Putting "Engine Carbon Clean" to the Test

[Rw@@dy]

Is it the revolution air intake? If so, I got 380 when I had mine rr with it fitted

[MikeFish]

I had about 400bhp on 2 separate occassions about a year apart on different rolling roads (MRC and AmD), both times with a revolution air intake and no carbon clean, so pretty much what you'd expect.
Even with heat soak I wouldn't expect it to be that low. It is either a bad rolling road or you have a vac leak.

[marc1]

The car has been run for 30minutes whilst it was cleaned. How long did it cool for before the after cleaning dyno run.

[RichieRS]

Out of all the performance cars I've owned the RS is definitely the worst for loss of power through heat soak.

I'm not saying the bhp will be massively reduced (although it might be) but the difference in feel from the times I have been stuck in traffic then tried to give it a boot full compared to giving it a boot full after a good run with a constant flow of air is night and day.

So if as Marc suggested above, you RR'd very shortly after doing the 30 min clean I would think your intake temps would be very high still but as Mike suggested. It sounds like vac leak territory with that significant a loss though

What is interesting is that based on your MAF readings from the previous day everything looked good with the calculations typically used to convert to a rough BHP from MAF (MAF 80% of BHP I think?). Yet come RR day, you power figures are almost as low as your MAF readings.

[Cuppa]

https://www.facebook.com/EngineCarbonCl ... 170410622/

[JCviggen]

The car was clearly struggling to keep the ignition timing on the red plot. As far as comparative testing goes the lack of good repeatable data sets is a bit of a disappointment. The graphs which are now being shown off for marketing purposes (obviously) tell a very incomplete and doubtful story.

Without knowing the mode this Dyno Dynamics RR was in and the "normal" numbers coming out of it for other cars the result means nothing. The car could do 430 on MRC's dyno who or 350 who knows. Do some real world testing to see where the car is at.

[FaisalJ]

Excuse me for a couple of days while I try to get all the data together (still need to do after MAF readings on both cars, and borescope the golf). Got a water leak at home to contend with now!!

It is indeed disappointing, mostly for me, that the rs4 isn't healthy. It's a shame nobody else was able to join me.

The golf made 197bhp before and after the clean, and the jag made 237bhp before and after...expected power levels for those cars. I think the dyno was reading correctly.

With regards to heat soak, the car was given 5-10 min to cool down, with the dyno fans on, before we recorded that 365bhp run. I watched the oil temp come down from 107 to 99 degrees in that time. The car had 3 runs pre clean and 4 runs post.

[jamiedal]

Just a quick question - how does the dyno work out flywheel hp?

I had my RS done several months ago and it was showing 315 whp ?

[FaisalJ]

There will be a drivetrain loss assumption somewhere to back out flywheel numbers from the recorded data at the wheels

[Robnic]

Power run in gear ratio nearest 1:1 ratio (4th or 5th) then dyno calcs trans losses on decelaration and produces a figure - a reason different dynos give differing total WHP reading never mind taking into account many other variables, ambient temp, heat soak, ability of fan to replicate travelling wind speed etc., etc. As the B7 ratios are 4th: 1.133, 5th: 0.919 probably dyno'd in 5th?

I do not know if some of the ultra modern dyno's have the ability to input the gear used and exact ratio for a more accurate result, I do know that back in the day an unscruplious dyno operater wanting to 'improve' their post tune results would tap the brakes on the decel run to increase their 'tuned' figures then take your folding from a smiling car owner leaving him to return to his local Camshaft Arms to share the results with his mates

[marc1]

Did it feel any different on the way home Faisal?

[jamiedal]

There will be a drivetrain loss assumption somewhere to back out flywheel numbers from the recorded data at the wheels

Ok cheers what's yours putting out through the wheels then?

[S4WON]

No surprises here, turns out you get what you pay for....

[FaisalJ]

I haven't got any at the wheels numbers unfortunately, will ask austec racing when I call them tomorrow to get the plots for the other 2 cars.

I managed to get out in the RS just now in the dry with no kiddies for the first time. My butt dyno tells me the acceleration feels smoother. It's hard to perceive what is only a 3% increase in power (if the dyno result is to be believed), but I'm confident that it is smoother. Usually, going up the hill near my house the acceleration is a bit lumpy and stuttery when the engine is cold, which wasn't the case today.

I logged the airflow as well. Got 365g/s on 2 out of 4 runs, again about 3% better.

None of these figures are massively out of the realm of statistical error territory, but I am sure I do feel a small difference.

However, the next thing I'm asking myself is; there was a lot of revving involved in the clean...isn't that all there is to an Italian tune up?

It'll be interesting when I get the golf back tomorrow and can borescope the valves, to see any visual difference in the carbon buildup. Or not.

[PetrolDave]

there was a lot of revving involved in the clean...isn't that all there is to an Italian tune up?

Yep.

And you don't have to pay anyone to do an Italian tune... and it's more fun!