FS: Mark VIII IRS Sub-Frame Bushing Kits

DLF

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Ford has discontinued the stock bushings for the IRS Sub-Frame.

Also, from a performance perspective, the stock bushings allow too much movement of the sub-frame, which can lead to wheel hop and/or poor 60' times in high powered cars.

I am developing performance bushings made from UHMW with hardcoated aluminum spacers.

I expect the full kit of 8 bushings and 4 spacers to sell for $400 shipped (lower 48) at this point.

I plan to begin shipments of the completed kits by mid-April.

However, I am offering a $50 discount to early adopters who prepay in full prior to April 1st.

See THIS post on SCCoA for more info.

Please PM me for payment details if you are interested.
 
Here are some renderings of the bushing designs.

The first two pics are of the upper, the second two are of the lower.
 

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Will the hardcoated aluminum sleeves pass through both?

There will be a single 1.5" diameter x 3.15" long hardcoated aluminum sleeve that will go through both bushings at each position. This sleeve will accept the stock M12x1.75x129.5 bolt (which BTW, are still available form Ford for $14.33 ea. p/n N805747S100).

I am also going to provide a 1 1/2" diameter .050" thick stainless steel washer, to go between the top of the sleeve and the frame to prevent the end of the aluminum sleeve from being damaged by the irregular holes in the frame.

The stock metal brackets/plates will be reused on the bottom of the bushing/sleeve stack.

The attached pictures show the bushings (upper - lower) as they will be oriented in the car.

Trust me, J.P., I've thought this one out. ;)
 

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Trust me, J.P., I've thought this one out. ;)

Oh I trust you, no doubt you have this thought through. I was just confused by your calling the aluminum piece a "spacer". In my mind that would be called a "sleeve". ;)
 
Oh I trust you, no doubt you have this thought through. I was just confused by your calling the aluminum piece a "spacer". In my mind that would be called a "sleeve". ;)

You're right, my terminology is incorrect. :embarrassed:
 
I received the aluminum bar stock for the spacers today, so the machining starts tomorrow.

Crap! Looks like I won't get the UHMW until the 25th. :mad:
 
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Revised Upper Bushing

Revised Upper Bushing

Took some additional measurements today, and I won't need as severe a chamfer on the upper bushing as I originally thought.
 

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cool cool

cool cool

Im watching this thread too. I wanted to do an upgrade when i put in new uppers and lowers in the front and new ones for the rear carrier pumkin ect, when i switch old rear end assembly over to the new car.
I have videos of the tires actualy moving forward with slicks on it even though the wheelhop never happened for me with all the other braces. Ive always thought there is alot to be gained to eliminate "twist up and flex" before the car launches with this project.
 
Im watching this thread too. I wanted to do an upgrade when i put in new uppers and lowers in the front and new ones for the rear carrier pumkin ect, when i switch old rear end assembly over to the new car.
I have videos of the tires actualy moving forward with slicks on it even though the wheelhop never happened for me with all the other braces. Ive always thought there is alot to be gained to eliminate "twist up and flex" before the car launches with this project.

Delrin control arm bushings and these UHMW sub-frame bushings will make that all go away.... :D
 
Machining the sleeves. Takes about 1/2 hour a piece to get them to this stage, and the diameters still need to be turned. Got another 8 to go in this batch, then they're off to be anodized. :)
 

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Sleeves are done! Off to be anodized.
 

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Anyone who is considering this, may want to purchase new bolts while they're still available from Ford.

From Tousley Ford:

N805747S100 $14.33 ea.

BOLT-M12X1.75X129.5
 

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Got the UHMW stock in today.

Made the prototype upper bushing and it fits just as I designed. I'm quite happy with it.

Tomorrow I'll make the prototype lower, and then start making a few sets.

Reminder: There are 6 sets in this batch and 3 are already spoken for.
 

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