Update on Acetron GP solid front control arm bushings....
08-17-2005, 04:09 AM
#1
AudiWorld Super User
Thread Starter
Update on Acetron GP solid front control arm bushings....
<center><img src="http://pictureposter.audiworld.com/711/solidbushing4.jpg"></center><p>
As Alex (Europrice) mentioned late last week these are going to become available but are likely still a month away on production units. The first production run will be limited to enough units to do 25 cars with 5 sets held back for warranty or collision replacements. Any additional production run will be determined by interest generated by the initial production run. If they move quickly and people love em I'll do another, larger production run. If not they'll go the way of the dinosaur and 25 cars is all there will ever be. Cost right now is "estimated" between $225/$250 for a front set (4 bushing assemblies per car).
These will not be the run-of-the-mill Delrin-style solid control arm bushings like those offered by Blau/2Bennett et al. These will be ultra close-tolerance kits which will far exceed the quality and precision of anything thats ever been available to us in the aftermarket previously, currently or in the future.
Components Used:
The heart of the new bushings will be the Acetron GP self-lubricating co-polymer. Very new to the control arm bushing industry but has been used by NASA extensively for close tolerance, high thrust, slow-moving high-load bearing/bushing assemblies. Unlike Delrin it is completely non-porous thru-out its extrusion diameter. It cannot abosrb water/humidity and swell like Delrin.
T-304 Stainless Steel is the material I've chosen for the pilot bore bushings. But not off-the-shelf like the other companies use. I'm having all stainless tubing "centerless ground" for two reasons; tubing cannot be extruded perfectly round. There always exists high/low spots along the full length of any seamless extruded tubing no matter what its composition. On stainless tubing it usually runs .003"-.004" eccentric (out-of-round). That means the tubing is not perfectly round, that it has high/low spots along its full length. In bushings that means there's high/low spots, places that contact the bore and places that dont. By having the stainless pilot bore tubing centerless ground I can make the stainless perfectly round to within .00001" Thats 10 millionths of an inch!! And also insure that it has a perfectly smooth/sub-micron surface finish over its entire length (think high-end flat bed scanner guide rails as thats how they're done too). This insures the internal stainless pilot bushing fits the bore of the Acetron GP bushing perfectly and has the same interference fit over its entire outer surface where it pivots on the Acetron GP vores. Having the stainless ground perfectly round also insures that when I drill the pilot hole for the control arm pivot bolts that the bores will be perfectly centered within the stainless bushing as cast seamless tubing bores can never be perfectly centered/aligned within the tubing. This allows me to re-drill them perfectly centered a few thousandths under-size to the desired finish size pilot bore then ream to a perfect-fit/perfectly centered internal bore diameter. Just because the pivot bolts are sold as 10mm bolts does NOT mean they are truly 10mm. They are closer to 9.8mm on the smooth shank that contacts the pilot bore ID. This means I can make the bore 9.85mm and have a FAR more precise pivot bore riding on the stock Audi control arm pivot bolt. For an example my PolyFlex bushings I never used have a pilot bore that measures 10.1mm that has been drilled. That would only be an loose fit if the bolts were truly 10mm. As it is with the bolts being 9.8mm actual size its a rather sloppy fit. Drilling a pivot bore to-size leaves a rough internal finish and in this case a too-large and too rough of an internal finish. By "reaming" I can get a glass smooth internal surface that is an ultra-close fit to the bolt. All related to the "if we're gonna be a dog, why be a chihuahua" philosophy. I want to make it right, no I mean really REALLY right... the FIRST time! If I wouldnt use it on my car I certainly wouldnt make it for yours!
Once stainless bushings are finished I will then add a groove helix along its full OD length. Basically a spiral groove to retain anti-seize lubricant. The internal bore of the Acetron GP that fits into the control arm bushings will also get the helix groove and anti-seize during final assembly. Not that these parts need it as they will never rust. But as a water-proofing to insure the integrated arm bushings never rust and to ward off any potential for squealing like when you run a wet finger around the rim of a clean glass.
Stainless tubing is at the grinding shop now and should be finished on Friday. I wont start the Acetron GP production until I have the stainless back as I cant know what size center bores to put in the Acetron GP until I can measure the stainless OD after centerless grinding. Updates will follow as they occur.
Pic shows off-the-shelf "unground" stainless pivot bushings. The helix groove on that will also be replicated on the small diameter of the Acetron GP production units.
As Alex (Europrice) mentioned late last week these are going to become available but are likely still a month away on production units. The first production run will be limited to enough units to do 25 cars with 5 sets held back for warranty or collision replacements. Any additional production run will be determined by interest generated by the initial production run. If they move quickly and people love em I'll do another, larger production run. If not they'll go the way of the dinosaur and 25 cars is all there will ever be. Cost right now is "estimated" between $225/$250 for a front set (4 bushing assemblies per car).
