Finally the answer to driveline loss
04-15-2003, 06:59 PM
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Finally the answer to driveline loss Or maybe not...Let me share my thoughts on driveline loss with you. DISCLAIMER: I am not an expert, and have been wrong in the past. Good, with the legal issues aside, here it goes...
Take a stock Corvette which makes 300 RWHP. Say that same engine made 350 on the engine stand dyno right before you dropped it into your Corvette and had it dynoed, so you figure you lost 50 horsepower (about 15%) because you had to turn your flywheel, clutch, driveshaft, rear gear, axles, wheels and tires.
Ok, fair enough. You've just found out how much power it takes to turn that driveline. Now slap a 100 HP LS1 (sick, I know) engine in the car. Do you think that the car will dyno 50 RWHP, or 85 RWHP?
If you believe in the drivetrain % loss theory, then you should have answered 85 RWHP. But why does that make sense? That 100 HP engine still has to turn the flywheel, clutch, driveshaft, rear gears, axles, wheels and tires. Did the laws of physics get a memo from the engine shortly before the dyno operator let her rip requesting help to rotate the driveline with only 15 HP?
Now take the other extreme. We drop a 2000 Flywheel HP LS1 in your Corvette, and give it a run on the dyno. Do you think it will pull 1950 RWHP, or 1700 RWHP?
See where I am going with this? Why is it reasonable to believe that the same exact driveline takes 300 HP for a 2000 HP engine to turn, while only requiring 15 HP from a 100 HP engine? Did the driveline suddenly increase its mass by 20 times during the engine swap?
That is just rediculous. In the real world, a given driveline requires a certain amount to turn based primarily on mass and friction. Also, the 100 HP may lay down 45 HP, and the 2000 HP engine may lay down 1955 HP...who knows. The point is that the driveline losses are 'almost' linear. There are more variables to this equation, but they don't make that much difference...certainly not a direct relationship with engine output.
If there is a relationship, it is probably something like: L = X + Y , where
L is Total Loss in HP
X is HP it takes to turn the drivetrain
Y is 1% of actual engine output
so our engines in question may pull something like
100 HP engine - 49 HP
2000 HP engine - 1930 HP
That seems reasonable to me.
I say we should pick a number and stick with it, like 40 or 50 HP (I don't even know if it is even that high). We sound like a bunch of ricers saying, well my 420 RWHP engine really makes over 500 HP with 20% loss for my automatic.
Whatever. Why not just say, I make 420 at the wheels, or even, 470 if you figure 50 HP driveline loss.
I'd like to see everyone on this board get smarter as we learn from each other, not dumber because we keep spreading ignorance.
Take a stock Corvette which makes 300 RWHP. Say that same engine made 350 on the engine stand dyno right before you dropped it into your Corvette and had it dynoed, so you figure you lost 50 horsepower (about 15%) because you had to turn your flywheel, clutch, driveshaft, rear gear, axles, wheels and tires.
Ok, fair enough. You've just found out how much power it takes to turn that driveline. Now slap a 100 HP LS1 (sick, I know) engine in the car. Do you think that the car will dyno 50 RWHP, or 85 RWHP?
If you believe in the drivetrain % loss theory, then you should have answered 85 RWHP. But why does that make sense? That 100 HP engine still has to turn the flywheel, clutch, driveshaft, rear gears, axles, wheels and tires. Did the laws of physics get a memo from the engine shortly before the dyno operator let her rip requesting help to rotate the driveline with only 15 HP?
Now take the other extreme. We drop a 2000 Flywheel HP LS1 in your Corvette, and give it a run on the dyno. Do you think it will pull 1950 RWHP, or 1700 RWHP?
See where I am going with this? Why is it reasonable to believe that the same exact driveline takes 300 HP for a 2000 HP engine to turn, while only requiring 15 HP from a 100 HP engine? Did the driveline suddenly increase its mass by 20 times during the engine swap?
That is just rediculous. In the real world, a given driveline requires a certain amount to turn based primarily on mass and friction. Also, the 100 HP may lay down 45 HP, and the 2000 HP engine may lay down 1955 HP...who knows. The point is that the driveline losses are 'almost' linear. There are more variables to this equation, but they don't make that much difference...certainly not a direct relationship with engine output.
If there is a relationship, it is probably something like: L = X + Y , where
L is Total Loss in HP
X is HP it takes to turn the drivetrain
Y is 1% of actual engine output
so our engines in question may pull something like
100 HP engine - 49 HP
2000 HP engine - 1930 HP
That seems reasonable to me.
