high mile 2013 California Special Convertible suspension overhaul

[slowwhitevert]

Hey guys, so I just purchased a 2013 California Special 6R80 automatic. I got my car pretty cheap because it does have some miles on it(130k), and it needs some suspension work, and the tires are pretty much toast as well, which didn't deter me as I knew I pretty much wanted to swap out a lot of the suspension, and go with different wheel/tire combo anyways as I knew I was going to want to do some serious suspension/chassis mods to try to wrangle the weight of the convertible down and improving the handling of the car. Now I know it might sound kinda dumb to start with a convertible, and auto at that especially as I'm really new to motorsports in general and this is obviously not an ideal spec car to try to turn into a canyon carver.

Backstory as to why I'm here is I had base model 2013 V6 in around the 2015-2019 time frame, that I had a few minor mods done to it, basically just aftermarket wheels/tires, ported intake manifold, shorty headers into the stock mid-pipes/cats with a set of mufflers of some sort that was supposed to be for a 07-10 GT500, and a 93 Bama tune which is all I ended up doing with it, and it already had I believe a Ford Racing lowering kit, or some other very mild lowering kit, maybe an inch drop that the original owner put on. In the few years that I had it I took to 2-3 autocross events where I did pretty poorly but I thoroughly enjoyed it. I got rid of it because as much as I truly loved it, I had a chance to drive a 5.0 convertible and I just knew I wanted the coyote motor and the convertible experience, and I was traveling for work and living in the midwest, it just made sense to me to let the V6 go and get a daily so I could have the daily driver and now the drop top that I could have the HP/TQ I wanted from a Coyote, and have it moddied a bit more then I would probably want a daily driven car. So after researching stuff to death, I finally came across this forum and I am seeking some guidance from you guys on how to best approach modding this big fat automatic vert pig.

Again it does have some miles, 130k and counting, but the motor is still strong and trans is shifting good, body isn't perfect but definitely doesn't seem like it was ever wrecked or even knicked up too badly. I had it PPI'd by a Ford dealer, and they called for front upper control arms to be replace, the rear sway bar end links, front pads, and tires/alignment etc, but compression test on the Coyote came back good, and it sounds great, actually not sure if theirs an after market catback, I thought maybe the CS cars had slightly different muffler or something, but from what I can tell from the internet it should be same exhaust as a GT, and the trans is shifting pretty smoothly especially for the year and miles, if/when the trans or motor breaks, I will probably end up beefing up the drive train a bit, and honestly I can see myself keeping this car forever, even with all the dealer said the car needs, it doesn't drive that badly, when I get it up past 75MPH or so is when I feel the front end wobble a bit, and it does bottom outa bit harder then I remember my V6 bottoming out, but that car had less then half the miles this car does and is now 5 years older then my V6 was when I got rid of it. obviously you never know, shiznit happens in life, but I honestly really do like how this car looks with the CS package, and I feel like this could be a car I keep and maybe hand down to my son some day, it just feels right.

With all that preamble out of the way, I basically want to approach the suspension on the car first, as that is the weak point of the car, and I basically want to do a clean sheet with the suspension, I want to take this car to some autocross events, I want also want to retain most of the street ability of it as well, I want to take this car on road trips, I understand you can't have everything but I'm willing too put in the money to get it as close to my ideal as possible. From my research the 3 companies that keep coming up as possibly options are Steeda, BMR and Maximum motorsports. Steeeda seems like they would provide the most OEM like experience, BMR seems like they could be the best for weight savings/bang for the buck and Maximum seems like they are the "you get what you pay for" and you pay more you get more so to speak brand.

I plan on calling up Steeda, BMR and Maximum Motorsports and hear what they all have to say and recommend, If you put a gun to my head right now, based on what little I know, I think I would probably go with Maximum Motorsports Road and Track Grip Box,
https://www.maximummotorsports.com/2011-2014-Mustang-Road-and-Track-Grip-Box-P1443.aspx

and boss 302 front control arms, and probably a BMR K-member and light weight radiator support, and the radiator support brace (maybe down the line even a Boss 302 steering rack?) I know the MM K-member is beefier, and their is some question as to if the BMR k-member is beefy enough, but again the goal here is some autocross and mostly daily driving, I think as long as I get the supporting bracing mods I think it would be sufficient, and the BMR K member drops a good 20lbs of weight.

I mention the Boss 302 stuff as thats pretty much the bench mark for what I hope I can achieve with this car, strictly from handling performance, the stock 5.0 is good for right now, maybe I'll get a tune after I get the suspension figured out, I'm also planning on going with lighter weight wheels, these california special wheels are 31lbs wheels only I believe, I'm eyeing a set on Eneki's an 18x8.5/18x9.5 staggered set that are coming in at like 21LBS wheel only, although after reading some of the Vorshlag S197 track build on Grassroots motorsports, I am reconsidering just going to a bigger square set up, I do like the staggered look, but I could definitely be swayed on that.

