Intake manifold (fix or RFD) / Pre-cat (question)

[Leco_GTI]

Hi all,

I would appreciate some advice about fixing a problematic intake manifold or just doing a runner flap delete. A few months ago I had the intake manifold motor replaced. Everything was fine until another code showed up and my mechanic had a look at it and said the flaps are not moving fully. My questions are:

1- Would be better off doing a runner flap delete so I can rule out any future problems with the motor again and the flaps?

2 - Why do the gaps on the sides of each flap need to be filled?

3 - With the flaps deleted, do the motor and sensor need to be disconnected? If so, how to work around the codes that will show up? Just ignore them?

4 - Or the best option would be getting a new intake manifold? I have no mechanical skills so everything would be carried out by an independent garage.

With regards the pre-cat removal, it might sound stupid to a lot of people but how do the gases go through the end of the exhaust if there is a "wall" in the middle? I called an independent VW specialist garage in London and when I enquired about it because I wanted to have it removed, they told me not to do it. The person who I spoke said to me that unburnt fuel could end up in the catalytic converter and damage it. Also a gain of 5bhp was not worth considering a decrease in MPG because of more airflow and risking damaging the catalytic converter.

I would appreciate everyone's opinions and experiences so I can decide what to do with the intake manifold. The questions about the pre-cat was just to try to understand a bit more about it.

Cheers guys.

[spesh]

Cant help you so much with the RFD aside from if its not broken why fix it.  If you were having to remove the inlet for another reason (like inlet valve carbon/oil removal) then perhaps it would be worthwhile.

As for the precat removal I think you'll find your garage is talking poop.  I removed the precat on ours and saw an average 2mpg gain over the last 6 weeks (note that ours does alot of short journeys so not sure if that is a factor).   Quite how removing a restriction could cause a decrease in mpg is beyond me.  IIRC the part is not required in the UK and relates to cold running only as the main cat takes a little while to warm up.  This is not tested in the UK MOT.  Also if you have unburnt fuel reaching any cat you have a more serious problem that needs solving.

[slix]

Cant help you so much with the RFD aside from if its not broken why fix it.  If you were having to remove the inlet for another reason (like inlet valve carbon/oil removal) then perhaps it would be worthwhile.

As for the precat removal I think you'll find your garage is talking poop.  I removed the precat on ours and saw an average 2mpg gain over the last 6 weeks (note that ours does alot of short journeys so not sure if that is a factor).   Quite how removing a restriction could cause a decrease in mpg is beyond me.  IIRC the part is not required in the UK and relates to cold running only as the main cat takes a little while to warm up.  This is not tested in the UK MOT.  Also if you have unburnt fuel reaching any cat you have a more serious problem that needs solving.

+1

Get it done  been running aftermarket downpipe with pre cat delete and 200 cell cat and been fine for 8 months with no codes or eml.

[Leco_GTI]

Thank you for the replies guys.

The intake manifold is faulty. The flaps are not moving fully. I guess I will replace the whole intake. I can feel the performance diference when the intake was working before. And the exhaust doesn't make that nice "frrrreck" sound when changing from 1st to 2nd, only in sport mode. It used to make the sound in D if I floored it but not anymore.

Pre-cat removal will be done at some point. My car is not an ED30 and is completely stock. I only had it for 4 month and at the moment is fast enough for me. The only problem is the intake playing up since I bought it so I guess I will buy a brand new one and replace the whole thing. My car didn't spend a month without going to mechanic :(

[Leco_GTI]

I have just been quoted by a VW specialist in London £718 inc. VAT to change the intake manifold (£430 for the part + £288 labour) including 2 year warranty. VW quoted me £864. Does that sounds right?

[spesh]

if the runners are faulty then sure do the RFD.  Personally I'd diy it, plenty of guides around

[Leco_GTI]

Thanks for your input. I think I will replace the whole thing and have the 2 year warranty included for piece of mind. It seems the intake manifold on the MK5 it's prone to different types of failure.

[Paradox1]

Thanks for your input. I think I will replace the whole thing and have the 2 year warranty included for piece of mind. It seems the intake manifold on the MK5 it's prone to different types of failure.

Better to do the runner flap delete mate. Whats tpo say in 2-3 years the new manifold wont become faulty again?
If you delete the flaps then your deleting the problem

[Pesky jones]

I would buy an operational, 2nd hand £30 inlet manifold off one of the facebook groups opposed to buying new.

[colesey]

ECS offers a cheapish option

www.ecstuning.com/News/Volkswagen_Bremmen_Intake_Manifold_20T_TSI_22491/?trk_msg=DH8874SSFDB430FNNV536C0GRK&trk_contact=1LO8KJHB2B6N2PR2PQV1S6T4L4&trk_sid=5JAK0LS7I0HM3J278T30SQ0PLO&utm_source=emailcampaign&utm_medium=email&utm_term=Bremmen+Intake+Manifold&utm_campaign=Volkswagen_MK5_GTI_ECS_Project_Build_06202017_TR_24430

[Leco_GTI]

Hi guys,

Thanks for the replies.

I am on the same opinion about deleting the flaps. I am just not sure yet if the problem is only the flaps or if there is also a leak due to another faulty part on the intake. If it's just the flaps then deleting them would be a better and cheap alternative. If there is more things to do I will just get a new one. I want to avoid a 2nd hand unit because I have a feeling that this intake will give me a headache again down the line.

Thanks for sharing the link. I saw a few intakes on Ebay and there are different part numbers for different engines. My one is the AXX and I am not sure if the ECS intake will fit on my engine. I need to check my intake part number.

Thanks guys, much appreciated.

[v4rley]

The above ECS won't fit as it's for a TSI not TFSI

[colesey]

The above ECS won't fit as it's for a TSI not TFSI

My bad, was included on an ECS Mk5 mailshot I received earlier.

[Paradox1]

Thats crazy cheap, they give you an intake manifold as well as the delete kit and injectors kit!

[Leco_GTI]

It is an amazing price. Pitty it won't fit :(