OllieC

sorry Chris .... got a bit carried away.

RLE

iTrader: (2)

I think Greasmonkey has got a point and he certainly knows what he's talking about. I agree with what your saying mate, of course tuning companies are going to put the hardware on their demo cars but I was thinking more of the likes of Rich Wild and his UK97 Turbo. (Jap Innovations) Surely someone who has spent so much in obtaining near on 390 bhp from a UK spec turbo would not want to damage it with a meaningless dump valve.

That said I must admit to the following. The dump valve that I have had on my car for the last 2 years was extremely loud and it became a bit ott IMO. I took the car to Jap Innovations to have a boost controller fitted and they commented on the dv and recommended I removed it and if necessary replace with an HKS/ Turbo XS one. Now it was coincidence that I'd bought the HKS one on the recent group buy so it had nothing to do with them trying to get me to spend more!! Sure enough when replaced the car ran better and appeared a lot smoother etc.

I think quality of the product speaks volumes. I cant help thinking how my car would run again with no DV attached though.

EddScott

I've got an HKS one and find that if I don't want to make it whoosh then I just drive the car accordingly and it doesn't or not as much.

As for "Rally car" sounds isn't that the wastegate? Also, greasemonkey mentioned taking the DV off altogether, I've heard of a lad with an EVO5 doing it but thought it sounded a bit iffy - I guess it gives a half-assed rally sound but at much reduced turbo life (stalling?)

Go on tell me I'm talking carp again

marklemac

Agree with EddScott,

If you lift off smoothly you get no whooshing at all. If you want the full dump sound then give it some full throttle then lift off quickly

OR, if you want a high pitch whistle, give it fulll throttle and lift off slowly

SirFozzalot

I read somewhere on here a while ago about someone with a dumpvalve that did both Recirc and VTA, and the amount that was recirculated or vented was adjustable. Anyone know if these are available? and are they any good? i.e. are they any better for the turbo etc. than a fully VTA.

greasemonkey

No, it's pulseback past the compressor blades. Impreza WRC's don't have dumpvalves, so there's only one way the air can go when the driver lifts off and the anti-lag takes over.

It gives an almost identical sound to the "chirp" produced by the rally cars, as it's the same sound. As for "much reduced" turbo life, that's a piece of string question. All depends which turbo you're using (TD's seem to cope better than IHI's in general), and with how much boost. WRC cars run over 40psi at times, which partially explains why their turbos only last a few hundred miles.

greasemonkey

I think you'll find it's Turbosmart who do the dual recirc/VTA product. As for whether they're any good, well, they're "less bad" than a pure VTA, but still a compromise. The only way to have the engine running right would be to set them so that they were 100% recirculating, in which case, what's the point of changing???

Lemmy

I have a VTA on my Scoob and a SECS unit that shows the air fuel ratio. When I lift off the gas it momentarily indicates a richening of the AFR before going lean. It does this when running off boost as well as on boost. So I would agree that this borewash theory is a bit OTT.

Furthermore a well respected ecutek mapper told me that a VTA would not damage my engine.

Alan

Jay m A

iTrader: (2)

Trying to be a tad more constructive, IIRC I read an article about high power cossies and I THINK that if you're boosting over 1.5 bar (or something) on a particular turbo setup then its best to vent away some of the manifold pressure on lift off.

Might have been something to do with BTCC in the early 90s but this is the only time I have ever heard anything positive about VTAs.

Or did I dream that

PS £40 posted to your door, It'll fit on any pre97 as it is, and dare I say with a bit of tubing will fit anything. It'll be in the FS section once diggy pics are taken