RS4 - not making the 414bhp out of the factory - why?

[berg]

Seen a few threads on here where it was stated that quite a few of the RS4 (mk2) did not make the stated power output - why was this, was it ever confirmed? What did they make - 390bhp? 395?

is it common with the bigger normally aspirated engines ie did all the E90 M3's make their 414bhp? 

[Poverty]

They make the power from factory, until the valves get coaked up with sh*t

[rich83]

Same with a lot of cars to be honest. Clio RS200..... 200bhp??? Nope... more like 190!

[Oli]

Seen a few threads on here where it was stated that quite a few of the RS4 (mk2) did not make the stated power output - why was this, was it ever confirmed? What did they make - 390bhp? 395?

is it common with the bigger normally aspirated engines ie did all the E90 M3's make their 414bhp? 

Yes mine didnt either!  But when performance stats were check it always hit the book times??  Not sure why this was?

[berg]

They make the power from factory, until the valves get coaked up with sh*t

so was this a particular issue with this car that Audi resolved, or would your TTRS possibly suffer also?

[Poverty]

Only the newest VAG cars which are just coming out now won't have the issue ie new S3.

My valves will also sh*t up, not quite as bad as the rs4 as Audi have tried some new things to try and stop it but it will envitably happen.

I don't think it affects turbo cars as much though.

[Scottymon]

Does this mean the R32 is no longer the fastest VAG car?

[tony_danza]

It's a problem with VAG direct injection cars, the fuel doesn't clean the valves/inlets. I'm sure they've done something to restore it by now.

FWIW I really like the B7 RS4, I had a day at Silverstone in one courtesy of Audi a good few years back, if you forget the whole "struggle making it faster" bit, the engine is an absolute gem.

[berg]

It's a problem with VAG direct injection cars, the fuel doesn't clean the valves/inlets. I'm sure they've done something to restore it by now.

FWIW I really like the B7 RS4, I had a day at Silverstone in one courtesy of Audi a good few years back, if you forget the whole "struggle making it faster" bit, the engine is an absolute gem.

So the BMW has no such issues being recorded?

[tony_danza]

The V8 M3? I think that's on individual throttle bodies??

[Poverty]

BMW Lexus Mitsubishi all have had similar issues to name a few.

Audi are now going back to port injection combined with port injection to stop it from happening.

[garrardrj]

BMW Lexus Mitsubishi all have had similar issues to name a few.

Audi are now going back to port injection combined with port injection to stop it from happening.

What ?

[Poverty]

Port and direct injection

[PDT]

I've dyno tested a fair few RS4's and never seen claimed power. 360-380 is normal, dyno tested one with a rebuilt head (due to coking) that was done by Audi and it made 370ish.

See this coking problem with the N54 BMW engine as well (335i etc) and with TFSi engines. Fitting a 'proper' breather system from new helps.

[berg]

I've dyno tested a fair few RS4's and never seen claimed power. 360-380 is normal, dyno tested one with a rebuilt head (due to coking) that was done by Audi and it made 370ish.

See this coking problem with the N54 BMW engine as well (335i etc) and with TFSi engines. Fitting a 'proper' breather system from new helps.

Very interesting Dave. Sorry. for my ignorance but when you say "breather system" do you mean something similiar to a catch can system? 

Going back to the V8 M3 then, if it is on individual throttle bodies is this a more old school approach but because of this it is all the beter for it as not likely to suffer as many problems?