is my diverter valve screwed

[curtis11]

when driving my car today i noticed the dv making a different sound (running a induction kit) when lifting off the throttle . its is usually a WHAATOOOSH sound but now its more like fluttering sound .
anyone have any ideas .
the valve is standard and the car is chiped.

 

[curtis11]

it didnt sound this way until yesterday and the turbo does not seem to come in with the same force

 

[djjnrj]

any fluttering sounds from a turbo charged vehicle does normally mean compressor surge, especially if it happens at low rpm's. however, at low rpm's this is not an un-common occurrence and is quite normal. at high rpm's is when compressor surge causes serious damage (to the turbo). my S3 flutters at low rpm's, but i run a piston valve and this is normal in my case. this should not happen with standard valves.

change your valve for the new 710N DV which is fitted to S3's and alike. this valve will cope with your re-mapped and increased boost set-up with greater reliability. the valve is around £14.99+vat from your audi dealer. even if this doesn't solve the problem, you will have fitted a much better valve for little cost and it will eliminate the valve as being the problem.

be sure to buy new clamps for fitting your new valve!!!

 

[djjnrj]

[ QUOTE ]
Soupie69uk said:
Mine always makes the fluttering noise when it is fully warmed up.

[/ QUOTE ]

sounds like you need to back off the pressure of the spring in your DV.

 

[PaulJC84]

Oh right i am running one of those GFB dv where you can adjust the amount venting to the atmosphere and the amount resurc. I could only hear the flutter now that i have fitted a piperX.

 

[djjnrj]

[ QUOTE ]
Soupie69uk said:
Oh right i am running one of those GFB dv where you can adjust the amount venting to the atmosphere and the amount resurc. I could only hear the flutter now that i have fitted a piperX.

[/ QUOTE ]

as far as the VAG engine management system is concerned, you should run your (if this is the model you have) GFB Stealth FX valve at no more than 50/50 atmo to re-circ. run more than 50% re-circ if you can to be honest. this should give you venting wooossshhh sound and enough re-circ without causing engine management problems. i take it you know how to adjust your valve spring tension as well as the amount of venting?

i run a GFB Hybrid myself. i did have it 50/50 venting to atmos & re-circ but changed to full re-circ because the car was going into "limp mode" and reducing boost to prevent damage being done to engine and turbo. the VAG engine hates trying to cope with big differences in boost pressure changes.

my valve was set up like the first image. now its set up like the last.

 

[PaulJC84]

Oh right mine is about 50/50 cos i have the one which you can adjust on the car. I have it about 50/50 cos at that it made the best whoosh. I can just turn the nob on the top of the dv to adjust the spring rate. I think this makes the amount of boost needed to go whoosh different. I think.

 

[djjnrj]

[ QUOTE ]
Soupie69uk said:
Oh right mine is about 50/50 cos i have the one which you can adjust on the car. I have it about 50/50 cos at that it made the best whoosh. I can just turn the nob on the top of the dv to adjust the spring rate. I think this makes the amount of boost needed to go whoosh different. I think.

[/ QUOTE ]

what you say is correct in part, however, you should change the valve spring for different boost pressures, not just increase the standard spring tension! the real reason for an adjustable spring is for idle set up, to make sure the valve doesn't vent for too long after throttle release and cause the car to stumble at idle. its also for you to adjust the valve to prevent compressor surge.