Fox Body and IRS

[sneezingfox]

Any Fox owners out there running IRS on your ride? Want to get some input...

[MeanMike]

I don't have one personally, but I've seen a few on the corral. The biggest problem with the swap is the difference in the width. Wheel mount face to wheel mount face, the 99+ IRS is 1.5" wider than a fox rearend. It make wheel and tire selection tough.

With the available handling packages from Griggs and Maximum Motorsports, I can't see why someone would want an IRS in a fox.

[sneezingfox]

I guess your opinions are diferent than mine...

[LINELOCKSRUS]

YEA I`VE SEEN A FEW ONLINE & ONE IN PERSON :up: I`M ALSO A PRO IRS GUY BUT IT SUCK WHEN THE "DREADED IRS HOP" REARS IT UGLY HEAD :mad:

[sneezingfox]

Explain "dreaded irs hop..."

[66sprint6]

Wheel hop followed by a "snap" in some cases
Matt

[mustang347strok]

done one at the shop in woodbury put a irs in a 91 coupe .wheels stick out 1/2 inch . few brackets you will need to weild in. but not to bad . looks good from behind.if your looking to put one in or need parts let me know.

[sneezingfox]

I though that wheel hop is only on a straight launch and can be fixed by upgrading bushings...?

[LINELOCKSRUS]

^^^ true !!!! but can still do it sometimes my car hops some on the street but at the track with a good burnout hop is not a issue cause it will do 4k launches with no problem :up:

[JohnC]

How much more weight does IRS add over a stock 8:8 axel setup?

[mustang347strok]

How much more weight does IRS add over a stock 8:8 axel setup?
around 50lb

[TomS]

What is the intended purpose of the car?

About the only thing the Ford IRS on a Mustang is going to do is make it ride better, weigh more, and grip better on rough road surfaces. The geometry of the IRS is somewhat of a kludge. It will reqire lots of bandaid fixes to get it usable. Bushings, specially valved shocks, alignment trickery, etc...

If this car is going to see autocross or open track duty, well, most tracks are smooth enough that a properly designed torque arm/panhard is going to be faster. (Maximum Motorsports or Griggs Racing)

The Ford IRS installwise would be a fairly straightforward bolt-on affair. The only fitment issue is what's already been said about the wider rear track width.

[Tungsten]

I guess your opinions are diferent than mine...

Explain "dreaded irs hop..."

Wow. At first I thought you knew what you were looking for... then I saw the second statement and the Logic Train jumped it's tracks. :lol:

[Bob-E]

Dammit. I though this thread was about a new hottie at work. :(

edit: and nice new title for the forum "busted knuckle garage":lol:

[sneezingfox]

I guess input is not to put IRS on a fox...

[JohnC]

I guess input is not to put IRS on a fox...

No, I think it's a cool idea for a street and RR car. I'd actually like to see the work and progress if you do this. :cool:

If I could stomach adding the weight, I'd like to have an IRS rear in my junk. :)

[LINELOCKSRUS]

I guess input is not to put IRS on a fox... NO !!!! do eet!!!!!! i think it would be awesome !!!! & it would be the best to see if you could get a 03-04 cobra one cause its alittle beefier than the 99-01 I.R.S.`s :up:

[ReefBlueCoupe]

I think a better way to look at it is to look at the two main forms of competition involving fox body Mustangs. Two in particular: road racing and drag racing. How many fox bodies competing and winning in either use IRS? Not that many..

[sneezingfox]

Why is it that I have to be in competition to upgrade my suspension? I just wanted to get input from those that have it or have had it.

[KDPate]

I wouldn't upgrade. The solid axle would be my choice due to simplicity (no special brackets, half shafts, etc.) and with a rear suspension kit from either MM or Steeda it can handle good or even better than an IRS rear..

My :2cents:

[TomS]

Why is it that I have to be in competition to upgrade my suspension?


You don't. I'd certainly recommend upgrading the suspension to some degree. It's just that an IRS may not be the best money spent. It really depends on what you are trying to achieve.(Have you told us that yet or did I miss it?) I'd hate to see you dump a bunch of money and time into something that seems like a good idea but doesn't get the results you want.

just wanted to get input from those that have it or have had it.

I do not nor have not owned a Fox bodied Mustang. I have spent an enormous amount of time in and around them in both drag racing and road racing/autocross formats. I have owned a 97 Cobra that was set up for Street Modified autocross.

I looked long and hard at the IRS for the Cobra. The chassis of the 97 is effectively the same as the Fox body. The Fox body is effectively the same as a 78 Fairmont, seriously. All of my research just pointed out too many flaws in the design for my intended purpose.

