Intake Manifold Refurb and Deflap Guide

4.2 V8 32v Naturally Aspirated - 414 bhp
Anees
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Intake Manifold Refurb and Deflap Guide

Post by Anees » Mon Aug 19, 2013 2:54 pm

Hi Guys,

Is there a guide anywhere on how to remove the flaps from the B7 RS4 intake manifold?

Looking to have a go myself at doing it?

Is it also worth installing intake manifold spacers and can these be bought from the UK rather then US?

Thanks
Anees

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Re: Intake Manifold Refurb and Deflap Guide

Post by Rick_RS4 » Mon Aug 19, 2013 6:47 pm

no guide as such, just an inlet mani removal guide on the jhm site,

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Re: Intake Manifold Refurb and Deflap Guide

Post by Rick_RS4 » Mon Aug 19, 2013 7:00 pm


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guffy
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Re: Intake Manifold Refurb and Deflap Guide

Post by guffy » Mon Aug 19, 2013 7:08 pm

I used this one when I took my manifold off the other week...

http://audirevolution.net/forum/index.php?topic=439.0

One of these is essential to get to the bolts at the back of the engine..

http://www.ebay.co.uk/itm/RIGHT-ANGLE-O ... 8747792%26

I didn't deflap mine as i'm too far away (Aberdeen) to get a remap, would be happy to get rid of the whole vacuum system though, it's a pain in the backside.

Removing the flaps is the easiest part once the manifold is off!

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Youngben
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Re: Intake Manifold Refurb and Deflap Guide

Post by Youngben » Mon Aug 19, 2013 7:20 pm

i have a manifold in the for sale section if its something you wanted to take your time doing then just swap them over to save down time on your car. Then just sell yours when its all done for someone to do the same.

I have found many threads showing what material needs taking off! if you search there are many pictures about! its more about making the entry to the ports as round as possible and the ports nice and smooth and free of casting marks. If you struggle to find info let me know and i will do some digging again for you.
Image

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Re: Intake Manifold Refurb and Deflap Guide

Post by Rick_RS4 » Mon Aug 19, 2013 7:27 pm

guffy wrote:I didn't deflap mine as i'm too far away (Aberdeen) to get a remap,
no need to remap if you remove the flaps, just leave the shafts connected and working as normal.
Youngben wrote:ports as round as possible and the ports nice and smooth and free of casting marks. If you struggle to find info let me know and i will do some digging again for you.
not fully polished smooth tho? like a turbo manifold surely, i thought i read somewhere that you need a bit of stubble on the ports to create turbulence to help the air mix with the fuel?

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Re: Intake Manifold Refurb and Deflap Guide

Post by adsgreen » Mon Aug 19, 2013 7:42 pm

Rick_RS4 wrote: not fully polished smooth tho? like a turbo manifold surely, i thought i read somewhere that you need a bit of stubble on the ports to create turbulence to help the air mix with the fuel?
I've heard the same - I remember people got fascinated about removing the "lip" on the 48mm rover throttle body and it made things measurably worse on the dyno.

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Youngben
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Re: Intake Manifold Refurb and Deflap Guide

Post by Youngben » Mon Aug 19, 2013 8:10 pm

just going by what i have read but yeah i always thought the same!

here a quick find

http://www.audizine.com/forum/showthrea ... ifold-Info
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Re: Intake Manifold Refurb and Deflap Guide

Post by Anees » Mon Aug 19, 2013 11:36 pm

Thanks for the input guys (especially Young Ben)

I have already had the intake manifold off once for a carbon clean, so taking it off isn't the problem. :D I have a problem with stuck valves so I just want to make sure I have everything I need to deflap the manifold before I take it off again to minimise downtime. I have read a useful thread by ROY on here were he purchased 12mm core plugs. If I get the core plugs, gasket should that be everything needed?

I'm liking the sound of the JHM intake manifold spacers too but can't really we bothered to wait for them to ship them from the US unless someone knows of a UK supplier?

Thanks

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Re: Intake Manifold Refurb and Deflap Guide

Post by guffy » Tue Aug 20, 2013 7:31 am

I assume you have a random EPC light if you think you have sticky flaps then? Were the flaps sticky when you did a carbon clean? If they were that gummed up, it's an easy job to take the flaps off and remove the shaft for cleaning.

I thought i had sticky flaps, but they and the manifold only had a film of grime on them, it turned out to be the pot sensor, so de-flapping alone may not cure an EPC light. I persoanlly don't see the point in de-flapping without mapping out the position sensors as it's one less thing that relies on a vacuum!

It would be interesting to know if de-flapping alone would bring any 'noticeable' gains to power? Do the flaps not act like a choke when the engine is cold?

There's quite a bit of specualtion about the JHM spacers, apparently the intake does run cooler, so surely that can only be a good thing?

