B7 RS4 Rolling Road Day 18th April 2009 (Free of Charge)

[klauster]

erm mine gets to 120 easily

[Oli]

Nick, looking your graph whilst your car was running, I would say yours is a MAF fault also, by the way it just peeters off - These are very common for not throwing up a code - Let me know how you get on

[Dom81]

Yet, yesterday the difference between the best and worst stock car (supposedly without issues) is ~70hp.

Thats approaching 20% variance

I think you can look at it another way Jason...

The spread between Outlaw and Pad125 (I've conveniently ignored bn8959!) is just over 5% - surely with all the debate about temperature, time of day, fuel, mileage, time since service, ECU version etc then a 5% spread over 11 cars is to be expected. All of these graphs looked virtually identical.

Well below this and there will clearly be answers - Oli's Maff fault, Klauster perhaps the same, Mac's stuck exhaust flap and possible need for ECU to readapt. I missed Scaghead's run so don't know if there's a similar view?

Statistically (in the loosest possible sense) the only ones that really puzzle are the 340s - a bit behind the pack, but well ahead of the ones with errors / faults. Maybe on another day these would have recorded higher?

It was great meeting everyone, and only cost me a tenner, a miltek, a de-cat and a remap!

[Dom81]

Yes pulled 190 today

Am I missing an obvious joke, or is this for real??

Either way, I'm up for a VMAX

[Oli]

Vmax, surely a track day would be better, rather than a straight line speed test - where's the talent in that? How about a Nurburgring trip, then we can Vmax on the motorway - sounds like much more fun

[ArthurPE]

again, these are arbitrary numbers...they are calculated and ESTIMATED based on gearing, losses, cf's, etc.
a dyno measures torque, NOT HP...
why not just show a plot of the raw torque (uncorrected) graph/numbers...
in the states dyno numbers are seldom back calculated to crank becuase there is no easy way of knowing the loss factor...

excluding the top and bottom 5 results we have an average of ~350...
the 2 tuned cars average ~415 or so...

T = P x D / 4Pi and P = T x RPM
P = mean effective cylinder pressure, basically Cr
D = displacement or engine capacity

I'm not sure how the volumetric efficiency can be increased so dramatically to gain 20% more power...
that's ~20% more power with no increase in displacement, Cr or rpm...

I'ld like to see a drag between say bn8959 and timrs4, a 50 HP spread...bet they are close to dead even, despite a >15% HP delta

[ArthurPE]

as far as 2wd vs awd losses, rototest e92 M3 vs RS4
RS4 21% http://www.rri.se/popup/performancegrap ... artsID=769
M3 10% http://www.rri.se/popup/performancegrap ... artsID=768

twice as much, no flames, no explosions...

it stands to reason:
2 diffs (twice as many)
4 1/2 axles (twice as many)
a xfer diff of sorts
4 driven hubs vs 2
and if on a rolling vs hub dyno, twice the tire slip...

my opinion, the car makes the stated HP and has losses f ~20% for net wheel HP of ~330 HP or so...

[rAudiguy]

Vmax, surely a track day would be better, rather than a straight line speed test - where's the talent in that? How about a Nurburgring trip, then we can Vmax on the motorway - sounds like much more fun

you are missing the point Oli, we're talking about having space to do drag races to really see what the difference is in power in real terms on the road. you wouldn't be able to do that on a track unless you employed the Stig for the day and sent him out to do a lap in each car......

I f we have space you can do runs as Arther says between 2 or 3 cars to see how they fair over a mile strip. We can also have VAG com connected and look at all sorts of data which I would be very interested in.

J are you up for finding an air strip and doing some runs??

Jim

[Oli]

Not missed the point at all, I think it might be a bit boring (well obviously not, but when compared with my idea), with little skill involved. Don't get me wrong I would probably come along, but are cars are designed to be driven, not drag raced, if you get my just, hence why I suggested Nurburgring, it would be a quality roadtrip, and we all get to drive round the famous circuit, for not a lot more than what you are suggesting for the Vmax.

Anyway, just my tuppence

[pippyrips]

[quote="Oli"]Not missed the point at all, I think it might be a bit boring (well obviously not, but when compared with my idea), with little skill involved. Don't get me wrong I would probably come along, but are cars are designed to be driven, not drag raced, if you get my just, hence why I suggested Nurburgring, it would be a quality roadtrip, and we all get to drive round the famous circuit, for not a lot more than what you are suggesting for the Vmax.

Anyway, just my tuppence[/quote

The crappy pound to euro exchange rate has put pay to my plans to visit the ring this year

[ArthurPE]

Not missed the point at all, I think it might be a bit boring (well obviously not, but when compared with my idea), with little skill involved. Don't get me wrong I would probably come along, but are cars are designed to be driven, not drag raced, if you get my just, hence why I suggested Nurburgring, it would be a quality roadtrip, and we all get to drive round the famous circuit, for not a lot more than what you are suggesting for the Vmax.

Anyway, just my tuppence

I see your point, obviously the Ring and 'Bahn would be more fun, to say the least...

but to quantify power a drag with traps is easy, repeatable and objective, not subjective...do 3 runs and average, do 5 and toss the lo/hi, whatever...
awd makes the launches fairly repeatable...

I think drag racing is silly, but a far more accurate representation of a cars absolute power (not handling, quality, etc., just power)...dynos have a place a test tool, but not a yardstick, unless raw data is compared to a common baseline...and even then the varience may be as high as 10%...

[scaghead]

i think arthur is right the only way you can tell is in a straight line over a couple of runs... on yesterdays rr mine clocked in the lowest 310 you cant really count olis and macs runs.. so i have got the chip van

[Oli]

bloody fast chip van

[scaghead]

can someone put my details to the list bit technical for us fish and tatoes drivers... amd re-map, 22k, 4.5k oil cheers in advance.

[rAudiguy]

Just to say I wasnt suggesting for a moment that I dont want to do a track day or go to the ring (If they let me on!!) but I was talking about sorting out power figures etc.

Anyway here are a couple of pictures which show a few B7's.........