ModdedMach
Detailer of shiny things.
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- Sep 14, 2013
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I thought this is probably the most appropriate place to post this. (If not, sorry Mods, lol)
As most of you have read, in the future BMR will be offering a Synthetic Elastomer Bushing option for its more popular parts. Kelly Aiken was kind enough to let me try a "test set" of TCA019 Lower control arms that had the new SuperPro Elastomer bushings installed.
Before i decided to be on board with this, Kelly and i exchanged many emails discussing the difference between the "normal" Polyurethane and the Elastomer option. My car, specifically, will be built to corner as well as possible but is a street machine, so im not looking for a complete reduction in deflection, as some is needed in cornering, so for now i will run the new elastomer.
As I understand it, the idea/advantage behind the elastomer vs poly is as follows.
1. The durometer is only slightly lower (about ~13%, 83 vs 95), so the straight-line performance is comparable(w/normal power levels) as far as reducing unwanted deflection (wheel hop) However, the elasticity of this material is MUCH better than regular poly, so the bushing allows more initial deflection under cornering loads and as it compresses/deflects it progressively gets stiffer.
So, if youve handled a Poly bushing before, youll know that it feels sort of like very hard, slick plastic. These new bushings in the hand arent as slick to the touch, more rubbery/grippy to the touch, and the firmness in hand is very similar.
2. Since the material is much more elastic, its vibration dampening properties are better than poly (about 15% quieter as measured by BMRs test). Well greased poly rides great on the street, but these newer bushings are OEM QUIET- i shit you not. I rolled the windows up, radio off, over bumps, in corners, under acceleration, braking, slaloming....Zero added sound that i could detect (and im one of those people that hear all the sounds a car makes). Now- i do have very loud o/r exhaust, but i listened very carefully at low rpm and the things are dead quiet.
3. Another advantage to the better elasticity is much better "cold flow" resistance, essentially, the amount of articulation a bushing can take before it is permanently deformed (think of a dented or cracked poly bushing). These Elastomer bushings are able to be compressed against themselves a bit more and still "bounce back" to normal shape over and over- so the idea is that they can be more durable to poly (if maintained properly).
4. Rather than a Fluted style inner casting, these bushings have a texture of a bunch of tiny little pockets that hold grease along the entire center insert- so, in theory, the frequency of re-greasing is lessened.
When i installed the arms i greased each fitting with approx 1.5 pumps of Amsoil Synthetic Polymeric Truck/Chassis Grease, as well as coated the bushing outer surface, torqued all the bolts to 130 ft/lbs and took it for a drive. Minus these BMR LCAs, my cars suspension is 100% stock Brembo GT setup. Prior to the control arm install, 1st and 2nd gear was wheel hop city, no traction, hopping everywhere, 3rd would shutter/spin a little and 4th would get a wheel.
NOW:
1st gear wheel hop is greatly reduced but still has a small amount of wheel hop under WOT (as to be expected running a stock UCA).
2nd gear has ZERO hop- still has traction problems, but the spinning motion is smooth and the car tracks straight and i bet with a higher road/tire temps it would grip more while spinning. (it was high 50s outside during the test drive)
3rd- Spins a little bit but doesnt shutter, much smoother. I need stickier rubber to hold down the power with these 3.73s.
I noticed under hard cornering that my rear it was a tad more planted, the rear feels like its more synced up with the frontend movement, but when i pushed it hard i could almost feel it want to step out a tad more, it didnt, but it felt like i was closer to the edge- i chock this up to other parts of my suspension and my tires becoming the "weekpoint" so-to-speak. The LCAs put the power down and force the tire to the pavement in cornering harder than the factory LCAs, thus, the tire's responsibility in cornering become larger and the 255 F1s arent exactly flypaper lol.
Thanks to Kelly from BMR for letting me test out their new bushings. If you are considering Elastomer- do it. Obviously each application is different, but for a street car that may see the track on occasion, it seems like the perfect solution. Tight, Quiet, and performs.
I would say for street driven cars, these bushings are a win, with zero sacrifice in comfort and comparable performance to poly. That being said, my plans are to eventually go full spherical i think, as i dont DD my car, im not worried about some extra cabin sound.
