Fox k member differences

nelzfoxes

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Aug 20, 2013
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Ok! I have a 1989 4 cyl. donor car. Is it true that the control arm mounting points are narrower? I would like to run longer control arms from the sn95 chassis on my fox and this I think would help me. My fox already has sn95 spindles paired with 2000 cobra r brakes. I am attempting a suspension rebuild and I might as well go all out if I can.
 
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revhead347

Just rub Vaseline all over
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I've never heard of running SN95 control arms on a Fox. I have heard of running Fox control arms on an SN95.

Kurt
 

General karthief

wonder how much it would cost to ship you a pair
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Sn95 control arms are one inch longer, k member mount to ball joint (this is what I've read on many searches) than fox control arms, most use the fox control arms.
No difference at k member control arm mounting points between the 4cyl and V8.
 
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Warhorse Racing

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Yes, the SN95 A-arms are 1 inch longer. You will get a better turning radius with the 99-04 A-arms than the 94-98 A-arms. But, there are also drawbacks, like fender clearance.

What performance benefit are you looking to achieve by using SN95 A-arms?
 

nelzfoxes

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Aug 20, 2013
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Sn95 control arms are one inch longer, k member mount to ball joint (this is what I've read on many searches) than fox control arms, most use the fox control arms.
No difference at k member control arm mounting points between the 4cyl and V8.
Ok. Then I guess it’s just the pre 87 K member that is narrower?
Yes, the SN95 A-arms are 1 inch longer. You will get a better turning radius with the 99-04 A-arms than the 94-98 A-arms. But, there are also drawbacks, like fender clearance.

What performance benefit are you looking to achieve by using SN95 A-arms?
Yes. I am just looking to maximize the handling and turning capabilities of my car. With the narrower k member and longer arms I figure I can get a slightly wider front track width. Add to that front terminator control arms which give added tire clearance for turn radius and it would be a win I think.
 

Mustang5L5

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4-cyl K-members are the same as the pre-1988 V8 k-members. Starting in 1988, the control arm mounting points moved out about 1". It is common to add the SN95 control arms to correct this on 4-cyl cars with the original K-member.

Yes, the cutoff is 1988, not 1987.

There are also some subtle differences in K-members. The V8's used welded spring perches while the 4-cyl use stamped.

'79-'87 Mustang K-member (and all 4cyl) front A-arm bolt center to center - 22.75"
'88-93 Mustang K-member front A-arm bolt center to center - 23.75"
Mustang SVO K-member front A-arm bolt center to center - 23.00"


'79-'87Mustang K-member (and all 4cyl) rear A-arm bolt center to center - 30.125"
'88-93 Mustang K-member rear A-arm bolt center to center - 31.125"
Mustang SVO K-member rear A-arm bolt center to center - 29.5"

'79-'93 K-member angle of A-arm off centerline of car - 16.5 deg.
Mustang SVO angle of A-arm off centerline of car - 14.5deg.

'79-'87K-member overall width from ball joint to ball joint - 51.37"
'88-93 K-member overall width from ball joint to ball joint - 52.37"
SVO K-member overall width from ball joint to ball joint - 53.36"

Stock Mustang A-arms '79-'93 - 13.00" long
Mustang SVO A-arms - 14.00" long
1987-1988 Thunderbird A-arms - 13.75" long.
Sn95 A-arms - 14.00" long

That info was taken from this book

 
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Warhorse Racing

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Feb 10, 2019
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Ok. Then I guess it’s just the pre 87 K member that is narrower?
Yes. I am just looking to maximize the handling and turning capabilities of my car. With the narrower k member and longer arms I figure I can get a slightly wider front track width. Add to that front terminator control arms which give added tire clearance for turn radius and it would be a win I think.

If I’m reading your original post correctly, you’re looking to modify a V8 Fox, correct?

The 1993 Cobra R came with a revised K-member that allowed for the use of SN95 length A-arms. But, I don’t think a 4-cylinder K-member is the best way to accomplish what you want to do.

SN95 A-arms with a V8 K-member will increase track width, reduce understeer, help with corner speed and provide better ball joints. You’ll also be able to get more negative camber up front. The Fox A-arm/SN95 Spindle combo creates a negative camber limit of around -1.6 degrees.

But, you will need to use 94-04 inner and outer tie rods. And you might have to cut up the fenders to keep the tires from hitting (depending on tire size).

If you don’t want to cut up your car, there are several things you can do to improve the front suspension to get the car to handle better without switching to SN95 A-arms.

