Defiling a 85.5 SVO, or Please, not another Fox Mustang Thread

Even with a watts, I would take those upper control arms off and throw them as far away from the car as possible. (or at least do a poor mans 3-link, removing one of the UCA's)

You now have two competing roll center definitions (one from the UCA's and one from the Watts) in the rear and the only give will be something flexing. That means that something will eventually fail.

It would be a good idea to get a factory style upper on there with some compliance because of this. If you are lucky the control arm breaks, if you are unlucky, they tear out your floorpan where the UCA mounts are.

That said, the ultimate solution would be to get a griggs or maximum motorsports torque arm (not ESP legal) or get a steeda 5-link (IS Esp legal).

My '97 has the "Race" set (not super-race) with Koni Yellows, the reds might be under-damped for race springs, so there may be improvement there by upgrading the shocks. I kind of wish I had gone for the "super-race" on mine for auto-x.

I also upgraded my front swaybar to a big huge Addco bar (cant remember the size off the top) and it helped mine a ton. It is kind of counter-intuitive, but it reduces understeer by limiting roll and the resultant camber loss.

As far as rear-seat delete, I am not sure how it was done on the '93R, but for mine the comparison is the '00R and (from what I read) I can only do it if I replicate the delete panel that was used on the '00R, so you may want to research that if you end up going to a serious SCCA event with a rules weenie that wants to be punched where the sun doesnt shine.

Oh, and standard warning about avoiding suspension parts from UPR and Granatelli. That stuff could get you killed on a road course.

UPR is junk.

In reply to stukndapast:

I dig this build. That rear suspension is sexy as hell.

Great to see an SVO getting worked on here. I've always dug them.

In reply to Apexcarver:

Thanks for the information. Very interesting and insightful feedback. I had always thought that the combination of the four links and the watts would work together OK when the rear was moving straight up and down, but trying to mentally visualize what was happening when roll came into play seemed to indicate that there could be some fighting going on. I have autox'ed the car a couple of times with this setup and I have heard some odd noises coming from the rear on cornering and also when just driving normally and going over uneven terrain such as driveway entrances and such. I have the original upper arms complete with their 30 year old bushings which are pretty compliant. Should I do the "poor man's three link" you mentioned with just one of those arms, keeping the spherical bushing in the rear end eye? Or, should I replace the solid arms with a single aftermarket arm such as the Steeda 555-4100 which has a polyurethane bushing on the chassis end? I have heard bad things about using poly on the upper arms due to the need for compliance. I am planning on seam welding the upper arm boxes to the floorpan too.

When I first started looking into this stuff my plan was to do the Steeda five-link setup but went with the watts after reading a lot of positive feedback. Perhaps I was misguided, wouldn't be the first time!

I have thought sending my OEM Koni front stuts back to be rebuilt and have them set up to be more compatible with the race spring rates. I am using Koni yellow DA's on the rear.

I had planned on just carpeting over the rear seat area. I am not planning on doing any "pro" level auto-x so if anyone gripes about such minutia I would just put it in prepared and call it a day.

Thanks for the feedback.. any and all is welcomed!

The original Steeda five-link is held in pretty high regard. I believe it requires exhaust dumps somewhere ahead of the rear axle.

I'm not really sure what the "best" approach is if you can't get a torque arm setup from MM because of racing class rules. Probably the original upper control arms with new bushings. I don't think those arms are compatible with spherical bearings or really anything but the factory bushings.

Others may have better suggestions. The noises you heard while turning is going to eventually crack the floor of the car.

My absolute favorite part of Fox builds is the range of opinions on how to 'fix' the car. There have been so many of them built for so long that no matter what you could possibly imagine, someone can give you feedback.
Cool car. The drag car looks cool too. Any info on that other than three foot wheel stands on nine inch slicks? Because that's pretty bad ass right there.

mazdeuce wrote: The drag car looks cool too. Any info on that other than three foot wheel stands on nine inch slicks? Because that's pretty bad ass right there.

It can be a fun ride. Problem is that the rides are way to much $$ per thrill. The car is a '71 429SCJ Mach I. I ran it in NHRA and IHRA "Stock" class. Unlike bracket cars, stock class has a lot of rules about allowable modifications. The engine is in a basically stock configuration meaning it has to have the original heads, intake manifold and carburetor. You cannot port or polish the heads or intake nor make major changes to the carb (including keeping the choke). Stock bore and stroke with some small allowances. You can use aftermarket pistons and rods but it has to have the OEM compression ratio and ring pack and the rotating assembly weight has to meet specs. The cam and lifters have to be the same type as OEM (hydraulic, solid, roller, flat-tappet, etc) and have the OEM lift. However it can have any duration and you can use killer valve springs to get the RPMs up if need be (which it almost always is). Headers are OK as well as aftermarket ignition systems.

