[Neversatisfied1]

Can either of these be installed with the subframe still in car. I've see where the M3 bushing can be installed by just dropping subframe enough to work around it. I have not seen a write up where someone installed aluminum or delrin without complete subframe removal and disassembly?

Considering substantial price difference I was hoping this can be accomplished without complete disassembly

Thanks matt

[feuer]

subframe just need to be dropped not completely disassembled
http://www.n54tech.com/forums/showthread.php?t=27779

[techwhiz]

I would not do aluminum on a street car.
Delrin will be bad enough.
If it's a street car, find some urethane bushings.

[justpete]

Originally Posted by techwhiz

I would not do aluminum on a street car.
Delrin will be bad enough.
If it's a street car, find some urethane bushings.

Honestly it doesn't add to NVH at all. Either one is fine for a street car as long as the RFTs are changed out to non-RFTs. Would be a good idea to change to M3 links and arms as well so the combined spring rates in series are closer to reasonable than they'd be otherwise.

[chris82]

Why not M3 bushings?

[justpete]

Originally Posted by chris82

Why not M3 bushings?

Sure, why not. Although I don't think it really matters if the bushings are stiffer than the M3 parts.

[feuer]

Originally Posted by chris82

Why not M3 bushings?

Not cost effective, neither from parts nor labor perspective, for the effect acheived. Inserts would yeild similar result for a lot less money. If one is to remove the existing bushings why not install superior to m3 parts?

[k335d]

Originally Posted by feuer

Not cost effective, neither from parts nor labor perspective, for the effect acheived. Inserts would yeild similar result for a lot less money. If one is to remove the existing bushings why not install superior to m3 parts?

Cant agree more. Just picked up the delrin bushings from turner motorsports and can't wait get the subframe locked down how it should have been from the factory.

[chris82]

Originally Posted by feuer

Not cost effective, neither from parts nor labor perspective, for the effect acheived. Inserts would yeild similar result for a lot less money. If one is to remove the existing bushings why not install superior to m3 parts?

For a street driven car, the M3 parts are superior. They were designed by BMW for these cars and to be driven on for many years and hard street miles. Solid subframe bushings are designed to give you the extra bit of performance at the track so unless you're at the track, the solid parts are pointless over the M3 RSFB. Currently, the only argument I'm seeing here as a reason not to do M3 parts is cost, which I really shouldn't be too surprised about

[k335d]

Originally Posted by chris82

For a street driven car, the M3 parts are superior. They were designed by BMW for these cars and to be driven on for many years and hard street miles. Solid subframe bushings are designed to give you the extra bit of performance at the track so unless you're at the track, the solid parts are pointless over the M3 RSFB. Currently, the only argument I'm seeing here as a reason not to do M3 parts is cost, which I really shouldn't be too surprised about

Just wondering but did you have solid mounts in your car before?

[Cloud9blue]

Softer subframe mounts don't do much to improve the ride if you have already ditch the stock run-flat tires. I would just go with delrin since it will have slight give and make things a lot easier to install.

F8x have solid subframe mounts, it rides just fine just FYI. Shock mounts and damper settings will have much bigger effects on NVH than subframe ever will. You will want as stiff of a mount as you can for rear subframe once you are upping the power or upgrading to sticky tires.

M3 mounts are way overpriced for what it is, especially with the recent price increase by BMW. If you are set on elastomeric mounts, just get a set of PU mounts instead. Inserts are another good option if you are DIY this job. There is no advantage of using OE quality rubber over aftermarket PU in that area other than getting that nice M stamp on your parts, given that there is very little heat and range of motion in that area, so the wear and tear will be non-existence for the subframe mounts.

From my experience, the only thing you will want avoid on a street car is solid mounts any where near the drivetrain (motor, trans, diff, etc.). Everything else is liveable if you have quality parts and decent range of damping adjustment for your shock, especially on heavily insulated cars like ours.