The only issue with that is that the MM kit though, is it doesn't come with convertible specific shocks, and I I also understand that this car being a 2013 in 2023 its 10 years old, so I would want to address the bushings, and all the rubber components in the suspension, I basically want to gut the suspension, any suspension components I should be looking to replace I would like to upgrade them where possible over stock obviously, The next thing after suspension is probably finding an economical brake upgrade ( non-brembo car) then the next things on my hit would be aluminum drive shaft, probably a torsen diff, and possibly gears, its a 3.15 in the 6R80, honestly it might seem like a waste but I'm thinking 3.31(maybe 3.55?) would be good, it almost seems not worth but if I'm doing the torsen anyways, I might as well do the gear swap then, plus I'll get the chance to freshen up the diff fluids etc, the stock diff seems to still be putting the 5.0 torque through both tires, then longer term plans might include the 4 point Maximum Motorsport rollbar, then by that point maybe some of the powertrain stuff will start creeping up into sight, IDK I'm really basing this off of what I've read on the other mustang forums, but I come here as you guys seem to be the most technically savy and I would really appreciate any advice or input on any of the mods I've listed, thanks in advance.

 

[Dave_W]

Welcome, and congratulations on your purchase. Not sure about the dealer PPI recommending front upper control arm replacement. It uses McPherson front suspension, so there's only a lower control arm on the front.

The Ford Performance kit is also highly-recommended on this forum, but it appears it may not fit on a convertible. You may want to give their tech line a call to see what prevents it working on a 'vert.

I'd put replacing the K-member way down on the mods list, possibly never. For spirited street driving plus the occasional autocross and track day, I don't think it will be much of a benefit. Put the money into getting seat time at more events.

With 130K miles, your shocks may be shot, which could be causing your bottoming issues. Try not to lower the front end too much. Dropping it more than about 1.5" will get you into needing extended ball joints and a bump steer kit to fix roll center issues. You can lower the rear more than that so the car is level if you like.

Besides Steeda, BMR, and Maximum Motorsports, Vorshlag and Cortex are well-regarded on this forum, and are site sponsors. For Easy-button simplicity, the Vorshlag Bilstein setup is nice, as it come with their highly-rated camber plates, and shocks with no knobs for you to foul up. Or you can go with something like the MCS TT2 combo if you want to play with settings, or the Cortex Penske kit if you've got 6 large burning a hole in your pocket. Cortex has some less-expensive kits that can be ordered with extra clearance on the strut housings for wide tires. One other company I like, though they haven't as much concentration on the Mustang market, is Ground Control.

For wheels, you should consider site sponsor Apex - read their very detailed info on S197 wheel fitment -

S197 Mustang Wheel & Tire Fitment Guide

S197 2005-2014 Mustang Wheel and Tire Fitment Guide Vehicle Covered in this Guide2005-2014 Mustang Chassis IntroductionFord completely redesigned the Mustang for 2005, bringing back retro styling ...

support.apexraceparts.com

Most track rats here will recommend just getting a set of 18x11 wheels, 305- or 3115-width tires, and be done with it. Used track slicks can be had in 18" but some of the newer 200TW "extreme performance summer" tires have better wide width availability in 19" so you may want to pick a tire before picking your wheels. Note that using 11-inch wide wheels with the same offset front and rear (so you can rotate tires easily) will also require 25mm spacers and extended lug studs on the front hubs - check the Ford Performance hubs with ARP studs. If you're not looking at all-out performance, you may consider 18x10 or 19x10 square setup. Probably good to replace the front hubs with 130k anyway.

When it comes right down to it, just make it safe by fixing any major issues and get some seat time. Have some fun and get a feel for the car before you start making major changes.

 

[Theviking]

Wow, that was a lot of typing Having at GT/CS I can confirm the entire drivetrain, including mufflers, are just regular GT stuff. GT500 mufflers are my choice for aggressive without droning but this is all objective of course. I think you need a rollbar to run track events with most clubs/organizations but rules differ. Here are the SCCA Track Night requirements which if I'm being honest seem very strange.

Start Here - Everything You NEED to Know - Rules and Regulations - Track Night in America Convertible Policy

www.tracknightinamerica.com

Having been down the upgrade road in various phases I'd start with struts and camber plates. But if you can afford GOOD coil-overs that would be my recommendation as well. Then you can set (and change) spring rates and ride height. But there are way to many bad choices out there so avoid the budget options. As suggested, be careful with ride height. Most aftermarket spring options for these cars drop the ride height too much IMHO which causes more problems then it solves.

