S8 V10 Flaps Delete (Intake Manifold)

[M-A8]

Here it is, for everyone who suffers or may suffer in the future from a broken intake manifold flap/s.
This is an alternative to couple of £k manifold or a repair (£250) which I was going to do by sending the manifold to an engineer Ron knows, but decided nlt to purely as he couldn't provide any pictures of the repair so I can see how well this is done.

And this was the reason for it, one flap broken of laying at the bottom of the manifold and second one hanging up in the air.


Oil separator was faulty hence a bit more than usual of filth inside the manifold.

Prons:
- more engine growl
- louder exhaust
- BHP gain at the higher revs
- huge satisfaction from doing it yourself

Cons:
- slight loss of BHP at the very low end of revs, but not noticeable on this powerful engine. After talking to remap place this loss can be easily recovered with the remap on the dyno which is my next step but also you will double gain BHP on the higher revs.

I followed this guide in order to remove the manifold.
http://audirevolution.net/forum/index.php?topic=3221.0

Please note:
- Inlet wont come out just like that like this guy claims
- You will have to remove both fuel pumps, one on each side of the manifold
- Remove two the most obvious and easiest to undo fuel lines and move them aside.
- This is the worst part which he did not mention at all, unless someone had his manifold out before and did not bother to bolt on the electrical connectors bracket for the fuel injectors which is bolted by two torx bolts to the bottom/front manifold and which will prevent you from removing the manifold.
You WILL NEED a pair or small hands, lots of patience and this mini ratchet with a torx bit (T25 or T30) on the end to unbolt the bracket. This is one of them bolts I've dropped and recover using endoscope camera and grap tool. Both bolts are visible thru the square cut out with the pin in the middle of the crash frame where the bonnet's latch goes.
http://www.screwfix.com/p/titan-scre...questid=550707

Now, this is where it gets interesting as manifold is made from a tough mix on magnesium, zink and aluminium which is also fragile to chips/possibly even cracks when you try to lever it while splitting to hard. That is mainly due to the silicon gasket being very very strong which was applied at the factory not only around the edge but also around each inlet and internal ribs for each intake channel.

Patience, patience, lots of patience, swearing in between and sweat running down your back.
First attempts on the bench where a complete failure even with my mate giving me a hand so time came for attempt no. 2, screwing the manifold to a pallet I quickly made for the engine which fits under my engine hoist. This was the way to go.


Tools:
- Torx bit
- heat gun
- thin ish but as wide as possible flat head screwdriver (worth thinning the end off slightly with a grinder)
- stanley knife
- WD40 Specialist Fast Acting Degreaser (for decoking/cleaning the inlet channels and variable inlet flaps) together with few green scouring pads
- 2-3 packs of plastic spudgers for removing the silicon from the grooves
http://www.ebay.co.uk/itm/3-X-PCS-PL...EAAOSw6btXRmwk
- couple of small brass wire brushes for removing fine pieces of silicon seal left behind and final preparation of surface for resealing (it's much harder with the big brushes)
https://www.amazon.co.uk/175MM-BRUSH...wire+brush+set

Splitting is the worst part so as soon this task is done rest is just a time consuming job.

Front right corner is the best place to start as the ridge/grove which is all round the manifold is only set back 2-3mm from the edge and this particular corner and front of the manifold has approx 8-10mm of flat surface before the ridge.

You will only be able lift a tiny section, cut only some of the seal and when you get as far as approx. 1/3 of the way down the side its worth lifting the corner again and wedging and leaving a second screwdriver.
Don't know if that helped much, but I was heating up the manifold from the inside by blowing high temp down the whole where the T piece is bold on.

I only done once and for the first time in my life so can't give you a better advice unfortunately. I haven't seen anyone splitting it before either, but all I can say its doable without damaging it

There are 26x torx bolts you will have to undo, 10x at the top around the edges and 16x from the bottom

Here is the manifold with the bottom part removed.
All the black/grey stuff around each groove is the silicon gasket, there is plenty of it around to be removed.
You can also see how the exits to each inlet on the engine are coked up as well (part I mentioned in the decoke thread which really pushed me into decoking the whole engine)















Few shots of the flaps













Flaps removed, actuator motors removed and manifold ready for cleaning.
One row of flaps was in very good condition while the other driven by the main set was absolutely worn out damaged in multiple places which makes no sense as you would expect the main set to be ruined which is driven the by actuator motor mounted at the front of the manifold.

Breaking off them ain't very easy, a strong flat head screwdriver with thin end is needed along with the hammer to break off three plastic rivets on each flap. You can see how some holes are worn out there where the flaps got loose before detaching from the base.

















As mentioned earlier removing the silicon is a real pain and here are some shots of all the sealed are preped for sealing, all the inlets along with variable flaps cleaned/decoked and both parts of the manifold drying out in the sun after last and final rinse with the WD40 Degreaser.













For sealing the manifold I've used JB Weld Ultimate Grey Silicon
Very very hard to squeeze out so expect some rushing, sweating and your hands hurting at the end as hell.
I followed the instructions by hand tightening all the bolts first, leaving the silicon to set for half an hour and then doing all the bolts up by further quarter/half a turn using a torque wrench.
I got 4 tubes, used only 2, but there was more than half left in each left.
What could help is probably warming the tubes up in a bowl with very hot water.





And here is the middle part bolted on and bottom and top part finally sealed.









All actuators bolted back on (had one arm securing clips missing from the back on one of them so decided to pop in to Audi and order and replace all 3 of them).
All the excess of the silicon from outside trimmed.










DONE !!!
Very pleased with the job and result