Drivetrain losses
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Drivetrain losses
This relates most specifically to the 24 valve HO engines and drivetrain.
In cars, in past years, the commonly accepted drivetrain power losses were expressed as about 15% for manual transmissin vehicles, and nearer 20% for automatics.
Now with these later TRUCKS, as we dyno them, how do we convert power losses relative to the various drivetrains - anyone seen any reliable data? *I* would think that with much larger and massive drivetrain conponents, gearboxes, etc, there would be significantly more parasitic drag.
We have:
1. HO, 6-speed manual
2. HO, 6-speed, 4WD
3. HO, 6-speed 4x4
4. Standard 24 valve, with all the above variations, 5-speed tranny
5. Automatic, with all the above variations
LOTS of different power loss variables there - anyone have a clue as to assigning reasonable power losses to each?
In cars, in past years, the commonly accepted drivetrain power losses were expressed as about 15% for manual transmissin vehicles, and nearer 20% for automatics.
Now with these later TRUCKS, as we dyno them, how do we convert power losses relative to the various drivetrains - anyone seen any reliable data? *I* would think that with much larger and massive drivetrain conponents, gearboxes, etc, there would be significantly more parasitic drag.
We have:
1. HO, 6-speed manual
2. HO, 6-speed, 4WD
3. HO, 6-speed 4x4
4. Standard 24 valve, with all the above variations, 5-speed tranny
5. Automatic, with all the above variations
LOTS of different power loss variables there - anyone have a clue as to assigning reasonable power losses to each?
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Re:Drivetrain losses
[quote author=emjay link=board=4;threadid=15327;start=0#144067 date=1054348758]<br>Do you think that the figures for automatics do not take into account the TCC?<br>[/quote]<br><br>Shucks, *I* am still trying to find out what the figures ARE - let alone what they apply to! ;D ;D
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From: El Dorado Hills, CA
Re:Drivetrain losses
Well, I don't have an answer for that, but like you said, there are lots of variables, like shaft speeds in the transmission/transfer case, the viscosity of the oil, and for automatics, whether or not the TCC is locked, and the power required to pump the oil throughout. I suppose it could be calculated thermodynamically, but that sounds like a lot of work!
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Re:Drivetrain losses
Best approach available so far, is comparing what Cummins claims as stock flywheel HP, to what the average stock truck dynos... In my case, my stock HO dynoed at 204 HP at the rear wheels - 20% less than the claimed flywheel HP... Pretty unscientific tho'... And that's with a manual tranny and 2 WD - start introducing other power draining items like 4WD and such, and I would imagine you could hit 30% drivetrain losses pretty easily...
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From: Sandy, Utah
Re:Drivetrain losses
[quote author=Gary - KJ6Q link=board=4;threadid=15327;start=0#144085 date=1054350500]
Best approach available so far, is comparing what Cummins claims as stock flywheel HP, to what the average stock truck dynos... In my case, my stock HO dynoed at 204 HP at the rear wheels - 20% less than the claimed flywheel HP... Pretty unscientific tho'... And that's with a manual tranny and 2 WD - [/quote]
Well, that's a start.
My non-HO stock 2002 auto tranny 4x4 dynoed at 205 HP.
Two modifications might have scewed that number though,
35 inch tires and no muffler.
I'm thinking about dynoing with the stock tires back on in September for comparison, still with no muffler.
(gonna put them back on for the drag race portion of the get-together, so why not, maybe do both on the same dyno the same day for a real head to head competition)
phox
Best approach available so far, is comparing what Cummins claims as stock flywheel HP, to what the average stock truck dynos... In my case, my stock HO dynoed at 204 HP at the rear wheels - 20% less than the claimed flywheel HP... Pretty unscientific tho'... And that's with a manual tranny and 2 WD - [/quote]
Well, that's a start.
My non-HO stock 2002 auto tranny 4x4 dynoed at 205 HP.
Two modifications might have scewed that number though,
35 inch tires and no muffler.
I'm thinking about dynoing with the stock tires back on in September for comparison, still with no muffler.
(gonna put them back on for the drag race portion of the get-together, so why not, maybe do both on the same dyno the same day for a real head to head competition)
phox
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Joined: Dec 2002
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From: Long Island, NY
Re:Drivetrain losses
jacobs electronic the maker of High performance ignition systems has book with a whole section on how to determine vehicle horse power without a dyno. it also explain how to determine how much horse power is gobbled up by ur drive train.
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Joined: Jan 2003
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From: The "real" Northern CA
Re:Drivetrain losses
I know that it takes around 50 HP to run a Turbo 400 trans. I was under the impression it took a lot less to turn a manual. The differential takes a lot of power though. I dont think the transfer case takes any real amount of power. All you are doing there is just shooting straight through it. The real drag is having to turn some part of the front driveline while cruising in 2wd.
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Joined: Nov 2001
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From: Heber, Utah
Re:Drivetrain losses
Gary, where do you come up with these brain busters? 
