WRX STi noises

Do any of those noises vary with terrain?

I moved recently and noticed a strange sound on the drive home. A "hum" at

62-66 MPH -- no more, no less -- on a newly paved blacktop surface over a long causeway. I really freaked until I realized that, for whatever reason, it only occurred right on that 3 mile stretch of road at those specific speeds. I let off the clutch and it went away making me think it was tranny; turns out that if the car was slowing through those speeds that the noise wasn't present, during acceleration of stead pace, however, (perhaps it's related to the harmonics of the suspension under load, too, or the dynamics of tire deformation) the noise was present. It had probably always been there but for whatever reason only was amplified enough at that point along the drive.

My point is, that as the road surface varies so too should "tire" noise, if that is in fact what you've got. Do some experimentation and see for yourself.

Mine has always done that with the RE 070s on. It doesn't happen with the winter tires (they have a softer sidewall). It sounds like a harmonic and it only seems to happen to me when the road surface is particularly smooth and doesn't change much. It is reaslly pronounced on concrete.

There is a hum which seems to be a combination of the turbo and some of the gearing noise. I get it at about 125 KPH (I'm in Canada) which as around 75 or 80 MPH. That one is more noticeable with the winter tires on (they are actually quieter than the RE 070s).

There are all sorts of weird noises coming from the thing every now and again. Because I had never driven anything like the STi, it used to concern me when I first got it. Now, as long as the noises don't change much and the thing still goes like hell, I am a happy camper. It does and I am still a happy camper.

No, the periodic speed-related one and the high-speed hum don't seem to - at least, they don't vary on regular paved roads, which are the only roads on which I drive the car at any speed. There is another sort of noise, which tends to sound like combinations of white noise, which varies markedly based on the type and quality of the road paving: I'd assumed that was a louder version of the tire noise I'm used to in more normal cars.

That is interesting - it does sound related to my 75mph high-speed hum

- it's probably pretty much the same thing! The hum I mentioned also only occurs within a narrow speed range.

Interesting - I'll give that a try! (-: Thanks for the great description.

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Mmmm. I'll be interested to see what changes when I switch to winter tires in a few months.

-- Mark

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How very interesting - thanks! The G35 I borrowed also had some kind of Bridgestone tire on large wheels, I think. Let's see how the winter tires go for me, then. (-:

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That's also very interesting, and would fit with what the other guy wrote. I appreciate the information.

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Yes, me too. (-: The STi's certainly at a sweet spot in the performance/price tradeoff I think. As well as going like hell, it corners and brakes well too - I'm very happy to have a car that seems to have all-round excellent performance.

-- Mark

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The hum in mine doesn't seem to be changed if I don't throttle, if I put it out of gear, etc. Still, it's no worry to me, at least.

-- Mark

So has mine. My winter tires are Pirelli PZero Nero M+S, and the noise is much less pronounced (but not gone.)

Something that cropped up lately was a clunk coming from the rear right trunk area. I read online that it was the top of the rear-right strut banging around. It was odd: I'd be screwing around downshifting going down a hill and right at the end of the stop, I'd be completely stopped, it'd pause for a moment, then the rear end would settle down almost imperceptibly with an annoying clunk. It was really getting obnoxious for a while, and then suddenly--it was gone. All better. No clunk. Fixed itself basically.

Cool. No more Chinese water torture. :-)

I think you mentioned before, but what's your winter tire again?

Same!

That seems real common on the MY04 STi's...seen a lot of it over on NASIOC, US dealers will replace the struts under warranty. Not sure if the replacements start after a fashion as well...

I had that. Subaru replaced the rear struts at no charge. Apparently it is a know issue with the STi. The car handles so well that you don't notice the difference; only the sound. But once they replace the struts, it is a HUGE difference in the handling.

Really? That's interesting. Well now I'm going to have to push my dealer for a replacement. The noise may be gone, but the weird little jerky movements at the end of a stop are still there, and given how closely I pay attention to the car, I'm fairly certain the movements weren't there before.

So what's the difference before/after? Are they just new struts, or are they completely different? Is the rear-end tighter, or is it more/less oversteer post-replacement?

I didn't even know they were shot; the dealer just told me my struts were in. I responded, "What struts?"

Anyway, it turns out that the infamous STi clunk was a bad batch of struts that came with some of the cars. They replaced them with OEM equipment; just not faulty ones.

Differences:

There is less understeer going into the corner and the ass-end sits a little higher. It also doesn't squat as much under hard acceleration and there is less oversteer on corner exits. You can carry more speed through a turn and the wheels stay planted better. It just handles better. Also the AFSR (Auditory Female Speed Restrictor) doesn't get chipped teeth from yapping about the speed any more. Her uterances are now crystal clear; there is a downside to everything I guess...