Running A/T Diesels on Dyno

[mperkins40]

Running Diesels on a Dyno

I took my 98 quad to a local speed shop that had a dyno. After the test I was questioning the results. He said that my truck produced 169 HP and 592 Ft/Lbs Torque. Since I have a 180 engine and a TST #8 plate (230/605) I feel that the results were inaccurate. Especially the way the power graphs were. The torque was measured at peak HP not after like all of the other diesel graphs that I have seen where torque peaks after peak HP.

(Actual Graph is Attached as JPEG)



The tech then said that he had to do the whole test in second gear because with my A/T my vehicle down shifted every time he added a load. He said with Manual Transmissions you can control the shifts. He said if there is a better or different way to do it that he would re-run the test for free.



Does doing the test in 2nd produce different results. If so, can anyone help me out.



Their website is http://www.totalperf.com/Dyno.html if needing to know what dyno they use.



Thanks Guys



Mike

 

[mperkins40]

I took my 98 quad to a local speed shop that had a dyno. After the test I was questioning the results. He said that my truck produced 169 HP and 592 Ft/Lbs Torque. Since I have a 180 engine and a TST #8 plate (230/605) I feel that the results were inaccurate. Especially the way the power graphs were. The torque was measured at peak HP not after like all of the other diesel graphs that I have seen where torque peaks after peak HP.

(Actual Graph is below)



The tech then said that he had to do the whole test in second gear because with my A/T my vehicle down shifted every time he added a load. He said with Manual Transmissions you can control the shifts. He said if there is a better or different way to do it that he would re-run the test for free.



Does doing the test in 2nd produce different results. If so, can anyone help me out.



Their website is http://www.totalperf.com/Dyno.html if needing to know what dyno they use.



Thanks Guys



Mike



http://mperkins40.tripod.com/dodgedyno.html

 

[KLockliear]

You want to make the runs in OD with the converter locked. Usually, this means starting the run between 1900-2000rpm (about 65mph w/3. 54 gearing and stock tires).



At that speed/rpm, the TCC will stay locked and it will not downshift.



A dyno run made in 2nd gear will show a lot less power, plus the TCC is not locked, so you also get all the slippage from that. The run is bogus.



Go find yourself a Dynojet dyno to play on.



Here is a list of them in Maryland: Maryland Dynojet Dyno Owners List

 

[lmills]

Yeh, the dyno tech botched something up. He shouldn't have dynoed it in 2nd and you should have more HP than that

 

[HEMI®Dart]

mperkins40,



I think the trick to dynoing an A/T truck is to get it high gear and lockup the torque converter. I think this is a must.

 

[KLockliear]

See your other thread.

 

[lmills]

Hey MPerkins40 are you located around Mt Airy? I work in Damascus and run through Mt airy everyday

 

[Gary - K7GLD]

I assume the TC is not capable of lockup in direct gear? Seems that doing the dyno bit in OD would also be a bit slanting on readings, but if that's all ya got to work with...



Also, I personally feel the power curves displayed, especially on a dyno that can't fully load the engine will be significantly lower than the truck is capable of IF it was fully loaded - both times mine was dynoed, the boost never came even close to maximum, as it does at the same speeds when towing in the hills - and would be reasonable to assume maximum power is not being registered on those dyno runs - but ya gotta start somewhere - and at least yer in the same boat as other similar trucks for the sake of comparisons or changes between runs...

 

[mperkins40]

Originally posted by lmills

Hey MPerkins40 are you located around Mt Airy? I work in Damascus and run through Mt airy everyday

Yeah I live on the west side of Frederick Co. in Middletown. Nice guys at the speed shop but I think I wasted $75. I even asked before I went if they did diesels. Then during the test I told to make sure their monitoring my EGT guage when doin runups. He had no idea that 1300 F was too hot.



Mike

 

[mperkins40]

T/C Locked

So basically what you guys are saying is that the T/C needs to be locked. Should the truck just be put into Drive and run until it is in 4th w/ OD, then apply the load (terminology the dyno tech said that the truck down shifted everytime he applied a load). Then accellerate until it shifts back into 4th. Or run it in Drive with O/D off then turn O/D on? Then how long should it be run until max torque is displayed?



PS I have 4:10 gears

 

[HEMI®Dart]

Originally posted by mperkins40

Nice guys at the speed shop but I think I wasted $75.

Mike

Mike,



Print what Keith from Diesel Dynamics said (or this thread) and see if you can get a free re-test.

 

[lmills]

Originally posted by mperkins40

Yeah I live on the west side of Frederick Co. in Middletown. Nice guys at the speed shop but I think I wasted $75. I even asked before I went if they did diesels. Then during the test I told to make sure their monitoring my EGT guage when doin runups. He had no idea that 1300 F was too hot.



Mike

Oh OK. I know where you are. We have a couple jobs we are getting ready to do up there. One in Braddock, the other is off of Middletown Parkway. I live even further west up in Hagerstown. I work out of an office in Damascus.



Maybe you should do what other said and try to get them to re dyno it for free. If not, maybe you could hold off till our next dyno event. I think the guys are talking about having one in Februaury. We usually have some nice high HP trucks show up to spin the rollers.

 

[KLockliear]

Put the truck in drive, with the OD engaged, then drive it up through the gears until you feel all 3 shifts, and the TCC lockup. Then, go full throttle and see if it downshifts or unlocks. If it does, repeat starting at a higher RPM until you find the spot where it will not downshift or unlock.



Make your run from there. I'm not overly familiar with the Mustang dynos, but you want them to put in a load amount and do a "sweep test".