I think, you have answered your own question with your truck on a dyno....I have seen, witnessed approx. 400 dyno runs, with various stock trucks on Edges test dyno in Odgen, Utah over the past years, not including events outside. I've seen you take 2 -3 identical stock trucks, all manual or all auto, same dyno sameday, and HP will vary between 10-15 HP, high and low. In one case, a guy had a 25HP difference...Brett at Edge tells me, he'll see that about 1 in 1000 trucks....That's the one you want!!!
On average, 15-20% whether auto or manual, seems to be the power loss from flywheel to rear wheel. I'm not sure if that increases with bombing or not because there are too many variables, and some trucks again perform better then others with the same up-grades ie., injectors, fueling boxes. I would guess, if your trans (auto or manual) does not slip, the same power loss % would be the same as stock levels. I do know the guy that owns the 2000 CDT that power levels "stock" is 25hp more then it should be, and even with his bombing, he has continued to keep that amount of edge over others. I guess sometimes you can get lucky and find that 1 in a 1000.
Steve
P.S. Phox..When we last dynoed at "phantom", I'm not sure if the the results were after a correction factor, or without a correction factor. At our altitude ( I'm not sure about the exact number) but if the correction factor was say 1.05 then if someone dynoed 200 x 1.05 the corrected HP number would be, 210 HP. I'm not sure if the rear wheel tire size makes any difference on a Dynojet, but at a race track, tire size, width, tread pattern would play a big part in launching. I'll call Larence at Diesel Dynamics next week, and see if tire size afffects HP results? I would love to see you change about 10 sets of tires on a dyno, to squeezeeee that HP.
Besides, your truck is too bad looking to put on some 245x75x16's white walls. 8) 8)
I think, you have answered your own question with your truck on a dyno....I have seen, witnessed approx. 400 dyno runs, with various stock trucks on Edges test dyno in Odgen, Utah over the past years, not including events outside. I've seen you take 2 -3 identical stock trucks, all manual or all auto, same dyno sameday, and HP will vary between 10-15 HP, high and low. In one case, a guy had a 25HP difference...Brett at Edge tells me, he'll see that about 1 in 1000 trucks....That's the one you want!!!On average, 15-20% whether auto or manual, seems to be the power loss from flywheel to rear wheel. I'm not sure if that increases with bombing or not because there are too many variables, and some trucks again perform better then others with the same up-grades ie., injectors, fueling boxes. I would guess, if your trans (auto or manual) does not slip, the same power loss % would be the same as stock levels. I do know the guy that owns the 2000 CDT that power levels "stock" is 25hp more then it should be, and even with his bombing, he has continued to keep that amount of edge over others. I guess sometimes you can get lucky and find that 1 in a 1000.
Steve
P.S. Phox..When we last dynoed at "phantom", I'm not sure if the the results were after a correction factor, or without a correction factor. At our altitude ( I'm not sure about the exact number) but if the correction factor was say 1.05 then if someone dynoed 200 x 1.05 the corrected HP number would be, 210 HP. I'm not sure if the rear wheel tire size makes any difference on a Dynojet, but at a race track, tire size, width, tread pattern would play a big part in launching. I'll call Larence at Diesel Dynamics next week, and see if tire size afffects HP results? I would love to see you change about 10 sets of tires on a dyno, to squeezeeee that HP.
Besides, your truck is too bad looking to put on some 245x75x16's white walls. 8) 8)
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Re:Drivetrain losses
;D ;D ;D<br><br>ACTUALLY, *I* would think that once various driveline losses have been established over a given RPM range, they would remain pretty constant - in other words, if a 100 HP engine lost 20% thru its drivetrain to its rear wheels, for a dyno reading of 80 HP, doubling the engine's HP to 200 HP *should* still reflect pretty much the same 20 HP loss, for a new dyno reading of 180 HP or so - of course, there WOULD be SOME additional losses due to increased torque and friction losses, but overall, pretty minimal I would think - main point being, I wouldn't think the same 20% applies completely across the potential HP increase curve...<br><br>BUT, I'm sure some sharpie will correct the error of my logic if I'm wrong...
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From: Sandy, Utah
Re:Drivetrain losses
[quote author=HeberRam link=board=4;threadid=15327;start=0#144141 date=1054365687]
P.S. Phox..When we last dynoed at "phantom", I'm not sure if the the results were after a correction factor, or without a correction factor. At our altitude ( I'm not sure about the exact number) but if the correction factor was say 1.05 then if someone dynoed 200 x 1.05 the corrected HP number would be, 210 HP. I'm not sure if the rear wheel tire size makes any difference on a Dynojet, but at a race track, tire size, width, tread pattern would play a big part in launching. I'll call Larence at Diesel Dynamics next week, and see if tire size afffects HP results? I would love to see you change about 10 sets of tires on a dyno, to squeezeeee that HP.
[glow=red, 4, 400]Besides, your truck is too bad looking to put on some 245x75x16's white walls[/glow]. 8) 8)
[/quote]
That said by HeberRam is a real compliment.