These will not be the run-of-the-mill Delrin-style solid control arm bushings like those offered by Blau/2Bennett et al. These will be ultra close-tolerance kits which will far exceed the quality and precision of anything thats ever been available to us in the aftermarket previously, currently or in the future.
Components Used:
The heart of the new bushings will be the Acetron GP self-lubricating co-polymer. Very new to the control arm bushing industry but has been used by NASA extensively for close tolerance, high thrust, slow-moving high-load bearing/bushing assemblies. Unlike Delrin it is completely non-porous thru-out its extrusion diameter. It cannot abosrb water/humidity and swell like Delrin.
T-304 Stainless Steel is the material I've chosen for the pilot bore bushings. But not off-the-shelf like the other companies use. I'm having all stainless tubing "centerless ground" for two reasons; tubing cannot be extruded perfectly round. There always exists high/low spots along the full length of any seamless extruded tubing no matter what its composition. On stainless tubing it usually runs .003"-.004" eccentric (out-of-round). That means the tubing is not perfectly round, that it has high/low spots along its full length. In bushings that means there's high/low spots, places that contact the bore and places that dont. By having the stainless pilot bore tubing centerless ground I can make the stainless perfectly round to within .00001" Thats 10 millionths of an inch!! And also insure that it has a perfectly smooth/sub-micron surface finish over its entire length (think high-end flat bed scanner guide rails as thats how they're done too). This insures the internal stainless pilot bushing fits the bore of the Acetron GP bushing perfectly and has the same interference fit over its entire outer surface where it pivots on the Acetron GP vores. Having the stainless ground perfectly round also insures that when I drill the pilot hole for the control arm pivot bolts that the bores will be perfectly centered within the stainless bushing as cast seamless tubing bores can never be perfectly centered/aligned within the tubing. This allows me to re-drill them perfectly centered a few thousandths under-size to the desired finish size pilot bore then ream to a perfect-fit/perfectly centered internal bore diameter. Just because the pivot bolts are sold as 10mm bolts does NOT mean they are truly 10mm. They are closer to 9.8mm on the smooth shank that contacts the pilot bore ID. This means I can make the bore 9.85mm and have a FAR more precise pivot bore riding on the stock Audi control arm pivot bolt. For an example my PolyFlex bushings I never used have a pilot bore that measures 10.1mm that has been drilled. That would only be an loose fit if the bolts were truly 10mm. As it is with the bolts being 9.8mm actual size its a rather sloppy fit. Drilling a pivot bore to-size leaves a rough internal finish and in this case a too-large and too rough of an internal finish. By "reaming" I can get a glass smooth internal surface that is an ultra-close fit to the bolt. All related to the "if we're gonna be a dog, why be a chihuahua" philosophy. I want to make it right, no I mean really REALLY right... the FIRST time! If I wouldnt use it on my car I certainly wouldnt make it for yours!
Once stainless bushings are finished I will then add a groove helix along its full OD length. Basically a spiral groove to retain anti-seize lubricant. The internal bore of the Acetron GP that fits into the control arm bushings will also get the helix groove and anti-seize during final assembly. Not that these parts need it as they will never rust. But as a water-proofing to insure the integrated arm bushings never rust and to ward off any potential for squealing like when you run a wet finger around the rim of a clean glass.
Stainless tubing is at the grinding shop now and should be finished on Friday. I wont start the Acetron GP production until I have the stainless back as I cant know what size center bores to put in the Acetron GP until I can measure the stainless OD after centerless grinding. Updates will follow as they occur.
Pic shows off-the-shelf "unground" stainless pivot bushings. The helix groove on that will also be replicated on the small diameter of the Acetron GP production units.
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08-18-2005, 05:06 AM
#9
AudiWorld Super User
Thread Starter
Probably not as it takes 25 sets minimum to make this modification cost-effective...
But if you send me a CQ cast rear control arm with the bushings removed I'll be happy to tell you specifically what they'd cost to make. Might run $50-$75 more per vehicle to manually make rears in limited numbers than a CNC'd quantity production run.
08-18-2005, 05:09 AM
#10
AudiWorld Super User
Thread Starter
Mine are GREAT! But they'll never find their way into production due to...
having to be made custom for each cars upper shock mount due to mount-welds not being similar or even close from car to car or even left-to-right. Mine were "so" custom that even the right setup couldnt be used on the left and vise-versa.
Win some-lose some.
Win some-lose some.