Don't get me wrong, a STOCK Mustang IRS is better than a STOCK live axle for everything exept drag racing where the solid axle is better in every regard. But if your spending the money for upgrades then I'd explore doing a torque arm and panhard bar or maybe even the Steeda 5-link.

[sneezingfox]

Finally did research in comparing prices of upgraading IRS and solid axle. Dollar for dollar, it seems that solid axle would perform better than IRS. Although it would be cool to do the swap, it would be money wasted to get IRS, espeially if I really got into raod racing. You guys are right. Between Steeda, MM, and Griggs, there would be no point other than to say, "look what I did!" And that's not why I am building my car...

[LINELOCKSRUS]

Finally did research in comparing prices of upgraading IRS and solid axle. Dollar for dollar, it seems that solid axle would perform better than IRS. Although it would be cool to do the swap, it would be money wasted to get IRS, espeially if I really got into raod racing. You guys are right. Between Steeda, MM, and Griggs, there would be no point other than to say, "look what I did!" And that's not why I am building my car... :( DONT WHAT EVER YA DO DONT BUY THE STEEDA BULL$*** please !!!!!!!:mad:

[SWIFT]

Finally did research in comparing prices of upgraading IRS and solid axle. Dollar for dollar, it seems that solid axle would perform better than IRS. Although it would be cool to do the swap, it would be money wasted to get IRS, espeially if I really got into raod racing. You guys are right. Between Steeda, MM, and Griggs, there would be no point other than to say, "look what I did!" And that's not why I am building my car...

Good choice!

[TomS]

Oh, let me clarify on the Steeda stuff...

Only the 5-link and nothing else suspension related from them. It would be my last choice of the other solutions. Heck, I'm not sure if they event still make the thing now that I mention it.

If you're interested in more in depth tech, let me know.

[LINELOCKSRUS]

M. M. FTW !!!! F-STEEDA :reef: crooked bishes :reef:

[Mr. Pink]

I would only install an IRS if -

I had one for free or near free
The car didn't already have an 8.8 in it
I could luck out and score some 99-04 front spindles and get the track width where I could run '05+ wheels with FWD style offset.

Cool factor? 9
Daily Driver ride quality? 9
Handling & braking? 7 (but better than stock)

Race-ability? its a wash.

[sneezingfox]

That's what I decided. I already have something decent and it would not take much to make it phenominal...

[sn8kbit]

Hmm, so tempting. I haven't posted in months upon months, and this is baiting me. But I digress....

Go the cheap route first. Box up your stock arms, add urethane bushings (all around to include the sway bars), H&R super or sport, your choice, but the supers would be best for later upgrades, a set of Bilstiens, a swaybar from adco (sp?) then figure out what you really want to do with the car afterwards before dropping the big checks to MM or Griggs. That'll give you more than the average driver will need.

Aside from drag racing, the benefits to a properly setup IRS to include the mild weight addition have obviously been lost on most readers, not users. The reason you don't see the IRS in most grassroots racing levels is that when setup properly (geometry not stock in the cradle) it's been deemed illegal. I've not driven a straight axle car that has the feel an IRS will give you in overall handling, but that's my 2 pennies. 1:09's at NSS on a stock 99 Cobra at somewhat near full weight ain't too damn shabby. Oh, were those times with street tires? ;) Don't knock it till you try it. Should I do another track car, which will end up being a fox body, it'll have a properly setup IRS, again.

Damn I miss that car sometimes.....

[The Rascal King]

:eek: Man, sure is good to see you come out of the woodwork, Steve...

[TomS]

a swaybar from adco (sp?)

REAR swaybar, right.....?


I've not driven a straight axle car that has the feel an IRS will give you in overall handling,


I would agree that an IRS certainly feels better, but feeling better does not coincide with faster lap times.


Should I do another track car, which will end up being a fox body, it'll have a properly setup IRS, again.



What would YOU do to properly setup a Mustang IRS?

[sn8kbit]

:eek: Man, sure is good to see you come out of the woodwork, Steve...

Heh, now that's a comment I never thought I'd see!....LOL

Hifi,

Yup, rear swaybar. Sorry for not adding that in there, I assumed it'd be understood since we're addressing the rear suspension, but I did add bushings throughout the car, so I guess I should have clarified.

While I can only go by what lap times I've done myself, I kinda based that off the NASA American Iron times from when they also ran NSS. I can dig up the link if I have to, but 1:08 1:09 on track tires were the norm for AI cars at NSS, and I hit those 1:09's on steet tires in a full weight car and stock K member and arms. Maybe the use of "feel" was the wrong word.

As far as setting up an IRS in a fox? What're we doin'? What I'd do to mine, or just an overall drop in for multi use?

Mine would have the Kenny Brown adjustments made, again. I've never been a huge endorser (is that really a word...LOL) of Kenny's parts, but they nailed the IRS. I'd solid mount the rear attachment points (ie: welded plate, not bushings), with Delring bushings in the front. If I couldn't dig up an 03 rear diff, I'd do at least an 01 diff, I never had issues with my 99 diff, but I don't think I'd feel comfortable with the 28 spline halfshafts. Stock arms with Delrin bushings and spherical bushings at the spindle attachment points. Additionally, I'd make my own rear tie rod attachment points, adjustable at both the inner and outer attachment points. For any performance use, a diff cooler is mandatory, Torsen T-2 or T-2R diff (although the redesigned TruTrac diff kinda falls in between the two and has been beefed up from older designs). I'd yank the rear swaybar and start tuning from there. Brace both the front and rear of the differential. I never had an issue with the rear of mine, but I ran a Delrin bushing at the rear attachement point. To change this from a me vs other times, I'll dig up the old Wilson/Tone AI mustang from 2 years ago, which started the whole IRS in competition brew-ha-ha, which at the start of that season was handing damn near everyone their ass. The frame had to be notched to clear the KB arms which, (and this is from a personal discussion with Kenny about this) is simply a weight advantage, not a geometrical advantage. This notch started the rule deal, then it became an "other than stock" geometry issue in the cradle attachment points. My cradle came from Dean Martin's Grand Am cup car, which Grand Am also chose to go the same route about attachment points. You can find all that garbage reference in the NASA boards, I've long since lost those links. I just wanted to clarify the "no IRS in competition" reason, not because it's setup won't work, it's simply not allowed. Put me with the group of guys that believe it's the "big shop" drivers worried about the IRS, to nitpick it to death when used in competition. Understand, I've driven full Griggs and MM cars, and personally I'm faster with the IRS, but that's me.

For an everyday setup? Urethane or Delrin (your noise tolerance would decide this) cradle bushings, urethane arm bushings, coilovers (I will say that you can add the 00R rear bilstiens and H&R race springs, but the coilovers would be a better choice), at the very least shim the inner rod ends down I *think* .05 (I may be off here, it's been a while), and brace the nose of the diff and add either urethane or delrin, where solid aluminum would work also, again, noise tolerance would dictate. You could add the Mathis "support plate" at the rear cradle attachment points, but if you're really not going to push the car, I wouldn't screw with it. If you're going to have an extra set of sticky tires to throw on the car for the occassional drag day, pick up a rear diff cover brace. Aside from exhaust choices, I think it'd make a cool street driver.

I guess my point is, the only negative I've ever seen in setting up and IRS car is cost, not performance. Then again, a cambered live axle from Griggs ain't exactly cheap either. I suppose it's just irritating to see the IRS bashed when it can and does work. It just takes some money to make it right (as does anything). Any rear end addition is a bandaid to a goofy 1978 setup, the IRS happens to be my bandaid of choice. If you choose to steer someone in a certain direction, don't rely on competition use or lap times to justify the argument, use the cost. Always remember, a well setup IRS is currently illegal in competition use, so the comparison is apples to oranges, and doesn't make for a valid argument. Last time I checked, that ain't a stick axle in the back of a Z06....;)

[sneezingfox]

I want this...
http://images.google.com/imgres?imgurl=http://www.performanceautosport.com/images/cars/CCC%2520F%25203%2520500.jpg&imgrefurl=http://www.performanceautosport.com/detail.asp%3Fcar%3D5819&h=261&w=500&sz=87&hl=en&start=5&um=1&tbnid=qoA3L8833HCP6M:&tbnh=68&tbnw=130&prev=/images%3Fq%3Dmodified%2Bmustangs%26svnum%3D10%26um %3D1%26hl%3Den%26sa%3DG

[sneezingfox]

sn8kbit, are there any sites that reference IRS in a fox? Or do you just use the same upgrade parts for any IRS Cobra?

[sn8kbit]

I have to check and see if the guys that did my diff bushings set up a site. If they didn't, I can either get them for you, or give you the contact info, so long as they agree to it. There was a site I have to dig up from a Corner Carver member (Lewis Tanner) that did the swap and detailed it with pics. Have to dig around for that too. As far as the upgrading goes, same stuff as you would any other IRS. The only concern I'd have is spring rate since there is a weight difference between the two (fox - SN). I've got my MM receipts somewhere (I don't think I gave that mess when I sold the car) and I'm pretty sure I had 625 or 650 lb springs for the rear. That'd be the only other thing you'd have to really dig up. That's coilover by the way.

You can wait until after the first of the year and give Mark Wilson a call, his online store site is here: http://on-trackperformance.com/ He'd be able to set you up with some things for the IRS also. He used to have pics of the car there somewhere, but I couldn't find them on the site anymore.