Maybe width would be the only factor, as more tire is holding on to the rollers, less slippage perhaps.
phox
P.S. Phox..When we last dynoed at "phantom", I'm not sure if the the results were after a correction factor, or without a correction factor. At our altitude ( I'm not sure about the exact number) but if the correction factor was say 1.05 then if someone dynoed 200 x 1.05 the corrected HP number would be, 210 HP. I'm not sure if the rear wheel tire size makes any difference on a Dynojet, but at a race track, tire size, width, tread pattern would play a big part in launching. I'll call Larence at Diesel Dynamics next week, and see if tire size afffects HP results? I would love to see you change about 10 sets of tires on a dyno, to squeezeeee that HP.
[glow=red, 4, 400]Besides, your truck is too bad looking to put on some 245x75x16's white walls[/glow]. 8) 8)
[/quote]
That said by HeberRam is a real compliment.
Maybe width would be the only factor, as more tire is holding on to the rollers, less slippage perhaps.
phox
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From: Heber, Utah
Re:Drivetrain losses
Phox...my girl friend always said, width does make a difference. As a matter of fact I ran into Danny Waldon in Odgen yesterday, we call him "grampa rabies" because he is a real funny guy and always doing and testing stuff to his truck. 
Anyway, he did the very samething your questioning Phox, about tire sizes on a dyno and did so on Diesel Dynamics a week ago.. He stepped up 2 sizes from stock (he has a "purple" dually) dynoed before, and after with the new tires and was within 2-3 hp less after the tire change over. Danny's truck is one bad *** "sleeper 12v" doing 545hp on diesel. His biggest obsession, is to beat Dee Rawson, whatever it takes!! ;D ;D Watch-out for "grampa" in a PURPLE dually....
Gary, I can see you won't sleep, until you get your answer.. :
: When I call Larwence, I'll see if he can shed some facts to your question..Lawence, has dynoed everything, from sport bikes, lawn mowers, UPS turcks, CTD's, RV's, you name it and if it can spin a Dyno-Jet he's done it. 
Steve
P.S. Phox, yesterday I bought a new set of tires, went from 305-70-16 to 315-75-16 , Pro-comp Xtreams. With my 16X8 after-market rims, and a 2"- leveling kit, I thought NO problem!! "Well", I had to pound the metal on the front wheel- well back panel to death, and now clears maybe a-1/32". Have to drive straight only, no turns, no bumps , no mud, no snow.... :'( :'(
As a matter of fact I ran into Danny Waldon in Odgen yesterday, we call him "grampa rabies" because he is a real funny guy and always doing and testing stuff to his truck. Anyway, he did the very samething your questioning Phox, about tire sizes on a dyno and did so on Diesel Dynamics a week ago.. He stepped up 2 sizes from stock (he has a "purple" dually) dynoed before, and after with the new tires and was within 2-3 hp less after the tire change over. Danny's truck is one bad *** "sleeper 12v" doing 545hp on diesel. His biggest obsession, is to beat Dee Rawson, whatever it takes!! ;D ;D Watch-out for "grampa" in a PURPLE dually.... Gary, I can see you won't sleep, until you get your answer.. :
: When I call Larwence, I'll see if he can shed some facts to your question..Lawence, has dynoed everything, from sport bikes, lawn mowers, UPS turcks, CTD's, RV's, you name it and if it can spin a Dyno-Jet he's done it. Steve
P.S. Phox, yesterday I bought a new set of tires, went from 305-70-16 to 315-75-16 , Pro-comp Xtreams. With my 16X8 after-market rims, and a 2"- leveling kit, I thought NO problem!! "Well", I had to pound the metal on the front wheel- well back panel to death, and now clears maybe a-1/32". Have to drive straight only, no turns, no bumps , no mud, no snow.... :'( :'(
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Joined: Jun 2002
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From: West Jordan, Utah
Re:Drivetrain losses
I'm thinking that tire size isn't going to affect the numbers as much as tread design, inflation pressures, etc. The best way to test is by using 2 different sizes of the very same tire design. <br><br>Can't you measure driveline losses in the form of heat? That's go to be where most of the loss is going.<br><br>Are we going to see a "Phox" lift job on Heber's truck soon?
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From: Sandy, Utah
Re:Drivetrain losses
[quote author=HeberRam link=board=4;threadid=15327;start=0#144527 date=1054484882]<br>P.S. Phox, yesterday I bought a new set of tires, went from 305-70-16 to 315-75-16 , Pro-comp Xtreams. With my 16X8 after-market rims, and a 2"- leveling kit, I thought NO problem!! "Well", I had to pound the metal on the front wheel- well back panel to death, and now clears maybe a-1/32". Have to drive straight only, no turns, no bumps , no mud, no snow.... :'( :'(<br>[/quote]<br><br>Yup, exactly what I did.<br>Got the rims and tires and the 2-inch leveling kit.<br>Straight driving only, really wide semi-like turns.<br>Had to go to the 4.5 inch kit, now turns like a charm.<br><br>I think a 5inch lift would look just perfect on your truck.<br>I suggest either Tuff Country or Mr. Cepek, the skyjacker is a bit harsh of a ride.<br><br><br>phox