Valves- carboning up

[no_RS]

Prefer the sound of non-FSI..

[Sims]

This was a £55K car.

I don't expect to see my performance take a hit like a £20K 2.0TDi.

That's an unrealistic expectation - your £55k car is subject to the same rules of physics and chemistry as the £20k car, so to expect it NOT to be affected in the same way is just never going to happen.

Not sure if that's true. I do know Alpina & M Car engines are made to an even higher standard than the normal BMW ones. I suspect the same goes for the GT2/3 engines and certainly does for the Ruf/Manthey Porsche engines

And the AMG & Brabus engines for the Mercs

Surely the Audi RS engines are built better to cope better with the "physics and the chemistry", as ABT/MTM engines are.

[ArthurPE]

whether it's a Ferrari, Porsche GT2, or a Golf Tdi, they are all equally susceptable to deposits, price has absolutely NOTHING to do with it, it's the engine type/configuration...

[ArthurPE]

the accuracy of VagCom airflow measurment is at best 6%, so a 2% difference is meaningless, lost in the noise...
I know a lot about airflow measurement...and an inline, full section, multi-pitot, averaging sensor with airflow straighteners with a 0.1% transmitter can't do much better than 3% overall...add in temperature, atm P and humidity compensation, and the AFM and VagCom MIGHT be able to do +/-8%, maybe...doubt it though
so how can a 2% difference mean anything?

but the accuracy doesn't matter, becasue it's only 1 variable in the fuel rate equation: throttle position, calculated load, rpm, temp, O2 sensors, etc....it's a rough approximation, trimmed (in control parlence, reset) by many other variables...

the 3k to 8k run takes almost all variables out of the equation...it's why magazines use timed runs, not dynos or flow measurements
it is far more indicative of a cars performance than a dyno...that's why most builders call them BS for rating, take it to a track, with a known driver, then see what it will do...many B6/7 S4's around claiming 370+ WHP, yet are no faster in the 1/4 than the RS4, despite also being a little lighter...more DYNO HP, less weight, and slower...

3 to 8k run, temp and wt compensated, and you're good to go...
anybody run this test with a 20 mph tailwind? how about even 10 (<2HP)
most have run it in both directions to cancel incline, but then again, most are smart enough to run it on level ground...
how much impact does slope have? it's in the Bosch book...a 10% grade is steep, power loss? negligable, varies as the cosine, so at 5%, nothing...

people are trying to impinge the method with junk science...why?

[scaghead]

at the rolling road day last year i think i am right in saying 2 cars pippyrips and raudiguy were the only two that hit around 414 bhp.. the thing i cant get my head round is pippyrips car as we know had been cleaned raudiguys had not. so if coking is a factor on output does that mean raudiguys car if cleaned would be running close to 450 bhp??

[ArthurPE]

at the rolling road day last year i think i am right in saying 2 cars pippyrips and raudiguy were the only two that hit around 414 bhp.. the thing i cant get my head round is pippyrips car as we know had been cleaned raudiguys had not. so if coking is a factor on output does that mean raudiguys car if cleaned would be running close to 450 bhp??

do you recall the mods on each car?
how many miles on each?
how many miles since pippyrips was cleaned?

you raise a good point

[2manytoys]

Didn't APR put up a graph from a car where they updated the software (on another website) Because of the shape of the graph, it was suspected that the car had carbon build up problems. They then went away for a while and found another car that wasn't carboned up and posted that up. I'm pretty sure, but if you talk to APR you may find they will be able to confirm this.

Does anyone know.

PS: Arthur, here is another virtual cuddle for you >---' '---<

[scaghead]

at the rolling road day last year i think i am right in saying 2 cars pippyrips and raudiguy were the only two that hit around 414 bhp.. the thing i cant get my head round is pippyrips car as we know had been cleaned raudiguys had not. so if coking is a factor on output does that mean raudiguys car if cleaned would be running close to 450 bhp??

do you recall the mods on each car?
how many miles on each?
how many miles since pippyrips was cleaned?

you raise a good point

i think the two would be able to comment better on the mods, and pippyrips definitly on how many miles since it had been cleaned, but i am sure it was less than 1k..

[mark758]

Aside from the revised inlet system modification, haven't Audi just put essentially the RS4 engine into the RS5?

[ArthurPE]

Aside from the revised inlet system modification, haven't Audi just put essentially the RS4 engine into the RS5?

yep, exact same engine (other than the dual intakes)
makes the same torque, HP is increased by raising the redline...

[PetrolDave]

people are trying to impinge the method with junk science...why?

Ignorance of the subtleties involved?

[P_G]

i think the two would be able to comment better on the mods, and pippyrips definitly on how many miles since it had been cleaned, but i am sure it was less than 1k..

I think you are right. Pippy's car has a straight through Milltek non res non valved system and MRC remap plus ITG filter; rAudiguy's was an RS fabrications gutted cats 3" pipes (Milltek are 2.75") and a Paramount remap and K&N filter?

On the day it was also noted that heat soak and engine temps made a difference.

[Sims]

yep, exact same engine (other than the dual intakes)
makes the same torque, HP is increased by raising the redline...

Exact same engine?

[P_G]

Unless you know anything otherwise Sims then I was led to believe by Audi people at Geneva that it is the same 4.2 FSi V8 unit with revisions as per the press specs, i.e twin air intake rather than single and dual 70mm throttle bodies rather than a single 90mm one on our cars as per the pics I posted up oin the RS5.

The dual air intake is the basis of the mod some German tuners are doing on RS4's; essentially they are taking the designed air intake system off the RS5 and putting it direct on to the RS4 after rehousing the hydraulic fluid and coolant resevoirs into the false battery space in the engine bay.

[HYFR]

so does that mean with modification our RS 4's can make 444 bhp.....MRC...??