So explain how his TQ can be super high and his HP is still real low. I did read the SCC article but it never mentioned that I don’t think. They should be related. Also, the guys running the Mustang dyno were not even hooking up the rpm sensor. That seems real sloppy if you ask me just to save about 1 minutes time. You pay $40 you should get a accurate rpm reading as well. I guess that last bit has nothing to do with the dyno type argument just the sloppy nature of the dyno operators at that one event. Oh, and I am not trying to be a jerk about this. You seem to know something about this whole thing.

 

I agree that before balluzos dyno shop was innacurate. They have gotten new programing for the dyno. A dynojet IS NOT as accurate as a mustang (using wideband). Call Balluzo @ 825-6647. Ask for Todd, Tim or george. I don't know the mathmatical formula to prove/explain it. I will try to find it though....

 

I will say that the Dynojet is a very simple device. Basically your car accelerates a drum with a known mass (ie:weight). The quicker your car can accelerate the drum the more torque your car produces. It does not require any calibration to perform the simple task. All it does is plot on a graph how quickly your car accelerates the drum. The software in the computer then calculates the HP and TQ based on how quickly your car accomplishes this task. The computer has the ability to gather humidity, temperature and other information to allow you to compare your results on different days with different temperatures. This is where most dynojets vary a small amount. The operator has the option of choosing from several different programs to perform this task. It would seem that the mustang dyno is a much more complicated device then just a big heavy drum with a speed sensor attached to it. I think it has the ability to vary the amount of resistance given to the wheels and can perform a variety of different type of test. It would seem that the Mustang dyno has the greater potential for discrepancies to occur due to the nature of it being more complicated device. When you are talk accuracy you need to specify what you mean by this. Are you talking about repeatability of data from one run to the next, repeatability of data from one day to the next or accuracy of HP to the wheels in comparison of HP to the crank.

 

they told me i have 174 HP and i forgot the torque number but it was real high on the mustang dyno.

 

when a mustang dyno takes readings it is more accurate to what you're putting on the ground.
http://www.mustangdyne.com/ChassisDyno/chassisdynos.htm
check that out. It doesn't explain it as well as i'd like though. Dynojets are simple and there isn't much to go wrong....i agree with that. I'd rather tune on a mustang though. Not sure if a dynojet can do partial loads and partial throttle.

 

"Ignorance Is A Voluntary Misfortune"

 

It can't.

 

thats one of its advantages.

 

And I guess only the ignorant would know that.

Actually the G-Tech was right on the money friday night at VMP. It was off in the hundredths of a second. On one of my runs the timeslip read 13.36 while the g-tech read 13.39.

 

gtech is pretty accurate.