dyno lies....

[ArthurPE]

good questions...
I'm guessing on an inertia type, drums/mass are measured independently
on one that measures force directly, I bet it messes with the control systems of the car, and that's why RS4's read low, they reduce torque, they think the car is slipping/unstable...

I just calced engine power from accel graphs:
looked at the 1000 rpm at the end of 3rd to determine avg power...
measured time delta
measured v delta
calc'ed a = v delta/t delta
calc'ed m in slugs
calc'ed force in lbs thrust F = ma
calc'ed delivered torque = thrust/tire radius/overall gear ratio
calc'ed power = torque x rpm/5252 (used midrange rpm, RS ~ 7400, M ~ 7600)
they were within 3%

this and the rest of the thread, SR71's stuff cleared a few things up, tells me a couple things:
RS power ~ M power ~ rated
the slight advantage the M3 has in straight line speed is due to wt difference
losses are offset by the awd: higher drivetrain, lower tire/surface
the RS punches above it's wt class

time to go play

Out of curiousity, on a constant force braked dyno, how does the dyno deal with the 40:60 torque bias?

Does it force the car into 50:50 mode because not all drums are individually braked?

That said, if you don't input the torque bias, how does it know how to brake the individual drums?

If the car is running in 50:50 mode versus 40:60 mode, are the losses now artifically high?

Does a GTR on the dyno show a 50:50 torque split on the dash as opposed to a 95% split to the rear on the road?

The Shootout Day would be great....although it'd no doubt create more questions than answers...

[ArthurPE]

+1

Think somebofy mentioned it on here earlier but is there any reason the rs246 club have not organised a 1/4mile day or a day at bruntingthorpe or the like. Reckon it would be far more fun and interesting than a dyno day and would certainly put this argument to rest. You could invite rs6's along m3 etc and would be a good laugh

4 different mags:
108.1
109.7
109
110

the M3 usually a few higher

[ArthurPE]

Wow, 9 pages of Artur Buildup, and I thought Carbon Buildup was a problem.

Note to self: untick box "Notify me when a reply is posted" so I don't have to return

you are not helping anything
let the grown-ups discuss this please
thank you

[ArthurPE]

Did the test you asked for. 3rd gear timed from 3000 - 8000 rpm. Not impressed by the time though. Either people at this forum tell "stories" or my car lack some power. Average timing was 6.7 sec. Used the built in lap timer so it might be inaccurate to +- 0.2sec. Tried one drag 0-100 km/h as well, a little wheel slip in the start, result was 4.1 sec( using the racelogiq performance box).

Weight of the car is 1720kg + me at 80 kg + some extra due to mods, maybe 20-30 kg or so, a total of 1820-1830.

Any comments ?

6.7 is amazing, the avg of all the runs I have is 8.3+ or so temp adjusted for stock cars...1.6 sec is a huge delta!
I estimate +25% power or so...

that tells me you are making much more power than stock...and is kind of where I thought it should be...there is a video out of the new APR sc system prototype, I've timed the same run, comes close to 6.5, but they use all the gears...your car is making mucho power...

[larshs]

I think it's only 0.45 bar. But MTM told me that usually all B7's output ~380 bhp, but after a remap ~435 bhp. If thats the case the calculation will probably be a little different or? But with the new exhaust I expected to see 535 bhp on the dyno (Corrrected power).

Never cleaned the valves, and wasn't there when they installed the SC

0.45 bar ~ 6.5 psi...

I don't buy a remap regaining 55 HP, that is 15%, huge...

I'm guessing your baseline is close to stock, 410 or so...low as I said
your SC gain: 1 + ( 0.6 x 6.5/14.7) x 425 ~ 520 HP
I would say you are about right, but remember, the dyno numbers may vary (accuracy) by 5% or more, 20 to 25 HP...or more...

