Torque curve for the 4.2 (from the 2001 Audi brochure). The graph is small, so these numbers are an
10-24-2002, 12:44 PM
#11
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Yes, that is not what Audi's curve looks like for the 2.7T engine...
1000 rpm: 155 lb-ft
1850 rpm: 258 lb-ft which remains constant until it drops at 4000 rpm
5000 rpm: 215 lb-ft
6000 rpm: 172 lb-ft
The differences in the APR numbers is likely due to how it is measured...not an actual difference in engine output.
When comparing Audi figures for the 2.7T and the 4.2...it is best to use figures based on the same measuring system/device...not some aftermarket company's measurements.
1850 rpm: 258 lb-ft which remains constant until it drops at 4000 rpm
5000 rpm: 215 lb-ft
6000 rpm: 172 lb-ft
The differences in the APR numbers is likely due to how it is measured...not an actual difference in engine output.
When comparing Audi figures for the 2.7T and the 4.2...it is best to use figures based on the same measuring system/device...not some aftermarket company's measurements.
10-24-2002, 12:44 PM
#12
Go look at a 996TT torque curve. It does the same thing it just has another 200ft-lbs!!....(m)
Porsche's being doing these flat curves for years. In the "old" (1987) days they used a flapper valve in the intake tubes that opened and closed, as needed, to accelerate the air through the intake under low air flow times.
But then again, Porsche also designed the air intake ports of one of their cars in a negative pressure region when moving to create a natural "mini" forced induction system.
Anyway, Porsche's been doing these flat curves for years so it's about time Audi started doing it. I haven't seen any of the new Porsche intake systems but air is the key!!
But then again, Porsche also designed the air intake ports of one of their cars in a negative pressure region when moving to create a natural "mini" forced induction system.
Anyway, Porsche's been doing these flat curves for years so it's about time Audi started doing it. I haven't seen any of the new Porsche intake systems but air is the key!!
10-24-2002, 12:50 PM
#13
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gearing.
both tips will do 1/4 in about same time but the 2.7t gets to an average mph quicker but its final mph at the 1/4 is ~94mph. i believe the 4.2 is higher mph at the 1/4.
Lets just say the 2.7 tip did a 15.1@94mph and the 4.2 15.2 @96mph. The 4.2 will be ~1 ccar length , about 15 feet behind but it will be traveling faster at that moment, so it will overtake the 2.7t. The 2.7T takes advantage of its gearing down low, but compared to the 4.2 will run outta steam when the speeds hit triple digits.
ANother thing, in my own opinion even though both cars do a 60mph virtually the same 6.6(2.7T) to 6.7(4.2) according to mags,, the 2.7t will be a shade further ahead than what the time to 60mph says. Example:
2 cars take 6 seconds to 60mph. car one does 0-50 in 2 seconds and 50-60 in 4 seconds. Car two does 0-50 in 4 seconds and 50-60 in 2 seconds. What car do you think will be further down the road after 6 seconds?? time to 60 will be the same but the distance travelled will be diferent, thats were the gearing helps the 2.7t.
Lets just say the 2.7 tip did a 15.1@94mph and the 4.2 15.2 @96mph. The 4.2 will be ~1 ccar length , about 15 feet behind but it will be traveling faster at that moment, so it will overtake the 2.7t. The 2.7T takes advantage of its gearing down low, but compared to the 4.2 will run outta steam when the speeds hit triple digits.
ANother thing, in my own opinion even though both cars do a 60mph virtually the same 6.6(2.7T) to 6.7(4.2) according to mags,, the 2.7t will be a shade further ahead than what the time to 60mph says. Example:
2 cars take 6 seconds to 60mph. car one does 0-50 in 2 seconds and 50-60 in 4 seconds. Car two does 0-50 in 4 seconds and 50-60 in 2 seconds. What car do you think will be further down the road after 6 seconds?? time to 60 will be the same but the distance travelled will be diferent, thats were the gearing helps the 2.7t.
10-24-2002, 01:25 PM
#14
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The Apr Figures are correct for 2.7T 250 HP But
The cars in the UK are De-Tuned to 230 HP I will try to get a comparison chart out but according to the guide I have it is as follows:
2.7T 230bhp 152 mph 0-60 7.1 24.2 mpg
2.7T 250bhp 146 mph 0-60 7.5 22.0 mpg Allroader
4.2 300 bhp 155 mph 0-60 6.9 21.7 mpg
S6 340 bhp 155 mph 0-60 5.5 19.6 mpg
RS6 450 bhp 155 mph 0-62 4.7
I have asked for more technical data from a friend who will forge anything i request so I can realy make a 1.1 saturn look even better than a RS6
(just kidding) Hope this helps as far as I am aware when I spoke to APR they did confirm that the graphs they have for the standard car is accurate.
2.7T 230bhp 152 mph 0-60 7.1 24.2 mpg
2.7T 250bhp 146 mph 0-60 7.5 22.0 mpg Allroader
4.2 300 bhp 155 mph 0-60 6.9 21.7 mpg
S6 340 bhp 155 mph 0-60 5.5 19.6 mpg
RS6 450 bhp 155 mph 0-62 4.7
I have asked for more technical data from a friend who will forge anything i request so I can realy make a 1.1 saturn look even better than a RS6
(just kidding) Hope this helps as far as I am aware when I spoke to APR they did confirm that the graphs they have for the standard car is accurate.
10-24-2002, 02:26 PM
#15
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The Passat W8 has a shorter ratio for North America...
...to get that quicker effect off the line. The S6 doesn't bother, but Holy **** is it fast (by my seat of the pants perception) from 100 to 200 km/hr.
10-24-2002, 05:11 PM
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The only way it can be a difference in measurement is through driveline loss
HP is just torque * speed, so if APR measured the torque 20% too high they would get the HP too high also. But they don't.
There are only two explanations:
1. Audi lies about the torque.
2. APR's driveline loss (at wheels versus at shaft) figure is off.
#2 is of course quite possible. #1 is also very possible since Audi has a more expensive car above the 2.7T and it doesn't look good for the 2.7T's torque figures to "threaten" the 4.2s. Plus, it is quite unlikely that the car would have an exactly flat torque curve across such a wide band.
Anyway, to determine torque at the wheels a big factor is the rear end gearing. The lower gearing of the 2.7T makes it quite likely it has as much or higher torque at the wheels than the 4.2 much of the time. In fact we know it is likely since the 2.7T is quicker to 60. Torque at the wheels is what accelerates the car, and the 2.7T out accelerates the 4.2. Yes, weight is also a factor of course.
There are only two explanations:
1. Audi lies about the torque.
2. APR's driveline loss (at wheels versus at shaft) figure is off.
#2 is of course quite possible. #1 is also very possible since Audi has a more expensive car above the 2.7T and it doesn't look good for the 2.7T's torque figures to "threaten" the 4.2s. Plus, it is quite unlikely that the car would have an exactly flat torque curve across such a wide band.
Anyway, to determine torque at the wheels a big factor is the rear end gearing. The lower gearing of the 2.7T makes it quite likely it has as much or higher torque at the wheels than the 4.2 much of the time. In fact we know it is likely since the 2.7T is quicker to 60. Torque at the wheels is what accelerates the car, and the 2.7T out accelerates the 4.2. Yes, weight is also a factor of course.
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