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Discussion Starter · #1 ·
Here is the link click me

Here click me you can find more cars for comparizon on the same dyno.

Numbers may be higher than the typical US Mustang dyno but are comparable with each other.:)
 

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feeling really dumb right now...
help me read that report please???
(dont understand the relevance of the accuracy percentages)

also would love to see an aftermarket exhaust dyno vs this one
 

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Any idea why there was such a difference in the R8 and the RS4 readouts? Other dyno tests have not shown that much difference. Were they both stock?
 

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Discussion Starter · #4 ·
The grey lines are the figures posted by the factory at the flywheel.
The color lines are the dyno reading on the wheel.

There is always a loss of power due to drivetrain friction etc. so wheel figures will always be smaller than flywheel (engine) figures. The percentages refer to wheel readings compared to the factory flywheel claims.
So R8 seems to have 90% of the power and 92% of the torque on its wheel, the factory claims at the flywheel.
Usualy wheel readings are 15% or more lower than flywheel on 4wd vehicles. So R8 does pretty well (compared to the moderate RS4 performance)


All cars are stock. The difference in performance between RS4 and R8 does seem a little bit difficult to explain.
What is certain is that the cars have different calibration, intake and exhaust. R8 is tuned more for hp while RS4 has more torque at the lower revs.
 

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excellent summary- thanks!!!

The grey lines are the figures posted by the factory at the flywheel.
The color lines are the dyno reading on the wheel.

There is always a loss of power due to drivetrain friction etc. so wheel figures will always be smaller than flywheel (engine) figures. The percentages refer to wheel readings compared to the factory flywheel claims.
So R8 seems to have 90% of the power and 92% of the torque on its wheel, the factory claims at the flywheel.
Usualy wheel readings are 15% or more lower than flywheel on 4wd vehicles. So R8 does pretty well (compared to the moderate RS4 performance)


All cars are stock. The difference in performance between RS4 and R8 does seem a little bit difficult to explain.
What is certain is that the cars have different calibration, intake and exhaust. R8 is tuned more for hp while RS4 has more torque at the lower revs.
 

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All cars are stock. The difference in performance between RS4 and R8 does seem a little bit difficult to explain.
What is certain is that the cars have different calibration, intake and exhaust. R8 is tuned more for hp while RS4 has more torque at the lower revs.
But there was another dyno test posted on this forum comparing an R8 to an RS4. Although the torque peak of the RS4 came a bit lower in the rev range than it did on the R8, the peaks of the two cars --measured at the wheels -- were within 1 lb/ft of each other. And the hp peaks were within 7 hp of each other, if I remember correctly. (I'll have to try to find that link again.)

This test showed a much wider divergence in the peak-to-peak comparisons between the two cars as measured at the wheels.
 

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That's it! Thanks.

While that test showed somewhat differently shaped torque curves between the two cars, the peak numbers -- measured at the wheels -- were almost identical.

So I wonder why the tests which spawned this thread show such significant differences between the R8 and the RS4. Could there be that much unit-to-unit variation in either of the two cars?
 

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Discussion Starter · #9 ·
That is a good question.
To be honest, I don't believe such great differences are valid given Audi states for both engines the same horsepower. Though I do believe that the R8 has somewhat more hp at the wheel.

Many things can spoil a dyno reading with wheels of the car being one of them. The 257KW RS4 and the 277KW R8 both have 18'' wheels while the 245KW RS4 has 19" wheels. Though this may be just coincidense.

Also it is said that production R8's have differences on the engine tune compared to the magazine pre-production test vehicles. Still the R8 in this dyno has quite high mileage to be a regular production R8.

To cut things short, all we need is patience for more dynos to find out what is really going on.
 
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