injen vs k&n vs fujita CAI

That is why we have Dyno Days... Same dyno, same day... no arguments :D .... (Minus the fact the temperature changes throughout the day)

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Originally Posted by yfin

Yeah I know you are an engineer - that is why you are so smart :D So am I right in saying that even a small drop in power at low RPM is going to correlate to an even bigger drop in torque at low RPM?

And the same would not necessarily hold true at high RPM?

The torque in that first Injen graph (without MR tech) is terrible. It dips below stock quite a few times in the curve - not just down low :eek: The revised Injen looks much better.

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At low RPM, a small drop in power is equivalent ot a small drop in torque. At high RPM, the same small drop in power is equivalent to a larger drop in torque.

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Originally Posted by aaronng

At low RPM, a small drop in power is equivalent ot a small drop in torque. At high RPM, the same small drop in power is equivalent to a larger drop in torque.

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Then you can chuck gearing into the equation and throw the torque graph out even further :)

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Originally Posted by ginganggooly

Then you can chuck gearing into the equation and throw the torque graph out even further :)

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You're thinking about tractive force. That's the raw figure measured by the rollers.

Power at the wheels (hp) = Torque at the wheels (lbf.ft) (corrected for gear ratio) x RPM/5252

This is used to calculate power at the wheels on the dyno. A dyno can't measure power. It measures torque put down on the rollers (which have a known resistance) and then calculates the power from it using the engine RPM at each point.

Quote:

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Originally Posted by aaronng

You're thinking about tractive force. That's the raw figure measured by the rollers.

Power at the wheels (hp) = Torque at the wheels (lbf.ft) (corrected for gear ratio) x RPM/5252

This is used to calculate power at the wheels on the dyno. A dyno can't measure power. It measures torque put down on the rollers (which have a known resistance) and then calculates the power from it using the engine RPM at each point.

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I didn't realise that the dyno used engine rpm to calculate outputs, I assumed it was using roller speed vs tractive effort and whatever calculation is required to plot power.

So when the operator calibrates engine RPM vs Speed on the dyno, its going a little deeper than just changing values on the graph?