wastegate knowledge needed!!

[Slim m]

After reading some threads on wastegate's and boost presure, I started to get a bit worried!! When I bought the car, one of the guy's selling points was a stronger spring in the w g to give more boost.
Is their anyway of telling if the spring is actualy a stronger one or not? Another worry is something the previous owner also did, In the middle of the w g is a big screw, (correct me if im wrong but thats what it look's like) but on mine it looks like someone has cut half of it off, as it sits quite deep in the hole and has no notch cut into it, and the surface of it look's like it has been cut with a hacksaw!! when I asked him why it was like this he just said, "Oh it's to stop you from turning the boost up" I just thought OK then. I dont have a boost guage so I cant tell how much boost it is running at! This is my biggest worry! Anyone with any idea what i should do?? Liam.

[terrybullwon]

Would like to see the hacksaw damage, never seen that one?

The "screw" in the WG is it alen key bolt?

[4WheelDrifter]

Get yourself a boost gauge to measure the boost, that would be a good start.

[Fat Audi 80]

IMO it sounds dodgy. Get yourself to a specialist (MRC) for example and have the car checked over before you do more harm than good. These cars should be set up properly not have the wastegate held shut with a bodge.

Cheers,

Steve.

[Jamo]

You wastegate has been messed with but you need to post pics of the boost pipes.

If you ECU is still controlling boost i dont see this being a problem. But if theres some sort of bleed setup it will be.

[Knight Rider S4]

Mine is screwed up should look like this

[Slim m]

if someone can tell me how to get pics from my computer onto this site then i wil do so tomoro! the boost is stil being controlled electronicly! Liam.

[terrybullwon]

www.photobucket.com

And then link you img's by copy and past

[S2central.net]

@Slim - Sounds like much WG bodging alright. Before you go rushing off to MRC for a checkup - as trusted and experienced in these cars as they are - I advise you do some of the basic tests yourself.

Get a boost guage - cheap as you like and T it into the boost line at the ECU - doesn't need to be permanently installed... Just enough that you can read it while driving.

On standard 3B you should see max boost of 0.8bar and on ABY its nearer 1.2bar maximum. Multiply those bar figures by 14.5 for boost in old money (PSI).

Then disconnect the electrical connector at the WGFV - search the forum for how to find it - and then you should see approx 0.4bar maximum boost on a standard spring.

The reason that the mechanical spring provides lower pressure in the factory configuration is so that the ECU software provides real-time boost control by modulating the amount of boost presure presented to the WG (thats what the WGFV does).

Stiffer WG springs can provide faster turbo spool and reduced lag - this is especially true on bigger/custom turbos - but the big downside of stiffer springs is that the ECU s/w has less of a part to play in boost regulation... The ECU has a number of safety routines that are invoked to reduce boost in times of high air temps and/or poor fuelling that causes knock conditions... If the WG spring is too stiff then there is no way that the ECU can reduce boost to the safe realms of 0.4bar.

Phooking about with stupidly stiff WG springs is an old turbo 'upgrade' bodge from the days of the awful early turbo cars as there was little or no software control for boost.

Would advise to do these couple of tests and see what figures you get... Then we can help advise what to do next.


PAul

[Slim m]

Hi Paul,
can you tell me two things? 1: where exactly do I T it in too? as i dont know where the ecu is. and 2: what diamiter T do I need to do this?
Thanks! Liam.

[4WheelDrifter]

Have a poke around under the dash in the passenger footwell, you should find the hose that goes to the ECU. Stick a T-piece in that hose - 4mm IIRC.

[Greg_S]

Knightrider, looks like your WG has been modded since it has the bolt on the top too.