OK, so I've been wondering this for a while, and finally decided to ask some people that might know. I'm always reading that when people dyno their cars, they should do it in teh gear that has a ration closest to 1:1, but what I'm wondering is that since the dynograph is usually corrected for whatever gear it is done in, why does it matter?

It's going to be corrected for the gear ration and FD ratio anyways, so why does it matter how close to 1:1 the gear is?

Reason I ask is that I have a first gen auto, so the only gears we can do a dyno in to get the full range of rpm's is 1st and 2nd. If we did 3rd we'd only get 4400 rpms to redline, which doesn't relaly show very helpful information. maybe peak hp/tq, but what about all the other stuff?

what's teh deal?

 

I always thought a higher gear was preferable due to the fact that the car takes longer to wind through it, and it covers a greater wheel RPM range, so the resolution of the graph ends up being superior to a lower gear. But I'm probably mistaken.

 

yeah I was thinking that too. I mean obviously you don't want to do the dyno in first gear if you can help it, but besides the speed at which it runs through the specific gear, I can't think of any other reason.

 

4 speed auto = 2nd
5 speed auto = 3rd
5 speed manual = 3rd
6 speed manual = 4th

I haven't heard of corrected dyno's correcting gears. Only temp & air factors.

 

hmmm, I wonder why it lists the gear ratio's on the dyno graph then?

 

Well you want the gear thats closest to 1:1 for mathematical reasons if I'm not mistaken.

 

Correct. Doesnt matter what gear it is, as long as it is the closest to 1:1.

 

right, that's what I stated, but what good does that do on an auto if you can only see from 4400-redline because it will downshift if you go WOT otherwise.

guess I'll just do mine in 2nd no matter what.