Dynamometer Results & Comparisons - Dyno pulls in 2nd

I had my car dyno tuned a while back and we did my pulls in 2nd gear (th350) since my car still has stock 2.73's and would take FOREVER to pull through 3rd.

When I change the rear end gears to 3.73 and do the pull in 3rd should I expect to see any gains from the gear change and pulling in 3rd? I've heard people tell me that the numbers I have now are inflated since the pull was done in 2nd. I have also heard that I will pick up power from pulling in 3rd.

What do you think?

It will pick up power in third. I tried this before on a few cars, if your not in the 1:1 gear it loses power. Thats my observations. We tried every dyno trick in the world a few years ago.

It will pick up power in third. I tried this before on a few cars, if your not in the 1:1 gear it loses power. Thats my observations. We tried every dyno trick in the world a few years ago.
Thank you, I was being told too many things.

Now just to see how much I pick up and not to do dyno pulls on 99 degree days with a ton of humidity

Any time you dyno try to use 1-1 ratio aka 3rd for our A4 trannies, Also post your before and after dyno sheets i'd be interested in seeing them, i think there could be 5% hp and more than that in TQ
Also its Much better to tune the engine in 3rd because thats where the engine see its highest load over a much longer period, In fact it would be better to just dial in the tune separate for all gears, probably take too much time though

Any time you dyno try to use 1-1 ratio aka 3rd for our A4 trannies, Also post your before and after dyno sheets i'd be interested in seeing them, i think there could be 5% hp and more than that in TQ
Also its Much better to tune the engine in 3rd because thats where the engine see its highest load over a much longer period, In fact it would be better to just dial in the tune separate for all gears, probably take too much time though
I know the 1:1 ratio gets you the most accurate reading. I would've done the dyno pull in 3rd but with 2.73 gears, 1:1 ratio, a 27 inch tall tire, spinning to 6500 rpm is something around 190 mph. lol, we would be there all day waiting to get to peak rpm. I will post the difference when I get the differential built but that might not be for a while. Life is claiming my time and money every where else except my car

Interesting point on the 1:1 ratio. Now, with the new 6L80E transmission there is no 1:1 ratio so it probably should be done in 4th gear with the 1.15:1 ratio. I assume there would be a very slight horsepower loss compared to a true 1:1 ratio?

^you are correct. Most dynos are calibrated to 1:1, supposedly. There isnt much diff on a 6l80, but its something. could make the diff between say, 395 and 400hp

Any time you dyno try to use 1-1 ratio aka 3rd for our A4 trannies, Also post your before and after dyno sheets i'd be interested in seeing them, i think there could be 5% hp and more than that in TQ
Also its Much better to tune the engine in 3rd because thats where the engine see its highest load over a much longer period, In fact it would be better to just dial in the tune separate for all gears, probably take too much time though



Unless you have a load dyno like myself. A low powered car with 2.73's will overheat the motor trying to do 1-1 dyno pulls. 2nd gear is safer on a setup like that and they have plenty of load. The numbers will be lower in 2nd, but they are only the dyno numbers, not the engine.

^ agreed. if you have 150 hp and a 2.73, you are lucky to make a full pull. I wonder if anyone has tried dynoing a malibu wagon or old trans am that had 2.41? gear in them

We dyno'd a honda once. Started the pull, went out and got coffee, came back and it was 1/2 way done..LOL

We dyno'd a honda once. Started the pull, went out and got coffee, came back and it was 1/2 way done..LOL

Now that's some sig worthy shit right there! :D

^ :lol:

The car made 368rwhp and 342rwtq on a mustang dyno.

I'll let everyone know what it does when the rear end is done and can do a 1:1 pull