RS4 Intake flaps, purpose and why delete improves performance ?

[ifrancal]

Hi... This is for RS4 Experts.. I am fortunate to own one of these monsters and have been enjoying its performance for some years without too much to concern. However, of late an engine management illumination and a misfire has led to the engine coming out to gain access to the drivers right cylinder Head. The diagnosis, well, unluckily carbon came off one of the exhaust valves and was caught between the valve and its seat. Some of you will know my pain as the expense to this point is mainly down to the chains being inboard which prompts all out in order to get the heads off..
My main question is related to the recommendation of the intake flap delete by the garage concerned. The head will need a re-furb and possibly the other bank should also be done while all is out.. The intake flaps one side have some play and again while apart should either be repaired or 'deleted'. Why are they there in the first place? What is the downside of their removal?
Seems the published performance figure of 414 BHP is a nonsense but with the flap delete this and little more can be attained.?

Having had the car for 13 years (130k Mileage) this all is quite a shocker to now know the engine is not only difficult to service but has a reputation not fully deserved.. Perhaps another fib to go with the recent scandal.!

Be of no doubt despite my grumbles, i love it to bits and hope to keep it as one of the last few big guns with a manual box.. Please can you knowledgeable people offer your experiences with the flap delete or any other do's or do not's while the engine is sitting out on tyres..!
Regards
Ian

[Kenny147]

Could be wrong but I thought if you had play in the flaps, you’re kind of up the proverbial creek as you can’t replace them without replacing the whole manifold.

[MikeFish]

I assume you are talking about the B7 RS4 by the 414bhp figure you quoted? Might have been a better idea to post in the B7 RS4 section rather than in the welcome section.

However, I've seen most cars reach the published power figures after just a decent carbon clean and any vacuum leaks fixed so the factory figures are true but unfortunately without regular carbon cleaning it won't stay that way for long.

[Covkiller]

I had play in my flaps, MRC noticed something was wrong on one of their Big Rumbles, ie power down. So booked it in, inlet off and video sent of play in the inlet flaps. Hence flaps removed and mapped out. Afterwards, you will notice on start up and drive away a very tiny stutter. This disappears within seconds of becoming warm.

I'd only recommend removal if anyone's having problems, as before this I was reaching 447ps with flaps in situ.