APS remap, Milltek exhaust and GruppeM fitted today

[ArthurPE]

here's another take...

look at any decent ET or trap speed calculator...
there are many that are quite accurate within a given tolerance...
using a weight of 4200 and trap of 106 gives ~380 RWHP...'wheel'
the ET is ~13 flat...

[sonny]

Intresting, are you on about the dashboard mounting performance devices, (cant think of name now)

[SR71]

Hey ArthurPE,

It is an age old debate...

However, you might be interested to know that at least one owner here in the UK has been able to get Audi to "take their car back" because it has not produced the numbers they've quoted...

If you trawl back through the forum you'll find the posts.

I think a fair summary might be that it is NOT reasonable for an owner to have to pull their engine in order to verify OEM stats.

The owner in question provided various RR generated figures extrapolated backwards which demonstrated over a significant period and multiple facilities that the car did not produce the OEM figures.

So the law-suit has already happened....

Whether or not you're happy with your particular car is a question only you can answer....

[BlingBling]

SR71 the lawsuit never happened. The owner came to an agreement with Audi. He then went out and bought a V10 S6 IIRC. The RS4 engine has SAE certification for its given rating. SAE certifiactions are not given out on a whim.

[SR71]

BlingBling,

For anyone interested: http://www.rs246.com/index.php?name=PNp ... 5&start=45

Technically you are correct.

I should have put "law-suit" in inverted commas. I did say Audi "took the car back".

The gentleman concerned was, however, quite willing to take it all the way.

We can argue about why Audi decided to capitulate in this case.

SAE certifications may not be given out on a whim, so why settle out of court?

Personally, I think the engine probably does make 414bhp....at some unobtainable optimal test-point!

However, name me another Audi that doesn't make the OEM figures quoted on such a consistent basis as the B7 RS4...

There isn't a SINGLE unmolested car in the UK that has ever tested over 400bhp, let alone 414bhp...is there?

[S2tuner]

Regarding dyno measured numbers, I'll beg to differ but Maha dynos are what the factory uses to check power on most of their cars, they own about 20 of, and a B7 RS4 on a Maha dyno pretty much always comes out at around 380 crank, give or take and maybe more for a lucky few who have "good" engines. You can speculate about dynos not being able to measure losses correctly as long as you wish, I know that if Audi use MAHA chassis dynos and use the crank numbers measured by those to check power of their cars, then Maha can't be doing everything wrong and even though the losses can't be measured properly, I'm sorry but every time I've had a B5 RS4 or a B5 S4 on a Maha, they always came out at 380 respectively 265 crank HP standard, give or take a few HP but never 40 down on the rated standard crankshaft figure. It's always been a BIG debate with american people, who only seem to use wheel numbers (I only know of one US dyno that displays crank HP or people that use corrected crank HP measured on a dyno in the US, and that company has been bust for a few years now).

So there'll always be an argument, I'll just say that whenever I've measured a B5 or whatever other car in standard trim on a european dyno, it always came out somewhere not too far away from the factory rated crankshaft HP numbers, if the car was healthy of course.

Just my 0.02,

Mihnea

[ArthurPE]

I'm talking about something like this: http://www.race-cars.net/calculators/et_calculator.html
they are very accurate, based on a mathematical model of many data points...

say the RS4 weighs 4100 lbs with driver
say it runs 13 flat and 106...pretty representative numbers...
that avgs ~ 370-380 RWHP

even at 4100 lbs and 105 mph trap ~370 RWHP...
these indicate to me with REAL WORLD measured data, drag times/speed, that a 4100 lb car needs at least 370 RWHP to trap ~105 mph...

RotoTest http://www.rri.se/popup/performancegrap ... artsID=281 RWHP ~350 ~17% less, torque 277 l-ft 13% loss
these guys are one of the largest testing agencies in the world....

