How beneficial is an aftermarket K-member?? - Ford Mustang Forums : Corral.net Mustang Forum
 
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post #1 of 22 Old 12-03-2011, 09:38 AM Thread Starter
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How beneficial is an aftermarket K-member??

I'm wondering if you guys can shed some light on aftermarket k-members, ie: MM or Griggs. Aside from weight savings, how beneficial would it be to get a tubular K? I have MM offset front control arms to get better front end geometry and an MM k-member brace for extra strength. Would handling improve with an MM k-member? Pros/cons? Thanks!

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post #2 of 22 Old 12-03-2011, 01:15 PM
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If your a pro and maxing your setup to its full capability maybe. Other then that not really.

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post #3 of 22 Old 12-03-2011, 02:36 PM
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looking at going to one eventually for weight saving. I'm not sure but have heard it changes the steering rack in relation to the a-arms to help with geometery or something like that and depending on the drop you can adjust the pivot point for the a-arms on the k-member.
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post #4 of 22 Old 12-03-2011, 03:00 PM
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Only saving like 10-15lbs going with an mm kmember vs stock.

Sure it let's you tweak it, but you won't be able to use its benefit unless ur a pro.
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post #5 of 22 Old 12-03-2011, 04:51 PM
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Lighter, more room for LT headers, two pickup points to keep the control arms at the right angle with alot of lowering, allows engine setback for better weight distribution, built in lower chassis brace for improved stiffness, they claim better suspension geometry, also allows for more caster to be set in.

To answer one of your other questions, the rack is relocated with the bushings, not the k-member itself.

I'm not sure that all these benefits are only felt by pros. I did a bunch of stuff to my car at once so I don't have any before/after feedback to give on what the k-member alone did for my car.

Last edited by MJ91GT; 12-03-2011 at 05:37 PM.
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post #6 of 22 Old 12-05-2011, 11:49 PM
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MM is much better than the stock one! im about to order mind soon

lighter
stronger
better geometry
much more front grip
more room
u can mount a arms 1 inch higher or 2 inches higher enabling u to lower ur stang and still have a arms parellel to the ground

lowering a stang with stock k member makes everything worse

uh u can set engine back an inch (better weight distrubution)
standard offset a arms with mm k member pushes wheels 3/4 of and inch forward (again better weight distrubution and balance)

MM knows what they are doing,

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post #7 of 22 Old 12-06-2011, 08:13 AM
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Not a good comparison but I will share anyway...
My track car had a stock k and arms (SLA now) my street car has mm k, stock offset arms. Wheel rates are comparable. Track car has a more aggressive alignment. The street car has WAY more front grip. This is certainly not a fair comparison but I feel that the geometry of the mm k helped alot.
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post #8 of 22 Old 12-06-2011, 02:18 PM
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Quote:
Originally Posted by Apocolipse
If your [sic] a pro and maxing your setup to its full capability maybe. Other then [sic] that not really.
Quote:
Originally Posted by Apocolipse
Sure it let's [sic] you tweak it, but you won't be able to use its benefit unless ur [sic] a pro.
Do you have some lap time data to back that up? It doesn't take a pro driver to realize that the stock front suspension doesn't allow for enough static negative camber, doesn't allow for enough positive caster, has a poor camber curve, crappy bumpsteer, etc.

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post #9 of 22 Old 12-06-2011, 02:39 PM
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Im assuming that you already have the coil overs and tubular A arms so why not go for the K member too? Ya its expensive, but it looks bad ass! plus all that stuff said above.. lol
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post #10 of 22 Old 12-06-2011, 02:42 PM
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For classes where an aftermarket K member is not permitted, the stock K member can be modified to behave similar to the MM unit:

Improve roll center / camber curve:
- raise A arm pickup points 1 to 2 inches (requires some fabrication)
- 2 inch racecraft drop spindles

Improve caster:
- forward offset A arms (in combination with caster-camber plates)

Adjust Ackerman:
- fwd offset A arms with steering rack bushings of variable thickness

Maybe that's what he meant?


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post #11 of 22 Old 12-08-2011, 06:53 PM
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Quote:
Originally Posted by Patrick Olsen View Post
Do you have some lap time data to back that up? It doesn't take a pro driver to realize that the stock front suspension doesn't allow for enough static negative camber, doesn't allow for enough positive caster, has a poor camber curve, crappy bumpsteer, etc.
So lets compare here.

