'92 foxbody and 17*9s on front question

Discussion in 'Fox 5.0 Mustang Tech' started by aurdraco, Oct 9, 2008.

  1. So I recently swapped to the complete 98 Cobra disc setup, front and rear, on my 92 LX notch auto-x car (Texas A&M Sports Car Club for those of you in the SW region of the SCCA). BTW, it stops now! Amazing feeling, a fox body that actually stops. BTW, I have a 98 cobra parking brake handle for sale as I decided to use my stock one. I hear they sell for about $50. If anyone in Texas wants to make me an offer, PM me.

    Anyhow, I used the 98 axles (and I have the ABS wiring that came with the brakes in case I want to try to hook that up in the future. Imagine a fox body with ABS, whacky!), so my track width in the rear is 3/4 inch per side wider than stock. I already have the 17*9s with the 36mm offset/6.42" backspacing ordered for the rear. If I understand the math, to get the front track width to match the rear, I need to get some 94-95 front spindles (need to find and buy, got a lead) and 94-98 control arms (have a source). Currently, I have the 98 spindles with 92 control arms. With the '99 GT 17*8 wheels, the car looks great and no problems with rubbing.

    Okay, my question is, has anyone else done the correct front setup (94-95 spindles and control arms) and can you run 17*9s without a steering rack limiter? Because it's an auto-x car, a limiter is out of the question. I think I'd need the 36mm offset/6.42" backspacing wheels if it were possible that they would fit, just like the rears, but I don't want them rubbing. Anyone done this combo before? Does the longer 94-98 control arm give more fitment room to run 9s on the front?

    I really really really want 275s on all 4 corners (think ~2800 lb. fox body with that much rubber and it should be an auto-x buggy).

    Thanks in advance.
  2. 275's re waaaaaaaaayyyyyyyyyyy to big for the front..i got 235's on mine and they rub when i turn the wheel all the way
  3. What year is your car? Also, did you swap to the 94-95 spindle and control arms?

    BTW, I have 245s, on the 17*8 99 GT wheels, on it now with no problems at all. I know people used to put 255/16s on fox bodies for SCCA Solo II ESP auto-xing with no problems. Perhaps you have the wrong backspacing/offset on your wheels?

    Edit: Sorry, I just saw that your car is an '89. I forgot to check your .sig. My 92 has more room due to better fender clearance in those years. Thanks though!
  4. I don't know specifics, and I haven't done this myself, but I believe that the '94+ control arms are longer and I've heard of people running them and having issues with the tires rubbing the wheel well. Also, the 96+ spindles push the wheels out even further, so you'd have a really wide front track. Probably great for handling and auto-x, but it would look ridiculous and I'm sure you'd have tire rub issues, especially with 275s. I mean, some people struggle to fit 275s under the rear wells!

    That being said, I actually hope you are successful in this. I'd LOVE to see a Fox with low profile 275 series rubber at all four corners, I've been curious about doing it myself, but every time I look into it, it seems like a lot of work and fabrication would be involved.
  5. While I'm at it, how great are the brakes? I'm planning a full cobra brake conversion for myself this winter.
  6. The 94+ control arms are longer than the fox ones, I want to say about 1 1/4 longer, I'm not sure at the moment. If you do use those control arms you might need to use the longer SN95 inner tie rods; then you might as well use a SN95 or '99+ rack, and it has a tighter steering feel which is something you might like.

    Here's a good link if you haven't seen it yet.Brazeau Racing - Tweaked Fenders
  7. Don't use the 94+ control arms. you'll never get camber back into the realm of acceptable. I have 97 spindles on my 93 with Cobra brakes & 17x9" 10th Anniversary wheels with 275/40/17s. I run 2 rack limiters per side & put coil overs on it to get the ride height perfect so the tires don't rub the fender under extreme braking on the track.
  8. *nod* The 94-98 control arms are 3/4 inch longer on each side than fox stock. The 96+ spindles are an additional 8mm longer than stock, iirc. The 94-95 spindles are not longer, so with those and the 94-98 control arms, the front track width will match the rear track width.

    I'm hoping to do this without modifying the fenders, but I know it's doubtful without a steering rack limiter or without buying some aftermarket 94-98 control arm that is the right length but shaped differently.

