I have just purchased a 2nd hand Forge VTA for MY00 Classic and I have taken it apart tonight only to find out that a top plunger part (light blue) was jammed. I freed it up cleaned it all and greased all the springs etc (oh yea and it has a red spring too) and refit it all. However what I did notice was that inside the top part of the valve (where the blue bit was jammed) there are 2 small rubber inserts. One of these has come adrift and it looks like the blue bit was jammed on it! So i gently fed the rubber insert (which resembles an elastic band), back into the recessed ring (this will make sense if you have seen one) where it should be and bolted it all together. Now Having driven the car again it feels very quick indeed and there is barely any lag but there is also barely any sound from the dumper. It appears that its not dumping until I use WOT and go over 5K rpm even then the sound is very quiet? When I drive below this amount it is like a recirc - no noise at all. I lifted the bonnet and held my hand over the d/v and revved up the car again using the throttle linkage and its dumping but only when you rag the ***** off it. Surely this isn't right ? I have heard problems with the red spring being to stiff but what symptoms would I get with running it with the 'red' ?

All help would be appreciated.

 

It does sound as though as the spring is too stiff. If it has spacers in there, take them out and the spring will be more free to open the valve.

Forge will give you a blue one free. It should dump loudly at half - full boost otherwise its actually restricting air flow. Not too much negative effect, although it will place a bit more load on the turbo bearings. If its completely blanked off it will eventaully damage the turbo

MB

 

Thanks for that MB - the car just feels so good at the moment - virtually eliminated lag and I can only just about hear a slight sound when changing up at anything over 4.5K rpm. I am thinking though that it is not really acting like a dump valve at all hence the way the car is running I'll get on to Forge and see if I can get the spring and shims tuning kit

Thanks for your advice

 

When you get the kit from Forge, try one spacer and the blue spring. Worked about best on my old MY99.

Dave.

 

Thanks for that Dave - I'll give it a try

 

If the spring is too weak it can leak on boost, and you will lose power.

MB

 

OK I have the spring and shims kit arriving from Forge but I have removed the forge VTA for the time being as I was quite worried about the extra stress it would be putting on the Turbo. Basically I could only get the valve to open (about half way) with a lot of throttle ? Its is the red spring and has no shims in place. It is a very tight spring though, as it is quite difficult to push with your finger, thus opening the valve. The thing is I thought that if the valve was barely venting anything then the car would drive badly maybe stalling it etc ?? but it has been quite the opposite ? The car drives with barely any Lag witht eh Forge fitted and it seems to hold boost better ? There is none of the Whooosh which I would generally assimilate with a VTA but you could hear a kind of wastegate chatter when pushing the car ? but only very quietly. When I lifted the bonnet at the weekend and revved the car stood still I could hear the chatter coming from the airbox ? although very quietly

My question is could the dump valve be hindering the car in any way ? putting bad extra pressure on the turbo etc ??

 

If the Dv is not releasing all the excess boost pressure, you 'could' risk damaging the turbo.

 

A spring that is too hard will put extra strain on the turbo, but you will notice reduced lag between gear changes (why the rally cars run without a DV).

A spring that is too soft will cause poor running/stalling.

What you are after by using the blue spring and shims is the middle ground where you don't get problems with running or put extra pressure on the turbo. But still get the noise.

As has been said before (many times) a VTA is not a performance mod, its just a way to get a (nice?) noise when you change gear. I ran a Forge VTA on my MY99 for about 35k miles without a problem. But now I know more I haven't fitted one to my current car (still using the standard one at 1.3bar).

Dave.

 

Thanks guys for your input - I think its best that I leave the Dumper off for the time being

Most helpful - thanks

 

Dave, rally cars have it blanked off but use anti lag to keep it spinning.

MB

 

I have just got a turbo smart dump valve to replace my forge, It seams that the spring tension is very hard, can anyone tell me weather the valve should be open on idle. My forge was open on idle and closed when I reved her up.

also the instructions for the turbosmart say that "at idle the exhaust port should be closed off by the piston, the piston should be hard up up against the seat and not floating or moving".

I was under the impression that the vacc from the hose held the valve open at idle and when possitive presure was reached then the valve would close while building boost and during lift off the boost would drop and the vacc would open it again.

my vacc connection is not strong enough to open the turbosmart valve on idle even with the valve set on softest setting.

can anyone shed any light. does the turbo smart valve work differently?

 

who has dump valves open on idle? my forge was open on idle but according the guys at turbosmart dump valves for turbo applications are supposed to be fully closed on idle.

Any oppinions on this.