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Should the front subframe on an Evo 8 be centered on the vehicle? Here's why I ask...
I have a fitment issue suddenly with my oversized wheel & tire package I use for autocrossing - front driver's side tire is rubbing hard on the frame. Spun during an autocross and the brand new front driver side tire got lathed on the inside tread face (see pic) due to contact with the frame or a brake duct hose bracket. Took it to a shop for diagnosis, and one of the things they noticed was the front subframe seemed to be shifted over to the passenger side of the vehicle. I don't know what portion of the car they were taking measurements from, but it was described to me that the subframe was shifted nearly 7/16" to the passenger side compared to measurements on the driver's side.
The plan was to adjust the subframe and center it, and then see if the situation improved. I had an S2000 owner who autocrosses with my region tell me I needed to get Spoon Sport rigid subframe collars or else the subframe would shift again. Pricey buggers, but I bought them. The shop installed them after partially dropping the subframe, but the subframe still measures out shifted to the passenger side, despite these rigid collars supposedly centering the subframe bolt holes and the subframe bolts.
They also found that my steering was off - lock to lock, it went over a full turn in one direction, and not a full rotation going the other way. Checked the tie rod ends and counted 6 threads on one side, 14 on the other. The shop is going to get the steering centered, balance out the tie rod ends, and get it aligned, but the apparent subframe shift is still a mystery.
Does anyone know where I might find definitive info on how the subframe should be lined up on the car?
What you rubbed on there was more than just subframe which would have only been along the edge. That kind of rub is extreme on something else I suspect.
But what you're seeing in subframe shift is definitely something I adjust for. I adjust the subframe based on what static camber ends up with equivalent camber setting left and right. But you have to be consistent in how you adjust the camber in the strut/upright connection. Either full sag (biased positive camber) or preload (biased full negative camber). And then the top hats at the same camber settings. Those two things, then I adjust the subframe to get close to same camber left/right.
But all that said, it can make ~.5-1deg difference in camber but not enough that it would cause the kind of wear you're showing. That is something else entirely.
You wore through a LOT of rubber there with how large that step is on the tire. It's not from one spin, you've been rubbing like that for a while.
What's the wheel and tire size you're rubbing with?
Have you checked the top and back of the wheel well? Given How severe that wear is I would guess it's the pinch weld at the back of the wheel well and you haven't folded it over and as you turn it's skimming the tire down.
You wore through a LOT of rubber there with how large that step is on the tire. It's not from one spin, you've been rubbing like that for a while.
What's the wheel and tire size you're rubbing with?
Have you checked the top and back of the wheel well? Given How severe that wear is I would guess it's the pinch weld at the back of the wheel well and you haven't folded it over and as you turn it's skimming the tire down.
Looks like it went full lock and tore the rubber literally off the tire, you can see the strips in the picture.
Looks like it went full lock and tore the rubber literally off the tire, you can see the strips in the picture.
That's exactly what happened - not sure what it caught on but it lathed off a strip of rubber off the tread side of the tire (not the sidewall). The piece that was machined off looked like a black leather belt. I believe it was lathed off because it appeared to come off very cleanly, as opposed to jagged edges from ripping off in the spin. Best guess is the tire deformed enough to catch something while rotating and sheared off the strip.
This is an interference issue, not a wear issue. My main question is whether the front subframe should be equidistant from similar points on the left and right side of the underbody.
Tire did NOT rub on the subframe and get damaged (not sure how anyone got that out of my description). Missing tire rubber is NOT from wear over time - it got ripped off during a spin by something in the wheel well; leading edge/pinch welds on inside of wheel well, bracket, etc.
Wheel & tire combo is the old Mark Daddio setup for an autocross Evo: 285/30R18 Hoosier A7s on 18x10 Enkei PF05 wheels (front), 18x9.5 Enkei RPF1 wheels (rear).
I never said it was a wear issue, hence why I told you to look at your wheel wells. A shift in the subframe (unless it's severely bent) should not be enough to rip a tread strip off the tire. The bolt holes to mount the subframe on the car don't have 7/16" of play in them so it sounds like they're measuring asymmetrical areas or something is bent. If this is the first spin you've had it's entirely possible this has always been a lurking problem.
Check the subframe for bends.
Check your pinch welds in the wheel wells.
Something fishy is going on. The steering rack should have been centered : meaning the tie rods should have been disconnected and the steering wheel unwound and centered on the column. Then the tie rods are adjusted to equal lengths on both sides. Hook up the steering arm on the front hubs to the tie rods and then go full lock in both directions in a parking lot to see if there are any fitment issues at that point. The steering wheel could have be off center after this point but that is a matter of disconnecting the wheel and putting it back close to center and then adjusting it with the tie rods.
Just to follow up on this thread, the guy who is working on my Evo found that the steering rack allows more turns in one direction than the other, contributing to the issue. It seems that the steering rack has some issues, and needs to be replaced. The BIG problem with that is that Mitsubishi no longer offers the steering rack for the car (MIT-MR594661), and we can't find one from a reputable source. I have this sinking feeling it may be time to move on from this long-loved vehicle and find something newer for the track.
Just to follow up on this thread, the guy who is working on my Evo found that the steering rack allows more turns in one direction than the other, contributing to the issue. It seems that the steering rack has some issues, and needs to be replaced. The BIG problem with that is that Mitsubishi no longer offers the steering rack for the car (MIT-MR594661), and we can't find one from a reputable source. I have this sinking feeling it may be time to move on from this long-loved vehicle and find something newer for the track.
Thanks for the links. Yeah, that $4XX one seems too good to be true - the shop my Evo is at mentioned one on eBay that they were shaky on; probably the same one. Found a similar $4XX one on Amazon from a Chinese seller. The used one at $1100 jives with a reputable seller I've dealt with before that I just found has a new one available for $1200+. Yikes. If I do find one to replace mine, I'm thinking it's time to retire the car from autocross to preserve the steering rack and not go through this unicorn search again.
Thanks for the links. Yeah, that $4XX one seems too good to be true - the shop my Evo is at mentioned one on eBay that they were shaky on; probably the same one. Found a similar $4XX one on Amazon from a Chinese seller. The used one at $1100 jives with a reputable seller I've dealt with before that I just found has a new one available for $1200+. Yikes. If I do find one to replace mine, I'm thinking it's time to retire the car from autocross to preserve the steering rack and not go through this unicorn search again.
That reman one looks like it may be a Lancer rack (I'm under the impression that the Evo has a unique rack that has a quicker ratio than the Lancer). I checked out the car-parts.com for part outs, but the ones offered looked like they were from Evos with front-end damage which makes me nervous.
