LeonV

Back in March, I finally go out for a track weekend after replacing the engine, installing a rollbar and a race seat, and what do I do?

Go off track of course! This was my first time spinning in 3+ years on track. It was a beautiful sunny weekend at Laguna Seca and this was the 9th of 10 sessions. The car had been much more loose than usual (more on that in a bit) but I got used to it after a few sessions. Figured it had something to do with me pushing a bit harder and running a more track-oriented alignment than before: -1.7°/-2.2° camber, 6.0° caster, +0.04°/+0.08° total toe, front/rear.

Here's what happened:


I drove the car back to the pits afterward and noticed that my front-left wheel was knocked way out of alignment. I towed the car back to the shop and got it up in the air. From a quick survey, I had a broken front ARB drop-link, a bent wheel (hit the LCA!), and my camber bolt had gone way the hell inboard (unfortunately flattening the eccentric clevis but no big deal). Upon noticing the broken drop-link, I couldn't help but think that it may have been broken before the weekend even began. That would explain the extra tail-happy behavior although unfortunately it's not an excuse for running out of skill!











I adjusted the camber bolt back to where it was, thinking it would bring the alignment back to where it should be. Well it certainly didn't!





We did some quick measurements with a tape measure and found the lower control arm to be bent. Yesterday, we replaced the control arm with a used one, installed new inner and outer tie rods for piece of mind, installed new drop links, put it back on the rack, and tried to align it. Looked much better this time! However, even after loosening the subframe and prying it over the the left, the front-left camber was maxed out at -0.4°.





I haven't taken any more measurements but my guess is that the subframe is damaged and needs to be replaced. I'd like to see if I can get any measurements on the knuckle before deciding to replace the subframe.

Does anyone have any experience with this type of damage and what is most likely to break in this scenario?


P.S. For fun and out of curiosity, I had our metrology guy 3D scan the bent control arm along with the used one I replaced it with.

Well it sure was bent! The scan matched up fairly closely to our quick tape measure check. You certainly couldn't tell the arm was bent just by looking at it. The arm bent over 8mm forward causing the caster to go way out as was seen in the first alignment check. As you can see, not much of an effect in the way of camber...

s2000maniac

its not the sub frame, it's the knuckle, I have fixed two s2k's with way worse suspension damage and the sub frame was intact.

LeonV

Interesting, thanks! Funny enough, I've also heard the opposite.

In any case, it's worth a look to see if I can detect any bend in the knuckle before tossing any parts at it.

Slowcrash_101

My 2 worthless cents, from what I've experienced, the knuckle gets damaged before any other suspension component when the suspension gets a good wack. The knuckle carries the load of the wheel, and the weight of the car, where it gets bent is where the lower ball joint connects to it.

nibble

Laguna can be brutal when you go off track.. especially if you run over those red blocks. I hope it's something minor than subframe.

LeonV

Thanks guys. Laguna was especially brutal this time as all the rain had completely rutted up the runoff. There were sandbags lining the track at turn 9!

When I was examining the knuckle I noted that the lower ball joint interface is really beefy. If it's bent, I'd almost expect the upper ball joint area to be bent. I'll try to measure it.

Reference photo:

DefSport

Keep in mind the lower ball joint connection transfers all sway bar and spring/damper forces to the spindle. The upper arm is just there to position the spindle.

So yes, the lower connection points are much stronger, but they also carry far more load. This is especially true in an off situation where you've got huge shock loads going into the suspension.

jyeung528

sorry to hear. those pics are awesome, thank you for that.

jyeung528

LeonV, is this an ap1?

would you mind telling if you have stock suspension, what wheels and tires were you running? any bumpsteer kit? also, is it accurate to say you let off the gas when trying to correct?

have you ever run less rear toe before, and was it less loose if you did?

LeonV

True, and it looks as if Honda did a nice job of optimizing the pickup points for the load they'll be taking. Hence, the lower ball joint is beefier than the upper as it takes proportionally more force. In other words, both the lower and the upper took some of the impact, with the lower taking more. We'll see which is the fuse, if the knuckle is indeed bent!