I'm going to the dyno that gives my car the most HP! I'll feel better that way! :rofl2:

Contact some of the board members, they have some great Paint dynos, best numbers yet. ;)

Well, in *theory*, the value of a a ft/lb of torque is based on international standards. Therefore any machine reading ft/lbs of torque from the spinning wheels of a car under the same loading conditions (meaning, some standardized approximate simulation of the weight of the car and aerodynamic load), with the same (hopefully minimal) wheel-slip error on the rollers, should read the same value.

I understand, to some degree, why the situation is as it is, but I think there is a "right answer" as to how much rwhp is actually being put out of the car, and I think the dyno mfgs could be doing a better job than they are of getting their results in line.

To add to Ryan's reply...

Hub dynos, such as the DynaPack, will be more consistent from test to test than roller dynos. With roller dynos, you can have differing air pressures in the tires, the dyno monkey can strap a car down harder one day and lighter the next, etc. Hub dynos remove at least that portion of the variability. What's left is a solid drive train that should give you results well within the statistical error range of the dyno itself (0.5-1%ish range). A roller dyno can easily give you errors in the 5% range if not set up consistently.

Whatever style you choose to take a baseline on, stay with it after modding to see what gains you achieved. If it's a roller dyno, I suggest 2-3 different days (with hopefully different guys setting it up) to average out inconsistencies in setup. Yes, this obviously gets expensive on a roller dyno, but if you want solid numbers you can either do it that way or go with a hub dyno. The same thing should be done after the mods are in place to see what was gained. If you go from one style to another, you need to take another baseline. Mustang dynos are notoriously low in numbers, but that doesn't mean they're wrong, and hub dynos are typically the highest values. You cannot compare one person's Mustang dyno to another's hub dyno run and expect to compare apples to apples.

Even then, taken the same day, within the same part of the day if possible.

thanks fellas for all your input. This is why I asked the question because I really didnt believe the loss myself. I will stick with one dyno the whole way through.

I dynoed my car on a Dynojet today and the weather conditions were 90 F 29.91 Hg. I don't think they used fans. My best run was 272.17HP and 221.93 Torque. Despite the weather conditions, doesn't that seem awful low?

No. That's in the range of stock whp on a DynoJet. It's not the highest but that could definitely be a result of the conditions.

And the mere variance of different dyno's, naturally.

:tup: Word.

What gear should be used when dyno testing? Is there a formula that you can use to adjust for weather conditions such as temperature, humidity & atmosphere pressure?

Some allow for things like these, but the best thing to do is either a) do the dyno tests on the same day b) try to recreate the weather conditions as best as possible.

For your 6MT, do it in 5th, as this is the 1:1 ratio and it's what others have been using. 7AT guys have to do it 4th at the highest, as we hit the stock speed limiter before we hit redline in 5th and higher, even though 5 is also our 1:1 ratio (we have a different rear end ratio, that's what makes the difference).

I believe I was told the dyno was done on 3rd or 4th gear. How does that affect the results?

If that's the case, the operator probably ran it in 4th, possibly under the assumption that it was a 5 speed. If it was run in 4th, you can probably add 5whp or so.