I just made these suspension mods to my 1992 GT autocross car. It has Fox A-arms, 96-04 Spindles and 04 Cobra brakes. It handles pretty well and I didn’t have to cut up the car at all.

Part 3: SUSPENSION UPGRADES, details the suspension mods...

View: https://www.youtube.com/watch?v=rXn_0QXo4vk&t


PART 3A covers my INITIAL THOUGHTS & INSTALL TIPS for the improvements I made in Part 3…

View: https://www.youtube.com/watch?v=Lc8aJ4W8CQM&t


Your goal with the front suspension is to limit understeer. Many common mods actually increase understeer, so it’s important to choose mods that make the car neutral.

This video breaks down that process and discusses what mods impact understeer and oversteer…

View: https://www.youtube.com/watch?v=9HiS-t4_O_w&t


If you have any questions about the mods or installs, I’m happy to answer them here or in the comments on YouTube.
 

Jalapeno5

Member
Apr 9, 2020
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4-cyl K-members are the same as the pre-1988 V8 k-members. Starting in 1988, the control arm mounting points moved out about 1". It is common to add the SN95 control arms to correct this on 4-cyl cars with the original K-member.

Yes, the cutoff is 1988, not 1987.

There are also some subtle differences in K-members. The V8's used welded spring perches while the 4-cyl use stamped.

'79-'87 Mustang K-member (and all 4cyl) front A-arm bolt center to center - 22.75"
'88-93 Mustang K-member front A-arm bolt center to center - 23.75"
Mustang SVO K-member front A-arm bolt center to center - 23.00"


'79-'87Mustang K-member (and all 4cyl) rear A-arm bolt center to center - 30.125"
'88-93 Mustang K-member rear A-arm bolt center to center - 31.125"
Mustang SVO K-member rear A-arm bolt center to center - 29.5"

'79-'93 K-member angle of A-arm off centerline of car - 16.5 deg.
Mustang SVO angle of A-arm off centerline of car - 14.5deg.

'79-'87K-member overall width from ball joint to ball joint - 51.37"
'88-93 K-member overall width from ball joint to ball joint - 52.37"
SVO K-member overall width from ball joint to ball joint - 53.36"

Stock Mustang A-arms '79-'93 - 13.00" long
Mustang SVO A-arms - 14.00" long
1987-1988 Thunderbird A-arms - 13.75" long.
Sn95 A-arms - 14.00" long

That info was taken from this book



Absolutely correct.
 

nelzfoxes

5 Year Member
Aug 20, 2013
463
318
94
4-cyl K-members are the same as the pre-1988 V8 k-members. Starting in 1988, the control arm mounting points moved out about 1". It is common to add the SN95 control arms to correct this on 4-cyl cars with the original K-member.

Yes, the cutoff is 1988, not 1987.

There are also some subtle differences in K-members. The V8's used welded spring perches while the 4-cyl use stamped.

'79-'87 Mustang K-member (and all 4cyl) front A-arm bolt center to center - 22.75"
'88-93 Mustang K-member front A-arm bolt center to center - 23.75"
Mustang SVO K-member front A-arm bolt center to center - 23.00"


'79-'87Mustang K-member (and all 4cyl) rear A-arm bolt center to center - 30.125"
'88-93 Mustang K-member rear A-arm bolt center to center - 31.125"
Mustang SVO K-member rear A-arm bolt center to center - 29.5"

'79-'93 K-member angle of A-arm off centerline of car - 16.5 deg.
Mustang SVO angle of A-arm off centerline of car - 14.5deg.

'79-'87K-member overall width from ball joint to ball joint - 51.37"
'88-93 K-member overall width from ball joint to ball joint - 52.37"
SVO K-member overall width from ball joint to ball joint - 53.36"

Stock Mustang A-arms '79-'93 - 13.00" long
Mustang SVO A-arms - 14.00" long
1987-1988 Thunderbird A-arms - 13.75" long.
Sn95 A-arms - 14.00" long

That info was taken from this book

That's good info right there! Thanks! That gives me some options.
 

nelzfoxes

5 Year Member
Aug 20, 2013
463
318
94
If I’m reading your original post correctly, you’re looking to modify a V8 Fox, correct?

The 1993 Cobra R came with a revised K-member that allowed for the use of SN95 length A-arms. But, I don’t think a 4-cylinder K-member is the best way to accomplish what you want to do.

SN95 A-arms with a V8 K-member will increase track width, reduce understeer, help with corner speed and provide better ball joints. You’ll also be able to get more negative camber up front. The Fox A-arm/SN95 Spindle combo creates a negative camber limit of around -1.6 degrees.

