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-   -   S8 V10 Flaps Delete (Intake Manifold) (https://forum.a8parts.co.uk/showthread.php?t=12128)

M-A8 15th September 2016 10:56 PM

S8 V10 Flaps Delete (Intake Manifold)
 
41 Attachment(s)
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.
http://forum.a8parts.co.uk/attachmen...1&d=1473973805

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.
http://forum.a8parts.co.uk/attachmen...1&d=1473973805

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)

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

Few shots of the flaps

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

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.

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473973805

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

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.

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

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.

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

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

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

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.

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473977011

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

http://forum.a8parts.co.uk/attachmen...1&d=1473975785


DONE !!!
Very pleased with the job and result +++

http://forum.a8parts.co.uk/attachmen...1&d=1473975785

Artermis 16th September 2016 06:21 AM

Very well done mate - I think you should be rightly proud of that one. Removing manifolds is not always a job for the fainted hearted but having a guide available will certainly make the job much, much easier for many and is a sound alternative given the cost of garage and replacement. Good work.

I think as you suggest, the minor loss of low end BHP or torque on a 5.2 V10 is going to be negligible, especially when offset against the cost and/or risk of a broken failing manifold.

M-A8 16th September 2016 07:12 AM

Thank you very much +++
It was certainly a great thing to do for many reasons and satisfaction from doing it was and still is huge.
£250 repair seems a very good deal, but I only was 95% confident in it due to lack of pictures of the repair and this was the crucial 5% of me no, let's crack on with it and see what's is all about. On the end of the day if would have failed have way thru I could always sent a split manifold for the repair, but I knew from the beginning that the biggest challenge will be to split it, and it was.
I know that Ron is very pleased with his repaired manifold, but me being me and brutally honest, I've got slightly more doubts now in the repair process for such a small money considering what really is involved and how time consuming this process is. As a business I would probably charge at least £250 just for splitting the manifold and re-sealing it.
All in I'm very pleased and that loss of power if any isn't noticeable at all, when you floor it car responds the same way it was before with no weird lag or choking.

Norretal 16th September 2016 09:21 AM

Fantastic job Marcin, and an excellent write up too +++

My lack of photos probably did you a favour, now you've "been there, done that" yourself, and probably have a much better understanding because of it. It's over two years now since my saga and I was very much at the mercy of those who had the car. One garage, Swift Motorsport, a local VAG independent specialist diagnosed the fault and stripped and cleaned the manifold (I witnessed it stripped down and cleaned when they showed me the failed flap) and the engineer carried out the repair for them after I was directed to him by someone who knew he'd done similar work previously. Even TPS helped me out by being incompetent as I was resigned to buying a new manifold and would have done had they been able to deliver, but that's another story.

I'm sure this will give others the satisfaction that preventative maintenance can be done to prevent failure, and even if failure comes it's not the end of the world. At the time of my drama all I could find were examples of them failing and causing engine damage and after seven weeks I was just glad to get the car back running as it should, as you can imagine.

This great forum, and the many knowledgeable people on it never fail to deliver, great work +++

Architex_mA8tey 16th September 2016 01:41 PM

Awesome write-up with lots of detail thanks for all the trouble you've gone to to write these up Marcin - added to sticky! +++

Mechcanico Lee 17th September 2016 04:57 PM

Superb post, well done for taking time to post up

M-A8 18th September 2016 02:34 PM

My pleasure boys +++
It's something I've researched before, but a lot of detail was missing so I decided that's it, let's do it, document it and share with others as this is a common failure and no full guide out there.
Will post the graphs from the dyno run before the remap to see what the difference is vs. the one someone posted few months ago of a Silver S8.
It should be an interesting comparison.

Rick 20th September 2016 10:22 AM

Brilliant job.
I do this with my bikes. On them though its called flapper valve mod!.
Pull em out and it gives better induction and more roar under acceleration. It must sound awesome on our V10's. Once I move house next month I think this will definately be something I can get to grips with now with this perfect guide and the decoke.
Although Im still in 2 minds about paying the £800 AMD want to do it. Gotta be the easier option surely lol!!

M-A8 20th September 2016 10:30 AM

Rick, satisfaction from doing it yourself and guarantee of both jobs being done properly as you can't check the results afterwards is priceless.
Then spend £400 out of £800 for a proper dyno run and remap, but before you do that spend £150 on injectors cleaning and you will still be left with £150 toward the beer fund as both jobs will cost you approx £100 in degreasers, wire brushes and sealant for the manifold +++

Rick 20th September 2016 11:04 AM

Once thats done mate its back to the dyno to see how many of the lost horses have come back to stable!
I was 128bhp down due to the control arms not being connected to the flaps! No air flow into the engine. They did recommend a decoke at the tjme as well.


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