414bhp or ???bhp

[simple1]

As all who replied have previously posted dyno plots including T...... seems pointless doing it again but here you are

[GrahamS4]

I think I follow what information you are trying to gather Varsity. I am also not too surprised at the responses. Only a minority of people have a before and after dyno run after this type of work it seems.

Just to add what I think is essential. I think we all know dyno's vary. Even two different dynos of the same type vary, but not by much hopefully - as Simple1 has said the results in his expereince fromthe Dyno Dynamics at DMS very similar to the results from the DD dyno at WRC. We are talking 400+BHP cars here so even a small tollereance menas a good few BHP difference. This is not my concern though.

First off I think you must compare eggs with eggs. Where you say where was the dyno done, you must find out what type of dyno this was.

I would only compare power at the wheels figures (not flywheel corrected figures) from the same type of dyno if I were you.

I know from experience of taking the same car about 2 weeks apart to a (dont know the make) run down type inertia dyno and to a dynodynamics dyno that the engine power figures varied vastly, so much so it was a joke. I could have had a before run at one, dreamt a remap while driving to the other and had a 10%BHP increase.

You already have a mix of dyno results here and from my expereince you just cannot compare them. I also have no faith in a dynodynamics corrected flywheel figures, having on two different cars have them give readings entirely unlikely, where as the power at the wheels reading at a level beleiveable given the likely transmission losses.

[VARSITY]

Graham, thanks for the advice.

However there is evidence that the RS4 is running well under powered. WRC's dyno has seen unmapped cars reach 410 as well as mapped cars showing 435. After seeing a standard and mapped car today reach the same power output, within 2 bhp, at the wheels and flywheel.

It is interesting to see that the Audi's very own RS4 experience cars are also dyno'd every 6 weeks and they also show power down from that of the advertised power 414.

At this time I do not want to say anything other than thanks for those who have assisted here, even if it took a little extra effort, thanks Simon!, it is important info and is being used for a genuine reason.

I will also confirm that NO person, reg nimber or specifics will be divulged in this.

Cheers

[AntoRS4]

I want to start again this topic because I see that there are lot of questions about the real power of RS4...
first at all i want to sorry about my English, I'm from Italy and this the maximum that i can do with it

my car is a 2007 rs4, 19000km on the clock, same power now as in the beginning... tested lot of times and always the same results
apx. 390/395 hp at the engine. ( 100oct. VPower, intake temp. < 15 °C ) , power figure decrease if temp. is > than 25°C

we have a last generation bench ( 4wd, belt linked), so all the wheels run at the same speed, no electronic compensation
between the front and the rear axis.

wa have also tested lot of other rs4 with similar results, i can say that the real power is 387 hp with 100oct. fuel.

I've contacted AUDI and i'm still waiting a reply

In Italy we pay every year a tax of 3.- Euro per Kw and i think that Audi behavior is not correct,

on the paper RS4 is a fantastic car, the real car is not the same.

we test every day a lot of cars and from the bench and from the road tests we have deduced the following formula:

hp = ( kgm X 1000000 ) / ( t^3 * 330 )
where
kgm is the weight of the car + the driver weight
and
t is the time in seconds for a 0-1000m run ( average for both directions )

example :

my RS4 Avant weight + me is 1750kgm
average time (0-1000m) is 23.7 sec. at 10°C , Vpower fuel:
( 1750 x 1000000 ) / ( 23.7^3 x 330 ) = 398hp


if external temp. is higher that 25°C time also increase up to 24.4 sec and calculated power drops to 365hp.

seems that RS4 is a car that only works at the North Pole
i know about some guys in greece that are desperate...

[t_urbo]

Glad you bought this back to life Anto. Mine was Dyno'd at 393 before remap and 409 after.

Does anyone know how Audi stand claiming 414 when it seems that alomost every RS4 sold and Dyno'd is under that figure.

Under the Sale of Goods Act you have the right to a refund if the product does not do what its supposed to, bummer is i know there are different laws regarding the sales of cars in this country.

People are complaining about this the world over, time to get some compensation me thinks.