Ah, here we go, Lewis Tanner's write up on the swap into a fox:

http://www.mouthbreather.net/IRSSWAP.HTML

[TomS]

and I hit those 1:09's on steet tires in a full weight car and stock K member and arms


No doubt, those are rockin' times.


I assumed it'd be understood since we're addressing the rear suspension


I should have understood that but some guys run with no rear bar so I wanted to make sure. I actually liked my car without the rear bar.


Mine would have the Kenny Brown adjustments made, again. I've never been a huge endorser (is that really a word...LOL) of Kenny's parts, but they nailed the IRS. I'd solid mount the rear attachment points (ie: welded plate, not bushings), with Delring bushings in the front. If I couldn't dig up an 03 rear diff, I'd do at least an 01 diff, I never had issues with my 99 diff, but I don't think I'd feel comfortable with the 28 spline halfshafts. Stock arms with Delrin bushings and spherical bushings at the spindle attachment points. Additionally, I'd make my own rear tie rod attachment points, adjustable at both the inner and outer attachment points. For any performance use, a diff cooler is mandatory, Torsen T-2 or T-2R diff (although the redesigned TruTrac diff kinda falls in between the two and has been beefed up from older designs). I'd yank the rear swaybar and start tuning from there. Brace both the front and rear of the differential. I never had an issue with the rear of mine, but I ran a Delrin bushing at the rear attachement point. To change this from a me vs other times, I'll dig up the old Wilson/Tone AI mustang from 2 years ago, which started the whole IRS in competition brew-ha-ha, which at the start of that season was handing damn near everyone their ass. The frame had to be notched to clear the KB arms which, (and this is from a personal discussion with Kenny about this) is simply a weight advantage, not a geometrical advantage. This notch started the rule deal, then it became an "other than stock" geometry issue in the cradle attachment points. My cradle came from Dean Martin's Grand Am cup car, which Grand Am also chose to go the same route about attachment points. You can find all that garbage reference in the NASA boards, I've long since lost those links. I just wanted to clarify the "no IRS in competition" reason, not because it's setup won't work, it's simply not allowed. Put me with the group of guys that believe it's the "big shop" drivers worried about the IRS, to nitpick it to death when used in competition. Understand, I've driven full Griggs and MM cars, and personally I'm faster with the IRS, but that's me.



This is what I wanted to hear, some tech! Steve, I haven't been on here long enough to know you but most people's "IRS is better" arguments are pretty weak.

I would certainly agree it can be made to be good, but at a substantial cost in labor and dollars.
I wouldn't recommend that sneezingfox do a full blown Griggs World Challenge setup with cambered axle/$2000 diff/ relocated lower control arms etc... I think this would be way beyond what he's trying to achieve.

sneezingfox,

For fun street use I'd agree with sn8kbit's basic recommendation.

Shocks- Bilsteins or Konis
Springs- H&R whatever flavor
Bushings- pretty much all of them

The above will make a tremendous difference in the "feel" and grip of the car. It will take a lot of the "float" out of it.

Tire- I can't believe we overlooked this. The single most important factor in improving grip. Get something good here.

Once those things are done and you have a good idea what the car will do and what you'll be doing with it then you could consider.

Camber plates
Torque arm/panhard or IRS swap
K-members/control arms
Differential upgrades
Battery and weight relocation etc...

Once at this level, you are spending lots of money for smaller and smaller improvements. Granted camber plates and moving the battery aren't all that expensive. They just don't net you a lot on a street car.

[sneezingfox]

I'm looking at a tokico/H&R package from max motor. It is the premium performance shockas and struts. Should I get something with adjustablility, or will these be good enough? Or should I just buy the springs and shocks seperatly to get a better comnbo?

[sn8kbit]

If you're already talking to MM, and ready to spend the money, get the H&R Bilstien combination. Tokico is an alright shock, but the difference between the two are (believe it or not) noticeable. Unless you're looking at a drag specific shock strut combo that has adjustability for the track, avoid the adjustables.

If money is holding you up on the Bilstiens, get bushings (all of them) and springs, then save up on the shocks/struts.

Hifi, Didn't think you were putting him on the uber track stuff, just clarifying the IRS stuff. Most IRS tech anywhere, to include anti-IRS tech, is pretty weak. Informed choices are always best. ;)

[sneezingfox]

So is it ok to run H&R Sport springs on factory shocks and strut? They are not too soft? I believe I have Monroe Sensatracs (or whatever the highest level is..) with Cobra springs right now.

[sn8kbit]

It's your budget, so ultimately your call. If you're already running a higher spring rate (Cobra springs aren't telling me too much, and probably not exactly correct if "stock" Cobra springs considering you're in a vert) swapping the springs alone isn't going to net you the "feel of the pants" justification your looking for in spending the money. If they are stock "Cobra" springs, there's part of the problem.

