How to Dyno an Automatic

Hello everyone,

I have a Civic 2009 R18 Automatic Stock.

If you don't mind, could anyone please tell me in detail how to Dyno an Automatic Civic or cars in general. It seems that there are different school of thoughts (I'm still waiting for the answer on Hondata forum where I posted earlier today too).

I thought of disconnecting the solenoid in the transmission and going into limp mode to lock the gear. After some thoughts I guess that would mess up with the VTEC and the ignition timing.

I appreciate any honest attempts and hopefully once the answer is found, this topic could be a sticky because you can try googling "how to tune an automatic cars" and no one really have the answer..

Anyway thank you beforehand :)

Use D1? lol

Thanks for your answer but I dont think thats the correct answer. As far as I know we can only lock our cars up to 2nd Gear but usually Dyno is done on the 3rd or 4th gear as they have the 1:1 gear ratio. Otherwise your rpm is maxed out before enough wheel speed can happen.

CMIIW please :)

L=1st
2= is 1st and 2nd
D3 is 1st, 2nd and 3rd
D4 is 1st, 2nd, 3rd and 4th
Or use S and select the gear and punch it.

Mate


A dyno run is in the gear closest to (on or below) 1:1 ratio to the cars FD

for example , most manual cars do a dyno power run in 4th gear.

So, you would find your gear which is closest and run low rpm to redline in that to give the most accurate power at the wheels readout. Make sense?




PS if you ran in 1st or 2nd gear the readout would be higher than actual, relevant to the mechanical ratio.

Quote:

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Originally Posted by bennjamin

PS if you ran in 1st or 2nd gear the readout would be higher than actual, relevant to the mechanical ratio.

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I am sure modern dynos have a input for gear ratio.

So you could do it in 2nd, you would just have to tell the dyno what the ratio is so it can give the correct results

Quote:

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Originally Posted by Grayfox

I am sure modern dynos have a input for gear ratio.

So you could do it in 2nd, you would just have to tell the dyno what the ratio is so it can give the correct results

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It's to do with the losses coming from the other gears moreso than he ratio

A low gear (high ratio) will make all powertrain items (engine, trans,driveshafts etc.) spin faster than what it would with a 1:1 ratio, and the converse in a lower ratio (5th gear).

So to get the most accurate reading you use 4th.

Maybe it's worth dynoing each gear so you know what power you have everytime you shift

lol

I just remembered.

My old accord's 2 option locked the car into 2nd.

But the current car i am driving(given to my by the panel beaters) uses 1st and 2nd in 2 mode.

lesson here is autos are not really meant to by dynoed and honda is stupid for doing automatic only these days.