Can i change my dump valve on my 53 plate sti ?
which is best, dont want it too loud, but then again, "oh go on then !"
will it invalidate my 2year warranty ?
cheers me dears

 

Leave it alone. You will gain nothing, might lose a bit if you go VTA, and 'psssst' there goes your warranty.

Richard.

 

I run a turboXS rfl dump valve on my 03sti8, it sounds amazing not for the faint hearted. It hasnt void my warrenty and I have select monitor read outs that prove it looses no boost pressure and in 3rd and 4th gear looks as if it spools the turbo up quicker.

Matt

 

Ive got the same dumpvalve on my 98 sti4, sounds awesome. Again, the turbo does seem to spool up quicker. Some say that with these vta dumpvalves, you get bore wash, burn more fuel and basically knacker your engine. Can't really see where they are coming from.
If this is true, can somebody please back it up with experience or detailed despription of why vta's are so bad

 

VTA is not really a good idea.
As standard, you have a recirc. valve, therefore when you lift off the throttle the excess boost is dumped back into the inlet tract after the MAF.
So, this air is not re-metered by the MAF - Your ECU is expecting to see this air returning through the engine, and is mapped accordingly, as standard.
Obviously without this extra air, you are running momentarily rich, which can't be a good thing!.

 

See here for some more info and opinions.

 

Now this is an ideal thread for Greasemonkey to comment on!

VTA is bad!
Dumps metered air, ECU doesn't know that so puts in fuel for full air charge, excess fuel over rich and petrol washes bores of oil film, so more friction / wear / probable loss of sealing and lower compression and lower power.

Nuff Said.

 

Leave dump valves to the saxo/nova maxpower brigade, dump valves serve "absolutely" no purpose at all except make gay noises on lift off and cause running problems, unless of course thats what you want the std recirc is by far the best and was put on the car from new for a very good reason, bit like seats and a steering wheel

andy

 

Agree. I've just refitted my original dv. seems to run smoother than the turbo xs vta that I had. Turbo spool up is quicker and harder. All minimal increases, but I can notice them. The annoying 'vmmmtsssss' noise has also gone. (Thank God).
Plus I have the piece of mind that I have removed the possibilty of runnung rich and causing bore wash.
Now, onto decat downpipe!
Thanks for all the advice on here.
Leave your dv alone m8, you wont do better!

 

So keep the standard dumpvalve it definitely is. My son keeps banging on to me about getting a 'whooshtish' sounding dumpvalve but even though I like the sound, I keep telling him it will make the car perform worse not better - I think it probably applies to any car, not just Scoobies.