[whosdady]

I've spoken to the company that manufacturers the mounts for Turner. They said most of the time the aluminum subframe bushings are well handled with little NVH. (Occasionally there is a sensitive BMW owner) They also said the delrin bushings are the way to go for the diff. That there is some NVH but it's less than the aluminum bushings.

If I could do it over again, that is what I would do. Currently I have the yellow powerflex subframe bushings with purple diff bushings.

Another option for you would be all black powerflex bushings. This is another great option imho. However you must remember these bushings can fail. The aluminum and delrin bushings basically last the life of the car... And since these are a pain to install, a lasting bushing is a really nice thing...

[Cloud9blue]

Originally Posted by whosdady

I've spoken to the company that manufacturers the mounts for Turner. They said most of the time the aluminum subframe bushings are well handled with little NVH. (Occasionally there is a sensitive BMW owner) They also said the delrin bushings are the way to go for the diff. That there is some NVH but it's less than the aluminum bushings.

If I could do it over again, that is what I would do. Currently I have the yellow powerflex subframe bushings with purple diff bushings.

Another option for you would be all black powerflex bushings. This is another great option imho. However you must remember these bushings can fail. The aluminum and delrin bushings basically last the life of the car... And since these are a pain to install, a lasting bushing is a really nice thing...

I don't think PU bushings for subframe are suppose to fail down the line if you install them correctly. There is virtually no range of motion and they are fully supported by the metal casing of your subframe.

PU bushings for suspension arms are different matter though, since they will experience much higher of rotation and movement than the subframe ever will.

[whosdady]

Originally Posted by Cloud9blue

I don't think PU bushings for subframe are suppose to fail down the line if you install them correctly. There is virtually no range of motion and they are fully supported by the metal casing of your subframe.

PU bushings for suspension arms are different matter though, since they will experience much higher of rotation and movement than the subframe ever will.

I haven't checked mine lately. They are still relatively new and I don't anticipate an issue in the near future. But I can assure you that they do fail over time. Unlike the aluminum or delrin. The PU bushings move, lose their form and dry out. The grease has a shelf life as well.

Again I don't see this happening in the near future but the solid options are more long term...

[Cloud9blue]

Originally Posted by whosdady

I haven't checked mine lately. They are still relatively new and I don't anticipate an issue in the near future. But I can assure you that they do fail over time. Unlike the aluminum or delrin. The PU bushings move, lose their form and dry out. The grease has a shelf life as well.

Again I don't see this happening in the near future but the solid options are more long term...

Why would it fail if it is barely subjected to any movement at all? Grease is only there to assist installation and prevent the bushings from binding up when torquing the bolts. The only way it can fail is from exposure to oxidizing agent and/or heat, which really isn't there at that part of the car.

Delrin is just another type of plastic and suffers the same type of problem as PU, heat and oxidation aging. Aluminum can undergo metal fatigue and corrosion as well. With all due respect, what you are saying doesn't make much sense at all... There is absolutely no reason to choose delrin or metal bushings over a quality PU for subframe mounts if reliability is your sole concerns.

[Michael__kopp]

You think a aluminum bushing will oxidize out of tolerance before a PU dry rots?? then we need to change out all of our aluminum parts every so often right??? haha. no. Yes a good quality PU bushing with as little movement as the subframe will probably last a long ass time but it is nowhere close to as long as solid aluminum. Also delrin is not rubbery like PU. When it is hit it deforms permanently. Im pretty sure the noise difference between aluminum and delrin would be almost impossible to detect. I always thought the delrin option only existed because there are some race class rules that don't allow solid mounts so technically delrin isn't solid.

Just think of what play the subframe bushings are giving your car. It allows the entire subframe to twist in a different direction than the car is pointing. the play in no way helps the performance of the car and only provides a minuscule amount of noise isolation. If you are so sensitive to noise why are you even modding your car? You can easily increase noise more by the brand of tire you use than the subframe mounts. The diff mounts is where noise is made. So just go with PU diff mounts. It is so strange how many posts say solid subframe bushings are only for track cars but none of them have experience with solid mounts. I believed it too until my buddy go solid mounts, there is almost zero change. Now i have solid mounts and power flex black series diff bushings on order.