I say we should pick a number and stick with it, like 40 or 50 HP (I don't even know if it is even that high). We sound like a bunch of ricers saying, well my 420 RWHP engine really makes over 500 HP with 20% loss for my automatic.
Whatever. Why not just say, I make 420 at the wheels, or even, 470 if you figure 50 HP driveline loss.
I'd like to see everyone on this board get smarter as we learn from each other, not dumber because we keep spreading ignorance.
04-15-2003, 08:25 PM
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Re: Finally the answer to driveline loss I'm only a sophomore in highschool, so i don't know wtf you are talking about. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" alt="[evil]" title="" src="graemlins/gr_devil.gif" />
04-15-2003, 08:43 PM
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Re: Finally the answer to driveline loss He makes total sense. I think what happened was that it started out with everyone and there stock cars and we all saw the LS1 rated at 350 horsepower and on the dyno it lays down around 300. This is exactly 85%. So everyone thought the LS1 drivetrain loss is 85%. I cant think of any other way to explain it.
Thanks for reading
Rob
Thanks for reading
Rob
04-15-2003, 10:30 PM
#4
Re: Finally the answer to driveline loss Ok....a couple things to help you out.
If you put the car on jackstands so it is only turning the driveline and not moving any chassis weight and floor it with a 100 hp engine in it, it will take several seconds to accelerate the weight of the wheels and tires to redline. Now, that means that it takes (this is for the sake of example, not actual math figures) 100 hp to accelerate the weight of the drivetrain at an acceleration rate of say 1000 rpm per second. Makes sense, right. Apply 100 hp to move the wieght of the driveshaft, wheels, transmission, flywheel, etc and it will accelerate at X amount of rpm per second.
Now, do the same thing with a 2000 hp motor. It will likely hit redline in less than a second. The extra horsepower allows a faster acceleration rate than the previous example. Now, at this point you are accelerating all of the driveline weight from idle to 6000 rpm in less than a second. If takes more horsepower to accererate that weight at a higher rate of speed.
IF you are confused....try this one.
Take a bowling ball and just "roll" it down the lane. You can do this quite easily and it will get to the end of the lane. Right?
Now, take the same bowling ball, throw it as hard as you can. It will still get to the end of the lane, it just does so much faster (and you used alot more horsepower to move the ball, right?). In both cases you still covered the length of the bowling lane (the idle to 6000 rpm test), one just did it faster than the other and therefore absorbed more power in the process (throwing the ball really hard, you used more energy, to do the same thing....faster). That is the essence of driveline loss.
Or, take a bicycle and raise the rear wheel off the ground, grab a pedal with one hand and just easily crank the pedal, slowley accelerating the wheel. It takes little "power" to spin the wheel as fast as your hand can turn the pedals when you crank it up slowly (do this test in the highest gear on the bike). Now, crank it as hard as you can to get to top speed (by hand)....it takes alot out of you to spin it hard and accelerate it quickly. Did this make any sense? I'll try to clarify any questions I can.....
If you put the car on jackstands so it is only turning the driveline and not moving any chassis weight and floor it with a 100 hp engine in it, it will take several seconds to accelerate the weight of the wheels and tires to redline. Now, that means that it takes (this is for the sake of example, not actual math figures) 100 hp to accelerate the weight of the drivetrain at an acceleration rate of say 1000 rpm per second. Makes sense, right. Apply 100 hp to move the wieght of the driveshaft, wheels, transmission, flywheel, etc and it will accelerate at X amount of rpm per second.
Now, do the same thing with a 2000 hp motor. It will likely hit redline in less than a second. The extra horsepower allows a faster acceleration rate than the previous example. Now, at this point you are accelerating all of the driveline weight from idle to 6000 rpm in less than a second. If takes more horsepower to accererate that weight at a higher rate of speed.
IF you are confused....try this one.
Take a bowling ball and just "roll" it down the lane. You can do this quite easily and it will get to the end of the lane. Right?
Now, take the same bowling ball, throw it as hard as you can. It will still get to the end of the lane, it just does so much faster (and you used alot more horsepower to move the ball, right?). In both cases you still covered the length of the bowling lane (the idle to 6000 rpm test), one just did it faster than the other and therefore absorbed more power in the process (throwing the ball really hard, you used more energy, to do the same thing....faster). That is the essence of driveline loss.
