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View Full Version : Clunk from rear under side load/hard cornering - S13


KameTrick
10-03-2014, 04:34 PM
Hey all, I'm scratching my head over a clunk noise that is coming from the rear of my recently resurrected S13 fastback. I'm in the process of investigating the subframe and rear suspension trying to find it but I hope to benefit from someone's previous experience and shorten the troubleshooting time.

Car: S13 Fastback
Rear Suspension/Drivetrain Mods:
Stance GR+ Coils
Carbonetic carbon clutch 2 way LSD
1 piece driveshaft
Subframe Swap: S13 SuperHicas --> S13 Non-Hicas
Stance solid aluminum subframe bushings
Circuit Sports traction, RUCA, Toe rods
Energy Suspension poly bushings everywhere else

The clunk noise can only be heard during aggressive cornering (autocross or similar degree of side load on the street). Normal/brisk driving it doesn't make any noise. Based on the sound/feel/timing the clunk occurs it seems like something shifts laterally...slightly under the cornering load. Thus far I haven't noticed it disturb how the car tracks through a turn when this noise occurs, but I haven't taken many corners in the car yet.

From what I can tell does not occur in relation to bumps in the road while cornering. Pushing the car side to side while stopped won't recreate the clunk. It does not occur whatsoever with straight line accel/decel/shifting.

All suspension parts have about 900 interstate miles and 1 autocross on them, which was put on them in 2 days (moved to another state right after I finished rebuilding the car then autocrossed it). This car is also LS-swapped, but I doubt that has any relation to this issue. Let me know if you have any ideas about what could be causing it...I don't think there's much left in the suspension with enough play to clunk at this point...

Primo's Silvia
10-03-2014, 08:32 PM
Hmmm rear lower ball joints? Are your axel nuts torqued to the right #'s??

benja
10-03-2014, 09:16 PM
How low is it? Universal binding? End links in good shape (you mentioned accel/decel doesn't matter so it makes me think roll stuff). Good luck, Bud.

KameTrick
10-05-2014, 08:56 PM
Thanks for the comments, guys!
Axle nuts were in good shape, but as I just built the car there's lots of things that could have worked loose. I'll recheck them.
Universals looked okay.

I think I found the problem...I never leave my OEM scissor jack in the location made for it, but when I moved I stuffed it in there and I think it was banging around because I didn't tighten it down securely...lame to get caught off guard by that, but I'm 90% sure the clunk was a false alarm this time lol.
I'll update again if anything seems off but removing the damn jack seems to have eliminated the clunk. D'oh! :duh: