MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: TyGTI on June 04, 2024, 11:17:06 am

Title: TFSI Blow-Off Valve (BOV)
Post by: TyGTI on June 04, 2024, 11:17:06 am
Hey all,

Long time lurker, seldom poster - I was hoping I could get some pointers on my newly bought Caddy (bare with)...

I have a 2.0 TFSI (BWA) converted Caddy which a previous owner has tuned up with KO4 turbo and other supporting mods, one of which is a blow off valve.

I've had a look at the turbo and can see a wiring plug with no home which I assume is for the DV (recirc valve) that would have been on the KO3 turbo. I've also looked at the pipe going up to the throttle body as this is where the DV is on the KO4 turbo'd engine but nothing there.

Two questions I guess:
1) Any idea where I'd be able to find the BOV? I've followed the obvious turbo air pipes and can't see anything
2) What is the best way to reinstate a DV? I have read these engines are better with a DV. Also, its tuned for the BOV at the mo, I assume it'll need to be retuned once that's removed and DV installed.

Thanks in advance
Title: Re: TFSI Blow-Off Valve (BOV)
Post by: pudding on June 23, 2024, 01:50:17 pm
BOVs are no good on Mass Air flow measured engines, you need the proper VW recirc valve.  That can be done easily enough using K04 parts and a wiring harness extension.