Putting "Engine Carbon Clean" to the Test

[MikeFish]

I'm not one to normallly feel small differences in changes (couldn't tell any difference in standard non SS+ springs with broken DRC and old top arms for KW lowering kit with healthy DRC and new top arms), but I can definately say it was smoother revving thoughout the rev range after the clean. And my car has regular Italian tunes.

[iduff]

Encouraging to hear that an Italian Tune-Up is the same on both sides of the water.

[marc1]

We've heard about your furious Italian tune ups Mike.

[MikeFish]

We've heard about your furious Italian tune ups Mike.

Lol, furious but below the speed limit in case any plod are reading.

[Cuppa]

http://www.a5oc.com/forums/audi-a5-s5-t ... ost1083657

[FaisalJ]

http://www.a5oc.com/forums/audi-a5-s5-t ... ost1083657

Thanks for posting Cuppa.

That S5 is probably a better test subject than mine, as the engine power suggests it's healthy, and it probably had more carbon if it has unknown history. Mine was carbon cleaned in January at AMD, I don't know the mileage at that point but would have been over 10k miles ago and although MRC suspected carbon was an issue when they had the car over the summer, it shouldn't be horrendous. I also like the fact the S5 clean was done on the dyno.

I've got my car booked into MRC for a couple of weeks time so they can have a look, find any faults, and tweak the stage 2 map. I'm not asking them to carbon clean it. Lets see what power they can get out of it! Doug mentioned something interesting...he said that with the revolution intake, the MAF tends to read 40g/s higher than if the stock airbox was in place...therefore my 365g/s becomes 325g/s.

Cuppa - What's your view on why the golf didn't see any gains? It was 197bhp before and after the clean, having never been cleaned in 85k miles. Stock GTi's seem to dyno between 195-205bhp, so I would have thought there would be a small potential for recovery of power there? Is the turbo engine just less susceptible to losses from carbon?

I pick up the golf tonight, I'll see what my butt dyno, MAF readings and borescope tell me.

[IanH755]

TFSi seems to be less effected by carbon issues than FSi. It still happens but it takes longer to build, probably because the pressurised air doesn't have time to stick to the valves.

[Cuppa]

Not being there it is difficult to comment as was not able to feel the throttle response before/after or the sound/shake of the engine before/after, but the race setup Golf GTIs we did a dyno test on we struggled with temps as we couldn't get it down to a matching temp afterwards - closest we could get was 1.5 hotter and every degree matters.

Today's run on the S5 was strictly controlled. The S5 did not move once it was on the dyno and the temps were managed carefully by Surrey Rolling Road Ltd to match - impressed with them actually as my first visit there. So no change could be put down to temps or how it was strapped down, etc.

I can go and do two identical cars with same mileage and they can be completely different - one may have been driven hard with good fuel so fairly clean, one will have been driven gently with cruddy fuel and they can be completely different starting points, but usually end up same end result unless something mechanical is going on.

I've done plenty of B7 RS4s and B8 S5s now and can usually tell by sound and throttle response alone whether they are clogged up or not.

[Cuppa]

You have to remember also we are not talking about gains here. We're talking about recovering what is lost. Soon as you start talking 'gains' you get in the wrong mindset.

[Rw@@dy]

The difference with the golf based on the figures, could be more around mpg and emissions than power increase. Be interesting to see if that's the case.

[MikeFish]

Doug mentioned something interesting...he said that with the revolution intake, the MAF tends to read 40g/s higher than if the stock airbox was in place...therefore my 365g/s becomes 325g/s.

AHA!! Doug is saying that the revolution intake is allowing more air into the intake so they produce much more power, but on a dyno they suffer because of poor airflow!!

My MAF readings calculate to exactly what I saw on the dyno at MRC and AmD. But I have a cold air feed so that helps (and made a big difference when I swapped the MRC supplied pipe for a bigger one!.

[MikeFish]

So looking back, you saw a 13bhp rise. The car was sick at the time so potentially could have seen a bigger rise (but that is speculation). The car had had an old fashioned carbon clean 10 months ago. There was a nice torque rise too, but also it got rid of a big dip in the torque at about 2.5k (from memory).
Looks promising I'd say.

[FaisalJ]

I can't call it either way! I don't think I particularly helped in understanding this any better unfortunately!!

On the one hand, the car feels better and there was a power gain, albeit on a sick car.

On the other hand, the borescope on the golf shows no carbon shifted in the intake. So was any cleaning just in the combustion chamber and downstream? Would an Italian time have yielded the same results?

Needs more testing I reckon.

If MRC need my intake off, I'll ask for some pics to see what it looks like in there.

[Dolphie]

Out of interest, is an oil change recommended after this work?

[Rw@@dy]

They said to me it was recommended to be changed after