Try this:

Get some plate steel and box your lower arms and upper arms. While all this is out, go on and pick up the urethane bushings from MM, along with the urethane spring isolators (ers, irs, whatever). Add the sway bar bushings and endlinks. Drive the car like this for a month or so and get a "feel" for the car, and try to find the deficiencies you see. This also gives you that trial time to set aside the additional funds for the H&R/Bilstien combination. At the very least, you'll be setup for any direction you choose to go aside from swapping out the stock arms, and have a leg up on the upgrade. (Disclaimer: I understand the issues of bind in relation to a swap of all urethane bushings, along with issues of undesired lateral movement. It's unknown as yet how the car will be used, or the goal of the upgrade, for a street car, all issues of lateral movement and bind are moot, IMHO)

As a direct answer, no, I wouldn't run the H&R's with your stockish stuff for a long period of time, you'll end up being a bit upset at the cost for feel issue. You can run them, should you choose to do so, just so long as you understand, you may not end up with the result you were looking for. I usually skip recommending the sports and always go with the supersports for a street car.

It'd still really help to know what issues are bothering you with the suspension in your car, and how you're wanting to use it. Knowing that information helps others point you in the right direction.

[The Rascal King]

:eek: Man, sure is good to see you come out of the woodwork, Steve...

Heh, now that's a comment I never thought I'd see!....LOL...

<bringing the hard-core tech />

And now you know why. :no1:

[sn8kbit]

wouldn't call it hardcore.....LOL

And here I thought it was my jolly, sunshiney, warm fuzzy personality that was missed. LMAO!!

[sneezingfox]

My suspension is as follows,
FRPP strut tower brace, Granatelli upper and lower rear control arms, all bushings removed from new upper and lower and replaced with energy suspension bushings including axle housing, weld in sub frames with seat bracket, stock replacement quad shocks, as mentioned Monroe Sesatracs, it's a FRPP spring, but not sure on the model (have to pull a part number) but the springs are good for 2" drop. I have a MM k-member brace to put on but will not fit with my long tubes. I'm pretty sure that covers my suspension. I have Falken 235/45/zr17's up front, and just put a cheap replacememnt tire on the back (had nitto555r's). I got tired of trying to get my car to go fast in a straight line and not I want it to ride out the curves. With very little throttle, the ass end goes its own way. I have no traction until 3rd (crappy tires, I'm sure), the car wanders heavily on uneven surfaces. Suspension bottoms out easily. It's not a soft ride, and not stiff either. It sits heavy on the road and is very responsive. But not confident to drive it hard. I would really like to stiffen up the springs and shocks. The only reason for putting crappy tires on there is because I'm doing a 5-lug conversion and was going to 18's and well, didn't want to put a new set of rubber on a 17 when I was going to an 18.
But, 18's are not practical and would have a lot of clearance issues to deal with, and from what I researched, a correct suspension would allow you to dominiate with 17's. I just want my car to handle better. I want this car to be driveable on the street and in the same form be able to take it to the local autocross track on the week ends. I started off with imports and FWD handles fairly well, I think. My last performance car was an 04 STi. I would give anything to have my 89 vert handle like that. But then I got hooked in straight line driving and built the Mustang (first love anyways...) Let me kno wwhat other info you need.

[sn8kbit]

My suspension is as follows,
FRPP strut tower brace,

OK, now we're getting somewhere. Since it's a vert, I'll give you the strut tower brace, but put me in the "not necessary" school of thought on these, save it makes folks sleep better. A 'vert is gonna need any extra bracing.

Granatelli upper and lower rear control arms

Don't get upset if I were to recommend you eventually toss these, but we'll work with them for now.

all bushings removed from new upper and lower and replaced with energy suspension bushings including axle housing

OK, still on the right track....

weld in sub frames with seat bracket

Whose sub frames? Any help there is good, however, all subframes ain't equal. Again, you're driving a very, and ya need something beefy for the long run.


stock replacement quad shocks

Chuck 'em


as mentioned Monroe Sesatracs

Again, on the trash can list. I understand the cost difference between Tokico and Bilstien, but spend the money right once, been there done all that already.
I've had Tokico, Koni Red, Koni DA, Koni Series 30, Koni DA and Series 30 coilovers, Stock Bilstien and Race valved Bilstiens (Both with H&R, then coilovers). Fortunately, all of them were scored cheap, until I ended up getting the Race valved Bils, and was happy ever since.

it's a FRPP spring, but not sure on the model (have to pull a part number) but the springs are good for 2" drop

Probably the wonderful "C" spring. I'm still gonna push the H&R Supersports, especially with the vert. To add to that, 2" personally is cutting it close to "too low", (yes it matters). Without worrying too much how low it sets the car, look at the wheel rate, that's where the spring does it's work. Additionaly, I'm pretty sure the C spring is a fixed rate spring, where just about any other aftermarket springs are progressive rate.