[justpete]

Originally Posted by Michael__kopp

I always thought the delrin option only existed because there are some race class rules that don't allow solid mounts so technically delrin isn't solid.

Yeah, it used to be a limit on the amount of metal in a bushing per SCCA rules (I think) but has since been modified or eliminated, not sure which.

FWIW, AKG Motorsports makes polyurethane subframe bushings with a hardness equal to Delrin but being polyurethane won't permanently deform.

[justpete]

Thought I'd mention, being contrarian again, that solid mounts in the driveline don't significantly increase NVH above 2K rpm, if done correctly. The improvement in acceleration by removing driveline windup might be worth it to some on the street. Takes more than this to optimize rapid acceleration but it's a start.

[whosdady]

Originally Posted by Cloud9blue

Why would it fail if it is barely subjected to any movement at all? Grease is only there to assist installation and prevent the bushings from binding up when torquing the bolts. The only way it can fail is from exposure to oxidizing agent and/or heat, which really isn't there at that part of the car.

Delrin is just another type of plastic and suffers the same type of problem as PU, heat and oxidation aging. Aluminum can undergo metal fatigue and corrosion as well. With all due respect, what you are saying doesn't make much sense at all... There is absolutely no reason to choose delrin or metal bushings over a quality PU for subframe mounts if reliability is your sole concerns.

With all due respect your logic is flawed and your statement is incorrect. I have witnessed the opposite several times. Not to mention the distributor stated the opposite (Turner) (who sells and races both) and the manufacturer stated the opposite as well. If you question this, please contact Turner and ask them for yourself. The sales rep from the manufacturer is John. (I can't remember his last name but Turner will)

In addition, please remember that I have powerflex bushings in my subframe. I installed them over the delrin because I was advised the nvh could be too severe. I'm unhappy and can feel movement. The more movement, the more wear. And by the way, the grease that is supplied is used for lubrication. Not just for installation but also to prevent squeaking. Now ask yourself when it's cold, why PU bushings squeak... It's because there is movement. (Which causes wear)

Robc1976 is a good friend of mine and moved to delrin after his PU bushings failed prematurely. He had a lot of hp and had significant movement with his PU bushings. I should mention they were less than 2 years old.

[whosdady]

Originally Posted by justpete

Yeah, it used to be a limit on the amount of metal in a bushing per SCCA rules (I think) but has since been modified or eliminated, not sure which.

FWIW, AKG Motorsports makes polyurethane subframe bushings with a hardness equal to Delrin but being polyurethane won't permanently deform.

I would be careful making any purchases from AKG. I only made one purchase and will not buy from them again after an end link failed (after 3 months) and they denied my warranty.

They asked if I drove the car on the street and I said yes. Then they said their parts were not designed or warrantied for the street. Sure enough I looked at their website and the warranty corresponded with what the owner stated. He is a nice guy but I would never buy a part from a company that denies claims if the part is driven on the street... Who doesn't drive their car on the street? Even if it's a track car, many drive them to the track...

[Sered]

Pretty much none of the bushing or mount upgrades will add any NVH by themselves. It's when you add them together with others that it can become a problem. You can run solid diff bushings/mounts with OEM or M3 subframe bushings; and there's not much nvh added. And vice versa.

Generally if you want to go much stiffer on both, it's best to get the poly and/or delrin varieties for everything if you're concerned about NVH.

And FWIW, BMW has made all new M cars to have solid-mounted subframes and those cars have great street manners.

[feuer]

The subframe is a subject to movents, back and forth during accelerating and braking, sideways when turning left and right, and also up and down. With less give on other bushings, with stiffer springs and stickier tires these loads would increse and will speed up the process of any type of subframe bushing deformation. Stock bushings, PU, Derlin, and aluminum are all subject to failure. The subframe itself could crack, the bolts could shear. Is matter of when not if and will depend, of course of the product, and how is been put to purpose.