Steeda S550 IRS Differential Bushing Inserts

[EditorTurner]

Plug and Stay
Steeda Autosports offers a bolt-in solution for taming your S550’s Super 8.8
By Steve Turner
Photos by Steve Turner and courtesy of Steeda Autosports

The 2015 Mustangs are impressive machines. Ford engineers really brought the handling of these pony cars up a notch with a double ball joint front suspension and an independent rear suspension. However, we know all to well that those clever engineers have to strike a balance between ride quality and performance.
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[SID297]

That comparison video is pretty good.

 

[RSKtakR]

To bad the installation instructions just SUCK, and I'm not sure how a person is supposed to get the bushings into the front with the washer and bolt (let alone a torque wrench) without having to drop the rear of the sub frame too. Here is a pic of the MAYBE 1/2" gap I have between the gas tank and the front bushing (yes this is the correct bushing too). Both front sub frame 21mm bolts are complexly removed as well as the four 13mm bolts, there is about a 2" gap between the sub frame and the body of the car as I am taking this pic.

 

[SID297]

That looks pretty tight.

 

[shftn6]

To bad the installation instructions just SUCK, and I'm not sure how a person is supposed to get the bushings into the front with the washer and bolt (let alone a torque wrench) without having to drop the rear of the sub frame too. Here is a pic of the MAYBE 1/2" gap I have between the gas tank and the front bushing (yes this is the correct bushing too). Both front sub frame 21mm bolts are complexly removed as well as the four 13mm bolts, there is about a 2" gap between the sub frame and the body of the car as I am taking this pic.

I just pulled down on the IRS and was able to get the bolt in. I do agree the instructions were confusing. I had no idea they were just going over the stock bushings until I actually read instructions and started putting them on.

 

[gqneon]

So wait, these don't replace the factory bushing, they're just inserts that fill the voids in the stock rubber ones? Sort of like the Whiteline and Steeda MT-82 trans mount inserts? Hmm. Was thinking this was a painless install when I read the sales pitch, but that picture of the clearance issue tells stories of aggravation to come.

Did you ultimately get them in? What do you think of the work vs reward with this setup? I see you're using the aluminum inserts, I was thinking the black poly ones.

Let me know!

 

[dwaleke]

I just put these in last weekend. I went with the black 90 durometer poly inserts.

Install is a bit tricky with the exhaust in place. And I had to loosen the rear cradle bolts along with taking out the front cradle bolts completely. And disconnect the rear shocks so the cradle can come down far enough. The front bushings are the most difficult, but once you get past that it's not bad.

There is an increase in NVH from these. Mostly notice is when turning at slower speeds, but you hear more gear whine from the rear end also. If you have the radio up or loud exhaust you may not notice. Steeda also has the red inserts that are 80 durometer. Not sure how those would be. Better obviously, but I bet still an increase in NVH.

The biggest change I notice is my rear tires (285/35-20 BFG Rivals) spin a lot more than the rear end hopping. These definitely make a positive impact in this regard. So for now I will leave them in.

 

[gqneon]

Sounds like it was worth the time to install them to me. Wheelspin is wheelspin. Wheel hop, on the other hand, is bad bad bad. It seems like everything that says "absolutely no added NVH" always has some, so I kind of wondered.

Maybe when I swap my half shafts and driveshaft I'll do a set of the red or black ones then, where it will be almost part of the process

 

[dwaleke]

I love the improvement in wheel hop that's for sure.

If anyone is on the fence between the red and black and is concerned about NVH I will say install the red.

I just drove to work and back (80 miles) and the gear noise is definitely increased with the black. Don't use the black if you want your drivetrain to be quiet.

 

[RSKtakR]

I got mine installed the next day, just have to give them a couple "taps" to get them in.. I have the aluminum ones. There is no clunking, no other noises.. .the only things I noticed is the gear whine (that I don't care about), and the tire hop is gone... car squats and GOES.

 

[dwaleke]

What model car do you have? Do you have the Torsen Diff?

 

[gqneon]

What model car do you have? Do you have the Torsen Diff?

I also would like to know. I think the housing is all the same though, so install should be identical. Debating on this or the MBR bolt on deal.

