UK-POLOS.NET - THE VW Polo Forum

will a dump valve eliminate turbo lag? if so is there such a beast for diesels? if not whats does a dump valve do and will it give any noticable preformance gains. thanks si

I'm pretty sure yours will have a similar turbo to mine which is a recirculating one which means it recycles the pressure so there's always a pressure there without huge lag time. I only suffer lag between 1000-2000rpm.

I don't know much about engines so above is about all i know (well been told so may be wrong after my translation)

I always thought that dump valves were just ways of getting rid of excess air, or if a recirc on its just recycles used air, as said above...

The only way to eliminate turbo lag is prolly getting Anti-Lag.
Don't even know if they do it for Polo's, let alone diesels, i've only ever really seen it on Jap cars.

With my boyfriends Seat, he found it was a bit more laggy with a dump valve on, but suppose it depends on the kind of dump valve you get!!

Hope that makes sense and helps!

Yep sorry forgot to add a dump valve will most likely increase lag because it gets rids of the pressure and the turbo takes longer to build up the pressure again hence why they have recirculating turbos.

thanks - a revo thing it is then and maybe a sporty air filter but may leave it for a while.

A Dumpvalve is like apressure valve when the pressure on the inlet becomes to great it opens a vlave to release pressure, usually at about 7 k of revs on standrad turbo, which i presume therefore takes some pressure of the inlet and looses power?? i think it is just to make it sound good, dont get me wrong they sound well nice




Edit: well ignore all of that, my dad just said its supposed to keep the turbo running, to reduce lag at lower rpm,

erm dunno :s lol

really confused now?

I would suggest you get:

Cupra (tdi 160) air intake pipe £25+

Replacement air filter (K&N, Green Cotton) £40+

Revo remap and sp1 (if your really flush) £770

should be good for 130bhp+ and loads of torque

Matt

Dump valve is not even technically possible on TDI. Well ok actually there is a kit from forge that accomplishes this but it is ridiculously expensive. After all the only benefit is a "psshht" sound so definitely not worth the money.

btw, recirculating valve does not actually remove lag either but during fast gear changes it keeps the turbo spooled up a bit which in theory helps to reduce lag for some amount. But if you lift your leg from the pedal for longer period (e.g. engine breaking) then the initial lag is still always there when you start accelerating again..

actually on rally cars for example they don't use any kind of bypass valve at all so the pressure keeps striking compressor blades (making "tsihihi" sound) when throttle is lifted. Although this is not good for the turbo in longer run in rally cars they change the parts so often it's not worth the extra work fitting any valves in the engine bay anyway.. To sum it all I guess that performance wise the gain from using these valves is minimal and main purpose is just to make the turbo last longer..