I have a MM k-member brace to put on but will not fit with my long tubes.

Well..........Ok, with the vert I'll go with that, but not something you'll notice in "feel". Don't sweat it if you can't get it to fit using spacers.

I'm pretty sure that covers my suspension. I have Falken 235/45/zr17's up front, and just put a cheap replacememnt tire on the back (had nitto555r's). With very little throttle, the ass end goes its own way. I have no traction until 3rd (crappy tires, I'm sure), the car wanders heavily on uneven surfaces

Yup, you're gonna need tires all around. Allow me to recommend Khumo MX or the ASX in the 245 flava, depending on the rim width, 275's out back. Without 91-up fenders out front, you're stuck with a max width of 245 before ya have to start hacking at it. Absolutely wonderful tires. Ran the snot out of them back and forth and on track until Hoosier Cup tires won my heart for track days. I'd put the MX's up against any other "street" tire out there for overall performance. Just don't expect tons of mileage out of them. As far as the "wander" on uneven roads? The term is tramlining, and it's gonna do that. The wider the tire, the more noticeable it is.


Suspension bottoms out easily

Welcome to the "C" Spring owners club. Especially with stock style shocks/struts. I'm willing to bet the stock pinion snubber is on there, ya could be hitting that (yes, no, maybe?)

It's not a soft ride, and not stiff either. It sits heavy on the road and is very responsive. But not confident to drive it hard. I would really like to stiffen up the springs and shocks.

Stiff doesn't necessarily = sporty either. Off the top of my head, I *think* the rear springs from the H&R have a lower initial wheel rate than the C springs, but I can't find that damn link to verify it. I had it back from the old "TNspeed.net" days, but not anymore apparently. A properly matched setup with correct rates and correct valving in the shocks/struts will amaze ya. I don't know that I'd be confident to "push" the car either until you had decent tires.

I'm gonna reach and say the car is too low number one, and the C spring/Monroe combo is wearin' ya out. I'm gonna also throw out that you need to go on and pick up the swaybar bushings and endlinks, then find maybe a 4 banger rear swaybar, an LX rear swaybar, then maybe a GT one. Play with them, hell pull it too, and see what happens. While you're swapping swaybars around, remember to snag the stock rubber bushings for each, then pick up the urethane for what you decide to stick with if any. No offense, but right now, you're stuck with a hodge-podge of crap parts and trying to make sense of them. Some you can deal with for now, some need to go now. You're three big ones, unfortunately, are also you're most expensive ones: Tires, Springs, Shocks/Struts.

Did I mention Bilstiens?....LOL

[TomS]

FRPP strut tower brace,


Extra weight, sell it and lose 15lbs off the nose of the car.

I have a MM k-member brace to put on but will not fit with my long tubes

Sell it since it don't fit.


springs are good for 2" drop


Looks great but a little low for optimum Mustang handling. The H&R's do a good job. That's what I had on the rear of the Cobra. I did the MM coilovers on the front. Other than ride height adjustability they(coilovers) weren't worth the exra coin over standard springs for a street/ light autox schedule. I did like having a wider selection of spring rates with the coilovers but for you needs probably not necessary. Roughly, at ride height/race weight you want the front control arms parallel with the ground.


With very little throttle, the ass end goes its own way. I have no traction until 3rd (crappy tires, I'm sure),


It's a Mustang, that's what it's supposed to do. :)
Seriously, that's more of a driver mod and getting smoother/more patient/better with throttle application exiting corners. Autocross is great for teaching this.

Removal of the rear sway bar will help this too but will bring up some other issues that may or may not be a problem. The 4 cyl bar would be a good compromise. It's worth a try. I ran my car for a while with no rear bar and it hooked up great on good street tires.

The better tires will certainly help. The Falken's need to go. It's tough to beat the Kumho MX's fot the $. 17's or 18's really don't matter just put the widest wheel/tire combo on there that your pockets and sense of style/level of modification can tolerate.

Basically what sn8kbit said on everything else.

I started off with imports and FWD handles fairly well, I think. My last performance car was an 04 STi. I would give anything to have my 89 vert handle like that.

I also went from driving a Celica, Supra Turbo (mk3), Acura Integra(Gen2) to a 97 Cobra. A lot of what your feeling is just that, feel. The import cars are lighter, have very quick steering, and OK grip. The 04 STI has awesome grip, but a Mustang CAN make it around a track as fast or faster with the basic plan sn8kbit has given you. I've done it and I"m not a tremendous driver by any stretch of the imagination.