[ArthurPE]

Regarding dyno measured numbers, I'll beg to differ but Maha dynos are what the factory uses to check power on most of their cars, they own about 20 of, and a B7 RS4 on a Maha dyno pretty much always comes out at around 380 crank, give or take and maybe more for a lucky few who have "good" engines. You can speculate about dynos not being able to measure losses correctly as long as you wish, I know that if Audi use MAHA chassis dynos and use the crank numbers measured by those to check power of their cars, then Maha can't be doing everything wrong and even though the losses can't be measured properly, I'm sorry but every time I've had a B5 RS4 or a B5 S4 on a Maha, they always came out at 380 respectively 265 crank HP standard, give or take a few HP but never 40 down on the rated standard crankshaft figure. It's always been a BIG debate with american people, who only seem to use wheel numbers (I only know of one US dyno that displays crank HP or people that use corrected crank HP measured on a dyno in the US, and that company has been bust for a few years now).

So there'll always be an argument, I'll just say that whenever I've measured a B5 or whatever other car in standard trim on a european dyno, it always came out somewhere not too far away from the factory rated crankshaft HP numbers, if the car was healthy of course.

Just my 0.02,

Mihnea

how do you measure losses?
only 1 accurate way: dyno the engine out of the car, then in...
but they are not linear, they vary with speed, load, etc.

or do a coast down test, less accurate...run the car to 100 mph, then let it coast...measure the time to slow to a given speed and calculate the losses after deducting drag...
still not accurate...why? becasue friction is different under engine torque or road rolling resistance...forces in opposite directions...

technically 420 HP makes sense...
4.2 l
12.5:1 Cr
7800 rpm

M = Pe x V/(4Pi)
M = moment ot torque
Pe = effective compression ~ Cr + volumetric eff
V = displacement

RS4: M = 12.5 x 14.7 lb/in^2 x 256 in^3 / (4Pi) ~ 3743 lb-in ~ 312 lb-ft...
pretty close to the rated 317...

P = M x w
w = 2 Pi n
n = rps ~ engine speed...

so high Cr and high n (rpm) = high M and P...

from what I understand the German DIN and TUV ratings are very strict...to advertise a car at 420, it must make 420 within a very small tolerance...

[Gecko]

- The car was sold as having 307Kw (414bhp). As such this is the minimum the car should produce. I wasn't sold a car with a toleranced power rating of 307Kw +-15%.
- The car was stated as having specific 1/4mile and 0-100 times. Again these figures weren't toleranced so every car should be able to achieve them, in real world tests.

So why can't we just ask Audi for accurate information?

I know if I sent Audi a letter... I doubt I would get a reply.
But if a letter was sent to Audi on behalf of all owners, outlining the questions we want answered and carrying the signatures of every owner (from this and the other forums) then I would expect Audi to respond.
This could be done via a solicitor in a similar way to a group action. I'm happy to throw in $10 for my portion of the solicitor's fees.

Surely as a group we are a very powerful force.
It is cheaper for Audi to service an existing customer for repeat business than it is to find a new one and I know that if Audi ignored this letter, I would be one Audi owner looking at a different marquee for all future purchases... and I'm sure many of you feel the same.

[SR71]

ArthurPE,

I'm not sure what you're trying to say...

On the one hand you're posting links which generate results by curve-fitting the statistical database behind them...like you say, mathematical modelling.

They're not based on first principles but nevertheless can work, especially when the data set is large, because Newtons law's apply universally.

These suggest, that based on the times the car runs, the figures are good.

Then you post the RotoTest results which show, inspite of their pedigree, the car well down on power and torque.

Then you show, from "first principles", the car should approximate the quoted figures based on some of its specifications. I don't suppose, however, many of us doubt that!

As the previous debate will demonstrate, I imagine its only a small proportion of the board population that don't believe that Audi could demonstrate that the B7 will produce 414bhp on their uber-controlled test rig at Quattro GmbH.

However, neither is it fair to suggest that guys who spend their lives day in day out testing performance vehicles using chassis dynometers shouldn't be able to reproduce OEM results with a fair degree of accuracy inspite of the theoretical objections.

There are ways around these, and as your data set becomes large, the results should approximate OEM, as you build up an idea of the fair losses and/or how ambient conditions affect the result etc etc.

So how does one reconcile these two bits of information?

Well, conspiracy theories may abound, but for me, what AntoRS4 suggests is most plausible...