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Re: Intake Manifold Refurb and Deflap Guide

Post by adsgreen » Tue Aug 20, 2013 9:52 am

guffy wrote:I assume you have a random EPC light if you think you have sticky flaps then? Were the flaps sticky when you did a carbon clean? If they were that gummed up, it's an easy job to take the flaps off and remove the shaft for cleaning.

I thought i had sticky flaps, but they and the manifold only had a film of grime on them, it turned out to be the pot sensor, so de-flapping alone may not cure an EPC light. I persoanlly don't see the point in de-flapping without mapping out the position sensors as it's one less thing that relies on a vacuum!

It would be interesting to know if de-flapping alone would bring any 'noticeable' gains to power? Do the flaps not act like a choke when the engine is cold?

There's quite a bit of specualtion about the JHM spacers, apparently the intake does run cooler, so surely that can only be a good thing?
The key is to scan for the codes and use vag com. There is a specific diagnostic test for the flaps and you can also monitor "actual" and "requested" manifold flap positions from the logging. Using all three you can generally narrow down the problem pretty quickly. Ie, vacuum or solenoid issue will affect both flaps, sensor will show up on the logging etc...

Whilst I see your point about the mapping it's not something I think I would bother with on it's own. Leaving the shafts and sensors in place is a very good alternative and you won't really gain anything with the map other than reduce the potential for any further issues.

Deflapping could increase overall top end power over 3k rpm as they are simply and obstruction at that point. Below 3k rpm they close and line up with the fixed position flaps to direct air into the top of the cylinder. Also as the cross sectional area of the intake is now considerably reduced you get a venture effect and the air is accelerated. Both of these aspects cause the relatively small amount of air to tumble into the cylinder and it helps combustion. You may notice a very slight (1-2mpg I guess) drop in economy as under 3k things won't be as effective.

JHM intake spacers - No doubting they do exactly what they say on the tin. The manifold will run cooler. The only theoretical issues I can see is that the intake air temperature is measured between the airbox and throttle which is prior to the manifold as such the ECU would have already made it's timing and fuel decision well before the air has even arrived at the manifold. What it can do is if the manifold is heating the air charge above the measured value to a point that it causes ignition issues is prevent the ecu from backing off timing (and the subsequent "learning" and mapping adjustment). This is a good thing.
It can also stop the manifold contributing to the radiated heat in the engine bay so another bonus.
The extra 10mm length added to the intake tract will move the torque curve slightly down... by how much? I don't know and I'm not sure if it's been measured but any move down of torque will reduce overall hp (but in all fairness not by anything you'd actually notice) but I would hope that any drop is offset by preventing timing issues. As with anything heat soak related (like a CAF) you won't gain anything over and above what you have - you keep what you have for longer.
IIRC installation requires bending a metal high pressure fuel line.

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Re: Intake Manifold Refurb and Deflap Guide

Post by Anees » Tue Aug 20, 2013 10:10 am

Unit 20 did a Vag Com check on my car when it was in two weeks ago.

The main faults were:

005137 - Secondary Air Injection System: Bank 2
P1411 - 002 - Insufficient Flow - Intermittent

Unit 20 suggested that the vaccum pipe might have come off or not been put on properly (oops!) or be damaged

Cylinder 5
P0305 - 001 - Misfire Detected - Intermittent
Cylinder 8
P0308 - 001 - Misfire Detected - Intermittent
Cylinder 6
P0306 - 001 - Misfire Detected - Intermittent

Intake Manifold Flap, Bank 2
P2005 - 002 - Stuck Open - Intermittent

Unit 20 said the misfire will be because of the stuck flaps

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Re: Intake Manifold Refurb and Deflap Guide

Post by Anees » Tue Aug 20, 2013 10:11 am

Just to add I have no EPC light.... :)

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Re: Intake Manifold Refurb and Deflap Guide

Post by adsgreen » Tue Aug 20, 2013 12:48 pm

If the manifold arms were stuck you get an epc light very quickly.
The problem with basic scan is that there is no time or date information so those could be old codes.
Also cylinder 5 is on bank 1 so a problem with the manifold flap wouldn't cause a misfire on the other bank.
If the flaps are stuck open (as shown by the P2005 code and not a P2015 for stuck closed IIRC) then you wouldn't get a misfire as they would be the same in principle as a de-flapped engine.

I do agree on the
005137 - Secondary Air Injection System: Bank 2
P1411 - 002 - Insufficient Flow - Intermittent

Classic symptoms of a vacuum leak and this can cause problems with the manifold runners and random misfires (as the mixture is shot to hell).

Best option is to clear the codes and run the car for a while to see if anything more recent is logged.

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Re: Intake Manifold Refurb and Deflap Guide

Post by Anees » Tue Aug 20, 2013 1:08 pm

Thanks for the input! :thumbs:

The Vag Com scan was a full scan which was given to me as a print out. I only typed out the fault codes rather then typing out the full details. I can confirm the fault codes were new from the dates it recorded them.

My problem might very well just be a vaccum pipe disconnected or perished leading to the other faults as you mentioned!

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