SCUI Competition IRS suspension bushing kit production run and pre-sale.

XR7 Dave

Registered User
SCUI is once again offering competition suspension bushing kits for the IRS in T-birds and Mark VIII's. The bushings are non-compliant, high density, high strength competition material. These bushings do not give way under conditions of cornering or acceleration, thereby essentially eliminating wheel hop and other undesirable rear suspension movement without binding or materially stiffening the rear suspension or limiting it's travel or movement. We introduced this kit last year with the understanding then that it was a new product (at least to the MN12 world), and that real world experience of a non-compliant suspension system might have both positive and negative impacts. It's now been over a year that these systems have been in use on various member's vehicles and we now have a more comprehensive understanding of how they perform, both good and bad.

Ride harshness is slightly increased. It is slightly noticeable but for someone pushing the boundaries of performance with this chassis, the result is entirely streetable both for occasional use as well as continual or long term use. You will notice a difference. I don't believe you'll mind.

Road noise is not noticeably increased. All the vehicles I'm aware of that has these suspension components also have other noise making modifications so any change in NVH is essentially unnoticeable. In a stock SC, you might notice!

Due to the clearances and the non-compliant nature of the bushings, you may hear a slight "clunk" as you transition from forward-reverse or in a parking lot situation. This is normal, and this is one reason why the OE uses rubber.

The bushings can be installed dry but they may squeak if you do so. We recommend using a silicone based synthetic caliper type grease during assembly to minimize any squeaks.

Because the bushings are non-compliant, damage may result from impact. It is essential that the user be aware of the conditions they are driving in and take necessary measures if they hit something or might have reason to think that something may have happened. Operator responsibility is increased when using these type of bushings.

It is possible to wheel hop with these bushings in place. Nothing is bulletproof, but these are the best thing available to combat the problem.

That all being said, we are gearing up to produce these again, offering two kits, one for Mark Viii control arms and one for cast steel SC control arms. No bushings will be made for the old stamped steel arms, as they are imprecise and flexible. Any performance application needs be using either the cast steel arms or the Mark Viii arms.

From an install perspective, these are a 7-8 difficulty. If you haven't done suspension work and/or aren't familiar with the process of pressing in and out the old bushings, then this install is above your head. The install of the new bushings is easy. Removing the old ones is not. Just an FYI.

That being said, the kits will be ordered in two weeks, with a 5 week lead time for shipping. Cost is $650 shipped for a complete kit in the lower 48 states. We will require a minimum non-refundable $200 deposit by the cutoff date with the balance due prior to shipping. Any questions, just ask!

SCUI Bushings.jpg
 
Dave, does this kit include the bushings for the front ears of the differential? If not, what do you recommend that will perform well with this kit?
 
Dave, does this kit include the bushings for the front ears of the differential? If not, what do you recommend that will perform well with this kit?

With this setup I used stock replacement bushings for the center section and flipped the the cups on all 4 IRS mounts (large washers/cups on the 4 IRS mount bolts) , no longer had any wheel hop, even when spinning 28" Hoosiers at the track and the car handled way better on the street.
 
Dave, does this kit include the bushings for the front ears of the differential? If not, what do you recommend that will perform well with this kit?

It does not include diff mounts. As Paul said, stock mounts are fine, as are the Energy Suspension ones you can buy at AZ or SCP. We considered making bushings for the diff, but my concern is that as you remove compliance in the system you increase shock loads on hard parts. The purpose of this kit is to minimize wheel hop, not necessarily to take out all compliance from the system.
 
It does not include diff mounts. As Paul said, stock mounts are fine, as are the Energy Suspension ones you can buy at AZ or SCP. We considered making bushings for the diff, but my concern is that as you remove compliance in the system you increase shock loads on hard parts. The purpose of this kit is to minimize wheel hop, not necessarily to take out all compliance from the system.

I am interested in a Mk8 and t-bird set if it is not to late.
Also could you list the contents of the kit?
 
Update:

After some delays with the machine shop, production is underway. I realize this makes for a rather long wait for some, hopefully it's not too big an inconvenience. I'm hoping for about 2 weeks to ship.

I had a couple extra kits made, so if someone is just seeing this now, you might be able to get one still. Email me for details.
 
For those who have been anxiously waiting, these bushings are in stock ready to ship. I'm sending out emails today to let everyone know balances and confirm shipping addresses. :)
 
Back
Top