New dyno numbers (down with Dynapack, long live Dynojet :D )

[Guest bastaad525]

whoa hey dig it someone posting here NOT raggin me for posting it.....

 

 

I don't know how you guys were taking such a wrong intention from this thread to begin with.

[Drax240z]

Bastaad, it is't that we are ragging on YOU per se, it's that the information in the first post is quite typical of peoples (mis)perceptions of dyno's. That they give an absolute horespower and torque measurement. You said:

 

I compared, for instance, the torque and power numbers at 4200rpm (right about where the torque peaks). On the dynojet, it's at 269 lb ft at 4200rpm, on the Dynapack, 248 lb ft at 4200rpm.

 

At that same RPM, the Dynojet shows 208rwhp. The Dynapack shows 220rwhp... whaaa?? The Dynojet shows 20 MORE lb ft of torque but 12 LESS hp at the given rpm? Given that hp is just a derivative of torque, the number being determined by throwing the torque number into a set math equation... this totally does not make sense. Really odd... I'm gonna find that math equation and figure out which one is actually wrong...

 

EDIT: looks like the dynapack is the one that's off... 248 ft lbs x 4200rpm divided by 5252 is 198rwhp, not 220 like the dynapack graph shows. And the hp peak should read more like 210rwhp on the dynapack as well, if I'm figuring correctly. That seems really low considering I made 200 at 10psi w/o an I/C... with the I/C and 12psi and 99% identical air/fuel ratios I shoulda gained more than 10hp Unless the Hp number is right and the torque number is actually the wrong one??

 

I think everyones point is that neither of them are "wrong", they are just different. You can't expect results between 2 different dyno's, or 2 different days to make sense when compared with each other.

[Guest bastaad525]

No dude...

 

 

please would someone read the whole thing??? PLEASE?

 

 

the dynopack numbers are WRONG. It's NOT that they are too low, or too high for that matter... I'm NOT trying to compare the numbers between the two and saying that because the dynapack had lower numbers it must be wrong.

 

Look I'm gonna spell this out again. ANY dyno gives numbers based on the same principle. It measures one aspect (either only torque, or only hp... there is some confusion it seems as to which of these is actually, directly measured).

 

It then takes THAT number, and puts it into the equation we all know:

 

torque x rpm / 5252 = hp

 

But the dynapack numbers do NOT fit in that equation. They are way off, and I"m not talking in any way, in comparison to the dynojet... the dynapack was off with it's own numbers. You guys keep going on saying that the numbers will never match between two different dynos, but no matter what the situation, what dyno you test on, what the temperature was outside or WHATEVER, the numbers HAVE to fit in that equation above, PERIOD. The dynapacks numbers are wrong because they don't match with THEMSELVES.

 

Now... I know I write long posts and maybe you guys dont want to read the whole thing... hopefully you're still following along by this point... I will give an example from the dynapack and dynojet at... I dunno... 4000rpm... maybe you guys will finally see WHAT exactly my complaint is.

 

Okay... first the dynojet:

 

228hp and 300ftlbs at 4000rpm on the graph

 

Now put those into the equation:

 

300ftlbs x 4000rpm / 5252 = voila.... 228 and change

 

exactly what it's supposed to be

 

Now, the dynapack:

 

200hp and 243ftlbs at 4000rpm on the graph

 

Put that into the equation and....

 

243ftlbs x 4000 / 5252 = 185!!!! BZZZZZZZZZ NO MATCH!!!

 

This discrepancy is present on ALL SIX of the runs which I have the printouts for. I called the guy over at the shop and pointed this out to him and not only could he not explain to me why this might have happened, he wouldn't even humor me, but rather said that was how it was supposed to be, that I didn't know what I was talking about and that there's no way his dyno could be wrong. The dynojet numbers may not be 'right' in that they may not be an accurate representation of what power my car is making, but it's correct in that the numbers make sense the way they are supposed to.

 

By the way, I have figured this has GOT to be a problem with how the dynapack measures RPM... it doesn't do so directly with a magnetic pickup on a spark plug wire, like the dynojet does.

 

Do you guys get it NOW??? PLEASE? Sorry if I'm snapping here but this is very frustrating... it just seems like you guys somehow keep missing the point I was trying to make.