Certified dyno graph:

[ArthurPE]

When you buy an Audi from the dealer you purchase that item from that sales organisation, not the manufacturer. When you go to the 'dealer' to resolve a problem you still deal with the 'dealer'. At what point do Audi USA talk direct to you? Never, thats why if you want to sue Audi, you will never be able to, it will be 'dealer' supported by Audi USA or UK or whatever your location. So your problem will have been dealt with far before that would ever happen. It will only happen if there is a class action for something as severe as the Ford Explorer tire (spealt for the American among us) debarcle.

I 'talked' to BMW directly...it's called 'writing' and 'telephone'...
I sued BMW and won...sued the dealer at the same time...
settled in arbitration...no big deal, cost 2k to recover 15k, they covered 1/2 of the legal fees, so cost me 1k net...

the LAW says the manufacturer bears responsibility for the product...

what's your point?

So, APE, what was the problem on your car that BMW paid you out?

I for one don't think it happened. But hey, everyone needs to believe in something.

Tinker Bell, where are you.............

it doesn't matter what you think...it's what the arbitrator decided...and it's public record...

they performed the bearing SIB as required on the e46 M3...pic attached
afterwards the engine developed a knock, loose rod bearing
I sued for a rmfged engine
I got one...for free

from your posts, I think we've located the elusive tinker bell...

[ArthurPE]

What a very fine example of a stereotypical septic.

thanks for proving the my 2 referenced points

I am off from this one I cant compete with the mighty APE.

Arthur, good luck with your life, looks like you need it.

Adios.

luck has nothing to do with it...

I paid for my engineering degree by serving in the Army as an Officer
worked 10 years in the oil fields of AK
now I'm president of a 107 year old engineering firm, 4th in it's history...
we made record profits last year, this year is shaping up better due to obamas stimulus package, or as I refer to it, the engineer's retirement act but all that is nadda compared to...

I have my health, and more so, the love of a woman too good fo me...

so you need to lighten up, and stop taking this so personally, because it means zip to me, other than a mild diversion from 'real life'...and back off the personal attacks...they are also meaningless to anyone but you...

[scaghead]

arthur,[uncle albert] did bmw settle with you out of court,or did they fight you over it.. cheers del boy

[ArthurPE]

arthur,[uncle albert] did bmw settle with you out of court,or did they fight you over it.. cheers del boy

I prefer not to discuss details

[scaghead]

arthur,[uncle albert] did bmw settle with you out of court,or did they fight you over it.. cheers del boy

I prefer not to discuss details

fair enough

[RI_RS4]

There is ~20hp difference between even their own tests on a 06 and 07 RS4...

Really? Tell me more?

it's been addressed, read the posts...
it's ~15 HP, or 16 to be exact...
within tolerance, <5% difference...
the torque delta was 2%...which the actual measured variable...
2%...that's exceptional repeatability

that's extremely accurate for a device that converts mechanical energy to a signal...

Not so ... the rollers used on the Mustang four wheel drive AWD 500, are pre-characterized at the factory for mass and rotational inertia. The measurement load cells are 2000 lb cells with +/- 1 lb accuracy. This particular dyno is extremely accurate. Their load cell loop controller has a 10 ms control time constant, which solves the rotational lag problem that some dynos have, and they use a large number of teeth on their hall-effect sensor assembly, which give them high resolution measurement of changes in rotational velocity.

[ArthurPE]

Not so ... the rollers used on the Mustang four wheel drive AWD 500, are pre-characterized at the factory for mass and rotational inertia. The measurement load cells are 2000 lb cells with +/- 1 lb accuracy. This particular dyno is extremely accurate. Their load cell loop controller has a 10 ms control time constant, which solves the rotational lag problem that some dynos have, and they use a large number of teeth on their hall-effect sensor assembly, which give them high resolution measurement of changes in rotational velocity.

wrong.....again....

a motorcycle magazine did a test of those dynos, which the mfg says is calibrated to be within 0.5% repeatability dyno to dyno from the factory...

the magazine, same bikes, same day, found a 5 to 6% variation after atm correction...mustang refused to explain it...

if you are claiming 1/2000 ~ 0.05% accuracy, you must be tripping...

if you ramp up to speed, and hold for 60 sec like the EEC spec calls for, lag, etc., don't matter...steady state is the only way to achieve any sort of accuracy, not a 10 sec ramp run...

[RI_RS4]

Arthur

read what I said, don't guess. The load cells are accurate to 0.05% That is fact. Variation on the dyno is much higher, due to multiple factors. However, many of them can be controlled. When I placed my car on the dyno, several times, I had very good repeatability. In many cases, the variation is due to the engine ECU dialing back timing on successive runs. The largest problem with any dyno is intake airflow.

Again, apple-to-apples runs can be done. BTW, a Mustang Dyno can be run in steady state. But, you probably did not know that, did you?


Why not post the motorcycle magazine tests, and lets see how good their engineers were?

