Wierd Dyno run

[Nashiva]

I didn't really know which forum to post this on, so I picked this one. If there is another one I should have posted on, just let me know. Having said that, I just recently had a dyno session, making a couple 1st, 2nd, 3rd, and 4th gear passes. NONE of the numbers made sense, no one could figure it out. My 3rd gear dyno run is posted in my profile, 147.4 whp and 445.3 ft./lbs of torque. I realize that 3rd gear is a reduction gear, but it still makes no sense what so ever, why would I be pulling so little whp, and so much torque? For those who are a bit too lazy to look, I drive a 95' GS-T, with only basic mods. Any ideas?

 

[WICKEDTEEN84]

that dyno must be totally screwed up

 

[hystericfox]

With a horsepower to torque ratio like that, he must have the limited "GS-TDI" edition. The dyno must have been out of whack, diesels are the only think i know of that split numbers like that.

 

[91PlyLaser]

always knew Mustang dynos showed lower HP numbers but damn.. this one is off the wall...hopefully the shop didnt make you pay for it...

 

[DSMvroom]

i have interesting numbers as well but not as dramatic as yours.

 

[aero_sallee]

Something was messed up with the dyno, or the settings they were using. They probably did not have the dyno set up for your car's gear ratios.

 

[mirkoelek]

the thing is, you had no traction on the dyno.....maybe your wheels were wet or oil.... torque you measure totaly different than hp. HP = force.... torque = change of force. so you couldnt get enough force on the wheel because they were spining, and you could get a lot of torque because change was huge when you spining. go figure

 

[SpoOLxExO]

Dyno pulls are usually run in 4th on a 5-speed car, and 4-5th in a 6-speed.

Do you still have the t-25? Because there is NO WAY that a t-25 will belt out 440ft/lbs no matter what.

You need to make another pull in 4th, and make sure that the dyno operator has "SAE" correction factor for 2wd.

Try it again, this dyno sounds mega mis-calibrated.

 

[Nashiva]

Thank you,
Since the dyno is at my school (Denver Automotive and Diesel college) it's free. I'll make another 4th gear pass and let you know what I turned up.

 

[noz]

LoL
those numbers are funny. you need to re dyno that car.

 

[95blackGsTurbo]

Maybe you got the numbers backwards and it's 445 horsepower and 147 ft. lbs. or torque. At least that's what it would be if you were driving a Honda

 

[dnhieu]

Maybe you got the numbers backwards and it's 445 horsepower and 147 ft. lbs. or torque. At least that's what it would be if you were driving a Honda

hey he drives a mitsubishi not a honda HAHAHAHAA

 

[crankbender]

the thing is, you had no traction on the dyno.....maybe your wheels were wet or oil.... torque you measure totaly different than hp. HP = force.... torque = change of force. so you couldnt get enough force on the wheel because they were spining, and you could get a lot of torque because change was huge when you spining. go figure

No No No.....

Anyway I won't even try to break down that up there I will just start from scratch.

Basically torque is how hard the engine is trying to turn. Much like torque from a torque wrench (hence the name). This is a measure of how much force it would take to counter act the engine multiplied by the radial distance for this force...that is where we get foot-lbs.

Now power is basically that torque times the angular velocity. In metric units this works out exactly into KW in english units we have a correction factor to get HP. However you cut it torque and horsepower are always intertwined.

Now because of what I stated above the dyno is trying to coorelate how hard you are pushing by the acceleration of the dyno itself (or the engine depending on model) and the current speed of the rollers (or engine again). This means if the dyno thinks you are going much slower than you currently are they will give you a very low hp number. If the dyno suddenly starts reading speed correctly (a slip between the meter measuring RPM and the dyno roller) it will show huge torque numbers and low HP numbers.

Basically I am telling you that the dyno is either broken or not set up for your car...Since the dyno is at a diesel college it is likely that the setup is incorrect. Since you can't read the RPM of a diesel as easily they may use the speed of the rollers and have an imput for the tire size (look here first). Most TRUCKS (note big trucks) have the same size tires so you may not be able to adjust this.



*EDIT* I might add that if you post the graphs I may be able to rule out some possible problems.