MM IRS Bushings

[Pure Vennom]

I put on a MM Polyurethane IRS Subframe Bushing Kit. MM claim the polyurethane bushings in this kit are considerably less compliant than the stock rubber IRS subframe bushings. These stiffer bushings virtually eliminate displacement of the IRS subframe relative to the chassis. They say it reduces wheel hop during acceleration, braking and cornering however I haven't really seen any difference in the performance. The Kit is not very expensive but a real hassle to put on.

I thought I would give it a try but I still have significant wheel hop. No real improvement.

Anyone else use this kit successful?

 

[vector]

most seem to do the IRS mm bushings and steeda diff bushings and replace the 12mm bolts with 14's these will help to minimize wheel hope but not get rid of it.

 

[toofast4u]

Did you replace your stock 12mm bolts with the correct 14mm bolts? If you didn't that is your problem.

 

[vipergts281]

What bolts are you guys referring to? Does every Cobra have the 12mm bolts? Where do I look for them on my car?

Thank You.

 

[vector]

i think they are the front bolts for the IRS

 

[toofast4u]

Originally posted by vipergts281
What bolts are you guys referring to? Does every Cobra have the 12mm bolts? Where do I look for them on my car?

Thank You.

They are the front bolts of the IRS assembly. Every 03 Cobra I have heard of has the 12mm bolts. The 99-01 Cobra have the correct 14mm bolts.

 

[postban]

Originally posted by Pure Vennom
...snip...

Anyone else use this kit successful?

no joy here, negligible effect.

 

[Black2003Cobra]

I have both the MM IRS bushings and Steeda diff bushings and still have some wheel hop. It did help, but it didn't totally eliminate the problem. I'm going to try Cobra R shocks and springs, next.

 

[vipergts281]

Originally posted by toofast4u
They are the front bolts of the IRS assembly. Every 03 Cobra I have heard of has the 12mm bolts. The 99-01 Cobra have the correct 14mm bolts.

Thanks for the replies.

Does anyone happen to have a pic of where these bolts are though, I have no clue about the IRS.....I'm used to solid axle.

Thanks.

 

[Black2003Cobra]

toofast has a picture. Maybe he'll post it. The ones in the front are the 14 mm.

 

[Black2003Cobra]

actually, i found it. here it is. The red circles are where the IRS bushings are.

 

[toofast4u]

Originally posted by vipergts281
Thanks for the replies.

Does anyone happen to have a pic of where these bolts are though, I have no clue about the IRS.....I'm used to solid axle.

Thanks.

Even easier. The bolts are in the torque boxes where the lower control arm normally connects to the chassis with a solid axle.

 

[vipergts281]

Thanks everyone.

 

[toofast4u]

Here are the description for the picture above.
The red circles are the IRS assembly bushings. Sold by MM and SHM
The green circles are the crossmember #4 pinion differential bushings. Sold by Steeda and Kenny-Brown
The blue circles are the LCA bushings. Sold by Griggs Racing

 

[vipergts281]

So can I just pick up 14mm bolts at a Pep Boys or something. What about from Ford?

 

[toofast4u]

Originally posted by vipergts281
So can I just pick up 14mm bolts at a Pep Boys or something. What about from Ford?

No buy the Ford parts or they will fail. Maximum Motorsports also sells them for like $10/pair with bolts and nuts.

 

[3Pete]

I tried many diferent spring/shock combos on my 99, 01 and now 03 Cobra. The only shock that really fixed the hop were the HAL/IPS 12 way adjustables I used on my 99 Cobra. With the 14 mm bolts, MM subframe and Steeda Irs bushings, these shocks will do a great job of controlling hop. However the only way to eliminate hop totally is a solid rear axle.

 

[Cobra10thaniv]

Originally posted by toofast4u
Here are the description for the picture above.
The red circles are the IRS assembly bushings. Sold by MM and SHM
The green circles are the crossmember #4 pinion differential bushings. Sold by Steeda and Kenny-Brown
The blue circles are the LCA bushings. Sold by Griggs Racing

We were talking before about this stuff but I cant remember what you said if you replaced the LCA bushings with the griggs I thought you had but I know those are meant for auto cross type driving not really for street, Did they make much of a differance in you opinion when you tried them or was I mistaken and that was your next upgrade.

Since they have messed around so much with my warrenty or should say lack of I should do more of this on the car.

I have a local company I have made many of these type of bushings for machines at work. If anyone gets there hand on prints let me know. I can have them start making them for us. I can have them poured in whatever durometer we like from hard racing to the little more forgiving.

I also noticed when my rear pumkin was replace there is a rear bushing on the cover that would be nice to have harder durometer since the other front bushings I replaced by steeda ones. This place would make molds for us if they knew there was a market. I think allot more bushings in the UCA and LCA and the rear pumkin bushing would be nice to add to reduce the hop.

Just thinking out loud.

 

[toofast4u]

Originally posted by 3Pete
However the only way to eliminate hop totally is a solid rear axle.

I don't experience any more hop with my set-up today then I did with a solid in my 95 Cobra. I have no desire or intentions to go back to solid. The only way I would ever put a solid back in my car is if it was a dedicated drag car and I would also replace the T-56 for a C-4 at the same time. In addition to your list I have 00R shocks and 650# coil-overs on my car with Nitto555R 315 tires.

 

[toofast4u]

Originally posted by Cobra10thaniv
We were talking before about this stuff but I cant remember what you said if you replaced the LCA bushings with the griggs I thought you had but I know those are meant for auto cross type driving not really for street, Did they make much of a differance in you opinion when you tried them or was I mistaken and that was your next upgrade.

I haven't done the rear LCA bushings yet. I am waiting to see what MM is coming out with they are suppose to have a replacement LCA and UCA bushings soon. These are more for autocross then drag racing use. Specifically they help in cornering and reduce rear steer.