93R - K-Member upgrade

[drkhrse]

Hi guys, it's been a while (I got in an accident on my motorcycle, stupid Saturn). I'm pulling the original motor out of my 93R to put in storage before I screw it up. I have another 93 cobra motor (and trans) I’m building up into a race motor. While the motor is out I am considering replacing the front K-member and arms to a MM w/ coil overs. The dilemma is the 3/4" move forward. Besides trimming the front ground affects what other mods will the car need? I run a 255 tire on stock wheels and think it will clear the fender ok. Jason at MM has been great to talk to. He recommended leaving the stock K and only changing the arms over as to not cut up the car. If I plan to change it over someday I may as well do it now, thoughts? I autocross and open track the car. The car is far from stock, I have no problem upgrading it for performance, i just don't want to cut it up, much more.

I’m looking for the weight savings so I don’t have to go on a diet. :beer:

 

[grape]

if all that moves forward is the lower balljoint by 3/4", you're only gonna get half of that in a wheelbase change since the strut top doesn't move. I think you could adjust the holes where it mounts to the frame horns and get most of that back out........if you wanted to. Most important, i'm not sure how they told you to sqaure those things but i'd be curious as to what they tell the average public to do that don't have access to surface plates and all the other toys we have for aligning race cars.

 

[jimbbski]

Hi, former owner of you R here.

IF you opentrack the car you need a modified K-member, It will allow the tires to last longer.

I had modified and installed a stock Fox K-member (1989) in that car. It moved the wheels forward 5/8 of an inch and the engine back 5/8 of an inch (from the stock position.) but a bit over an inch on the K-member. This was done all per the Mathis book "Mustang Performance Handbook?

I removed it prior to putting the car up for sale.

I did no cutting to install this and only had to replace the front fender braces for tire clearence with longer non-stock one. I even added turnbuckles to the bottom of the front fender opening over to the bottom of the radiator support. About where the stock "X" brace bolts to it. I used the turnbuckles to force the fenders outward just enough for the tires to clear.

IF you want more info give me a call, my number hasn't changed.

 

[drkhrse]

Hi, former owner of you R here.

IF you opentrack the car you need a modified K-member, It will allow the tires to last longer.

I had modified and installed a stock Fox K-member (1989) in that car. It moved the wheels forward 5/8 of an inch and the engine back 5/8 of an inch (from the stock position.) but a bit over an inch on the K-member. This was done all per the Mathis book "Mustang Performance Handbook?

I removed it prior to putting the car up for sale.

I did no cutting to install this and only had to replace the front fender braces for tire clearence with longer non-stock one. I even added turnbuckles to the bottom of the front fender opening over to the bottom of the radiator support. About where the stock "X" brace bolts to it. I used the turnbuckles to force the fenders outward just enough for the tires to clear.

IF you want more info give me a call, my number hasn't changed.

Hi Jim! Good to know you still check in around here. I remember talking to you about this back when i bought it. I'm torn what to do. I should have got the one you had made up for it back then! I do have an extra i can modify myslef, however the MM seems really well built and saves a bunch of weight.

 

[jimbbski]

Going with the MM unit is a good way, it's lighter and stronger then the stock one. I did the modified stock K-member at the time as I wanted to keep the look of the car stock and that required keeping the stock springs and LCA's.
I did later convert to coil overs and was glad I did. With some other mods like aluminum heads I was able to get the F/R weight ratio down to something like 53/47; which in a Fox that was not a pure race car; is dam good!

Glad your driving the car, that's what their for. It was that kind of car when I bought it and I think that's why you bought it as well. I hope to finally get back on track myself this spring with my little VW race car. I need to take some newer pictures of it, a friend keeps asking me for some to put in our clubs newsletter.

 

[93SVTCobra]

Jim,

Did you notice a big difference with the K-member modifications? I friend of mine is asking me to make the modifications on his K-member and I'm just trying to get some feedback from anyone who has done it.

The stock k-member is MUCH stronger than the MM or Griggs part.

 

[jimbbski]

From everything I've read on the internet modifying the stock K member gains you everything you get with a Griggs or MM k member with the exception of:

The stock k member is heavier and you have less room/access to various engine parts.

What's the same:

Moves the front wheels forward.
Moves the engine back.
Moves weight from the front wheels to the rear. (Read earlier post)
On the strength/stiffness of each I can't comment.
All the handling benifits of the Griggs or MM unit is still there with a modified stock k member.

Downsides to moding a stock one:

You have to have all the required tools to cut, grind, and weld to modify a stock one. Time is also a factor but you could do one in one weekend once it's out of the car. On mine I had it sandblasted, did the mods and then had it painted by a bodyshop with the stock color paint without the clearcoat. I also did the mods is such a way that a quick look by someone would not show the mods, I filled holes, ground welds, etc.

Things I would do differently now would be to find an even earlier Fox k member. One with the narrower front track, I forget the years? Move the control arm pickup points inboard on that one and either fabricate custom LCA's as I did the first time when I went coil over or see if the late Mustang LCA's ('03-'04) will work. Part of the reason I went coil over after only a couple of years with the modified k member was that the T-Bird LCA's were a bit to long or I didn't move the pickup holes inboard enough. I had to much neg. camber and didn't want to cut up the strut towers to move the caster/camber plates enough to get the camber into a range that I wanted.

Custom tubular LCA's allowed me to make them to a size between the stock Fox and the T-Bird LCA's. I later made a set of LCA's with threaded ends and heim joints instead of bushings allowing even more adjustment of the suspension. I still have these sitting around but plan on keeping then for a future project (FF Type 65 Coupe).

 

[93SVTCobra]

Those are the same benefits I have read as well. Just was wondering if the first hand experience was the same as what I've read the benefits to be.

 

[drkhrse]

Well no one has given me a reason not to switch it out. I'm about to order the MM front set up. Brakes will be next.... man your phone Jim!