Subframe mounts/bushings

[MFKN3]

Thought this might help some others.

After having trouble with my alignment deteriorating at the track and trouble holding corners, my workshop has identified my subframe bushings are the problem. It was so bad I could see the incorrect toe in the back wheels after just a few runs. I'm stroked and supercharged and the power has caused them to wear out. My car is also very low milage, so it's a surprise.

Going to install solid mounts now. Just a heads up for anyone else who are tracking and/or have a lot of power.

[roastbeef]

That's kinda weird. It seems like the four bushings would sort of center themselves. I didn't think it could get that much out of wack.

[Pistonheed]

BMW upgraded to solid subframe bushes for the M3 GTS so I'd say this mod is a no brainer and one that doesn't have any negative affects.

[Rassilon]

Might be useful if you put a gopro under there and take a video to see how much subframe moved. It wasnt mustang bad under stock power IIRC but there is definitely movement in the subframe.

[rzm3]

How many miles do you have?

[roastbeef]

Originally Posted by edwardgtxy

Might be useful if you put a gopro under there and take a video to see how much subframe moved. It wasnt mustang bad under stock power IIRC but there is definitely movement in the subframe.

did you see the vid i made?

[Redd]

Even without a supercharger or track work, solid rear subframe bushings are a great mod with zero negative effects (other than money lol)

[Rassilon]

Originally Posted by roastbeef

did you see the vid i made?

Yea, but since OP has SC, I am curious if it's a lot worse.

[Bx Tpr]

Originally Posted by roastbeef

did you see the vid i made?

RB was that with oem subframe and diff bushings?

[roastbeef]

Originally Posted by edwardgtxy

Yea, but since OP has SC, I am curious if it's a lot worse.

i don't think it is necessarily worse with a supercharger, and here is my reasoning. these bushings (any bushings) are going to flex until they reach their limit of flex against the bushing housing/etc. and that is about what you're seeing in the video. the bushings are only going to flex until their limit and then the tires are going to break loose and the tension is going to be relieved. if it only takes 300 ft/lbs of torque to bring the bushings to their flex limit, 500 ft/lbs isn't going to flex them more, you're just going to exceed the traction of the tires sooner.

[roastbeef]

Originally Posted by Bx Tpr

RB was that with oem subframe and diff bushings?

yes sir. go look under your car and observe the subframe and everything attached to it. then watch the video again. you'll be surprised at how much that whole huge assembly is moving. that is your entire rear suspension with a bout 1/2 to 3/4" of slop. plus, the rotation of the differential contributes to less traction.

[MFKN3]

40,000km. Subframe moves and throws our rear toe, which throws out entire alignment. Happens after just a few laps around the track and culprit is worn subframe bushings/mounts apparently.