[alex_123_fra]

I want to start again this topic because I see that there are lot of questions about the real power of RS4...
first at all i want to sorry about my English, I'm from Italy and this the maximum that i can do with it

my car is a 2007 rs4, 19000km on the clock, same power now as in the beginning... tested lot of times and always the same results
apx. 390/395 hp at the engine. ( 100oct. VPower, intake temp. < 15 °C ) , power figure decrease if temp. is > than 25°C

we have a last generation bench ( 4wd, belt linked), so all the wheels run at the same speed, no electronic compensation
between the front and the rear axis.

wa have also tested lot of other rs4 with similar results, i can say that the real power is 387 hp with 100oct. fuel.

I've contacted AUDI and i'm still waiting a reply

In Italy we pay every year a tax of 3.- Euro per Kw and i think that Audi behavior is not correct,

on the paper RS4 is a fantastic car, the real car is not the same.

we test every day a lot of cars and from the bench and from the road tests we have deduced the following formula:

hp = ( kgm X 1000000 ) / ( t^3 * 330 )
where
kgm is the weight of the car + the driver weight
and
t is the time in seconds for a 0-1000m run ( average for both directions )

example :

my RS4 Avant weight + me is 1750kgm
average time (0-1000m) is 23.7 sec. at 10°C , Vpower fuel:
( 1750 x 1000000 ) / ( 23.7^3 x 330 ) = 398hp


if external temp. is higher that 25°C time also increase up to 24.4 sec and calculated power drops to 365hp.

seems that RS4 is a car that only works at the North Pole
i know about some guys in greece that are desperate...

I have absolutely no doubt that audi's 4.2 Ltr FSI RS4 engines produce an average of 414bhp. You have to remember the figure is arrived at through ENGINE DYNO testing of several units to obtain an average. This is the most accurate way of determining power output.

Working out flywheel bhp in 4WD cars has always been problematic and the RS4 is no exception. Converting WHP to flywheel HP is probably one of the most controversial dyno discussion topics. There is no point quoting dyno figures or formulas and saying that most RS4s are underpowered because that simply isn't proof of anything.

The best way to determine if cars are underpowered is to engine dyno them (impractical), or do specified timed runs. The latter could include standing start and in gear runs...e.g. 0-100, 0-150mph, 30-130mph etc and compare with cars with similar power to weight ratios/aerodynamic profiles. Several such events have taken place (e.g. Vmax and 30-130mph days) and standard B7 RS4s always fare exteremely well in my experience. This provides far more "proof" than any dyno figures.

I know that my standard saloon is faster than my 400 bhp/380 lb ft (250kg lighter) Evo was and I'm very happy with that.

[GrahamS4]

Working out flywheel bhp in 4WD cars has always been problematic and the RS4 is no exception. Converting WHP to flywheel HP is probably one of the most controversial dyno discussion topics. that.

Agreed. I don't believe dynos that claim to measure transmission losses and calculations can be misleading, as a 1 or 2 % varaition in your estimated loss percentage can make drastic diferences to the outcome.

I'd really like to know what figures people are getting at the wheels on a dynodynamics dyno from their B7s.

Any of the DMS guys get their figures at the wheels (stock or otherwise)?

[AntoRS4]

the problem is that 90% of tested cars give full power on the bench.
for example my other car is a new S3
270hp on the bench with 98oct.fuel , air temp 30°C ( and it's a 4wd too )

acceleration data from AUTO Magazine
0-1000 25.29sec weight 1522kg
calculated power 285hp

what i want to explain is that i want what i pay for...
RS4 is an expensive car, i want all the 420hp.
and i want them with 98oct. fuel not with rocket mixture.
i want all my hp with standard temperature 20/25°C
at 30/35°c RS4 is a dead car

[alex_123_fra]

the problem is that 90% of tested cars give full power on the bench.
for example my other car is a new S3
270hp on the bench with 98oct.fuel , air temp 30°C ( and it's a 4wd too )

acceleration data from AUTO Magazine
0-1000 25.29sec weight 1522kg
calculated power 285hp

what i want to explain is that i want what i pay for...
RS4 is an expensive car, i want all the 420hp.
and i want them with 98oct. fuel not with rocket mixture.
i want all my hp with standard temperature 20/25°C
at 30/35°c RS4 is a dead car

Again, that is a problem with the dyno and conversions to flywheel power rather than a problem with the car in my opinion. Not all 4WD systems are the same and a general conversion formula does NOT apply to all.

