2.8 dyno'd BS (before supercharger)
02-03-2003, 07:17 PM
#1
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2.8 dyno'd BS (before supercharger)
Do these look right? Did this about 2 weeks ago in Dallas. Ambient air temp was a damp cold 40-45 degF.
<a href="http://home1.gte.net/vzn05m0r/A4_28_V6qm.htm">Plot and Data</a>
<a href="http://home1.gte.net/vzn05m0r/A4_28_V6qm_files/image001.gif">Plot Only</a>
Eagerly awaiting group buy status,
Amro
<a href="http://home1.gte.net/vzn05m0r/A4_28_V6qm.htm">Plot and Data</a>
<a href="http://home1.gte.net/vzn05m0r/A4_28_V6qm_files/image001.gif">Plot Only</a>
Eagerly awaiting group buy status,
Amro
02-03-2003, 08:04 PM
#2
Re: 2.8 dyno'd BS (before supercharger)
That was on a 4WD chassis dyno? A 250hp S4 only put down 165.x hp at the wheels, and a 150hp A4tq only put down 91.x hp from the factory (ec/McMullen-Argus Pub. did the testing I think?).
No way you are only loosing 20-25hp through a quattro drive line, they aren't that efficient. Unless you have a super-freak 30v in your engine bay from Audi...?
No way you are only loosing 20-25hp through a quattro drive line, they aren't that efficient. Unless you have a super-freak 30v in your engine bay from Audi...?
02-04-2003, 01:23 AM
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I think the numbers your stating are a little low but his are still very high for a stock 2.8
I think I've seen ~140whp for a stock 170 hp quattro a4 and just shy of 200whp for a stock S4.
02-04-2003, 08:15 AM
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It is a 20-25% drive line loss so I dont exactly know how your saying a
stock 150 only put down 91 since that is 40% Now if your talking about a dyno from down under then you would be correct since a few of their dyno's only show a 60% of the power at the wheels, that is why their #'s are always low. If you wish to talk to someone about that talk to lucas he will explain it to you.
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02-04-2003, 02:15 PM
#9
Re: It is a 20-25% drive line loss so I dont exactly know how your saying a
I got the numbers from european car or sport compact car (I put them into an excel file back in early December, 2001) which I stated in my original post, as they were comparing dynos and dyno numbers for a few AWD cars. They had tested an S4, A4tq, and an Evo IV. The Evo was rated at 280hp, and put down 190hp. I do not have the magazine article anymore, since it was over a year ago. I don't remember if they did all their testing on the same day (so condition variables come into play). SO, if you want to talk about the numbers, talk to them, not me. I was just restating what they had found.
And honestly, I don't see how there is only a 20% loss in an AWD driveline, when thats about what RWD drivelines get. The AWD is going to have more paracitic losses, more mechanical components at both ends, more rotating mass, etc. Is 40% high? Probably. Is 20% low? Probably. Only way to really tell, is to do all the calculations you learned in various dynamics and machine design courses. OR, put the engine on an engine dyno, and then put the car on a chassis dyno. The more runs on both the better, to get a better mean value. That way even a music major could figure out the losses (sorry if any of you people majored in music, no offense was meant).
And honestly, I don't see how there is only a 20% loss in an AWD driveline, when thats about what RWD drivelines get. The AWD is going to have more paracitic losses, more mechanical components at both ends, more rotating mass, etc. Is 40% high? Probably. Is 20% low? Probably. Only way to really tell, is to do all the calculations you learned in various dynamics and machine design courses. OR, put the engine on an engine dyno, and then put the car on a chassis dyno. The more runs on both the better, to get a better mean value. That way even a music major could figure out the losses (sorry if any of you people majored in music, no offense was meant).
02-04-2003, 05:44 PM
#10
In all honesty, driveline loss should not be expressed as a percentage.
This has been covered numerous times in this forum. Some people insist that it is a percentage, some insist that it is a fixed HP number. My personal belief is that driveline is a little bit of both...with the fixed component being the larger factor.
Either way, dyno numbers are really no good except to compare modifcations to the same vehicle and under the same conditions. Comparisons between cars or between the same car on different dynos or under different conditions are worthless.
All that being said, the numbers you are quoting from Sport Compact Car are way too low. There is no way that there is a 35% - 40% DL on our cars. Even 30% is too high...23% - 25% is realistic if you insist on using straight percentages. I'm not doubting you that SCC printed those numbers, but I am doubting they are correct.
Most RWD driveline losses are quoted around 15% - 18%.
IMO, driveline losses are nothing more than fudge factors for tuners to use to market their products.
Scott
Either way, dyno numbers are really no good except to compare modifcations to the same vehicle and under the same conditions. Comparisons between cars or between the same car on different dynos or under different conditions are worthless.
All that being said, the numbers you are quoting from Sport Compact Car are way too low. There is no way that there is a 35% - 40% DL on our cars. Even 30% is too high...23% - 25% is realistic if you insist on using straight percentages. I'm not doubting you that SCC printed those numbers, but I am doubting they are correct.
Most RWD driveline losses are quoted around 15% - 18%.
IMO, driveline losses are nothing more than fudge factors for tuners to use to market their products.
Scott