The Temple of VTEC - Honda and Acura Enthusiasts Online Forums > 3rd Generation TL (2004-2008 models) - General Talk >

Jeff wrote:
you can't directly compare an automatic transmission plot to a manual transmission (see my brief discussion in the "road dyno thread"). Before the torque converter locks up, it slips and allows more rpms for a given speed, which results in torque multiplication. That's what you're seeing. I don't know how the dynojet handles the discrepancy between measured rpms and wheel speed.

For this reason I was actually thinking about shading out the 5AT plot up to about 3000 rpms where it appears the effect dissipates and putting a footnote that that portion of the plot is not really valid for comparison.

princed wrote:
Well, thanks to the recently completed dyno of the 5AT (thanks TOV!) and some photoshopping, I made a superimposed dyno showing both the 5AT and 6MT plots. The comparison raises some interesting questions. Unfortunately, I don't know how to post pictures here, so I posted the image over at A-TL.com. The link the the photo is below, as is the text:

http://www.acura-tl.com/forum/showthread.php?threadid=71365

Well, I thought it would be interesting to compare the 5AT w/ the 6MT. Unfortunately, the dyno plots between the 5AT and 6MT were not scaled identically, so I had to do some tedious photoshopping to overlap the two plots. If you look below, you'll see the results...

The 5AT has more torque/hp up until about 2600rpm, but then the 6MT has significantly more until about 6200, after which point they both become about equal. Why is there more more low end w/ the 5AT?

So even though there is only a 10hp difference in max hp, does the fact that the difference exists over such a broad rpm range account for the significanlty quicker 0-60 w/ the 6MT? Or is it more the gearing/weight difference?

One other interesting point is the sharp decline in the torque curve at about 6200rpm that exists ONLY on the 6MT curve. The people over at TOV mentioned that this dip looked like Honda trying to pull back some of the power w/ some ECU mods, but why don't we see a similar dip on the 5AT dyno? Did Honda alter the ECUs of the 6MT's to cut back power above 6.2k and leave the 5AT's alone? Could there be something in the manual transmission itself to account for the dip??

Oh, and the fuzzy, dim lines are the 6MT plots, while the sharper lines are the 5AT...