You need real brakes which don't fit under the GC/CS wheels so an upgrade is in order. As other said, if you're going to buy wheels spend once with with a 19x11 option as it sets you up for life, so to speak. The 14" Boss/GT500 brake setup is fabulous for the money with a good set of pads. The 6 piston 15" setup is even better but you're going to spend more and there is a big rotational mass penalty if you don't go with a lightweight rotor option. Again, more money.

You probably need to check all your suspension bushing considering the mileage but if the dealer tells you to change out the front UCA's I might find a new dealer I wouldn't touch a thing with the gearing at this point as it's more fine tuning than anything else. The Torsen is nice but if your traction lock is still working I'd focus on other things first.

 

[slowwhitevert]

I appreciate the replies, and yes apex wheels where the next wheels on my list. I did also like the idea of the ford racing kit, but as noted because it is listed as for "coupes only" that was what dissuaded me from considering it. Would contacting Ford directly be the best way to figure out what I would need to adjust from that kit to accomidate it for my vert?

As far as what was recommended by the ford dealer, I simply had the closest ford dealer near the car preform the PPI and they won't be preforming any of the subsequent repairs. I basically went and check out the car, could tell it needed some suspension work just from a quick drive around the block and I had the PPI done so as to assure that the under carriage/body and the major drive train components of the car where solid, and as a way to leverage the final price I paid for the car. I will dig up the full PPI and clarify exactly what was recommended, I know it was something to do with the front control arms, but I can't recall of the top of my head specifically what they diagnosed for repair/replacement.

I can definitely see the shocks/struts/springs of the car being the major culprit of the harshness of the and as the k-member, gears etc they are definitely lower on the totem pole at this point in terms of order of operation/importance, just things I'm also considering changing out at some point, so I threw those out there as to get additional input from members here to get more informed opinions on, as if i'm going to be tearing into the suspension maybe it would be worth having those mods addressed while having the car apart anyways.

After more reading here I am hesitant to go for a aftermarket k-member given my use case I see for this car, again given the age and mileage of the car I would really prefer to address any and all possible wear items on the suspension and upgrade where possible before I stat messing around with drivetrain/driveline pars, or adding more HP, TQ etc.

 

[TMSBOSS]

What exactly are you planning on doing with the car? DD, autocross, track days or cruiser?

 

[stevbd]

@slowwhitevert Welcome, sounds like you have a good fun street/autox kind of "do it all" car.

I think one challenge with Mustang world is there is so much you can do to these cars, and people use them in so many different ways, it's really easy to get lost with internet racing and research. I would fix the control arms and any other safety issues and then just go drive your car. Figure out what it's doing that you don't like, or isn't doing that you do like, and go from there. I think you're going too far down these rabbit holes without enough seat time. A full tilt race build - of which there are many on here - obviously looks very different than a fun street/autox 'tweener car.

IMO the single best thing you can do to improve handling is a decent set of shocks. With the possible exception of the Boss, all S197's are way underdamped from the factory and 130K miles isn't helping. Keep it simple. Bilstein or Koni, either is a huge improvement.

 

[slowwhitevert]

What exactly are you planning on doing with the car? DD, autocross, track days or cruiser?

Essentially all of the above, maybe not necessarily a daily driver as I have a AWD vehicle for winter/rainy day duty, and not quite ready to try my hand at actual track racing.

I have only done a couple of Autocross events, but I really did enjoy the couple of events I took my old V6 car too. I am not confident enough in my driving ability to try a true track event, but I would have this car to have the ability to not be a dog on a track, at some point, but to answer your question as succinctly as possible for the here and now this car will be used on autocross events but also used on the street quite a bit, so I guess a cruiser/autocross car.

I'm not looking to constrain the car for specific events, I just want the car to be as capable as possible for autocross, and hopefully maintaining say 80-85% of the stock/oem ride quality.

 

[slowwhitevert]

@slowwhitevert Welcome, sounds like you have a good fun street/autox kind of "do it all" car.

I think one challenge with Mustang world is there is so much you can do to these cars, and people use them in so many different ways, it's really easy to get lost with internet racing and research. I would fix the control arms and any other safety issues and then just go drive your car. Figure out what it's doing that you don't like, or isn't doing that you do like, and go from there. I think you're going too far down these rabbit holes without enough seat time. A full tilt race build - of which there are many on here - obviously looks very different than a fun street/autox 'tweener car.

IMO the single best thing you can do to improve handling is a decent set of shocks. With the possible exception of the Boss, all S197's are way underdamped from the factory and 130K miles isn't helping. Keep it simple. Bilstein or Koni, either is a huge improvement.