I would love to see some 3rd gear pulls, timed from 3000 to 8000 rpm using the OBC timer...2000 rpm, stomp it, lol

I have to assume whom ever installed the SC would have cleaned the valves if they considered them an issue...they would definitely want to maximize power to make sure you were satisifed, especially if they cost 50HP as is claimed

Did the test you asked for. 3rd gear timed from 3000 - 8000 rpm. Not impressed by the time though. Either people at this forum tell "stories" or my car lack some power. Average timing was 6.7 sec. Used the built in lap timer so it might be inaccurate to +- 0.2sec. Tried one drag 0-100 km/h as well, a little wheel slip in the start, result was 4.1 sec( using the racelogiq performance box).

Weight of the car is 1720kg + me at 80 kg + some extra due to mods, maybe 20-30 kg or so, a total of 1820-1830.

Any comments ?

Did you see my post above ArthurPE? What do you think?

[HYFR]

Arthur, your a wanted man

http://audisrs.com/about13305.html&highlight=

[ArthurPE]

Arthur, your a wanted man

http://audisrs.com/about13305.html&highlight=

oh shyte
I hope the under-rating/deposit mafia hasn't got a hit out on me !!

[larshs]

Did the test you asked for. 3rd gear timed from 3000 - 8000 rpm. Not impressed by the time though. Either people at this forum tell "stories" or my car lack some power. Average timing was 6.7 sec. Used the built in lap timer so it might be inaccurate to +- 0.2sec. Tried one drag 0-100 km/h as well, a little wheel slip in the start, result was 4.1 sec( using the racelogiq performance box).

Weight of the car is 1720kg + me at 80 kg + some extra due to mods, maybe 20-30 kg or so, a total of 1820-1830.

Any comments ?

6.7 is amazing, the avg of all the runs I have is 8.3+ or so temp adjusted for stock cars...1.6 sec is a huge delta!
I estimate +25% power or so...

that tells me you are making much more power than stock...and is kind of where I thought it should be...there is a video out of the new APR sc system prototype, I've timed the same run, comes close to 6.5, but they shift...your car is making mucho power...

Thanks for your comments. I should be happy with it then (?). Have to try up against a stock B7 to actually see the difference before I believe it.

[ArthurPE]

0.45 bar ~ 6.5 psi...

I don't buy a remap regaining 55 HP, that is 15%, huge...

I'm guessing your baseline is close to stock, 410 or so...low as I said
your SC gain: 1 + ( 0.6 x 6.5/14.7) x 425 ~ 520 HP
I would say you are about right, but remember, the dyno numbers may vary (accuracy) by 5% or more, 20 to 25 HP...or more...

I would love to see some 3rd gear pulls, timed from 3000 to 8000 rpm using the OBC timer...2000 rpm, stomp it, lol

I have to assume whom ever installed the SC would have cleaned the valves if they considered them an issue...they would definitely want to maximize power to make sure you were satisifed, especially if they cost 50HP as is claimed

Did the test you asked for. 3rd gear timed from 3000 - 8000 rpm. Not impressed by the time though. Either people at this forum tell "stories" or my car lack some power. Average timing was 6.7 sec. Used the built in lap timer so it might be inaccurate to +- 0.2sec. Tried one drag 0-100 km/h as well, a little wheel slip in the start, result was 4.1 sec( using the racelogiq performance box).

Weight of the car is 1720kg + me at 80 kg + some extra due to mods, maybe 20-30 kg or so, a total of 1820-1830.

Any comments ?

Did you see my post above ArthurPE? What do you think?

already responded, a post or 2 up...
what do I think?
I think I want your car :

[ArthurPE]

Did the test you asked for. 3rd gear timed from 3000 - 8000 rpm. Not impressed by the time though. Either people at this forum tell "stories" or my car lack some power. Average timing was 6.7 sec. Used the built in lap timer so it might be inaccurate to +- 0.2sec. Tried one drag 0-100 km/h as well, a little wheel slip in the start, result was 4.1 sec( using the racelogiq performance box).

Weight of the car is 1720kg + me at 80 kg + some extra due to mods, maybe 20-30 kg or so, a total of 1820-1830.

Any comments ?

