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DRS now offers their own Delrin control arm bushings for the Lotus S2 cars. Delrin is an excellent material with low-friction and low-wear properties. Eliminates bushing migration that is common with the stock units. Cost $375
 

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Awesome. That's great. I guess there are no multi-axial joints on the Elise? Do these start to make noise ever? Have you tested them for any extended period of time on a daily driven car?

I'm pretty interested in these.
 

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^ Good questions, interested in hearing more feedback on these as well. I have some clunking going on in the front suspension & I originally thought it was the steering rack. Replaced it last week with a Titan QR & the clunking is still there so my next step is to check out all the ball joints & wishbone bushings.

Id be interested to know at what point is there potential for the delrin to crack? I do like the idea that they are resistant to influence from temperature being it hot/cold.
 

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Discussion Starter #4
So far tests have indicated good results. We will share more longer term data as we collect it. We do have years of experience with using Delrin on other applications with great results as well. These cars respond well to this b/c the control arms are not multi-axial. While load torque the arms (what causes the migration of the stock units), our bushings are 2 pc on each pivot location, with a floating pin in the center. Allows the bushing to work more like a bearing in the pivoting direction, but less prone tolerance shift over time. A spherical bearing while in a new state is more precise; but in our experience the Delrin material is longer lasting with precision over time, and with almost as much precision in a new state. Also, less sensitive to road debris for cars that serve as track and street cars.

Feel free to contact us directly for inquiries.
 

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I’ve run Delrin bushings in other cars in the past…they do ware just like brass/bronze. The good thing is that they do NOT make noise (squeak) like polyethylene, but do NOT last like polyethylene does. The other good thing about Delrin is that they do not clunk like bronze bushings do when they ware…they are “softer” sounding, but not softer as far as material properties goes.
 

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While load torque the arms (what causes the migration of the stock units), our bushings are 2 pc on each pivot location, with a floating pin in the center. Allows the bushing to work more like a bearing in the pivoting direction, but less prone tolerance shift over time.
This is what is really catching my attention. On our cars, I notice that the OEM rubber bushing is getting smashed & beat up on the ends where it is pinched to the subframe.

With your kit, are these oversized or thicker to avoid these endcaps from getting squished in the wishbone? How are the tolerances between the endcaps & the subframe - its a tight spot to begin with.

Id be afraid these might crack overtime when the wishbone is shifting front/back with load during prolonged use.

I really like the idea though of creating a bearing like bushing with Delrin! Thinking if this needs any kind of lubrication to avoid an increased diameter from wear inside the Delrin endcaps from the metal sleeve - probably not though since the surface area is wide?
 

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I am betting that steel is more abrasion resistant.
 

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...and crush resistant since the mounting bolt torques through them.

Slightly2ned, that's a good observation about the bushings getting pinched in the subframe. They have to be a tight fit or else the arms will move parallel to the axis of the mounting bolt. That would be bad.
 

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Hard anodized aluminum spacers are not going to wear out or crush - they do not need to be steel. The main problem with the lotus is that there is so much zinc on the rear frame and the tabs are all a little different that each piece needs to custom made to fit. I guess shims could be used too.
 

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Buying a uniformly sized set of control arm bushing for an Elise/Exige would be a BIG mistake. I machined a set for my own car and EVERY ONE of them needed to be a different size. Why? Because the tolerances on the fabricated control arms are so sloppy! Lotus just put a Band-aid on the problem by using rubber.
And yes I machined the central metallic spacers from 7075 Aluminum because of its high Brinnell hardness, and then had them hard anodized. They were all over the map in length too! Saved some weight in the process, and now all of the control arms move up and down freely under their own weight.
This ended up being a VERY time consuming piece of work!
 

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Buying a uniformly sized set of control arm bushing for an Elise/Exige would be a BIG mistake. I machined a set for my own car and EVERY ONE of them needed to be a different size. Why? Because the tolerances on the fabricated control arms are so sloppy! Lotus just put a Band-aid on the problem by using rubber.
And yes I machined the central metallic spacers from 7075 Aluminum because of its high Brinnell hardness, and then had them hard anodized. They were all over the map in length too! Saved some weight in the process, and now all of the control arms move up and down freely under their own weight.
This ended up being a VERY time consuming piece of work!
Do you have any pics of when you did the install?
 

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Discussion Starter #16
I don't have any pics of the install process, but it is pretty straight forward.

Although the steel pins are slightly heavier than aluminum, 1/2 of the weight is low in the chassis. The entire bushing kit with steel tube only weighs 2.2 lbs. At this time I do not want to increase the cost of the kit for relatively low weight savings.

Kris
 

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Discussion Starter #17
As an update to this thread I thought I'd share that we have 7 race cars that have completed 4 race weekends with this product, and 2 on the street that have several hundred miles. So far there have not been any signs of premature wear and no road noise above the normal driving experience of these cars.

We're satisfied with the results thus car.

Kris
 

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OK, been a little over a year. How are these holding up on the street cars?
 

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Also curious, think I may need some of these soon. Not a polymer chemist, but is Delrin=>Ertacetal? 1st noticed eliseparts units.
 

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Delrin vs MonoBalls

Does anyone have an opinion on the Delrin vs MonoBalls for a car getting around 4,000 street miles a year and a 1000 or so track miles?

I just don't want to have to redo either in a couple of years.

:up:
 
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