My car makes a weird noise when I let off the throttle

[vr4gasmtt]

When I drive, I usually like keeping it in gear so I don't have to press down the clutch to throw it in neutral and then holddown the clutch to throw it back in gear. But everytime I just leave it in gear and let off, it always seems like the wastegate is making a bucking sound, its kind of a hard to explain and it can't be heard from a camera. I'm not sure if anyone else has this problem but I was wondering if that would mean my wastegate is bad or is that just normal? It doesn't sound normal. When I let off my vac goes to 23-25, and then I usually just throw it in neutral, or I just give it a little throttle so it goes to 20vac .

My friend who drives a saab 9-3, ( has a t-25 in it) doesn't make this sound, but then again hes FWD.( Not sure if that matters or not).


Another question I have is, would holding in the clutch at a stop light and having it in 1st gear be bad on anything? I don't like being stuck at lights and not being able to have it be in 1st gear, since it doesn't go into first sometimes.

 

[Cs4g63]

I dont know about first section. I am a little stumped on that part.
But the part about whether or not its bad to keep it in gear and holding the clutch in while stopped at a light I can give some insight. Its not bad as in its going to hurt the trans or anything but it will cause your clutch to wear out quicker than it would if you didnt do that.

 

[vr4gasmtt]

I dont know about first section. I am a little stumped on that part.
But the part about whether or not its bad to keep it in gear and holding the clutch in while stopped at a light I can give some insight. Its not bad as in its going to hurt the trans or anything but it will cause your clutch to wear out quicker than it would if you didnt do that.

Can you tell me why it would wear out the clutch faster? Since when the clutch is pushed down its not really engaging with anything right?

 

[kenamond]

Can you tell me why it would wear out the clutch faster? Since when the clutch is pushed down its not really engaging with anything right?

About all I can think of is that the TOB is under load longer if you hold the clutch in while in gear. However, this also applies load to the crank which ***might*** hurt in terms of crankwalk.

I fear crankwalk, so I put it in neutral whenever practical.

Can you describe the sound you hear?

During shifts (like going through the gears accelerating), when you let off the gas to shift, the throttle closes, but the turbo is still fully boosted. The BOV is designed to sense this condition (via a vaccuum line from the intake manifold), open a valve, and bypass the compressed air back into the intake pipe so that it is "recirculated" - it gets fed back into the inlet of the compressor. This keeps the turbo compressor from surging (stalling) which is bad. The BOV recirculation may be what you're hearing if it sounds like a "whooosh!".

If the BOV is malfunctioning (not opening), you may be hearing the compressor surge. I've never heard it, but folks say it sounds like a chirping/studdering sound.

There is no reason you'd hear the wastegate during a shift.

So I ask again, "Can you describe the sound you hear?"