Or, take a bicycle and raise the rear wheel off the ground, grab a pedal with one hand and just easily crank the pedal, slowley accelerating the wheel. It takes little "power" to spin the wheel as fast as your hand can turn the pedals when you crank it up slowly (do this test in the highest gear on the bike). Now, crank it as hard as you can to get to top speed (by hand)....it takes alot out of you to spin it hard and accelerate it quickly. Did this make any sense? I'll try to clarify any questions I can.....
04-15-2003, 10:34 PM
#5
Re: Finally the answer to driveline loss Did the driveline suddenly increase its mass by 20 times during the engine swap?
Nope, the weight remained the same, teh rate of acceleration of the driveline increased. It takes more hp to run 10's than to run 15's in the 1/4 mile. Same for spinning a driveline. (Maybe this makes more sense). You have the weight and RPM part correct, you just forgot to account for time (the faster acceleration rate).
And, 2000 hp puts lots of strain on the gears, and increases frictional losses (wasted as heat), etc.
I'm done....unless there are any questions....
Kevin
Nope, the weight remained the same, teh rate of acceleration of the driveline increased. It takes more hp to run 10's than to run 15's in the 1/4 mile. Same for spinning a driveline. (Maybe this makes more sense). You have the weight and RPM part correct, you just forgot to account for time (the faster acceleration rate).
And, 2000 hp puts lots of strain on the gears, and increases frictional losses (wasted as heat), etc.
I'm done....unless there are any questions....
Kevin
04-15-2003, 10:47 PM
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Re: Finally the answer to driveline loss </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by trackbird:
<strong> Did the driveline suddenly increase its mass by 20 times during the engine swap?
Nope, the weight remained the same, teh rate of acceleration of the driveline increased. It takes more hp to run 10's than to run 15's in the 1/4 mile. Same for spinning a driveline. (Maybe this makes more sense). You have the weight and RPM part correct, you just forgot to account for time (the faster acceleration rate).
And, 2000 hp puts lots of strain on the gears, and increases frictional losses (wasted as heat), etc.
I'm done....unless there are any questions....
Kevin </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">exactly, no one seems to know the exact answer to this but it is NOT the same with a 100 and 2000 hp car. I've been through physics II and Calc II and and pretty well educated in sciences. if that give me any credibility... lol
<strong> Did the driveline suddenly increase its mass by 20 times during the engine swap?
Nope, the weight remained the same, teh rate of acceleration of the driveline increased. It takes more hp to run 10's than to run 15's in the 1/4 mile. Same for spinning a driveline. (Maybe this makes more sense). You have the weight and RPM part correct, you just forgot to account for time (the faster acceleration rate).
And, 2000 hp puts lots of strain on the gears, and increases frictional losses (wasted as heat), etc.
I'm done....unless there are any questions....
Kevin </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">exactly, no one seems to know the exact answer to this but it is NOT the same with a 100 and 2000 hp car. I've been through physics II and Calc II and and pretty well educated in sciences. if that give me any credibility... lol
04-15-2003, 10:56 PM
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Re: Finally the answer to driveline loss trackbird...that was a very good explanation. I did forget to take time into consideration...but even with this newfound variable, I still don't understand why the % loss "constant" works out...
let me think out loud here for a sec...
...so any engine uses all of its power to move the driveline (and subsequently the car if it is on the road). Cars with more power more their drivelines quicker, which results in lower ETs and achieving any given MPH sooner...that makes sense.
...I still don't understand how that relates to 15% (or whatever %) driveline loss. We are talking about the driveline absorbing energy and turning it into friction/heat (loss), and not being able to use that power to motivate the vehicle.
...so whatever power the engine is making, only 85% of it will be used to move the vehicle? No matter what power level the engine is at? Do the top fuel dragsters loose 500-1000 HP in their drivelines (6000+ HP)?
What you said makes complete sense, but I don't see the connection to the question of why does 15% make more sense than 40 HP?
let me think out loud here for a sec...
...so any engine uses all of its power to move the driveline (and subsequently the car if it is on the road). Cars with more power more their drivelines quicker, which results in lower ETs and achieving any given MPH sooner...that makes sense.
...I still don't understand how that relates to 15% (or whatever %) driveline loss. We are talking about the driveline absorbing energy and turning it into friction/heat (loss), and not being able to use that power to motivate the vehicle.
...so whatever power the engine is making, only 85% of it will be used to move the vehicle? No matter what power level the engine is at? Do the top fuel dragsters loose 500-1000 HP in their drivelines (6000+ HP)?
What you said makes complete sense, but I don't see the connection to the question of why does 15% make more sense than 40 HP?
