gain simply because the rpms are low (as the equation indicates).

You can read the tq values from the chart, plug them into the equation above, obtain power, and compare calculated values to values on chart, which is what I've done. The numbers match.

The real question is the loss percentage entered into the dyno.

I don't think he's done the pulleys. He's reflashed the ECU and installed the new exhaust. Those I know he did for sure. Anyway, he'll tell us and we'll know more.

Different mods will yield different torque gains along the rpm range.
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