6.7 is amazing, the avg of all the runs I have is 8.3+ or so temp adjusted for stock cars...1.6 sec is a huge delta!
I estimate +25% power or so...

that tells me you are making much more power than stock...and is kind of where I thought it should be...there is a video out of the new APR sc system prototype, I've timed the same run, comes close to 6.5, but they shift...your car is making mucho power...

Thanks for your comments. I should be happy with it then (?). Have to try up against a stock B7 to actually see the difference before I believe it.

if your times are anywhere near accurate, you should have a large advantage over a stock car...

just side by side in 3rd gear, 3k to 8k, >1 sec
that may be as much as 8+ car lengths, more like 12!

[dlextreme1977]

good questions...
I'm guessing on an inertia type, drums/mass are measured independently
on one that measures force directly, I bet it messes with the control systems of the car, and that's why RS4's read low, they reduce torque, they think the car is slipping/unstable...

I just calced engine power from accel graphs:
looked at the 1000 rpm at the end of 3rd to determine avg power...
measured time delta
measured v delta
calc'ed a = v delta/t delta
calc'ed m in slugs
calc'ed force in lbs thrust F = ma
calc'ed delivered torque = thrust/tire radius/overall gear ratio
calc'ed power = torque x rpm/5252 (used midrange rpm, RS ~ 7400, M ~ 7600)
they were within 3%

this and the rest of the thread, SR71's stuff cleared a few things up, tells me a couple things:
RS power ~ M power ~ rated
the slight advantage the M3 has in straight line speed is due to wt difference
losses are offset by the awd: higher drivetrain, lower tire/surface
the RS punches above it's wt class

time to go play

Out of curiousity, on a constant force braked dyno, how does the dyno deal with the 40:60 torque bias?

Does it force the car into 50:50 mode because not all drums are individually braked?

That said, if you don't input the torque bias, how does it know how to brake the individual drums?

If the car is running in 50:50 mode versus 40:60 mode, are the losses now artifically high?

Does a GTR on the dyno show a 50:50 torque split on the dash as opposed to a 95% split to the rear on the road?

The Shootout Day would be great....although it'd no doubt create more questions than answers...

What is your take on the new rs5? Is it the same engine as rs4 as many are claiming it is different. Evo mag are claiming the rs5 is barely quicker than an s4 despite the hp deficit, and lacks roll on power. Pattern emerging? Dunno- using your mighty calculations how should an rs5 stack up against an rs4? Maybe s4's are underated some seem to trap 107-109 i think...

[Terry1948]

dlextreme1977 what car do you run out of curiosity. I sold my M3 to buy the RS4 wished I kept it and bought the RS4 aswell because they are so different. The M3 for going sideways and being a holigan and the RS4 for covering ground quickly and without drama. I do not know why people try to compare them its like comparing a claret and a burgandy both red and lovely but very different.

[Sims]

dlextreme1977 what car do you run out of curiosity. I sold my M3 to buy the RS4 wished I kept it and bought the RS4 aswell because they are so different. The M3 for going sideways and being a holigan and the RS4 for covering ground quickly and without drama. I do not know why people try to compare them its like comparing a claret and a burgandy both red and lovely but very different.

I'll drink to that.

[ArthurPE]

good analogy...I have an e46 M3 and it's a great canyon carver/backroad racer...the RS is like a Lear jet, high speed point to point, weather impervious...

I had an amazing drive last night, 30 minutes, all mountain roads, a little drizzle, absolute concentration, a little Art Farmer on the squawk box...
it felt good and stable, very nice pace...
wife was hanging on though, lol
her hand bumped into the shift once, I asked if she was trying to shift?
she said 'shift!, I need a brake pedal!"

dlextreme1977 what car do you run out of curiosity. I sold my M3 to buy the RS4 wished I kept it and bought the RS4 aswell because they are so different. The M3 for going sideways and being a holigan and the RS4 for covering ground quickly and without drama. I do not know why people try to compare them its like comparing a claret and a burgandy both red and lovely but very different.

[HYFR]

looks like a good drive Arthur...whats the speed limit on those roads in the US ?