My car originally had a 4 speed but I ran it with a full manual C4 automatic along with a 5600 RPM stall speed converter and 4.88 gears on a spool. The car is foot-braked at about 3200 RPM as trans-brakes are not allowed in stock. The 9" slick is the maximum allowable width. You have to keep the OEM style suspension with only bolt-on aids. So leafs in the rear, good shocks, good traction bars and lots of weight transfer on launch. Torque, the converter and gears are primarily responsible for the wheelstands aided by a ridiculouly loose front suspension on extension and some clever traction bars in the rear. My best 60' was 1.38, best ET was 10.72 at 123 MPH. Minimum weight for my class was 3650 lbs. with the driver.

A lot of people have a hard time believing that old muscle cars with limited modifications can be so quick. They usually think you have some 500+ CID stroker engine with nitrous or something and it is really hard to convince them otherwise. There are a lot of '60s and early '70s cars that can run in the high 9's and low 10's at 130 within these rules. All it takes is $$ and time, and a lot of both.

Apexcarver and I personally witnessed an SN-95 equipped with aftermarket poly bushing UCAs snap one of the arms at an autocross late last year. He's lucky the arm failed and not the chassis.

Sky_Render wrote: Apexcarver and I personally witnessed an SN-95 equipped with aftermarket poly bushing UCAs snap one of the arms at an autocross late last year. He's lucky the arm failed and not the chassis.

Ummmm... yeah... I think I'd rather avoid that sort of thing. So keeping the OEMs with the soft bushings is the safer way to go, do you think? One arm or two?

The spare well fuel cell is really a great idea! Unfortunately our car has no such well. :-/

DLD

stukndapast wrote:

Sky_Render wrote: Apexcarver and I personally witnessed an SN-95 equipped with aftermarket poly bushing UCAs snap one of the arms at an autocross late last year. He's lucky the arm failed and not the chassis.

Ummmm... yeah... I think I'd rather avoid that sort of thing. So keeping the OEMs with the soft bushings is the safer way to go, do you think? One arm or two?

I'd put the stock ones back on for now, but I'm more familiar with the later 3-link.

I know class rules have changed recently, especially in CAM and ESP. Why can't you use a torque arm, exactly?

Sky_Render wrote:

stukndapast wrote:

Sky_Render wrote: Apexcarver and I personally witnessed an SN-95 equipped with aftermarket poly bushing UCAs snap one of the arms at an autocross late last year. He's lucky the arm failed and not the chassis.

Ummmm... yeah... I think I'd rather avoid that sort of thing. So keeping the OEMs with the soft bushings is the safer way to go, do you think? One arm or two?

I'd put the stock ones back on for now, but I'm more familiar with the later 3-link. I know class rules have changed recently, especially in CAM and ESP. Why can't you use a torque arm, exactly?

My understanding is that adding a torque arm IS allowed in *SP. The issue with the Fox in particular is that all the available arms attach to the subframe connectors which is not allowed. I could very well be mistaken, and that may be an old rule that has changed, but that was why I originally tossed that idea. Then again, since my primary goal isn't to crush the competition in ESP, I could very well just go with the arm and be done with it. It would work great with the Watts.

You have it right as far as the torque arms. To be legal, it would have to attach to the floorpan and that area of the fox/sn95 just doesn't have the strength and starts to tear. (in fact, some cars tear out at the rear of the front seat mount anyways without a torque arm!)

The watts is good, but a comparison for the 5-link is not really valid. Comparison-wise the watts vs the panhard rod that is part of the 5-link would have the watts be marginally better. What the 5-link does is swap the upper control arms for non-canted ones that mount to the axle instead of the pumpkin. This corrects the geometry for the rear suspension, which does a whole lot more for you than lateral location (anti-dive/squat). I really do think that the 5-link is the best solution for ESP. (if you do not want to go to an exhaust that terminates before the rear axle, they have the 5-linkII which has a shorter Panhard, but allows tailpipes.)

As far as your case. There are 3 ways to go, really.

5-link. spend $$$$ and you will have to resale the watts, but it is the best solution.

Throw the stock uppers back on. The roll centers still compete, but the bushing deflection allows the watts to win. (an aside, if the bushings are shot, you can get http://www.maximummotorsports.com/Upper-Control-Arms-C98.aspx good description of the arguments there as well, scratch panhard and put watts and the info is much the same)

The poor-mans 3-link... Remove one of the upper control arms. If you are doing this, you can keep the ones with the rod ends. It does put a good bit of strain on the floorpan, but it is general suspension strain, not binding suspension strain. A good many people have run this with success. to be perfectly legal for ESP you would have to add back the other UCA I think. That being said, bushings are open.. so.. think Nerf material... There are trade-offs as discussed here. http://corner-carvers.com/forums/showthread.php?t=6116

www.corner-carvers.com is probably the greatest source of knowledge for suspension on fox mustangs. They do not suffer fools lightly and have been referred to as the "league of extraordinary shiny happy people", but I count myself a member. Search lots, comment less. If the information is there already and searchable, starting a new thread to rehash a tired old topic doesn't go down well. Almost every conceivable suspension mod for a fox has already been done there.