 

[RSKtakR]

I have the PP car (if you were asking me).

 

[dwaleke]

I also would like to know. I think the housing is all the same though, so install should be identical. Debating on this or the MBR bolt on deal.

I was asking since he said he has no noises back there other than gear whine. Mine clunks and pops at slow speeds mostly when turning. Was thinking it was the torsen, but if he has the torsen and no noises then it must be something else.

 

[gqneon]

I was asking since he said he has no noises back there other than gear whine. Mine clunks and pops at slow speeds mostly when turning. Was thinking it was the torsen, but if he has the torsen and no noises then it must be something else.

I have the torsen and noted it has a clunk that scales with speed when turning, but only when the clutch pedal is pushed in and only noted it during low speed turning. Performs properly though, so I'm thinking its a design issue. My front suspension pops a little when I turn hard into drive way and there's a short incline, with stock suspension. Seems normal but I don't know about from the rear.

 

[RSKtakR]

I still have no noises or popping or anything of ANY kind, just the gear whine on the hwy in 6th around 1750 rpms. I can also hear the diff "whiring" back there as I get into it. Other then that, ZERO noise with the Torsen. Maybe mine is F'd up because its NOT making those noises ?? lol

 

[gqneon]

I just put these in last weekend. I went with the black 90 durometer poly inserts.

Install is a bit tricky with the exhaust in place. And I had to loosen the rear cradle bolts along with taking out the front cradle bolts completely. And disconnect the rear shocks so the cradle can come down far enough. The front bushings are the most difficult, but once you get past that it's not bad.

There is an increase in NVH from these. Mostly notice is when turning at slower speeds, but you hear more gear whine from the rear end also. If you have the radio up or loud exhaust you may not notice. Steeda also has the red inserts that are 80 durometer. Not sure how those would be. Better obviously, but I bet still an increase in NVH.

The biggest change I notice is my rear tires (285/35-20 BFG Rivals) spin a lot more than the rear end hopping. These definitely make a positive impact in this regard. So for now I will leave them in.

How's the long term liveability with the black inserts you went with? Did you end up swapping them or leaving the black ones in?

I just pulled down on the IRS and was able to get the bolt in. I do agree the instructions were confusing. I had no idea they were just going over the stock bushings until I actually read instructions and started putting them on.

Did you go aluminum, black or red on your install? How long total did your install take you with these? Considering purchasing them to go with my Cradle Lock Out kit since I'll be under the car a while anyway.

I got mine installed the next day, just have to give them a couple "taps" to get them in.. I have the aluminum ones. There is no clunking, no other noises.. .the only things I noticed is the gear whine (that I don't care about), and the tire hop is gone... car squats and GOES.

So long term are you happy with these? Are you still running the aluminum? Do you have any noise vibration or harshness noticed with them other than 6th gear gear whine and a little whirring noise under load?

I'm tempted to go red or aluminum and skip the black entirely, if I can get more performance for similar or less NVH.

 

[RSKtakR]

How's the long term liveability with the black inserts you went with? Did you end up swapping them or leaving the black ones in?




Did you go aluminum, black or red on your install? How long total did your install take you with these? Considering purchasing them to go with my Cradle Lock Out kit since I'll be under the car a while anyway.




So long term are you happy with these? Are you still running the aluminum? Do you have any noise vibration or harshness noticed with them other than 6th gear gear whine and a little whirring noise under load?

I'm tempted to go red or aluminum and skip the black entirely, if I can get more performance for similar or less NVH.

YES I AM!.. still no noises other than what I stated, no vibrations or anything. If I didn't say it before I installed these aluminum diff bushings, the Steeda shifter bracket and Steeda sub frame alignment pins all at the same time right after putting 10" wide wheels with MT 305/35R19's on the car. Still hooks damn good, no more noises (other then what I mentioned before), and no new clunks or anything.

 

[gqneon]

Has anyone else installed the aluminium version of these? If they don't add NVH im thinking about going aluminum. How loud is the gear whine? Loud, moderate, or hard to hear? Is it only at highway cruising speeds or is it all the time?

 

[dwaleke]

I pulled the black ones out. Too much gear whine and other noises with them in. Pulled them out and everything is quiet again.