    BTW, the car looked badass from the rear with the 275s on the 17*9 we test fitted (5.95" backspacing; we knew it wouldn't fit under the fender lip, but we threw them on to see how much room we could expect to have on the inner fenderwell if the BS was 6.42"). I'm hoping to cut 1.75 60' times on Azeniis :) (and the car is an auto-x car with a stiff suspension, not a drag setup).
  9. They are pretty frakkin' badass! When I auto-x'ed it for the first time like that last month, I was continually amazed at how late and hard I was braking, and how much better it responded to trail braking. The car seemed to squat and dig into the turns, as opposed to plowing, because the rear brakes were actually working. With my old brakes, I would have spun out or understeered around the corners had I tried the same maneuvers. I can't imagine how much better it will be with some good road racing compound pads, 275 Azeniis or R compounds, and 200 more pounds of weight out of the car.

    It took about 16 hours of labor to get them on, but alot of that was wait time as I ran to get parts, pizza, etc. Air tools for the win! My buddy, who is a mustang mechanic guru, did most of the work while I fetched tools, cleaned, moved stuff around, etc. We relied alot on that hobbit or bobbit's guy's webpage for advice. That webpage is awesome!

    Here's a few things we learned:
    The 95 v6 master cylinder is perfect for peddle feel (15/16" bore) with the 98 cobra brakes on a fox body. Plus, it was dirt cheap at the local junk yard. Be sure to get the plastic reservoir for it as they are different.

    The solution to having the extra brake line (fox is three port master cylinder, 95 v6 is two port) is called a "trailer brake t", part #7900 at Napa in their fittings bin, iirc. Costs like $9. We just plugged two of the brake lines into it then plugged it into the top of the stock brake prop valve (under the master cylinder) and the car was good to go.

    Merging the cobra brake lines with the stock rubber ones was fun. Be sure to pick where you want things to line up so that you can zip tie things/use the stock brake line holder clips on the axle tubes to keep these in one place.

    Make sure all of your rear caliper hardware moves and isn't seized. We had to unseize a couple of the float pins (correct name?) before slapping them on.

    You're going to have to zip tie the new parking brake cable lines to the rear control arm to keep them out of the way.

    You'll need a .033 spacer for the front ball joints if you use the stock ones. I think we ended up using two .0165s on each side as I couldn't find that size spacer ANYWHERE I looked (and I went EVERYWHERE in B/CS looking for a hardened spacer of that size).

    It was easier to drop the h-pipe and drive shaft to get to the parking brake stuff from under the car.

    There's probably more, but really, that bobbit sight was badass. I owe that guy a beer.
  10. Thanks for the website link! I'd never heard about moving the fender like that, but that might be worth it for the clearance. Thanks!

    I have a tighter rack in the car, but I forget the ratio. Popped it in last year when rebuilding the car because a friend had it laying around.

    The 94-98 control arms are 3/4 inch longer, to match the wider rear track width of the ABS axles. If I do the control arms, I'll definitely have to use the tie rods. Luckily, the control arms I'll be getting should already have the tie rods on them.
  11. I thought with the 94-95 spindles and the 94-98 control arms, the camber problem is not an issue. I'll have to research this more, thanks for the heads up, but I really want the front and rear track widths to match.

    I'm hoping to avoid the steering rack limiters because I auto-x the car. I have 1,000 lb/in front springs with koni yellows, so the car barely moves when braking (and it's even better now that the rear brakes are actually doing something). Coilovers would be nice eventually. My buddy has them on his auto-x/track fox. Are these the wheels you have? Speed Concepts - M-1007-A179 - Ford Racing 2003-2004 Cobra 10th Anniversary 17x9 Gunmetal wheel
    If so, they might rub because your BS/offset is 6.12/26mm instead of 6.42/36mm, thus they stick out more. Do you have any rear fender clearance issues?

  12. Let us know what your final setup ends up being. I just bought a 92 LX hatch that has 17x9's (cobra R's) on all four corners with 245/45 tires. The rear is just fine....the front rubs like a mofo. It rubs when turned all the way, plus it hits the inner fender pretty easily. It was rubbing the fender lip as well on hard turns with bumps. I took a little chunk out of the tire and bent out part of the fender lip.

    I'm running HR Race springs and FMS A-arms up front....it sits pretty low. I then realized the previous owner had a small spacer in, removed those and it helped not rub the fender but seems to rub inside on tight turns ever more.

    Couldn't imagine trying to run a 275 tire! I guess with the correct wheel dimensions if you can keep them tucked in the fender, but I'd still you you'd be rubbing something on the inside too. Or get something with an adjustable ride height in the front to keep it up above the tires.

