dyno data from emissions testing

[rockbender]

My '84 E350 w/ 6.9 came from Colorado where it is mandatory to undergo emissions testing. Going through an old vehicle inspection report I notice that it had some dyno information on it and was hoping someone might help me understand what it means.

At 59.9 MPH, it shows 110.6 whlpwr HP and 1113 GrndTq Clb-ft

At 49.7 MPH, it shows 97.5 whlpwr HP and 1183 GrndTq Clb-ft

At 39.7 MPH, it shows 90.4 whlpwr HP and 1373 GrndTq Clb-ft.

I'm using the exact abbreviations on the sheet hoping someone might be able to help explain the torque values. The rear wheel HP, though low, isn't too unrealistic. How do the torque values translate to something understandable?

I'm not sure if the OD unit was engaged or not for testing, or whether it matters. Also, this was obviously a test for emissions, not a flog it and fill the room with black smoke test for max power so that may make a difference too.

 

[RANOVRU]

A Google & Wiki search of "GrndTq Clb-ft" revealed nothing.

Its probably something stupid since it was for emissions but Im intrigued...

 

[88 Ford]

Got me on that man. Idk what that means. I'm kinda guessing but GrndTq I'm sure means torque to the ground but I wonder what calculation difference is between a regular torque reading? There has to be some kind of formula. Have you called and asked the place that did the emissions test?

 

[Sw1tchfoot]

I'm sure means torque to the ground but I wonder what calculation difference is between a regular torque reading??

Well the rear axle is multiplying the torque by 4.10 times from the driveshaft to the axle shafts right? Then there is the drivetrain loss since it takes power to move all those parts.

 

[George D.]

Thats wierd on the emmissions dynos here in nv we take it to 45mph and on the older sheets it showed HP and mine was like 30-50hp don't remember but definatly alot lower than 90 but they could be useing two compleetly difrent set ups. But the hp should be the hp to keep the dyno turning at that MPH and torque would be the torque for it odviously reads much higher than a performance dyno.

 

[George D.]

As for GRNDTQ CLB-FT My guess would be ground torque cubic pound feet?

 

[Wyreth]

CLB-FT, stands for Corrected Pound Feet, or corrected torque.

It looks like GRNDTQ is the acronym for the correction factor. I'm more used to seeing STPTrq, which is: Standard Temperature and Pressure. (sea level measurement) So the dyno is using some other correction factor to tare it's measurements. Not surprising for a smog dyno I guess. Prolly local temp pressure average for the area.

 

[rockbender]

Thanks guys. I kept thinking that the 'C' was a factor of 100 somehow as it is commonly used, but couldn't make the numbers work. Corrected wheel torque sounds like the best answer, and I assume that using the final gear ratio multiplier (4.10 in my case) puts me in the neighborhood of 325 lb-ft which I suppose is about right.