By using your own formula, my own car achieves 410 bhp while completely standard.

Vbox 0-1000m - 23.4s
Weight with me inside - 1730 kg

From what I've seen, most RS4 saloons achieve around low 23s-24s for 0-1000m runs. Your formula seems rather unforgiving in its tolerances too...a 24s 0-1000m run would have put my car at 379bhp vs 410bhp (at 23.4s). Not really an accurate way of extrapolating bhp from timed runs.

On an aside, you must be very light if you + RS4 avant weigh 1750kg in total.

I've driven my car in 30+ degrees and I honestly notice little if any drop in performance. If you want to see a real drop in performance in the heat, I'm sure you will agree, drive a turboed car.

I think this number chasing is futile. The RS4 has proven itself time and time again and even against the lighter E92 M3 and its timed performance is virtually identical to this. Either the cars you are testing are faulty, not serviced properly or your dyno tolerances are simply out. I just don't believe that most RS4s are underpowered.

[alex_123_fra]

Oh, I nearly forgot:

http://www.m3post.com/forums/showthread.php?t=80742

Standing 0-1000m 23.5s for M3 and RS4 and 0-150mph there was only 0.3s difference between the 2 cars. Not so bad for the (fatter) RS4.

[VARSITY]

Its called misrepresentation. Doesn't matter whether its a car or a torch. It just hurts more when its £55k!

[SR71]

I'm not a dyno-engineer but I've always suspected that getting hp from whp is working backwards towards the answer!

Any dope can do that...you just fiddle the transmission losses so that the hp figure is the one you want or the manufacturer claims!

I'll happily admit I'm wrong but its a supposition of mine.

Who gives a f**k what the dyno says if your car does the 1/4 in the same time as a E90/E92 M3 or, conversely, is faster than a 997 C2S.

1/4 mile times are a far better judge of power assuming you are able to consistently extract maximum performance from the car. This takes practise.

You won't get Audi under the TDA unless you show a significant number of cars all dyno on an engine dynamometer at well below 414.

[AntoRS4]

alex,

i work with a lot of tuners and all of them report same data..
if you want you can take a look here :

http://www.rri.se/
or here
http://www.caranddriver.com/comparisons ... mw-m3.html
you can download pdf files with m3,rs4,mb results....
seems that lot us don't want to see the real numbers of the rs4...
handling is ok, but i think that engine is not the state of art.

Vbox 0-1000m - 23.4s ?! ( both side average ? ), is it stock ? 35°C ?! i don't think so
we use a very expencive tool, 2cm accuracy over 1000m and never be able to obtain that result with stock Rs4
other similar car tested: R8 23,1 sec - E92M3 22,8sec

remember that 0.9 sec at 230km/h after 1km are more than 57m. ( this is the difference between new m3 and our Rs4 )
..and what about the clutch, to obtain good time you must destroy it!! but this is another topic.

i know that on the track Rs4 is the best ( 2min09 my personal best lap at Monza ) and i'm not a good driver...
but if you are on the motorway and a new m3 is coming .... it's better if you give it the way.
on new m3 if you are a good driver and if you disable every stupid power control,on dry track,it will beat Rs4 also on 0-100km/h. time.

and please don't say the the problem is the 4wd...it can not absorb 40 or more hp than a 2wd , 40hp produce lot of heat, you will see fire
coming from the bottom of your car after 5km.... the problem is the engine power, if you test the car at 0°C you will see that
it's a rocket, it's another car, but here in Italy (Monza near Milano) we don't have often that temperatures and new M3 doesn't seem to suffer of the same problem.

i think the problem is the knocking, the knock threshold is very low and with poor quality fuel or high air intake temperature
the ECUs start to remove lot of time advance and so power. less time advance increases exaust temperature and so on....

what i want to explain here is that i like my car but 85000 euro are a lot of money
and i pretend that the claimed performance must be respected. i don't want to know about weather condition
other cars give the full power at 20/30 °C i want the same by mine.

next summer you can come here in italy, we can meet at Monza circut, you will see your cars performance drop down after
2 laps. i think that car is like sex 2 laps = 4 minutes are not enough!!

