ouimetnick

Hi, so on my 2005 6 speed RX-8 (37,000 miles) I get what sounds like hail or heavy rain or perhaps gravel being thrown around the wheel wells. It only happens when it’s cold started (first thing in the morning, or after sitting for a few hours) I only hear is when the car is in motion, not when stopped, but it goes away after a minute of driving. I linked to a video so you can hear what I’m talking about. My old 2004 Black RX-8 (rust bucket) didn’t make this noise. Any ideas on what it could be? It’s definitely not road debris as the roads are perfectly clean, and there is no accumulation of any pebbles or sand or rocks in the wheel area.

Loki

iTrader: (1)

I don't know if it's the microphone, but it also makes an obnoxious amount of bump noise. I think you might have a blown shock, have you had a look under it?

What tires are you on? If they're stickier than what your last car had, it's possible they actually are small pebbles that the previous tires didn't pick up quite as well.

ouimetnick

Just got new Continental ExtremeContact DWS 06 on all 4 wheels just last week. Had the same issue with my bald 10 year old Dunlop’s too. Yes the microphone on my iPhone is a bit to sensitive. What makes you suspect a blown shock?

Loki

iTrader: (1)

It only happens while moving which tells me it's not the engine. Blown shock will cause the wheel to bounce endlessly, which might be what you're hearing. The thumping over bumps points in that direction also.

Another thing it could be is a broken sway bar endlink. It would make a similar rattle, but it would rattle all the time. I'd get that car in the air and check out the suspension visually. Could also be an exhaust heat shield, but again that would be a constant rattle.

Can you localize the sound? Is it actually the wheel well, and a specific one?

ouimetnick

Wouldn’t an issue with the shock or sway bar endlink be continuous? This noise goes away after driving for a minute or so, and only after sitting for a long time

Loki

iTrader: (1)

Shocks warm up with operation, it's possible (although unlikely) it gets better when warm and provides some damping as opposed to none.

I mean my first guess from the sound is that it actually is kicking up some kind of dust, but I can't get under the car and check everything else from where I am

ouimetnick

I would have thought dust, rocks, gravel, etc, but was happening even when I still had my old rusty black RX-8. The Black RX was quiet and fine while this one made that noise. I do notice that the black one had what felt like a harsher ride (more solid and firm) although this one isn’t bad.

The black one also felt like it had a more powerful engine (definelty a louder exhaust even though both were stock)

ouimetnick

Not sure if this new video I made this morning shows it any better. Strange how much other noise my phone’s camera picks up considering I’m holding it and my arm can dampen vibrations more than if it was in my phone mount thing.

REDRX3RX8

That whump whump from the rear is bad shocks.

I had noise like that although not as bad, and put a $700 Bilstein B12 kit all around.

I like the new firmness and no bottoming of shocks.

Kit put my 07 Gt at 14.25 inchs all around fender to center rim.

Mazda doesn't seem to have decent shocks, coils, fuel pumps, or manual trans synchros, but fix the first three and car is pretty solid.

ouimetnick

So confusing with what I need. I’m not a person that wants to mod their car but if I need new struts or shocks or whatever I should do it right. Do I get new shocks or coil overs? I know it’s a dumb question but I’m not familiar with suspension terminology (besides the basics)

Loki

iTrader: (1)

Replacing the shocks is significantly cheaper than good coilovers, and you don't want cheap coilovers. But the first step would be to confirm shocks are really the problem. Any garage can do that.

ouimetnick

Checked the shocks for leaks. No rust, no fluid leaks. Also the car is firm and the rear doesn't bounce either.