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04-15-2003, 11:16 PM
#8
Re: Finally the answer to driveline loss At higher acceleration rates, it will be far more than 40 hp. At F-body power levels....that may be close. My fiancee has a Mazda Protoge 5 (the sport wagon), rated at 135 hp....they typically dyno at 113hp at the front wheels. (not 40 hp, actually, 15% on that car is 114.75 hp....damn...that one is close). Front wheel drive cars (and rear/mid engine, rear drive....MR2's, Fieros, etc) tend to run around 15-18%, rear drivers tend to run 17-25% (as an average). I can tell you that I dynoed my 2002 Z28 in 3rd, 4th and 5th gear and I lost 15hp and about 13 ft lbs in 3rd and 5th gear over the run in 4th (and it was making 285.1 hp when it shut off at 158.1 mph on the dyno). I think the percentages are calculated on "coast down" hp measurements and are not always correct. Hell...a corvette motor on the actual dyno may make 385 hp (and be rated at 350), without knowing for sure, we have no good basis for the math. I have seen a 385 hp Z06 dyno at 331hp at the wheels, and a 2000 Z28SS dyno at 325 at the wheels (now, who makes what for hp?). My 310 hp Z28 did 299.7 at the wheels. Without knowing the engine dyno #'s on these motors, we can't do "good math" on this problem.
The "15%" also will have to do with the vehicle weight remaining the same, so, the rate of acceleration increases (proportionally...or mostly so) and the driveline is asked to accelerate faster by that percentage of increase (of the acceleration rate of the vehicle). I'm sure it is not constant, but it could work out to be remarkably close (or not). I've got some calculations around here somewhere, I'll have to dig them out and send the info along.
The "15%" also will have to do with the vehicle weight remaining the same, so, the rate of acceleration increases (proportionally...or mostly so) and the driveline is asked to accelerate faster by that percentage of increase (of the acceleration rate of the vehicle). I'm sure it is not constant, but it could work out to be remarkably close (or not). I've got some calculations around here somewhere, I'll have to dig them out and send the info along.
04-15-2003, 11:23 PM
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Re: Finally the answer to driveline loss ok, a couple of things:
1. We don't know the actual engine output like you said...it is entirely possible that the manufacturers just take the wheel HP and multiply it by 1.15 to get the 'rated' HP. We all know ratings are crap...or do we? Ford actually seems to rate there stuff reasonably (except for the lemon/cobra thing). The new 03 Cobras put down about 350 and are rated at 390.
The real point it, it is a flawed argument that relies on the manufacturers ratings to prove the 15% theory...especially if they use the inverse to get the ratings! Hah!
I am a programmer at for Toyota and work at an assembly plant. We have chassis dynos, no engine dynos...perhaps that is where they get the ratings...they build the prototypes, dyno them, add 15% "for drivetrain loss", and go on with their lives.
1. We don't know the actual engine output like you said...it is entirely possible that the manufacturers just take the wheel HP and multiply it by 1.15 to get the 'rated' HP. We all know ratings are crap...or do we? Ford actually seems to rate there stuff reasonably (except for the lemon/cobra thing). The new 03 Cobras put down about 350 and are rated at 390.
The real point it, it is a flawed argument that relies on the manufacturers ratings to prove the 15% theory...especially if they use the inverse to get the ratings! Hah!
I am a programmer at for Toyota and work at an assembly plant. We have chassis dynos, no engine dynos...perhaps that is where they get the ratings...they build the prototypes, dyno them, add 15% "for drivetrain loss", and go on with their lives.
04-15-2003, 11:29 PM
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Re: Finally the answer to driveline loss </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by richieg:
<strong> I actually feel smarter after reading this post. Screw college! Just go to ls1tech.com </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">ROTFLMAO <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
<strong> I actually feel smarter after reading this post. Screw college! Just go to ls1tech.com </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">ROTFLMAO <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
04-15-2003, 11:32 PM
#13
Re: Finally the answer to driveline loss One last dyno test to illustrate the lack of science behind most of this "educated guessing".
I had a 2000 Volkswagon GTI VR6 with a 2.8 liter V6 rated at 174 hp and 181 ft lbs of torque. I saw similar (absolutely stock) cars dyno at 173 hp and 180 ft lbs at the front wheels (I have to get some of Volkswagons magic gear oil....0 friction...or very nearly). How under rated do you think this motor actually was? If we apply "15%" it made about 198.95 hp at the crankshaft (though reportedly, 205-209hp was more accurate). Until we pull one out of a car and dyno it, and put it back in....we probably won't be able to prove much about this problem.....Just my thoughts....(part 5 or so).