Namely, that because of the state of tune, this particular car is highly sensitive to temperature and octane. You're just not going to get 414bhp unless everything is "spot on".

In addition, I'm not convinced that the Mo(t)ronic ESP/TC (call it what you want) isn't far too sensitive for the application. We all know that you have to disable the bloody thing just to get a good shift between 1st and 2nd when you're hussling....and that it'll switch itself back on if it doesn't like something....

It appears that dyno-testing the C6 RS6 has also delivered results nigh on useless although this may be more to do with the auto-box.

This means that on the RR, the car is a pig.

Put the two together and you get unhappy owners.

So you're back to the drag strip and your statistical databases or a relative comparison against your mate who runs a EVO 8 FQ400....whereupon the car always acquits itself fairly well.

Thats my $0.02 on the matter anyway...

[P_G]

I tend to agree with SR71, I have seen my B7 RS4 tw0 V10 S8's and a C6 RSD6 now not produce the quoted figures and it tends to suggest the Bosch motronic system or ESP9 or 10, which B6 S4's, B5 RS4's and the such do not have I would imagine R8's also have the same issue although I have not heard of any R8 dyno results. the new system which is accountable for the 60/40 rear power bias appears to be attributable to any car with this being a git on the r/r's.

Therefore like both SimonFV8 and myself did, is it not better the have our RS4's dyno on the same dyno, either Maha or Dyno Dynamics and ensure all our OEM cars are producing the same power? You would then hypothesise that all the cars have the same power loss through dyno tests whioch appears to be between 24 and 30% which Audi have been quoted to have suggested and therefore our cars are all the same. Then if someone of that group is brave enough for theirs to be bench dyno'ed then the true results could be determined.

Until that time this debat will rumble on uneccessarily unless of course you are unhappy with your car's performance which me personally I am not and if I were , I would remap it, stick a s/s exhaust on it or trae it up for something more poerful. You won't get Audi to admit to anything even if every RS4 owner petitioned them.

[ArthurPE]

ArthurPE,

I'm not sure what you're trying to say...

On the one hand you're posting links which generate results by curve-fitting the statistical database behind them...like you say, mathematical modelling.

They're not based on first principles but nevertheless can work, especially when the data set is large, because Newtons law's apply universally.

These suggest, that based on the times the car runs, the figures are good.

Then you post the RotoTest results which show, inspite of their pedigree, the car well down on power and torque.

Then you show, from "first principles", the car should approximate the quoted figures based on some of its specifications. I don't suppose, however, many of us doubt that!

As the previous debate will demonstrate, I imagine its only a small proportion of the board population that don't believe that Audi could demonstrate that the B7 will produce 414bhp on their uber-controlled test rig at Quattro GmbH.

However, neither is it fair to suggest that guys who spend their lives day in day out testing performance vehicles using chassis dynometers shouldn't be able to reproduce OEM results with a fair degree of accuracy inspite of the theoretical objections.

There are ways around these, and as your data set becomes large, the results should approximate OEM, as you build up an idea of the fair losses and/or how ambient conditions affect the result etc etc.

So how does one reconcile these two bits of information?

Well, conspiracy theories may abound, but for me, what AntoRS4 suggests is most plausible...

Namely, that because of the state of tune, this particular car is highly sensitive to temperature and octane. You're just not going to get 414bhp unless everything is "spot on".

In addition, I'm not convinced that the Mo(t)ronic ESP/TC (call it what you want) isn't far too sensitive for the application. We all know that you have to disable the bloody thing just to get a good shift between 1st and 2nd when you're hussling....and that it'll switch itself back on if it doesn't like something....

It appears that dyno-testing the C6 RS6 has also delivered results nigh on useless although this may be more to do with the auto-box.

This means that on the RR, the car is a pig.

Put the two together and you get unhappy owners.

So you're back to the drag strip and your statistical databases or a relative comparison against your mate who runs a EVO 8 FQ400....whereupon the car always acquits itself fairly well.