[mixja]

That's a bit silly to say the M3 will beat the RS4 on 0-100km/h time - the RS4 has a definite advantage in this respect. Here in New Zealand, NZ Autocar did 0-100 in 4.62s for the RS4, 0-100 in 4.95s for the M3. They commented they got very few 0-100 times on the M3 below 5s due to loss of traction. RS4 on the other hand is a simple recipe, dial up 5000-5500RPM and let the clutch go quickly, and you will always get sub 5.0s 0-100 times...

I've seen 12.8s 0-400m times for stock RS4s - given the weight of the car, to get that sort of time, definitely need more than 400HP...

[alex_123_fra]

alex,

i work with a lot of tuners and all of them report same data..
if you want you can take a look here :

http://www.rri.se/
or here
http://www.caranddriver.com/comparisons ... mw-m3.html
you can download pdf files with m3,rs4,mb results....
seems that lot us don't want to see the real numbers of the rs4...
handling is ok, but i think that engine is not the state of art.

Vbox 0-1000m - 23.4s ?! ( both side average ? ), is it stock ? 35°C ?! i don't think so
we use a very expencive tool, 2cm accuracy over 1000m and never be able to obtain that result with stock Rs4
other similar car tested: R8 23,1 sec - E92M3 22,8sec

remember that 0.9 sec at 230km/h after 1km are more than 57m. ( this is the difference between new m3 and our Rs4 )
..and what about the clutch, to obtain good time you must destroy it!! but this is another topic.

i know that on the track Rs4 is the best ( 2min09 my personal best lap at Monza ) and i'm not a good driver...
but if you are on the motorway and a new m3 is coming .... it's better if you give it the way.
on new m3 if you are a good driver and if you disable every stupid power control,on dry track,it will beat Rs4 also on 0-100km/h. time.

and please don't say the the problem is the 4wd...it can not absorb 40 or more hp than a 2wd , 40hp produce lot of heat, you will see fire
coming from the bottom of your car after 5km.... the problem is the engine power, if you test the car at 0°C you will see that
it's a rocket, it's another car, but here in Italy (Monza near Milano) we don't have often that temperatures and new M3 doesn't seem to suffer of the same problem.

i think the problem is the knocking, the knock threshold is very low and with poor quality fuel or high air intake temperature
the ECUs start to remove lot of time advance and so power. less time advance increases exaust temperature and so on....

what i want to explain here is that i like my car but 85000 euro are a lot of money
and i pretend that the claimed performance must be respected. i don't want to know about weather condition
other cars give the full power at 20/30 °C i want the same by mine.

next summer you can come here in italy, we can meet at Monza circut, you will see your cars performance drop down after
2 laps. i think that car is like sex 2 laps = 4 minutes are not enough!!

I think we'll just have to agree to disagree Anto. I certainly don't feel short-changed owning an RS4 in the UK. It may be too hot for it to perform optimally in Italy, I don't know.

The websites you quote have been discussed here previously. The first in particular shows clear evidence that the authors have no idea about the differences between whp and flywheel bhp. I also refuse to believe that an RS4 which is running well mechanically is putting out such low bhp as 320s...that is just ridiculous. Again, there is something wrong with the dyno or the car. It is not proof that RS4s are underpowered.

Plenty of people have quoted mid 12s for quarter mile times which, as mentioned by others, is indicative over >400bhp given the RS4's weight. My personal 0-1000m run was done at Bruntingthorpe in one direction (the slight uphill side) at 20 C or so. The car is totally stock.

I would expect the M3 to be quicker and better handling than an RS4 as it is lighter, RWD and is a coupe, yet still it doesn't clearly achieve this. In the end, if you feel the M3 is a better car, by all means go and buy one. I respect it hugely, but I'm certainly not envious of anyone who has it and I don't consider it a superior car to the RS4.