Don't fall into the trap of trying to make a Mustang handle like xxxx. It won't do it. It may be just as fast through a course but it will require a different driving style. A lot of the AWD cars and FWD cars are driven by slamming the throttle at or before the corner apex and the car will pull itself through. Granted these cars in a stock or close to stock condition aren't as powerful as yours and can't blow the tires off in 2nd or 3rd gear if they wanted too.

this is a decent write up on this concept http://www.protoworks.com/cgi-bin/C-C_Wiki.pl?Can_I_Make_My_Mustang_Handle_As_Well_As_ 'X'_Car by Matt Miller of CC.com fame.

[sneezingfox]

You guys rock! So I pretty much wasted money on the control arms and replacement bushings, huh? Ok, here are some more questions…
The Bilstiens on MM are listed as HD, MM Sport, MM Race, and Old HD. Any preference there? I am set on the H&R Super Sport springs and that will be in my shopping cart soon. Regardless of what spring I have in there already, I don’t care, I’m removing it.
Since you don’t recommend those control arms, which do you prefer? I want to get the torque arm and panhard kit and MM says after that, you can lose the upper control arms. That true?
The sub frames came free with the purchase of the upper and lower (looks like any 5 year old with a welder could have made them). They are about ¾” x 1 ½” box style. They do not curve with the bottom of the car and didn’t realize the bottom had a curve until I welded them up there.
My wheel size of choice is going to be 17x9 up front and 17x10.5 out back. Not sure on the style yet, but not sure that it matters.
I was not aware that 91 and up fenders were different. Will they bolt up to my 89? If so, how much more of a tire will that let me fit? (going the H&R/Bilstien combo)?
By the way, checked up on those MX’s…. WOW those are cheap! Who cares if they don’t last as long if they grip as you say they do!
Now as far as wander (tramlining), learned a new word today, as far as that goes, I’ve seen advertised rack mounts to fix that? Do they work? Do you recommend? At the very least is it worth it to swap the 20 year old ones with that?
Again, I didn’t know that the LX and GT had different sway bars. What are the differences there? They are both for 8cyl and 8.8” rear, right?
I’m not worried about swapping the springs. They came with the car and it badly needed shocks and struts (2 years ago) and at that time and put replacement shocks/struts cuz it was my Friday night drag car and I didn’t care. Now it has turned into my DD.
I know I have some learning to do on driving on a road course. I wa sat the last open track day at the speedway and got to ride in a few track cars there and since that day, I stopped trying to go fast in a straight line!
After I do the springs/5-lug swap with MX’s/Bils, I want to get a tubular k member, tubuar a arm, panhard, and torque arm. I think I would need to invest in camber caster plates at that point, right? Is this the right order to go into as far as suspension upgrades? And let em know what to do about subframes and control arms, I can probably swap those when I put the springs in… Thanks again, guys…

[sneezingfox]

i forgot to ask a couple things....
Torque boxes... What are they, why do I need them,,, where do they go?
Second... I want a roll bar, but not if it's going to hinder me. I was thinking 4 or 6 point... But I want the door bars, you know, the part that goes toward the front, I want those to be cut down to accomodate the entry and exit of the seat...

[sn8kbit]

You guys rock! So I pretty much wasted money on the control arms and replacement bushings, huh? Ok, here are some more questions…
The Bilstiens on MM are listed as HD, MM Sport, MM Race, and Old HD. Any preference there? I am set on the H&R Super Sport springs and that will be in my shopping cart soon. Regardless of what spring I have in there already, I don’t care, I’m removing it.
Since you don’t recommend those control arms, which do you prefer? I want to get the torque arm and panhard kit and MM says after that, you can lose the upper control arms. That true?
The sub frames came free with the purchase of the upper and lower (looks like any 5 year old with a welder could have made them). They are about ¾” x 1 ½” box style. They do not curve with the bottom of the car and didn’t realize the bottom had a curve until I welded them up there.
My wheel size of choice is going to be 17x9 up front and 17x10.5 out back. Not sure on the style yet, but not sure that it matters.
I was not aware that 91 and up fenders were different. Will they bolt up to my 89? If so, how much more of a tire will that let me fit? (going the H&R/Bilstien combo)?
By the way, checked up on those MX’s…. WOW those are cheap! Who cares if they don’t last as long if they grip as you say they do!
Now as far as wander (tramlining), learned a new word today, as far as that goes, I’ve seen advertised rack mounts to fix that? Do they work? Do you recommend? At the very least is it worth it to swap the 20 year old ones with that?
Again, I didn’t know that the LX and GT had different sway bars. What are the differences there? They are both for 8cyl and 8.8” rear, right?
I’m not worried about swapping the springs. They came with the car and it badly needed shocks and struts (2 years ago) and at that time and put replacement shocks/struts cuz it was my Friday night drag car and I didn’t care. Now it has turned into my DD.
I know I have some learning to do on driving on a road course. I wa sat the last open track day at the speedway and got to ride in a few track cars there and since that day, I stopped trying to go fast in a straight line!
After I do the springs/5-lug swap with MX’s/Bils, I want to get a tubular k member, tubuar a arm, panhard, and torque arm. I think I would need to invest in camber caster plates at that point, right? Is this the right order to go into as far as suspension upgrades? And let em know what to do about subframes and control arms, I can probably swap those when I put the springs in… Thanks again, guys…

