Jake

I am now running an HKS FMIC with a forge VTA DV and experiencing a lot judder when I lift off the throttle, is the VTA DV causing this?

Would an HKS SQV solve the problem as it clips straight onto the pipework.



[Edited by Jake - 5/12/2003 9:38:01 PM]

Jake

Anyone???

AndrewC

Probably the VTA DV is causing it, you are not the first to experience this problem, try a search, this subject has been discussed at length before.

Andrew...

john banks

The larger volume of boost pressurized air in the FMIC and its pipework is more of a faff to vent or recirculate than the really quite small volume in the TMIC and pipework. Because of this some dump valves chuff or chatter away in a rather jerky fashion when dealing with so much air. This can affect the MAF signal integrity in both VTA and recirc setups - the first because of the large mass of unmetered air which is vented, the second because of the reversions on the back end of the MAF.

Jake

After speaking to TDI they recommend the SQV and say the Forge stuff is well to put it politely, not as good.

P20SPD

iTrader: (1)

Why do they say that?? What reasons?

I know of a lot of cars that run the Forge DV, including a lot of high powered cars.

From memory John Banks and Bob Rawle have tried a few different ones, sure they will be best placed to advise.

You can change the springs on the Forge which can help, they change them for free from memory.

Steven

Jake

I have changed the spring to a blue one and still no joy.

john banks

The red spring should sort it. Then the DV only really operates if there is more than about 1.4 bar across the throttle body. I'll go back to it once I am back on ECU boost control I think - problem was surge on part throttle with a Dawes setup to run over 1.7 bar (which the ECU will not control properly on the original MAP sensor).

Trout

iTrader: (1)

Increasing the spring pressure will actually make it worse - much worse! You need to try a softer spring.

Recently I have fitted a much better flowing inlet pipe and this has caused the turbo to stall with a shimmed Forge and FMIC. Reverting to the softer spring has all but made this problem go away.

I am sure that TDI are not in any way influenced by the fact that the margin on the HKS is so much higher on the Forge, oh, and the fact they sell the HKS stuff

Rannoch

VinnyP

As was said this is a common problem I had the same with a PACE FMIC and Forge VTA. This only happens with Forge, I tried all different springs and whilst it could be improved it was never sorted. Only changing the VTA can really help. I've gone for an SQV

Vince

Jake

Vince - did the SQV solve the problem???

VinnyP

Don't know yet. Having an new engine / rebuild, headwork and new turbo etc. at the same time so the results will not be conclusive. I will post an update when it's all finished but will be a few weeks yet I imagine

Vince

john banks

Trout, the sort of judder I get is far better with a stronger spring, so we must be having different judders.

Spoon

I thought we were meant to enjoy our judders?