UK-POLOS.NET - THE VW Polo Forum

Hey all
I've never been one for modding cars. But now I've hit 23 got some no claims under my belt, it doesn't cost much to declare on the insurance so looking at a few mods now. I've been looking at installing a cone in box, only for noise and cosmetic value.

I've seen videos on YouTube of this install on various cars, and on a lot of these videos after the install there is a large amount of turbo chatter. I know that this isn't good for the turbo and should be avoided, so my question is. If i install this on the polo 9n3 gti, can the stock diverted valve cope or will it cause turbo chatter?

Cheers
RamJam

Prepare for a long reply..

I presume when you say cone, you're talking about a cone filter? No this won't cause the turbo to chatter. It will inhanse the noise that the turbo and engine gives off because it's less restrictive and opens the car up a bit. Kind of like if you were to remove the baffles in a back box, the exhaust will be louder. A cone filter is a good first mod because it's considered necessary to get the best performance out of your car. It won't add much HP, you'd be very lucky to get 10HP but it's nice to know that it's done and you'll get the added noise which is better than the added power lol!

To make the turbo chatter you need to eliminate the ability for the pressurised air (boost) to escape the boost pipes when the accelerator is released. This is done by removing any existing blow off valve (BOV) or diverter/rescirculator valve. Most people will recommend NOT to do this because that turbo chatter you will hear is the boost forcing its way backwards through the turbo which can cause damage over time. If you want a nice "Pssh!" sound then you want a BOV or an aftermarket diverter valve (the car already has a stock diver valve). A BOV will simply release all the boost into the atmosphere with an impressive "Pshh!" but at the cost of your boost obviously so the car will become laggier. A diverter valve takes the boost and puts it before the turbo so it goes back through the turbo and is ready to use when the accelerator is pressed again. The downside to a diverter valve is that they are much quieter than BOV's. You can make them sound louder by getting an induction kit/cone filter. I recommend a Forge splitter valve. This is effectively a BOV and a diverter valve in one. It lets out some boost into the atmosphere and diverts some into the system.