I have recently noticed when at 4500+rpm I get like a squeel sound, its not a hiss. Any ideas before I take the car back to the dealership, the problem only occours when you have got your foot well in. It is not an alternator belt problem or sound.

Darren.

What model and year is your car?

It may be a leaking dump valve... this was a known problem on 97 year cars... valve spring was uprated for 98 cars, so fitting a 98 valve might fix the problem. I did this on my STI 3 and it did fix it, for a while.

The car is a UK 98 model.