But, you will need to use 94-04 inner and outer tie rods. And you might have to cut up the fenders to keep the tires from hitting (depending on tire size).

If you don’t want to cut up your car, there are several things you can do to improve the front suspension to get the car to handle better without switching to SN95 A-arms.

I just made these suspension mods to my 1992 GT autocross car. It has Fox A-arms, 96-04 Spindles and 04 Cobra brakes. It handles pretty well and I didn’t have to cut up the car at all.

Part 3: SUSPENSION UPGRADES, details the suspension mods...

View: https://www.youtube.com/watch?v=rXn_0QXo4vk&t


PART 3A covers my INITIAL THOUGHTS & INSTALL TIPS for the improvements I made in Part 3…

View: https://www.youtube.com/watch?v=Lc8aJ4W8CQM&t


Your goal with the front suspension is to limit understeer. Many common mods actually increase understeer, so it’s important to choose mods that make the car neutral.

This video breaks down that process and discusses what mods impact understeer and oversteer…

View: https://www.youtube.com/watch?v=9HiS-t4_O_w&t


If you have any questions about the mods or installs, I’m happy to answer them here or in the comments on YouTube.
The car in question is a hodge podge of fox and sn95 and new edge. It's a fox chassis station wagon. I am not sure what k member is under there because the donor car was v8 swapped before I got it. Then I upgraded to Cobra R brakes. The spindles are from the original m-2300-k Cobra brake kit. The wheels are gonna be 1995 Cobra R 17x9's. Out back I have a Terminator Cobra IRS. I do have the deeper offset Cobra R rims for the back of the car to compensate for the wider IRS rear track. The goal is 100% street handler. Power is EFI 351 windsor. I just installed stock Cobra Terminator springs up front. Because I have the Cobra springs I plan on using the 4 cylinder sway bar up front to keep the ride streetable. It actually has stock Cobra springs at all four corners.
 

Warhorse Racing

Active Member
Feb 10, 2019
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United States
The car in question is a hodge podge of fox and sn95 and new edge. It's a fox chassis station wagon. I am not sure what k member is under there because the donor car was v8 swapped before I got it. Then I upgraded to Cobra R brakes. The spindles are from the original m-2300-k Cobra brake kit. The wheels are gonna be 1995 Cobra R 17x9's. Out back I have a Terminator Cobra IRS. I do have the deeper offset Cobra R rims for the back of the car to compensate for the wider IRS rear track. The goal is 100% street handler. Power is EFI 351 windsor. I just installed stock Cobra Terminator springs up front. Because I have the Cobra springs I plan on using the 4 cylinder sway bar up front to keep the ride streetable. It actually has stock Cobra springs at all four corners.

I'm a big fan of "unicorn" projects. And yours seems like a very cool one. I'm guessing the car is heavier than most Mustangs, so OEM Terminator springs sound like a good choice.

In terms of sway bars, you're in interesting territory. If you're using the stock rear IRS sway bar, and you install adjustable shocks and struts, you might be able to use a larger front sway bar to help with body roll and transitions. But, it's probably a good idea to wait on that decision until you have some seat time in the car.
 
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KRUISR

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Excellent and very helpful book for knowledge and understanding and if you are into and capable of building your own parts. I used it to mod my k-member, build my sub-frame connectors, fab anti-squat brackets, continuous weld all rear suspension mounts and modify stock rear control arms (to stiffen them up a bit). I may build a version of a torque arm as well sometime. Feels great doing it your self and happy with overall result of car.
 

Jalapeno5

Member
Apr 9, 2020
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10
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Minnesota
The car in question is a hodge podge of fox and sn95 and new edge. It's a fox chassis station wagon. I am not sure what k member is under there because the donor car was v8 swapped before I got it. Then I upgraded to Cobra R brakes. The spindles are from the original m-2300-k Cobra brake kit. The wheels are gonna be 1995 Cobra R 17x9's. Out back I have a Terminator Cobra IRS. I do have the deeper offset Cobra R rims for the back of the car to compensate for the wider IRS rear track. The goal is 100% street handler. Power is EFI 351 windsor. I just installed stock Cobra Terminator springs up front. Because I have the Cobra springs I plan on using the 4 cylinder sway bar up front to keep the ride streetable. It actually has stock Cobra springs at all four corners.


Pictures?
 

nelzfoxes

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Aug 20, 2013
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098725DF-D171-446B-A2AE-2FE581751498.jpeg
I had to upload pic... what gives?