S2K23

After reading about the different dynos available, I wanted to know if the +HP gain is the same on all the different dynos out there.

For Example:

DynaPack - 233HP --> 243HP
DynoJet - 215HP --> 225HP
Dyno Dynamics 200HP --> 210HP

Is that +10HP increase the same +10HP on all of them. Or is it all different?

So if that is true.... can you say that a certain mod will give you 10HP no matter what Dyno your using, as long as you have the baseline # and the dyno number after the mod. Just wanted to clear it up. Thanks

qbmurderer13

If you used the same dyno before and after the mod then it will be valid. But if you baseline on a mustang at like 190whp, add an exhaust and go do a dyno at a dynapack, you get people start saying they gained 20whp from this or that mod. The only way to get accurate results is to use the same dyno you baselined on. Every dyno reads differently.

Neutered Sputniks

I'm curious about this: since Dyna-pack dynos are at the hub and eliminate wheel/tire slip (which is the argumet for why they have higher readings), wouldn't that mean that even if you went back to the same roller-type dyno, you might not get accurate gain readings? I mean, if tire slip is enough of an issue that you would expect to have a 10-15hp difference between a measurement taken at the wheel and one taken at the hub, then how would you be able to tell if that 5-10hp gain is not just the tires gripping better?

qbmurderer13

Im not exactly sure if tire slippage IS the exact reason that dynapacks read higher, but thats why 90% of the time the only valid results will be back-to-back dynos without even getting the car off the dyno to see the results of the mod.

I mean if you drive your car for say 4,000 miles after you last base dyno, your tires are going to have less traction and slip more, even if it is on the same dyno, so that could affect the numbers. Someone else with more knowledge on dyno tire slip should chime in on this. I know most dyno's have grooves on the rollers to help this kind of thing.

S2K23

With the comments about the tire grip and slippage... is it THAT much of a difference on a dyno?? I never knew that tire grip makes that big of a difference on the same dyno. But if someone with more details on it that would be helpful

Neutered Sputniks

If 2 laps on the track (at PIR) can make a difference in tire traction, couldn't the distance you drove to the dyno make a difference on how sticky your tires are? Even the speeds you drove to the dyno that day could affect the stickiness of your tires.

Hence the "same dyno, same day, without pulling the car off the dyno" for 'more' accurate differences...

But even then, there's no real measurement of how much tire slip you're getting on each pull... Especially not if we're talking a difference of 15-20 between a hub-type dyno and a roller-type dyno with no mods...

My point is: if there's that much of a margin of error that's acceptable, how would you know if you 5-10hp gain was really a hp gain and not a result of less slip (since it's well within the given margin of error)?

S2K23

Makes sense....

Spec_Ops2087

Tire slip is hardly EVER an issue on a dyno, if its an issue it shows on the dyno graph very clearly.

The difference between dyno-pack and roller type dynos is rotational mass difference between the wheels being mounted and not being mounted.

The reason why dynoing now and dynoing 4k miles later is different is because the conditions in which the car was dynoed are different. This is why dynos use STD or SAE smoothing to try and account for differences in temperature/altitude/humidity/etc but of course it is not 100% accurate.


The only accurate dyno is the delta horsepower and torque of back to back dynos. Who is to say one type of dyno is very accurate at showing horsepower numbers but yet another one isn't? The only thing they are accurate at is showing the difference between two numbers as that will never be different between dynos (again to a certain degree of dyno error).

S2K23

^^ So a +10HP that you gain is the same on all 3 dynos then.... correct? just that of course the numbers are gonna be different based on the dynos but the delta is the same which is the difference.

Spec_Ops2087

I won't say ALWAYS but a good amount of the time they are the same within a few percent random error.


Just for an example to prove my point:

Dyno jet: base=200hp, modded=210, so dhp=10

Dyno pack: base=230hp, modded=240hp, dhp=10

The only difference will be the actual hp numbers but the dhp should be the same across the dynos.