This is assuming the ONLY difference is the k-member + arms.
Compare a car with the same bumpsteer kit, c-c plates, coil overs, etc. I am not comparing stock to modified MM full suspension.

The difference between the 2 k-members:

-MM allows for a few extra degrees of caster (due to forward offset)
-MM locates the arms 1-2" higher then stock to enhance the camber curve
-10lbs weight difference

That's about it. Oh plus a nice $700 price tag.

So are you trying to say that a moderate level driver can tell between 5 and 7deg of caster? And the difference of maybe 1-2deg extra of use-able neg camber in the compression curve due to the higher arm mounts?

I don't think, so but that's me.

Also the MM is not "stronger" than the stock k-member.

I also do not want you to think I am bashing MM... because I am not. Their stuff does what they design it for... and that is used by professionals.

I have a lot of MM suspension parts and they work amazing.

Now...

If you want added caster, run forward offset arms from MM on your stock K.
Want more camber in the compression curve? Dial in more static camber with the plates (I know its not the same through the curve... but you get where I am going)

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post #12 of 22 Old 12-08-2011, 09:20 PM
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I've recently went from stock to MM k-member on my 94. I will honestly say that the k-member was worth every single dollar, including the installation. No matter how aggressive you can get with alignment and whatever, the k-member enhances it that much more. It relocates the rack back quite a bit more than possible with the stock k-member. The control arm pivot points are moved up significantly more too, well past what's possible on stock k-member.

Finally, the new k-member is much stiffer than the old one. I can tell that because once it has been installed, suspension started to work a lot better. Before, it used to kinda just skip around over bumps, not really contouring the surface. Now that the front end is stiffer, it no longer flexes under such driving surface, and makes the control arms do the work, not the chassis flex. The front end over bumps is much more stable and conforming. That's defintely the testiment of the MM k-member rigidity.

The grip level has improved quite a bit. In slow tight corners where it used to push and overpower the front tires, it grips pretty hard now, which is most welcome. The best way I can put it, is the difference I felt when I switched over to torque arm setup. Car just bites and goes. I still have some understeer at higher speeds, but I think it's mostly the weight distribution that is to blame. Stock all cast iron engine leaves me still at 57/43, which is a nightmare. Nothing trick suspension can do about that, other than take away grip from the rear to make the car more balanced.

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post #13 of 22 Old 12-09-2011, 10:25 AM
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Originally Posted by ReplicaR View Post
I've recently went from stock to MM k-member on my 94. I will honestly say that the k-member was worth every single dollar, including the installation. No matter how aggressive you can get with alignment and whatever, the k-member enhances it that much more. It relocates the rack back quite a bit more than possible with the stock k-member. The control arm pivot points are moved up significantly more too, well past what's possible on stock k-member.

Finally, the new k-member is much stiffer than the old one. I can tell that because once it has been installed, suspension started to work a lot better. Before, it used to kinda just skip around over bumps, not really contouring the surface. Now that the front end is stiffer, it no longer flexes under such driving surface, and makes the control arms do the work, not the chassis flex. The front end over bumps is much more stable and conforming. That's defintely the testiment of the MM k-member rigidity.

The grip level has improved quite a bit. In slow tight corners where it used to push and overpower the front tires, it grips pretty hard now, which is most welcome. The best way I can put it, is the difference I felt when I switched over to torque arm setup. Car just bites and goes. I still have some understeer at higher speeds, but I think it's mostly the weight distribution that is to blame. Stock all cast iron engine leaves me still at 57/43, which is a nightmare. Nothing trick suspension can do about that, other than take away grip from the rear to make the car more balanced.

very nice real world experience. hope when i get mine on i feel the same way. i take you've driven your car on the street pretty frequently? unlike other manufacturers of aftermarket k's, how's it holding up to the stress of potholes, and road imperfections? i assume you check your suspension every so often to make sure there's no stress cracks, or if its powdercoated any spider webbing?

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post #14 of 22 Old 12-09-2011, 10:31 AM
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Originally Posted by 87Fox5.0 View Post
For classes where an aftermarket K member is not permitted, the stock K member can be modified to behave similar to the MM unit:

Improve roll center / camber curve:
- raise A arm pickup points 1 to 2 inches (requires some fabrication)
- 2 inch racecraft drop spindles
i'm glad you brought this up as i'm on the fence about the racecraft drop spindles. with the ability to raise and lower the mounting points of the A arms, does that mean that the spindles are now not necessary? i wanna put my put my car back to stock suspension height geometry, but would still like to have the body lowered.

