Flaps !

[sonny]

No CB is here to stay. It may alter the way in which it builds up, i.e patterns may form on both sides of valve instead of one side... This is only a guess. My experience of taking apart engines is nil so I would not like to say. Audi did change the style of the flap post 07, there is now a depression in one side. Like the plenum of the IM, the earlier cars have a black ring around the trumpets, later cars don't. :/

[rs4lee]

Hi Lee, would you mind clarifying a few things?

[...]The only reason i am posting this is so others realise how much of a nusance these inlet manifold flaps are ,and that getting them removed could save you a massive repair bill when one goes through your engine.[...]

1- Was this engine ever opened prior to the incident?
2- What upgrades (if any) had been done physically or engine management/mapping?

The reason I ask these things is because I am surprised. I know very little myself about the RS4 engine bar what I have gleaned from this website over the last few years, and I am surprised that I have not read much this issue if it is as important as you consider it to be. I know flaps are taken off when porting and other times when the engine is opened, but I thought that was because the had a knack of failing when interfered with. You are a professional mechanic, I'm a novice and here to learn.

[...]Plus once removed you can have the piece of mind knowing the little buggers cant cause any problems as most peoples cars are getting to the mileage were problems can occur.[...]

3- Is it really milage related?
4- Is it ok to generalise that all cars are at some imminent risk of flap failure?

Ultimately I'm just wondering if this truely is something that needs to be done to every car. I might be wrong, but you are inferring it is.

Anyone else want to throw in their two pennies?

Stu.

Hi stu

To my knowledge the engine had not been opened proir to the failure .... the car is fitted with a milltek and a pipercross panel filter ,car is on stock map.

I personaly think that the carbon build up causes the flaps to start sticking which leads to problems .... the reason i mentioned mileage is because most cars may now have a significant amount of carbon build up by now that could start affecting the flaps (unless the car has been cleaned of the build up)

Ive worked on 3 cars that have had flap failures ,one was very lucky and the piece never did any damaged and ended up in the manifold , one had an engine swap and was never stripped due to it being visable via a bore scope that it had killed the cylinder and this one which has been stripped.Plus i have had issues with my own car being down on power due to a flaps sticking and vac leaks.The mileage of the cars where 70k 90k plus mine which is on 140k

Some people may not think its an issue but i thought i would share what i have seen so people can make there own decisions on whats best for there motor

With regards to de-flapping the manifold ...its a case of having the inlet manifold removed (might as well have a carbon clean while its off) knocking the blanking plugs out to access the flap retaining bolts , unscrew the bolts and discard ,remove flaps and discard ...now you need to find a good machine shop to make up some bungs to replace the blanking plugs that you knocked out ( and you could get your mani ported and polished while its off) Re- fit your manifold with new gaskets and your good to go

[stu]

Thanks for the info! Based on that I'll get it done when my car is de-carboned. I've no plans to do that just yet.

[api330]

Thanks for info rs4lee,

[OskiRs4]

Thanks for the Information never heard about this even with reading up loads,

could some one tell me how big/how much££ a job is removing this flap?
And any problems in doing so?
Also what does this flap do?
Thanks

[PetrolDave]

Thanks for the Information never heard about this even with reading up loads,

could some one tell me how big/how much££ a job is removing this flap?
And any problems in doing so?
Also what does this flap do?
Thanks

It's not a single flap, it's a flap per cylinder.

As has been already posted the flap is there to promote turbulent flow at part throttle - which allows areas of weaker and stronger mixture to be generated in the cylinder and improves fuel economy.

[stu]

It's not a single flap, it's a flap per cylinder.

As has been already posted the flap is there to promote turbulent flow at part throttle - which allows areas of weaker and stronger mixture to be generated in the cylinder and improves fuel economy.

Any idea what sort of mpg reduction you'd be looking at?

I suppose it might be hard to quantify as people probably get other things done to their car at the same time as the de-flap. I'm averaging around 19mpg at the minute in a stock car (empty northumberland roads are just too much fun).

[rsParnell]

It's not a single flap, it's a flap per cylinder.

As has been already posted the flap is there to promote turbulent flow at part throttle - which allows areas of weaker and stronger mixture to be generated in the cylinder and improves fuel economy.

Any idea what sort of mpg reduction you'd be looking at?

I suppose it might be hard to quantify as people probably get other things done to their car at the same time as the de-flap. I'm averaging around 19mpg at the minute in a stock car (empty northumberland roads are just too much fun).

Just having some flap issues of my own and wondering whether it is really better to just get them removed.

[PetrolDave]

Holy thread resurrection! This thread is over 3 years old...

[Frostie]

Well, that's made my mind up... Flaps are being removed when carbon cleaned in the next couple of months.