[ArthurPE]

Arthur

read what I said, don't guess. The load cells are accurate to 0.05% That is fact. Variation on the dyno is much higher, due to multiple factors. However, many of them can be controlled. When I placed my car on the dyno, several times, I had very good repeatability. In many cases, the variation is due to the engine ECU dialing back timing on successive runs. The largest problem with any dyno is intake airflow.

Again, apple-to-apples runs can be done. BTW, a Mustang Dyno can be run in steady state. But, you probably did not know that, did you?

Why not post the motorcycle magazine tests, and lets see how good their engineers were?

so we agree...5% overall accuracy on a dyno is probably the best we can expect, and 10% is probably the norm...OK
repeatability is even 'looser'

any dyno can be run steady state, just not fullpower/throttle...
bet you didn't know that...

the largest problem with a dyno is not combustion air, but cooling air...

consider the RS4
Cd ~ 0.31
A ~ 2.17m^2 or 23.4 ft^2

let's say the car is travelling 60 mph or 88 ft/sec...

CFM of airflow on the front of the car (need to consider the whole thing to consider the design cooling/airflow parameters)

CFM = 60 sec/min x 88 ft/sec x 23.4 ft^2 ~ 123,550 CFM...that's a big fan, as much as 200 HP...depending on static pressure drop, small in this case...

[S2tuner]

Arthur, it's strange, all cars that I tune on our Cartec dyno in France, I tune in steady state, holding the RPM constant by using the dyno's brake, INCLUDING at wide open throttle and at any revs, including peak power RPM.

I think you need to revise your thinking about a thing or two... certainly your last comment about dynos is completely false.

[RI_RS4]

arthur

no, we don't agree with respect to the dyno. A mustang dyno, and others, can be run at steady state under full power at full speed. It's just a matter of proper cooling of the load cells.

As for airflow, you and I would just be guessing at what pressure is seen in the intake airbox at speed, without instrumentation or some CFD simulations. But I doubt there is much impact. There are 3 entries into the airbox, all at different absolute pressure.

[aidanjaye]

Airbox speeds (ram air etc).

Think a bike mag did a test a while back and reckoned you have to be well into triple (MPH) figures to make any noticable difference - so if dynos are normally run in third gear - this effect on the road would be very small anyway for the RS4.

[ArthurPE]

Arthur, it's strange, all cars that I tune on our Cartec dyno in France, I tune in steady state, holding the RPM constant by using the dyno's brake, INCLUDING at wide open throttle and at any revs, including peak power RPM.

I think you need to revise your thinking about a thing or two... certainly your last comment about dynos is completely false.

no it isn't...

you hold a 400 HP car under full load for >10 minutes or so?
really?
that's ~300 KW that needs disapated...that equates to >350 A at 480 VAC 3 Ph

air ram effect:
V (fpm) = 4005 (sqrt(dp in "WC)

so at 90 mph you get ~0.15 PSI of boost...
this is ~0.15/14.7 x 100 ~ 1% more HP...not much, but it's something...
the actual is probably twice that due to amplification of the effect by the intake design...and without the flow, it probably loses 5-10%

the problem is not the extra HP due to ram effect, but the lack of air flow inhibiting even the rated HP...and the cooling for longer runs...

there are reasons the EEC does not allow power to be recorded until at a stable rpm for >1 minute...

[ArthurPE]

When you buy an Audi from the dealer you purchase that item from that sales organisation, not the manufacturer. When you go to the 'dealer' to resolve a problem you still deal with the 'dealer'. At what point do Audi USA talk direct to you? Never, thats why if you want to sue Audi, you will never be able to, it will be 'dealer' supported by Audi USA or UK or whatever your location. So your problem will have been dealt with far before that would ever happen. It will only happen if there is a class action for something as severe as the Ford Explorer tire (spealt for the American among us) debarcle.

that is not true...I just sued BMW NA (again) and the dealer, and won...
BMW NA cut the check...

it's all public record...
I have the doc, but it's a PDF, and I can't remove my name, etc.
any ideas?

[northernpar]

FFS! I've just read this thread from start to finish and am now wondering how I can get the 20 minutes of my life back. What appears to have started as ArthurPE posting some data (plus opinion) that throws further doubt into the accuracy/repeatability of RR testing moved rapidly into heated debate (no problem with this as it benefits the arguments - for and against) before degenerating into personal attacks and cheap digs.

If a number of folk want to pursue and debate the mystery of the RR figures then that's their personal choice (personally I choose not to as I have better things to do with whatever time I have left on this planet, as I've said before if the car feels fine then it is fine) but personal attacks and cheap digs really piss me off.

So far I've enjoyed reading and contributing to this forum but if this worrying trend continues it will not be healthy for the overall future of the forum. I'm all for free speech and opinion and recognise that there are some issues that won't be resolved/agreed on here but last time I checked it still wasn't against the law to agree to disagree.

Now, if everyone can pick up all their toys and put them back in the pram maybe we can resume normal service.....?