Hi Folks , well as the sun was nearly out today and the weather was dry I could not reset messing about with the car

First was the secondary air system, not too bad a job

Then was the removing the front metal bracket with the N112 and N249 on it

Then removed the black plastic can on the rocker cover, fitted the Forge blacking plate to where the EGR valve was and fitted resistors to each on the plugs where the N249, N112 and SAI components were removed.

All I had to do then was route a hose from DV to inlet manifold and job done.

Took it for a little test drive..

So far (fingers crossed) no cell light.

First observations is a much more steady tickover.

The motor fired up and went straight to around 1200 rpm whilst warming up, then settled to around between 750 and 800 rpm purring nicely.

The car feels smoother, I did suspect before a small air leak in one of the pipes i removed to DV. (but this did not show up at JKM RR Day few weeks back) Most of the pipes were in poor state though when i checked them.

The boost comes in nicely and holds well. Feels a little sharper (could be my imagination) The car was running sweet before so did not expect nothing else really, but you know what it is like sometimes car runs well you fiddle with it and it don't run well. :S

But not in this case today, very pleased with results.

I took lots of pics so will post up a DIY how too later.

did you get the blanking plate direct from Forge? or did you find a cheaper supplier as I need to get on with mine as the weather is improving?

did you get the blanking plate direct from Forge? or did you find a cheaper supplier as I need to get on with mine as the weather is improving?

Hi mate, yep got it from Forge few months back.

as someone stole the cheers icon

Edited 8 March, 201016 yr by karlbar2k

great write up, will be doing this myself oneday! what size resistors did you use?

:thumbup:

great write up, will be doing this myself oneday! what size resistors did you use?

cheers, I used 330 ohm ones.

Top Work Bodge, a very good read....Whats the advantage of removing the N112 and N249 (purely for less chance of boost leaks or the dreaded 17705?)

Bookmarked anyhow

Edited 15 March, 201016 yr by vRShafz

Sticky ?

needs to be copied over to the Octavia How to section...seems to be a lack of how to's in the octy section as opposed to the fabias

I'll copy this too the technical guides section

Cracking write up

The write up can now be found here

The forum doesn't allow me too make a copy sorry fellas so I had too move the posts.

As always, I bow to people's superior knowlege on this site. It amazes me how much some of you know about the vRS. I know what I know, but it doesn't stray into this sort of thing. Why do you need to remove this stuff? What benefit does it give and why is it there in the first place?

Sorry for the dumb questions, but I genuinely don't know what's going on. :(

Top Work Bodge, a very good read....Whats the advantage of removing the N112 and N249 (purely for less chance of boost leaks or the dreaded 17705?)

Bookmarked anyhow

Thanks, it is Bowders1 actually....

As you stated yep it should cure boost leaks as you don't have the dreaded old piping that cracks.

The N112 is used in line with the SAI I believe and serves a purpose of injecting extra air into exhaust when the engine is cold to make the cat more efficient for the first 60-90 seconds of running.

My SAI was vibrating when running as the rubber mounts on the asm were cracking. Also the SAI is joined together by rivots which can break and let air in.

Here is a tech on the N249 (not my work) from VW forum

N249 is controlling the DV (Dump Valve). It is installed between the intake vacuum source and DV itself. When no current is switched to the N249 (default state), the DV will get vacuum or boost from the intake manifold. This is how almost ALL turbo cars are worknig. When shifting gears, you let off throttle, TB closes and vacuum is generated which can open DV to vent boost (which cannot enter engine, because TB is closed).

On never 1.8Ts (2000+) they introduced the N249 (along with lots of other stuff) which is a possibility for the ECU to open the DV any time (!), even during full throttle/acceleration. When the engine is running and turbo is boosting, there is no vacuum generated, but to open the DV (which is mechanical), vacuum is needed. This is what the black vacuum reservior on top of the engine is used for. When idling, shifting, etc - so when vacuum is available, vacuum is led into this reservoir from the intake manifold and kept inside using a check valve (white/black), so when boosting again, vacuum will stay there (air cannot enter into the reservoir).

