billythekid

Got a piperx induction kit today for my 2003 WRX.

Fitted as per instuctions etc.

However over 3000rpm I can really hear the turbo - before it was a background whistle but now its very audible.

Also the waste gate sounds almost like a DV - is this right

Dont really like the woosh of DVs so not really that keen on it etc.

Do other people get the same results?

BTK

PS - I will try and put a sound clip on the web somewhere if I can so you can see what I mean.

greasemonkey

Need to be a bit careful here chap. Fitting this kit will invalidate your warranty, and if it causes a MAF sensor misread which results in a damaged engine, you'll end up stuck with a very big bill.

As expected. You've got rid of the baffled resonator, so there's a much more direct route between the turbo and the mouth of the induction tract.

It's not the wastegate that sounds like a dumpvalve, it's the dumpvalve sounding like a dumpvalve. It's making the same noise it used to, the difference is that now you can hear it.

Why'd you get an induction kit then?

Given that you don't even like the noise, you've really no reason to keep this thing on your car. You'd be far better off refitting the standard induction tract, and, if you want something "better" than the regular paper filter, get an STi or K&N replacement panel.

billythekid

I like your thinking...

To be honnest I was in a shop talking to a mate who sells this sort of thing - he happened to have one in stock etc etc...

Might take it off today but will go for a drive to see what the situation is.

Cheers

BTk

PS - "and if it causes a MAF sensor misread which results in a damaged engine, you'll end up stuck with a very big bill."

Why does it do this? I have had a lot of other cars with induction kits and the MAF ususlly just sees more air and changes the fueling - is the scoob different?

greasemonkey

IIWY, I'd take it back so you can save him the trouble of having to order another one in to replace it!

Should have added before that, if I remember right, Pipercross filters are the oiled synthetic foam type, which are bad news for MAF sensors in general. Dry or lightly oiled pleated cotton filters are a far safer bet as they don't tend to shed fluid.

Largely depends on which kit you use. Some don't put the readings out, others do to varying extents.

Reason is due to changes in the airflow characteristics as the air passes down the MAF tube. If, for example, the cone and bell design promotes the formation of a vortex, the air pressure will be lower in the centre of the tube (where the sensor head is) than nearer the walls. Thus, the sensor will under-read the amount of air going into the engine, and the ECU consequently under-estimate the amount of fuel that needs to be injected to achieve the target AFR.

As the Subaru engine is easily damaged by detonation, you don't need much of a percentage variation in MAF scaling before the mixtures (even on the rich standard ECU's) become critically weak.

As the standard induction tract isn't particularly restrictive in a stock or mildly modified scenario, there's no real advantage to be gained from fitting a cone. In fact, there's easily the potential to lose more on the swings than you gain on the roundabouts, as the standard system gives you a good supply of fresh cold air straight from the front intake. Unless you fit a cold air kit, your cone will be taking in air from the engine bay, which is likely to be considerably warmer, and thus less dense.

billythekid

took it off the car today. I am sure its taking longer to come on boost but I will be getting the PPP soon so not that bothered about the filter.

thanks

btk

greasemonkey

Exactly, filter would have had to go before you had the PPP fitted anyway. Probably worth getting them to fit a decent panel at the same time.