I would probably go back to stock uppers myself and think about the 5-link for later.

In reply to Apexcarver: Thanks for the feedback Apex. Your arguments all make sense and I have spent a bit of time on corner-carvers and you are so right that there is a ton of information on there.

Meanwhile, I get a message that points out that within the precise wording of the SCCA rules for SP my fuel cell is not legal. Section 15.2.K.2 says: The location of the fuel cell may differ from that of the original tank by no more than 6" in any direction. The well cell is completely different shape than the OEM tank which is a rectangle with various bumps that sort of surrounds the spare tire well on the passenger side and bottom of the well. But, just the height of the fuel cell is more than 6" from the OEM tank where it passes under the well. The cell is 9.5" tall. Like I mentioned before, there are cells which fit into the same space as the OEM tank, with all its lumps and bumps, but their price is in the thousands of dollars so THAT ain't gunna happen, bubba. I doubt that anyone would care within my local SCCA chapters, but what the hell.

So screw this ESP guideline junk in as much as those rules were self imposed as a target for the build. I can just run CAM when I autocross, which opens the door to lots of possibilities. I HAVE to meet the SVRA rules but they are almost all safety and originality based which is expensive but easy. SVRA limits me to UTQG 200 tires just like CAM, and those are way cheaper than R-comps! So I think that is the path I will go down at this point.

That being decided, now I CAN install a torque arm IF that is the right way to go. I have looked at the Griggs and the Max Motorsports and I like the MMM better. The front mount on the Griggs doesn't look that sturdy, especially compared to the MM. I like how the Griggs mounts to the rear diff cover since the Fays Watts competes for space with the MM TA on the axle tubes. But there is a thread in Corral.net where someone did exactly what I would do and the two will work together with the proper adjustments.

So, if I CAN use a TA along with the watts, is that a better setup than the 5-link? It certainly is simpler!

Great build and keep it turbo!

In reply to crankwalk: The 2.3L w/turbo will definitely stay!

Hey stuk,

Really enjoyable reading. You can write.

I like this.

Nice build but damn you for making me search Craigslist for SVO's.

Love seeing these still out and rolling!

Some progress recently. I HATE working in a cold shop. I have a decent shop but there is no heat or cooling in it and it sucks bigtime. I should be spending this money on HVAC for the shop instead of providing boat payments for those aforementioned entrepreneurs. Oh well, no one has ever accused me of being overly wise.

Got a roll bar installed by a local fabricator. Four point chrome-moly welded in. He can make it a full cage in the future, if there is a future and this thing doesn't wind up in a wall somewhere on it's first outing.

I dun gots me won a dem dare fancee racin' seats two.....

Is'a gunna make this thing look sorta likea racin' car from way back, the 1980's that'll be, so its sorta gunna lookey like these fine chariots:

To that end I been sprayin' paint all over the place, having never held an automotive paint gun in my life. It's sorta getting there. I fergot ta take some pictures earlier, but rest assured, there is yeller paint under that masking paper and all the runs have been sanded out, multiple times. I'll post some pix of the finished mess in a cupul a daze.

As for the rear suspension I have taken the advice of the knowledgeable participants of this fine forum and achieved a high degree of muscular development by throwing those sexy looking but disease ridden upper control arms as far as I could, which wasn't awful far, but enough that they would no longer inflict undue stress and strain on my otherwise pristine floorpan and torque boxes. I am currently running with the "PM3L" setup using one of the OEM upper arms on the passenger side. It will soon be replaced with a torque arm supplied by one of the fine establishments dedicated to the task of keeping poorly designed cars from disrupting the flow of other vehicles which are unfortunate enough to share the track with said steed.

More to come, now that the temperature is in that magic zone of 70 to 80.....which won't last long....

On a stock car I worked on we had a similar rear suspension in a Monte Carlo. We also ran one "good" upper arm and one that was just because we had to. On the one that did nothing we drilled a few holes in the bushing to make sure it was good and soft.

stukndapast wrote: It will soon be replaced with a torque arm supplied by one of the fine establishments dedicated to the task of keeping poorly designed cars from disrupting the flow of other vehicles which are unfortunate enough to share the track with said steed.

You should be fine...my MM equipped '93 Cobra passes more cars on track than gets passed...and that's on street rubber (Nitto NT-05s).

Sounds good, looks good!