    Good luck.
  13. Yes those are the wheels. I just went out to the warehouse & measured the length difference between Fox front control arms & SN95 front control arms. It is over an inch from the center of the bushing to the center of the balljoint.. I vaguely remember reading on another forum that the exact difference is 1.33". I know of a couple of guys running the SN95 arms on their Fox (track only cars) & they relocated the control arm mounting points on the k-member to get all the geometry correct. Your biggest concern will be the massive amount of negative camber you have when using the SN95 arms on a Fox. While negative camber is desired, you'd be at the point of adversely affecting the contact patch of your tires.

    Let me know how those 36mm offset wheels work on the front. I know I can't fit my pinky finger between my coil-over & the tire with my wheels, so hopefully you don't run in to strut clearance issues.
  14. IF you want to run 17X9's with 275 on a fox, you better either do a Mark VII 5 lug swap, or 94-95 spindles. 96-04 spindles will make 17X9's stick out. I tried it with 96-04 spindles. They won't stick out with 94-95 spindles, but they will be right out to the edge. If your car is lowered, I'd recommend 255's 0r 265 tires. Since most brands are stretched on 9" wheel,s get a tire with a rim guard on it.

    My Dads GT500 has 18X9.5's and the fronts from the factory come with 255-45's and the rim guard makes them look not streched.
  15. Hrm, I thought they were only 3/4 inch longer, to match the wider rear width.

    I'm not opposed to relocating the mounting points, I've seen old auto-xers do it when they put thunderbird control arms on their fox bodies (iirc, they are identical to the 94-98 control arms, but I could be wrong). The car isn't being built for an SCCA class, more for a local "run what you brung" class, so not worried about the rules too much. The SCCA's Street Prepared rules are too out of touch and always have been, and Prepared requires a car that really can't be daily driven.

    Re: the negative camber, yeah, I have ~-3 degrees right now, and that kills front tires on the street (and I only drive it about 300 miles per month because I live in a small town). If I could get that same amount with the new setup, I'd deal with it. For contact patch and braking, that's not as big an issue during an auto-x as it is on a track because most of your breaking should occur while turning (very few straight line braking chances in an auto-x). We once attached a camera to the side of a mustang during an auto-x and realized that a mustang would need ~-6 degrees of camber at rest for the wheels to be flat during a hard turn (this was with springs, shocks, bushings, etc.). At that point, most of the fast fox drivers sold their cars and bought 3rd gen camaros (and proceeded to kick ass in SCCA Solo II Stock class at Nats).

    I only ordered only two of the wheels so far as I know they will work on the rear. We already tested the same size on the front. In the current configuration (98 spindles and stock control arms), they won't fit. I'm just hoping that the spindle and control arm change would let them fit. If not, I'll test out the 5.95 backspacing 17*9. I might have to go to an aftermarket tubular control arm designed to give more clearance (pretty sure MM makes these) to get one of those to fit. Then again, they might never fit without serious modifications (like that previous link with the fender relocation).
  16. Thanks for the info. Which backspacing works with that setup? Since I've already done the '98 Cobra brakes, the Lincoln stuff is out of the question. Were you using the 5.95 BS? If so, the 6.42, while sometimes hard to find, might have worked with your combo.

    If I can't get 275s on the front, I'm hoping to run at least 255s. 245s are ok, but I want massive amounts of grip up front.

    Thanks again!
  17. you will rub on the control arms... im running a upr kmember with 94/95 spindles, cobra brakes, 17x9 fr500s and 245/40s and no probs up fornt... she sits pretty low too.
  18. Like said before, don't use the SN95 control arms. it will mess a lot of stuff up
    Also, you are going to have a tough time fitting those 17x9's on the rear with the Sn95 axles out back pushing the wheels out. More than likely the rear wheels will stick out slightly and you migth rub your fender lips.

    If you really want to run 9" or 10.5" wheels on a Fox, you need to run the fox lenght axles out back and the North Race Cars brackets. It will pull the wheels in slightly in the rear.

    With SN95 wheels, the extra 1" of width is mostly added to the outside of the wheel in an attempt to fill the wheels wells more. If you've ever seen an Sn95 with stock wheels, they tend to look sucked in. So 9" and 10.5" wheels tend to add the extra width to the outside.

    I am in the same dilemma in the rear. I want to keep the SN95 width so i can run ABS, but i also want to run 17x9 or 10.5" rims. I'm looking into S197 wheels as they offer deeper BS and offset than the Sn95 wheels.

    Up front, 94-95 spindles will keep the wheels in slightly...but they still add about 5mm more than using the Lincoln Fox rotors.

    275's on the front of a fox is going to be TOUGH. It can work, but limiters and possible fender tweaking might be required. This is a fender designed in 1979 when 14" wheels and 205 series rubber was all the rage :)