When ECU wants to open DV durnig full throttle/acceleration, simply "energizes" N249, which will "de-select" the DV from the intake manifold (boost), and "switches" it onto the vacuum reservior. The vacuum in the reservoir will open the DV instantly and release your boost, which, in most of the cases (tuning, etc) is not that highly required . In the case ECU sees a little overboost problem, it can turn N249 on/off repeatedly for very fast (just as N75 is working), which will open/close DV all the time, trying to settle (lower) the boost level.

By removing N249 valve, you can prevent this bad habit of the ECU, and by removing N249 valve, you are removing an approximately 2mm narrow bottle neck restriction (ID of the N249 valve) in the line to the DV, which will result in a somewhat faster DV response.

hope this helps

Edited 15 March, 201016 yr by Bowders1

no such thing as a dumb question

the N249 controls the Diverter Valve and is one thing that can be by-passed easily to see if it improves things before fully removing. I had a problem with surging after getting remapped and the n249 bypass helped, I just havent got around to deleting it yet.

The N112 controls the Secondary Air Pump which is used to warm the CAT up quicker (somehow? not really looked into it much:D) it is purely an emissions thing but a lot of people have problems with the pump rivets breaking up so with just a resistor and a blaking plate the system can be removed (weighs a bit as well)

HTH

Edit: Damn it! the SWMBO called my half way through typing that. Beaten again :p

Edited 15 March, 201016 yr by karlbar2k

My DV definitely makes a different sound now I've pulled out most of that stuff!

And my SAI pump had failed rivets and was splitting.

As always, I bow to people's superior knowlege on this site. It amazes me how much some of you know about the vRS. I know what I know, but it doesn't stray into this sort of thing. Why do you need to remove this stuff? What benefit does it give and why is it there in the first place?

Sorry for the dumb questions, but I genuinely don't know what's going on. :(

Hiya

I have no superior knowledge myself, just very inquisitive at taking things apart and finding out how things work, and also reading up where i can. Sometimes I end up making things worse when actually car runs fine in the first place.

See my previous thread above which hopefully helps explain a little, I am sure someone else will be able to detail this some more.

Note: I think this has been made a sticky now if folks wish to follow the write up.

My DV definitely makes a different sound now I've pulled out most of that stuff!

And my SAI pump had failed rivets and was splitting.

Agree to both those points...

hehe sorry Bowders1, i had another tab open in firefox and was reading Bodges thread and got it mixed up! *face palm moment*

thanks for the reply anyhow, answered my question

Wow, some very comprehensive answers there. Thanks for the info. It seems mad that all this stuff can be taken off with no detrimental effect to the running of the car - seems that there is a bit of over complication going on at the design end. I know they have many regulations now, but if it isn't totally necessary, then why bother?

When ECU wants to open DV durnig full throttle/acceleration, simply "energizes" N249, which will "de-select" the DV from the intake manifold (boost), and "switches" it onto the vacuum reservior. The vacuum in the reservoir will open the DV instantly and release your boost, which, in most of the cases (tuning, etc) is not that highly required . In the case ECU sees a little overboost problem, it can turn N249 on/off repeatedly for very fast (just as N75 is working), which will open/close DV all the time, trying to settle (lower) the boost level.

Umm I wonder If this Is the cause of my boosting fluctuation :S

Wow, some very comprehensive answers there. Thanks for the info. It seems mad that all this stuff can be taken off with no detrimental effect to the running of the car - seems that there is a bit of over complication going on at the design end. I know they have many regulations now, but if it isn't totally necessary, then why bother?

Yep does seem a little overkill, but as the VAG cars cater for a number of different country and euro regulations and outside Europe for that matter, the cars are generally made to suit worst case running conditions and emmision controls. For UK some of that is not needed.

Umm I wonder If this Is the cause of my boosting fluctuation :S

Could be, since removing all that stuff my boost is very stable and power delivery sweet. although to be honest it was reasonable before.

I had boost flutuation when i got car remapped some time back changed the N75 for a ECS race one and changed the Forge uprated DV spring to yellow one, been cool ever since.

Got a cell light today so probably one of the resistors gone, still running sweet though. Going to get the cell remapped out anyway and fit a de cat soon.