Couple pics of the Arms next to the OEMs and on the car, sorry the pics suck, it was dark and i snapped them real quick on the cell:
As most of you have read, in the future BMR will be offering a Synthetic Elastomer Bushing option for its more popular parts. Kelly Aiken was kind enough to let me try a "test set" of TCA019 Lower control arms that had the new SuperPro Elastomer bushings installed.
Before i decided to be on board with this, Kelly and i exchanged many emails discussing the difference between the "normal" Polyurethane and the Elastomer option. My car, specifically, will be built to corner as well as possible but is a street machine, so im not looking for a complete reduction in deflection, as some is needed in cornering, so for now i will run the new elastomer.
As I understand it, the idea/advantage behind the elastomer vs poly is as follows.
1. The durometer is only slightly lower (about ~13%, 83 vs 95), so the straight-line performance is comparable(w/normal power levels) as far as reducing unwanted deflection (wheel hop) However, the elasticity of this material is MUCH better than regular poly, so the bushing allows more initial deflection under cornering loads and as it compresses/deflects it progressively gets stiffer.
So, if youve handled a Poly bushing before, youll know that it feels sort of like very hard, slick plastic. These new bushings in the hand arent as slick to the touch, more rubbery/grippy to the touch, and the firmness in hand is very similar.
2. Since the material is much more elastic, its vibration dampening properties are better than poly (about 15% quieter as measured by BMRs test). Well greased poly rides great on the street, but these newer bushings are OEM QUIET- i shit you not. I rolled the windows up, radio off, over bumps, in corners, under acceleration, braking, slaloming....Zero added sound that i could detect (and im one of those people that hear all the sounds a car makes). Now- i do have very loud o/r exhaust, but i listened very carefully at low rpm and the things are dead quiet.
3. Another advantage to the better elasticity is much better "cold flow" resistance, essentially, the amount of articulation a bushing can take before it is permanently deformed (think of a dented or cracked poly bushing). These Elastomer bushings are able to be compressed against themselves a bit more and still "bounce back" to normal shape over and over- so the idea is that they can be more durable to poly (if maintained properly).
4. Rather than a Fluted style inner casting, these bushings have a texture of a bunch of tiny little pockets that hold grease along the entire center insert- so, in theory, the frequency of re-greasing is lessened.
When i installed the arms i greased each fitting with approx 1.5 pumps of Amsoil Synthetic Polymeric Truck/Chassis Grease, as well as coated the bushing outer surface, torqued all the bolts to 130 ft/lbs and took it for a drive. Minus these BMR LCAs, my cars suspension is 100% stock Brembo GT setup. Prior to the control arm install, 1st and 2nd gear was wheel hop city, no traction, hopping everywhere, 3rd would shutter/spin a little and 4th would get a wheel.
NOW:
1st gear wheel hop is greatly reduced but still has a small amount of wheel hop under WOT (as to be expected running a stock UCA).
2nd gear has ZERO hop- still has traction problems, but the spinning motion is smooth and the car tracks straight and i bet with a higher road/tire temps it would grip more while spinning. (it was high 50s outside during the test drive)
3rd- Spins a little bit but doesnt shutter, much smoother. I need stickier rubber to hold down the power with these 3.73s.
I noticed under hard cornering that my rear it was a tad more planted, the rear feels like its more synced up with the frontend movement, but when i pushed it hard i could almost feel it want to step out a tad more, it didnt, but it felt like i was closer to the edge- i chock this up to other parts of my suspension and my tires becoming the "weekpoint" so-to-speak. The LCAs put the power down and force the tire to the pavement in cornering harder than the factory LCAs, thus, the tire's responsibility in cornering become larger and the 255 F1s arent exactly flypaper lol.
Thanks to Kelly from BMR for letting me test out their new bushings. If you are considering Elastomer- do it. Obviously each application is different, but for a street car that may see the track on occasion, it seems like the perfect solution. Tight, Quiet, and performs.
I would say for street driven cars, these bushings are a win, with zero sacrifice in comfort and comparable performance to poly. That being said, my plans are to eventually go full spherical i think, as i dont DD my car, im not worried about some extra cabin sound.
Couple pics of the Arms next to the OEMs and on the car, sorry the pics suck, it was dark and i snapped them real quick on the cell:
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