[DigitalPunk]

I am dropping my subframe to do the reinforcement kit and was thinking i should replace the subframe bushings also. I am also doing the rtabs with shims,

This is a mostly street car that I do drive pretty hard, specially when I go hit the twisties on the mt passes.

I was looking at the Grand Am Cup Subframe Bushing Kit form turner motor sports but I am not sure how they will be for a DD car.

What do you guys htink? Stock or Grand Am Cup Subframe Bushing Kit?

Heres ia link to their kit.

http://www.turnermotorsport.com/html..._ID=TDR4680001

[DigitalPunk]

Or any recommendations for other bushings you would use?

[DigitalPunk]

or how about powerflex subframe bushings?

http://www.horsepowerfreaks.com/part...Subframe/14843

They have some Yellow polyurethane bushings that are suppose to be for street use.

Anyone help???

[nrubenstein]

LOL.

Delrin subframe bushings are a bad idea, unless you want to inspect for cracks at the mounting points every day. On top of that, you will hear an ENORMOUS amount of noise transmitted to the cabin.

As for the powerflexes, I'm not really sure what the point is. The stock bushings last a long time and work well. While I haven't seen much on the E46 pflex subframe bushings, there is a long history of trouble with the E36 ones.

[DigitalPunk]

Originally Posted by nrubenstein

LOL.

Delrin subframe bushings are a bad idea, unless you want to inspect for cracks at the mounting points every day. On top of that, you will hear an ENORMOUS amount of noise transmitted to the cabin.

As for the powerflexes, I'm not really sure what the point is. The stock bushings last a long time and work well. While I haven't seen much on the E46 pflex subframe bushings, there is a long history of trouble with the E36 ones.

You still have to check for cracks even with the reinforcement kit?

Every thing I have read (Inducing turner motor sports website) says that soft mounts cause cracking and solid mounts will help prevent it. I may have misunderstood stood them though.

As for sound, not a big deal to me. I use to drive around a gutted 700hp turbo charged drag car I built. I like to feel the road anyways. Not a Cadillac its a performance car after all :-)

And I figure why not replace them with something better and more solid since I already have the sub frame out? Not like its gonna be coming out again for the life of the car (Hopefully) so this may be my only chance to do it. I am doing all the other bushings too.

How come that's funny? I am confused.

Any one have any recommendation on improving the bushings???

[DigitalPunk]

From Turner motor sports website

""Any subframe work or reinforcement project on the rear of the E46 M3 should include a new set of subframe mounts. It's the worn rubber bushings that contribute to failed rear subframes on the E46 (but not the only reason). As the rubber gets worn, there is more flex to the mount. This flexing is then transferred to the sheetmetal in the floor where the spot welds will pop and the sheetmetal will crack. Additional force coming from stiffer suspensions and stickier tires will only increase the flexing of the mounts/chassis.

Of course, stiffer mounts would help prevent this problem but with a stiffer bushing comes ride harshness, vibration, and additional noise. Our engineers and technicians recommend replacement with the factory rubber bushings (along with the appropriate reinforcement of the floor). The rubber bushings help isolate bumps and impacts and are quiet. They are also a perfect fitment and require no maintenance. ""


If you didnt care about ride harshness or vibration and main consern was performance, would you still go with stock mounts?

[DigitalPunk]

Just tossing in some new stock ones. Prob over kill anyways cause my M only has 38k miles but why not.

[tonggi]

yea toss in stock guys. the NVH will be nuts and will be rough on ur subframe. Like nick said. for a street car just stick to OEM. the PF have spacer/washer issues.

[nrubenstein]

I would consider stiff poly in the race car.

And yes, the level of vibration transmitted to the chassis will likely cause failures even with the reinforcement kit. People running solid mounts that are tied directly to the CAGE (which is the only way to do it) still need to inspect for fatiguing.

[PerkM3]

I spoke with TMS about these specific subframe bushings/mounts last week and they said unless you are building a grand am cup car there is no real difference between the ones with delrin inserts and the solid mounts that they also sell. If your looking to get a solid type mount don't spend the extra money on the delrin when it's basically the same as a complete solid. Like others (and way more experienced than me) have said, stick with OEM if the car will see the street.