I'm just gonna throw a couple of things out and hope I snag an answer for some of the questions.

It's hard to direct you for an initial shock purchase, when you're unsure of just how you're going to finish up the car. I'm going to recommend the MM Sport valved, then drive the car like that for a while. Stop focusing for the moment on the TA/PHB setup, and go for driver improvement. Track days at NSS or autocross events will help you dial your skill in, which is the best improvement you can make. As your skill level increases, then address issues you're having with the car from there.

I'll say leave the arms you have in for now, it's something you can address later.

I've never seen anything that addresses the issue of tramlining. There are bumpsteer kits, but change in bumpsteer and tramlining are two different things.

91 fenders are a direct bolt on, and you can get a 9" wide rim with 275 tires with some rolling of the lip. Don't even think of anything over a 245 right now, and you might squeeze that 9" rim you have in there.

Swaybars are of different diameters, mostly used to tune out isses with rear suspension. Some don't run them at all. Some run adjustable ones. The cheapest way to experiment is try the different stock available ones, or none at all.

Don't worry about your front end just yet at all. Get the rear set and learn to drive the car first. Best mod you can make. If you hadn't done a thing to the car, or it hadn't come with whatever parts are on it, I'd be telling you to throw some good tires and brakes, leave it stock and go learn. Well, now we gotta fix the issues someone else has done to the car, but the same basic theory applies.... LEARN first, mod later.

Which has all brought up new issues, such as improving the braking with pads, lines (another good reason for good tires). There's a ton more than just throwing some parts on and going, trust me.

[sneezingfox]

Cool man, I will order the springs and Mx's for Christmas. I need to find some new wheels!

[TomS]

I think I would need to invest in camber caster plates at that point


I would do the camber plates well before you get into k-members/torque arm etc...

Not necessary for street duty but beneficial if you are doing lots of autox/open track. Mustangs like lots of negative camber up front -3degrees or so. Wait til you get some track time before worrying about any of this stuff.


Again, I didn’t know that the LX and GT had different sway bars. What are the differences there? They are both for 8cyl and 8.8” rear, right?



All are essentially bolt ons for any 8.8 rear. I had a 92 4 cyl bar on my 97 Cobra in its last iteration.

Basically, a thicker rear bar will allow the car to rotate/turn in quicker at the entry of a corner at the cost of traction at corner exit. A smaller or no rear bar will allow more bite coming out of a corner but may cause the car to push or understeer more at the corner entry. There's more to than that but that should give you an idea of what's going on. Honestly, I'd just leave it for now and get some seat time and address the other issues.

Second... I want a roll bar, but not if it's going to hinder me. I was thinking 4 or 6 point... But I want the door bars, you know, the part that goes toward the front, I want those to be cut down to accomodate the entry and exit of the seat...

This you'll have to decide for yourself. The car needs the chassis stiffening but it's not going to make you any faster at this point.

My opinion is to not do a roll bar/cage on a car that is going to see any street time. It is extremely dangerous for you and passengers if you have an accident. The bars a positioned where your head/body can make contact in a nasty accident. On a road course/autox you'll have a helmet on. If this becomes a track car without rear seat passengers then it may be worth it. For autox it's just unecessary weight +100lbs with very limited to no chance of rollover.

[sneezingfox]

Cool. I just thought a roll bar would help with chassis stiffening. That's good, I can save some $$. Looking for some tracks to go to. I know NSS and I have heard of a track out toward Shelbyville? Not sure, figured I would ask.

[sneezingfox]

OK. Question about posi. The stock one is shot. I had purchased a replacement FRPP 28 spline replacement. What kind of differential gear do autocrossers run? Should I keep the FRPP, or do I need to get something like a Detroit or Auburn?

[sn8kbit]

Detroit TruTrac or Torsen T-2.

There's a way to improve the stock diff, but it only lasts so long, extra clutches, use an F150 spring, things like that. I'd pick up either of the first two I listed.