[turbobuick]

I am still breaking my motor in, I don't even have 200 miles on it. I have never owned a subaru before, so I am new as to their sounds. By not being finished with the stereo yet, I hear every little sound out of the car. I have noticed that above 3000 rpm's when the engine is under a little boost at maybe half throttle, a consistent clicking is heard. I don't know if its a noisy valvetrain or an exhaust leak or what. If its normal, I can deal with it--just wanted to know if everybody else's does it too. It doesn't do it when you're light on the gas, just around medium throttle. I am being very careful breaking the motor in, so I don't know if it goes away when you lay into it.

 

[sakura-iro]

Extended Warranty

a little bit of noise is normal. a lot is probably a problem. have you checked your oil level? also i assume you can tell the difference between valvetrain noise and detonation, some folks have reported ping with low grade gas.

 

[bumpie]

Hub and lug centric

I am hearing the same as well. Anywhere from about 2500 RPM up and starts with just a little boost at half throttle and on up. Oil is fine here and gas is always 93 or higher. Part of me says that I am just being paranoid with a new engine/new sounds and with all the talk of detonation, but another part of me is say that just doesn't sound right. I have not heard serious detonation before, but I think I will recognize it when/if I hear it. Everything I read say it is very obvious.

 

[SupperPupp]

The only noises I hear in mine with the stereo off are the whine of the turbo and tranny.

The turbo noise is something I am still getting used to since I have never owned a turbo before. Although, its kinda neat.

 

[ha-evolution]

Great site

Sounds like the light detonation that I had been hearing when I was running 92 octane and it the temps were 80 degrees +. However, I never heard det under 4K rpms.

As for the normal STi sounds, I don't think I can hear the turbo over the tranny whine, but I may be confusing the sounds. The turbo is much more audible in a friends 04 WRX because the tranny is quiet.

 

[turbobuick]

It seems to be coming from the back side of the motor near the turbo. Did we end up getting that twin scroll turbo in the NA STi? I am used to hearing normal non-ball bearing turbos like I have in the Buick. Maybe that twin scroll sounds different. With all the talk of detonation, I'm a little bit paranoid too. I think I will put it up on the rack at work tomorrow to check for exhaust leaks.

 

[turbobuick]

Oh yeah, and the oil level is fine, actually a little bit over. And I am on my first tank of gas still. I actually told the salesman not to put gas in it and put 93 in it myself. They were about to fill it up with 87 :x

 

[ha-evolution]

It seems to be coming from the back side of the motor near the turbo. Did we end up getting that twin scroll turbo in the NA STi?

No, the 2.5L STi is not twin scroll. It is not needed as the 2.5L has plenty of torque. It would be interesting to see what kind of a difference a twin scroll header would make if it's possible to bolt up to our motor.

 

[awilson529]

If it is only at ~1/2 throttle in the mid-RPM range, it is probably just your boost solenoid figuring out what to do.

 

[ValvetrainEngineer]

There definitely is more valvetrain noise than most passenger cars. This is all part of the STi philharmonic - a singing turbo, whooshing gears, beeping shift alarm and clapping valvetrain. It's almost as if the valvetrain is applauding the work of the other components! Who needs a radio anyways (I haven't installed one yet!)

Seriously I wish I had a better technical answer, but it probably comes down to the design philosophy of the whole car - make it fast, make it strong, and don't worry about NVH (noise, vibration, and harshness). I haven't downloaded the tech manual yet to see all the valvetrain details...