I had a 2000 Volkswagon GTI VR6 with a 2.8 liter V6 rated at 174 hp and 181 ft lbs of torque. I saw similar (absolutely stock) cars dyno at 173 hp and 180 ft lbs at the front wheels (I have to get some of Volkswagons magic gear oil....0 friction...or very nearly). How under rated do you think this motor actually was? If we apply "15%" it made about 198.95 hp at the crankshaft (though reportedly, 205-209hp was more accurate). Until we pull one out of a car and dyno it, and put it back in....we probably won't be able to prove much about this problem.....Just my thoughts....(part 5 or so).
04-15-2003, 11:37 PM
#14
Re: Finally the answer to driveline loss The professor is in.....(lol).
I believe German law requires them to pull 10 motors off the assembly line, dyno them and take the lowest HP they get (hence the VW possibly being a "ringer"). German cars seem to always have "stronger" horses than most others (200 hp in Germany is usually at the wheels). But the other manufacturers have different standards, I just can't remember what they are these days (I believe the motor must be fully "dressed", smog, PS pump, alternator, etc for the dyno...but not sure what else).
Now, go get a beer before I start assigning homework.....lol
I believe German law requires them to pull 10 motors off the assembly line, dyno them and take the lowest HP they get (hence the VW possibly being a "ringer"). German cars seem to always have "stronger" horses than most others (200 hp in Germany is usually at the wheels). But the other manufacturers have different standards, I just can't remember what they are these days (I believe the motor must be fully "dressed", smog, PS pump, alternator, etc for the dyno...but not sure what else).
Now, go get a beer before I start assigning homework.....lol
04-16-2003, 07:52 AM
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Re: Finally the answer to driveline loss Different engines make their peak HP at different RPMs. Would this have an effect on the difference between engine dyno #'s and wheel #'s ?
04-16-2003, 08:05 AM
#16
Re: Finally the answer to driveline loss I'll add some fuel to the fire. Click here and scroll down to the bottom and read:
http://kammerracing.com/kmr/pages/superflowchassis.htm
http://kammerracing.com/kmr/pages/superflowchassis.htm
04-16-2003, 08:05 AM
#17
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Re: Finally the answer to driveline loss Lots of interesting information in this thread.
Some thoughts:
HP rated by the manufacturer is at the flywheel, tested on an engine dyno with all accessories, exhaust, etc. installed and corrected to certain conditions. The important thing is that these are "step tests" for each rpm; they are not taken at 300 rpm per second (or 600 or whatever you get on the chassis dyno), so rotating inertia (the resistance to acceleration) doesn't enter in.
On a chassis dyno, rotating inertia of every rotating part of the engine and driveline enters in and reduces the hp measured at the drive wheels. The heavier the wheel/tire combo and the lower the gear you run in, the more inertia loss.
Because most chassis dynos are just big inertia wheels, high hp combos spin them up faster than low hp ones, so there are more inertia loss with the higher hp.
Friction, especially in hypoid gears used in RWD rear ends have lots of friction which increases the power absorbed proportionally with the power transmitted. Winston Cup cars all have rear end oil coolers for this reason.
"Driveline losses" are NOT a straight percentage, unfortunately. That's the bad news.
Some companies, who have both an engine dyno, and a chassis dyno have taken the time to dyno an engine at the same rpm/second as run on the chassis dyno, then install it in a vehicle and dyno the vehicle, and correct both readings to the same temp, air density and humidity conditions, but this is rare. If done correctly, you can then get a good idea of actual driveline losses. The good thing is, once you get some good data on say a 9 inch Ford axle, or certain size tires (at a known inflation pressure), and a certain manual transmission, you can use those figures to fairly accurately estimate flywheel hp from chassis hp. The bad news is I've only seen one company do this. They happen to sell engine dynos and chassis dynos (and flowbenches).
So why do some 'stock' engines read more hp on a chassis dyno that the OEM rated hp?
Possibilities:
Engine not really 'stock'. A chip in a 2.8 VR6 makes a difference, and only the owner or Garrett Lim <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> knows for sure.
Bogus correction factor applied by less-than-honest dyno operator. If air inlet temp at the MAF was, say 80 F and dyno ooperator entred 130 F underhood temp, the correction to 77F or even 60F would be quite large. Voila, more hp, at least on the printout.
