Subframe Bushings NVH

[autoracer86]

So my superpro subframe bushings have arrived. When looking up install videos I saw a few comments saying they are very harsh.
I was a bit surprised by this as they were recommended to me by a friend who is NVH conscious. Oh and it also looks like the install is a real PITA

So for the people running subframe bushings how bad are they ?

Any install tips ?

Thanks

Note should be the same as Whiteline Positive Traction kit (KTD922)

[strat61caster]

Alone no big deal. Combine with other stiffer bushings and the effect adds up quick.

[StraightOuttaCanadaEh]

I have the whiteline inserts, not the full bushing replacements, and there was only added harshness over bumps. No noise or vibration

[autoracer86]

Originally Posted by StraightOuttaCanadaEh

I have the whiteline inserts, not the full bushing replacements, and there was only added harshness over bumps. No noise or vibration

That is more or less what I got. Good to know thank you

[Spawn_Of_Creation]

I had only the diff insert bushing, and basically no increase in nvh, but definitely improvement in feel. Once i added in the subframe bushing, it added in a lot of nvh but only a slight increase in feel. At the same time i did the subframe bushings, i did some lift spacers too, so comparison isn't 1:1.

[new2subaru]

I didn't have any NVH when I did the whiteline subframe inserts but when I added the diff bushings it increased. I removed the front diff bushings only and it was fine, for me.

[autoracer86]

Originally Posted by new2subaru

I didn't have any NVH when I did the whiteline subframe inserts but when I added the diff bushings it increased. I removed the front diff bushings only and it was fine, for me.

Yes this was a tip given to me by a friend. So far all I installed was the rear diff inserts. I have no plans to do the front diff bushings.

So far I am loving the rear diff bushing inserts. I didn't think it would have such a big impact on my enjoyment level when driving the car.

Subframe bushings next then TRD trans and motor mounts

[Ohio Enthusiast]

Originally Posted by new2subaru

I didn't have any NVH when I did the whiteline subframe inserts but when I added the diff bushings it increased. I removed the front diff bushings only and it was fine, for me.

Originally Posted by autoracer86

Yes this was a tip given to me by a friend. So far all I installed was the rear diff inserts. I have no plans to do the front diff bushings.

I read the same advise and followed it out of necessity (I forgot to release the handbrake and couldn't put the front diff bushings), then later added the front bushings as well. I found only the rear bushings to do too little to drivetrain lash and the front bushings were very helpful with eliminating it. These were the last bushings I put on the car and I agree that each bushing alone doesn't change NVH all that much, but they do add up. I love the mechanical NVH it adds.

[Capt Spaulding]

A couple of things. First, as others have said, the diff inserts do a lot to reduce drive train lash and "wind up." I have the subframe inserts in my "project" box in the garage, but have not yet persuaded myself they are worth doing.

When I was closer to doing the subframe, I took note of the number of people who have had problems with the subframe bolts cross threading on reinstallation. I looked closely at the installation and concluded that the cross threading problem is caused or at least exacerbated by doing the two ends of the subframe in isolation.

When you install the subframe inserts, you support the subframe assembly on a jack. If you snug the jack up, remove the front or rear bolts alone and the lower the jack a bit you can get the inserts in. But because they add thickness to the mount, and the rear of the assy is still bolted to the car they add a small amount of angle to the whole assy. When you try to reinstall the bolts, that added angle will try to cant the bolts slightly. Thus, the cross threading.

My advice is to support the assy with the floor jack, loosen (but do not remove) ALL the bolts about half way, lower the jack slightly, remove one set of bolts, install the inserts, then hand thread that set of bolts in 1/2 to 3/4ths of the way. Do the same thing for the remaining inserts, then raise the jack until the mounts are just touching the frame and hand tighten ALL the bolts as much as possible, then raise the jack to fully support the assy against the frame and torque the bolts.

[autoracer86]

Originally Posted by Capt Spaulding

A couple of things. First, as others have said, the diff inserts do a lot to reduce drive train lash and "wind up." I have the subframe inserts in my "project" box in the garage, but have not yet persuaded myself they are worth doing.

When I was closer to doing the subframe, I took note of the number of people who have had problems with the subframe bolts cross threading on reinstallation. I looked closely at the installation and concluded that the cross threading problem is caused or at least exacerbated by doing the two ends of the subframe in isolation.

When you install the subframe inserts, you support the subframe assembly on a jack. If you snug the jack up, remove the front or rear bolts alone and the lower the jack a bit you can get the inserts in. But because they add thickness to the mount, and the rear of the assy is still bolted to the car they add a small amount of angle to the whole assy. When you try to reinstall the bolts, that added angle will try to cant the bolts slightly. Thus, the cross threading.

My advice is to support the assy with the floor jack, loosen (but do not remove) ALL the bolts about half way, lower the jack slightly, remove one set of bolts, install the inserts, then hand thread that set of bolts in 1/2 to 3/4ths of the way. Do the same thing for the remaining inserts, then raise the jack until the mounts are just touching the frame and hand tighten ALL the bolts as much as possible, then raise the jack to fully support the assy against the frame and torque the bolts.

Oh I have notes on notes on notes for doing the subframe bushings they don't seem to hard after you read all the tricks

thanks for sharing yours as well

[Capt Spaulding]

Originally Posted by autoracer86

Oh I have notes on notes on notes for doing the subframe bushings they don't seem to hard after you read all the tricks

thanks for sharing yours as well

Those bolts have caused more than their share of tears. Glad you’re up to date. Good luck.

[NoHaveMSG]

I cheated and used a forklift

If you are just doing inserts, it's not difficult as Capt outlined. My recommendation is to loosen the subframe down on to stands so that it is even. The stock bushing has a pretty hard metal inner sleeve. I suspect people that are not keeping the subframe even are flattening the threads binding against them.

[Spuds]

I just did this. As others have said, loosen all the subframe bolts just a bit first. I didn't and got lucky, but the left rear did not go back in easy. I loosened all bolts afterwards and used a rubber mallet to nudge the subframe into alignment. Doing this first would have been better.

[autoracer86]

Thanks all. This is very helpful. I ordered the TRD motor and trans mount today as well. That should be it for mounts on this build I think