Thats my $0.02 on the matter anyway...

the curve fitting is very accurate within a given tolerance...
and it's based on real world, measured data...
not a wag (wild ass guess) on some 'power loss' factor...

the Roto test shows WHEEL HP of 350...
according to some the RS4 produces only 370 crank...
so the rototest 350 would imply only 5% in losses based on the 370 figure...impossible for an awd car with a 4:11 gear ration...
the rototest numbers imply 17% in losses for this type of driveline...
the 17% is in line with accepted figures...
this would seem to bear out that the RS4 makes ~420 HP...NOT 370...

the 2 positions support and reinforce each other...
at least for those who are objective...

you know what they say?
you get what you pay for...2 cents doesn't buy much

I see it in all forums:
trust some internet, self proclaimed, faceless guru's 'butt dyno', seat of the pants, expertise over DIN, Audi, TUV, SAE, RotoTest, etc.
I'm sorry...I can't make the leap of faith...

About SAE J1349 Certified Power

Power and torque certification provide a means for a manufacturer to assure a customer that the engine they purchase delivers the advertised performance. This SAE Standard has been written to provide manufacturers with a method of certifying the power of engines to SAE J1349 or SAE J1995. Document SAE J2723 specifies the procedure to be used for a manufacturer to certify the net power and torque rating of a production engine according to SAE J1349 or the gross engine power of a production engine according to SAE J1995.

a bit about the SAE http://www.sae.org/about/general/history/

[ArthurPE]

duplicate post...oops

[SR71]

I see it in all forums:
trust some internet, self proclaimed, faceless guru's 'butt dyno', seat of the pants, expertise over DIN, Audi, TUV, SAE, RotoTest, etc.
I'm sorry...I can't make the leap of faith...

You know what, we probably agree...

But you'd think Audi could design a DRC system wouldn't you...especially after getting it wrong in the C5 RS6 application.

Then along comes the B7, with, surprise, surprise, a DRC system which ain't up to the job!

You'd also think they could design a brake pad which doesn't start scoring your rotors when its only 45% worn.

Then along comes the B7, with, surprise, surprise, a brake pad with rivets that do the aforementioned! Let alone the issues that manifest themselves with the rotors if you actually use the car like the publicity suggests you should!

So, you can learn alot from those useless internet gurus sometimes...

It wouldn't be the first time a manufacturer f**ked up would it...



PS: My car made nowhere near 350 at the wheels. In fact I've never seen a B7 make 350 at the wheels! My driveline losses came out at ~22%. 5% of 420hp is a big number!

[ArthurPE]

I see it in all forums:
trust some internet, self proclaimed, faceless guru's 'butt dyno', seat of the pants, expertise over DIN, Audi, TUV, SAE, RotoTest, etc.
I'm sorry...I can't make the leap of faith...

You know what, we probably agree...

But you'd think Audi could design a DRC system wouldn't you...especially after getting it wrong in the C5 RS6 application.

Then along comes the B7, with, surprise, surprise, a DRC system which ain't up to the job!

You'd also think they could design a brake pad which doesn't start scoring your rotors when its only 45% worn.

Then along comes the B7, with, surprise, surprise, a brake pad with rivets that do the aforementioned! Let alone the issues that manifest themselves with the rotors if you actually use the car like the publicity suggests you should!

So, you can learn alot from those useless internet gurus sometimes...

It wouldn't be the first time a manufacturer f**ked up would it...



PS: My car made nowhere near 350 at the wheels. In fact I've never seen a B7 make 350 at the wheels! My driveline losses came out at ~22%. 5% of 420hp is a big number!

the 420 rating is not by Audi alone, but verified/certified by TUV, DIN, SAE, etc.

it's one thing to have a design/mfg flaw...entirely another to indict the company for outright lying...not to mention the legal consequences of them doing so...

within std tolerances ~22% loss for this driveline is not unbelievable...
the e46 M3 (I own one) usually dynos ~270, down from the rated 333 (US SAE), a 19% loss for a rwd car with a much lower Fd ratio (3.62)

so, for an RS4 at 420 (FW) to dyno ~335 rwhp with a 20% loss is within the range I would expect...

it depends on dyno, corrections, operator, fuel, amb conditions (atm press, temp, humid, etc.)...

but to accuse Audi (and the SAE, DIN, TUV, etc.) of criminal activity and conspiracy seems a bit over the top...