Chassis readings corrected to lower temp (60 F) than 77 F used by OEM. Ask for correction to 77F as installed conditions if you want to compare to OEM readings.
Just the tip of the iceberg.
My $.02
Some thoughts:
HP rated by the manufacturer is at the flywheel, tested on an engine dyno with all accessories, exhaust, etc. installed and corrected to certain conditions. The important thing is that these are "step tests" for each rpm; they are not taken at 300 rpm per second (or 600 or whatever you get on the chassis dyno), so rotating inertia (the resistance to acceleration) doesn't enter in.
On a chassis dyno, rotating inertia of every rotating part of the engine and driveline enters in and reduces the hp measured at the drive wheels. The heavier the wheel/tire combo and the lower the gear you run in, the more inertia loss.
Because most chassis dynos are just big inertia wheels, high hp combos spin them up faster than low hp ones, so there are more inertia loss with the higher hp.
Friction, especially in hypoid gears used in RWD rear ends have lots of friction which increases the power absorbed proportionally with the power transmitted. Winston Cup cars all have rear end oil coolers for this reason.
"Driveline losses" are NOT a straight percentage, unfortunately. That's the bad news.
Some companies, who have both an engine dyno, and a chassis dyno have taken the time to dyno an engine at the same rpm/second as run on the chassis dyno, then install it in a vehicle and dyno the vehicle, and correct both readings to the same temp, air density and humidity conditions, but this is rare. If done correctly, you can then get a good idea of actual driveline losses. The good thing is, once you get some good data on say a 9 inch Ford axle, or certain size tires (at a known inflation pressure), and a certain manual transmission, you can use those figures to fairly accurately estimate flywheel hp from chassis hp. The bad news is I've only seen one company do this. They happen to sell engine dynos and chassis dynos (and flowbenches).
So why do some 'stock' engines read more hp on a chassis dyno that the OEM rated hp?
Possibilities:
Engine not really 'stock'. A chip in a 2.8 VR6 makes a difference, and only the owner or Garrett Lim <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> knows for sure.
Bogus correction factor applied by less-than-honest dyno operator. If air inlet temp at the MAF was, say 80 F and dyno ooperator entred 130 F underhood temp, the correction to 77F or even 60F would be quite large. Voila, more hp, at least on the printout.
Chassis readings corrected to lower temp (60 F) than 77 F used by OEM. Ask for correction to 77F as installed conditions if you want to compare to OEM readings.
Just the tip of the iceberg.
My $.02
04-16-2003, 08:08 AM
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Re: Finally the answer to driveline loss </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Reckless:
<strong> I'll add some fuel to the fire. Click here and scroll down to the bottom and read:
http://kammerracing.com/kmr/pages/superflowchassis.htm </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Excellent! This testing was done at an AETC. I observed those tests. Yep, just like Kammer said.
<strong> I'll add some fuel to the fire. Click here and scroll down to the bottom and read:
http://kammerracing.com/kmr/pages/superflowchassis.htm </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Excellent! This testing was done at an AETC. I observed those tests. Yep, just like Kammer said.
04-16-2003, 08:37 AM
#19
Re: Finally the answer to driveline loss That was good information (I couldn't find exact numbers). I never really clarified the point that the "straight" percentages didn't work (not like I should have)....I kinda went after the whole "percentage thing" in general. I agree, that there is really only one way to find out and that link did it.
Until we pull one out of a car and dyno it, and put it back in....we probably won't be able to prove much about this problem.....Just my thoughts....
That was kinda what I was going after....but you made the point much more effectively than I did...
It is an interesting topic that comes up from time to time....
Until we pull one out of a car and dyno it, and put it back in....we probably won't be able to prove much about this problem.....Just my thoughts....
That was kinda what I was going after....but you made the point much more effectively than I did...
It is an interesting topic that comes up from time to time....
04-16-2003, 08:38 AM
#20
Re: Finally the answer to driveline loss This is what I meant to highlight....
The "15%" also will have to do with the vehicle weight remaining the same, so, the rate of acceleration increases (proportionally...or mostly so) and the driveline is asked to accelerate faster by that percentage of increase (of the acceleration rate of the vehicle). I'm sure it is not constant, but it could work out to be remarkably close (or not).
The "15%" also will have to do with the vehicle weight remaining the same, so, the rate of acceleration increases (proportionally...or mostly so) and the driveline is asked to accelerate faster by that percentage of increase (of the acceleration rate of the vehicle). I'm sure it is not constant, but it could work out to be remarkably close (or not).