I'm posting on behalf of my friend who owns an 06 STi with some light mods, including project MU 6 pot brakes and a set of Advan A032R tires. He has Ohlin (sp?) coil overs and upgraded sway bar. (None of which could make the noise described below)

Him and I went for a drive up and down Mt Hamilton/Mines road with his new A032 tires (which are R compound super sticky tires). We both drove the car with the same results, which were not what we expected.

We noticed that during hard cornering when breaking traction in the rear (breaking the rear end loose) we would hear a really loud THUMP as the car gains traction in the rear. The sound def comes from the rear and it scared the hell out of us!

The car was on Auto DCCD, and the sound came from the rear. What the hell was it?! I'm really hoping that the sound was the tires grabbing traction and hooking up and not something f'ed up like a broken diff. It ONLY happens when the rear tires break traction, and then the sound happens, then there's full traction again.

He said this is a new thing that only started happening that day which happens to be the day he went hog wild with the new tires.


Anyone have experience with this? It happened every time we cornered SUPER hard and broke traction... and you have to push the car REALLY hard to brake traction with those tires.

 

Edit. I fail at reading.

 

Sorry never experienced that, and I run 295 Hoosier A6 tires. It's not that diff clunk thing is it? If so, he can install those diff bushings and those should cure the clunk

 

I'm pretty sure it's the rear diff - it's happened to me once or twice when I switch back left to right really fast in the twisties. This was with the RE070 tire.

 

I am pretty sure the hard clunk would be the rear diff.
I get it when I accelerate through some loose dirt and rear needs to find traction and i shift gears sometimes it would clunk

 

Ah sweet, thats such a relief! So bushings will solve this? It def has something to do with too much traction, right? Thats why the diff does that?

What kind of bushing specifically? Can someone give me a specific name or a link?

 

beat me to it, yeah I got this when I used to run V700s on my STI, hope thats all it is!

 

Damn, its such a horrible noise... Something a car def should not make! Especially a newer car like the STi! It just sounds like destruction... Not a cool noise at all!

 

It's probably all your guns rolling around in the trunk mate

Mike

 

^^LOL!

 

You like the one I showed you today? And I'm not talking about my biceps or **** either, I'm talking about the new 5" one.

 

i have group-n 6spd tranny mounts that i can sell you.. gimme a PM if you're interested. they've been collecting dust since forever. it eliminates the rear diff clink on hard shifts. i don't know about your friend's issue though.

 

^^^ lol

 

I love banging the rear diff on hard shifts - it always scares my friends that own WRX's.

"You're gonna break a gear bro!! "

 

Rear diff support bushings, rear diff outrigger bushings, and MAYBE tranny mount and tranny crossmember bushings. I did, but cost is an issue for some...

Those are pretty much required upgrades in my opinion anyway...but I would also make sure one of the axles is not slightly popped out of the diff. I doubt that would cause the sound, but it happens.

THe rear diff clunk on hard shift/ clutch drop is a well documented issue.

Oh, also check the 2 studs that hold the diff in. After I did the first half of my swap (6 speed tranny, 3.54 R160), I forgot to tighten these all the way. I was getting a thud on shifting and going "WTF?!? I have EVERY bushing known to man!!) Well later I was under the car swapping in my 1 piece driveline, and when I grabbed the rear diff it moved!! I guess I forgot to tighten them completely after my rear diff and hub swap