I think you maybe correct, my thought process is that with the mileage of the car a lot of the suspension is already well worn so I'd hate to simply repair everything to stock spec only to replace the OEM suspension only for in a year or 2 start replacing the OEM parts again with aftermarket stuff.

But, I am humble enough to admit I don't know what I don't know, thus why I'm asking the guys here for pointers as this seems to be the most informed message board on the web interms of mustang autocross/track racing suspension and it made sense to gather some thoughts of the posters here before I go asking Maxmium Motorsports, BMR, Steeda, etc what parts I should go throwing at the car to get unbiased, informed opinions, but again your advice seems practical and perhaps starting with a more OEM type and learning what about the car I'm not satisfied with is the more prudent approach as much as I want to jump into this stuff with both feet.

 

[JDee]

At the risk of being a wet blanket, I'm going to say that nothing you can do to this car will make it a competitive car. First, it's a convertible, they are typically heavier than a coupe. Second, convertibles have less torsional rigidity than a coupe. Both of those things put it at a severe disadvantage for any kind of serious competition use.

It's also high mile, so just about everything that can wear in the suspension/driveline needs to be replaced. That's a lot of money and you are still going to have an uncompetitive base platform. That can't be fixed. For sure you are never going to get anywhere near Boss302 level performance from a convertible.

If all you want is to have some fun and not worry about where you finished then it will work. You don't really need to do much of anything to it for that kind of thing, just get a good safety check on it from a competent mechanic and have at it.

But typically, this hobby is addictive and when the urge strikes to really go fast/run with the big dogs you will need to start modding this platform and that's when the warts will show up. If you're serious about going fast and being competitive I'd unload it and find a good used 2011 or later GT coupe with a manual gearbox and start building on that. IMHO. Good luck!

 

[slowwhitevert]

At the risk of being a wet blanket, I'm going to say that nothing you can do to this car will make it a competitive car. First, it's a convertible, they are typically heavier than a coupe. Second, convertibles have less torsional rigidity than a coupe. Both of those things put it at a severe disadvantage for any kind of serious competition use.

It's also high mile, so just about everything that can wear in the suspension/driveline needs to be replaced. That's a lot of money and you are still going to have an uncompetitive base platform. That can't be fixed. For sure you are never going to get anywhere near Boss302 level performance from a convertible.

If all you want is to have some fun and not worry about where you finished then it will work. You don't really need to do much of anything to it for that kind of thing, just get a good safety check on it from a competent mechanic and have at it.

But typically, this hobby is addictive and when the urge strikes to really go fast/run with the big dogs you will need to start modding this platform and that's when the warts will show up. If you're serious about going fast and being competitive I'd unload it and find a good used 2011 or later GT coupe with a manual gearbox and start building on that. IMHO. Good luck!

Yeah, I have no visions of grandeur that I'll ever make an automatic/convertible competitive in any type of class spec racing or autocross. I know the verts weigh more and have substantially less chassis rigidity then a coupe, especially being its an automatic too boot. I basically want to put as much lipstick on my pig as I can without totally ruining the ride quality/comfort of the car. I understood the limitations of starting with a vert, and getting it even within ear shot of even a stock Boss was not likely, if I was really looking to make a dedicated competitive track car I certainly wouldn't have gotten the spec I went with, an auto, vert California Special I would have either went with a totally base model gt stick car, or a performance pack w/brembos or just bought a boss to start with etc. I do appreciate the blunt honesty though, and Im sure theirs good reason why there are only a couple of verts on this website, but after having my V6 car, not that it was actually fast I did like having a modified V6 as it was something different, and honestly if finances and my life situation had been different at that time I would have loved to have held onto that car, but I knew a vert was what I wanted.

I understand this probably sounds like a really dumb idea, but I like the idea of doing something different and unique, and maybe after a while of continuing to learn from the guys here, maybe in a few years or so maybe I can turn this silly project into something that suprises in terms of what I can push the platform into.

My father often told me nothing worth doing is ever easy, and I'm crazy enough to see if I can turn this vert into something interesting, at the end of the day this is about having fun for me more so then winning races, and having a car that you can drive with the roof down is a lot of fun too me, I want to see how far I can push this car going in eyes wide open about its limitations.

And who knows maybe after I really get into autocross/tracking this car maybe I'll snag a hardtop stick car, or a Boss 302, or something more track appropriate, but I want to do my dream convertible while I still have some hair on my head to enjoy the air blowing it all around.

 

[blacksheep-1]

The stock K member will be fine...

 

[blacksheep-1]

FWIW there are a set of Boss 302 springs, and panhard bar in the for sale section, Idon't know the guy but it's a low buck start on your project.