Stock vs 123 Wheel HP (All-Motor) Dyno Graph

[4MPG]

Originally Posted by richardholdener

I am very curious to know how you see where we are losing power due to tuning based on the graph provided. Since there is no evidence of the air/fuel ratio or timing values, how do you know where tuning may improve the power? To answer your question about tuning, we will be employing an FIC on the yaris motor (basically to increase the timing-since air/fuel is near spot on already. No plans on changing compression-the test motor belongs to another forum member and we don't think he will like us tearing his motor apart. BTW-The dips in the curves you are refering to are a function of the resonance waves from the long-tube headers and intake manifold.

Your seeing these kinds of dips etc due to the headers? The dyno sheets of the before/after of the headers really show some spots (4-5200) where it looked like a tuning issue, as it was present but not as exaggerated on the stock dyno, which I figured was a tuning issue. Its probably alot less important than it looks... on this scale every small change looks like a monster.

[thebarber]

Originally Posted by 4MPG

Your seeing these kinds of dips etc due to the headers? The dyno sheets of the before/after of the headers really show some spots (4-5200) where it looked like a tuning issue, as it was present but not as exaggerated on the stock dyno, which I figured was a tuning issue. Its probably alot less important than it looks... on this scale every small change looks like a monster.

its not really a dip in the dyno, its just a flatter tq curve vs stock.....

[richardholdener]

My point is that the only way to determine if any dips in the power curve (HP or TQ) are caused by "tuning issues" is to compare the dips versus the air/fuel curve or the timing curve. This way you can determine if the dip is caused by a lean or rich mixture or by excessive or insufficient timing. Simply looking at dips in the power curve will not allow to to determine the reason they exist. As indicated previously, the dips in the power curve are caused by resonace tuning offered by the new induction and exhaust, not by air/fuel or timing. We know this because both air/fuel and timing curves remained identical before and after the header and/or intake installation (we always monitor both while dyno testing). This should clear everything up.

Originally Posted by 4MPG

Your seeing these kinds of dips etc due to the headers? The dyno sheets of the before/after of the headers really show some spots (4-5200) where it looked like a tuning issue, as it was present but not as exaggerated on the stock dyno, which I figured was a tuning issue. Its probably alot less important than it looks... on this scale every small change looks like a monster.