1990 LINCOLN MARK VII SE
OLD COMBO- STOCK 302 WITH 1500 KB ON TOP.

IN THE WORKS- D.S.S. 331, AFR 185'S(FULLY WORKED OVER), EXTRUDE HONE GT40 LOWER, 2200 KB, 75MM TB AND SPACER, 4IN AFM POWER PIPE, 80 MM MAF, FRPP 1 5/8 UNEQUAL LENGTH HEADERS, MAGNAFLOW X PIPE, MAGNAFLOW MUFFLERS, CUSTOM 2 1/2 EXHAUST ALL THE BACK FROM X PIPE TO TAILS, MSD ELCTRONICS, AND AEROMOTIVE SYSTEM.

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post #15 of 22 Old 12-09-2011, 10:52 AM
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very nice real world experience. hope when i get mine on i feel the same way. i take you've driven your car on the street pretty frequently? unlike other manufacturers of aftermarket k's, how's it holding up to the stress of potholes, and road imperfections? i assume you check your suspension every so often to make sure there's no stress cracks, or if its powdercoated any spider webbing?
My car is mostly a daily driver that I take to the track pretty often. I've got 226k miles on it, and drive abou 25k a year. Honestly MM stuff is rock solid. Its heavy as hell by comparison to other manufacturers, but it puts up with my daily commute like a champ, and that's saying a lot since I live in LA, which has aweful roads. I have full faith in any component of my vehicle. Maybe that's me being a bit naive, but it also allows me to go fast

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post #16 of 22 Old 12-09-2011, 12:04 PM
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next to buy: MM front swaybar, MM bumpsteer conversion kit, MM k member

im excited !

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post #17 of 22 Old 12-09-2011, 12:13 PM
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i'm glad you brought this up as i'm on the fence about the racecraft drop spindles. with the ability to raise and lower the mounting points of the A arms, does that mean that the spindles are now not necessary? i wanna put my put my car back to stock suspension height geometry, but would still like to have the body lowered.
You can do one or both. Better to do both if your car is really, really low. But just doing the drop spindles alone is a compelling improvement over stock.

Just FYI, if you do get the racecraft units, make sure to get the ROADRACE version. It is more expensive. It has extra welds and re-inforcement which supposedly make them stronger. They are non-powdercoated. The standard (DRAG RACE) units are known to separate, leading to potentially catastrophic consequences. Search google or c-c.com, e.g. Racecraft Mustang Drop Spindle Review - Page 5 - Corner-Carvers Forums

At SCCA nationals this year there was a CP Mustang with racecraft spindles (reportedly an older version of them) where the left front spindle separated from the backing plate while on course and his wheel/tire was rolling all over the place; luckily nobody got hurt, but of course the car did not look pretty afterward.

I personally do use racecraft spindles (the updated, revised, non-powdercoated ROAD RACE units with extra welds/reinforcement, which as far as I know no reports of breakage thus far) only on my autocross car (which is not street driven at all and never taken on a road course), and I personally would not use them on a street car or road race car, EVER, PERIOD, even if you paid me a million BUCKS. PERIOD. This is just my opinion and probably being overly cautious, but take it or leave it. There are plenty of guys that do use them on the street or road course with good results. And if you do take a chance on these you better damn well inspect them frequently and religiously for cracks or signs of separation.

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Last edited by 87Fox5.0; 12-09-2011 at 05:25 PM.
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post #18 of 22 Old 12-09-2011, 12:29 PM
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When using Racecraft spindles with the MM-k you may not be able to set proper bumpsteer as there can be wheel interference.
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post #19 of 22 Old 12-10-2011, 07:43 AM
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MM's race car, 96- 04 spindles, No need to drop spindles. With the mm k member u can do a 2 inch drop from the location of the a arms

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post #20 of 22 Old 12-10-2011, 10:23 PM
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I just came back from the first track day since I've installed the k-member. The difference is very noticeable. Pretty much everywhere the car used to understeer, it grips pretty hard now. Feels like a completely different car now, love it. Still some understeer if I REALLY overdrive it, my guess mostly due to weight distribution. I am very impressed. Can't wait to get some weight off the front, and go even faster still.

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post #21 of 22 Old 12-12-2011, 10:22 AM
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repR what swaybar are you using up front?

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post #22 of 22 Old 12-12-2011, 05:08 PM
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stock SN95 GT

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