I am debating to either make delrin bushings or go with ebay poly control arm bushings. Keep in mind it is a full race car.

If I make my own delrin bushings I can offset some of them to get more camber. Currently I wear the outside of my tires and would like to get more life out of them. I can also use ultra wear resistant delrin. 2 questions

- Would I have binding issues setting toe in the rear? (no slop to skew the rear lower control arm away from parallel)
- what sleeve material/size would you guys recommend? (Just copy OEM?)

Or I go with poly?

Thanks

 

Binding issues both in toe in the rear and caster in the front. The $130 kit on amazon that has everything is a real fast way to fix a lot of the bushing deflection. BUT poly is a massive compromise and really shouldnt be used on a racecar since a lot of that deflection still remains. But with delrin you have to worry about the binding and also the pretty fast wear with them only seeming to last a couple seasons. Sphericals quickly gets you into thinking about how cheap delrin is, if you want them to last with $30-40 a piece for good sphericals.

If you've got a lathe and have time to kill making your own delrin can work out alright. sleeve wise, I would just go with whatever off the shelf tubing has the correct ID and cut it to length. I know some people do use poly in both lower control arm bushing to avoid the bind issue that you're worried about.

 

ISC Racing sells Delrin bushings with offsets already, if you want to avoid building them yourself.

 

I can't decide if the binding issues you might have with delrin are worse than the fact that poly is nearly the worst material in the world if you want your suspension to pivot freely without huge amounts of friction. the radial deflection is not nearly an issue as the amount of force it takes to move your a-arms after poly bushings have been on the car for a few months and all the grease becomes non functional.

 

Which is why you have to keep the grease from getting to be non-functional. Checking, and re-lubing mine is part of my in between race checks. Its just a hold out till I find the need to drop $1200 on sphericals.

 

Drill and zerk and relube?

--Ian

 

I can notice my poly bushings getting tight, so I add more grease

When I installed the polys, I added zerks. Some of the bushings in my kit (prothane?) weren't set to take grease, so I made them better...

 

so lets assume the greasing is a non issue because mine will get zerks regardless of material. poly?

 

Performance wise delrin win. You got to make your choice, man. Poly can go a long time just needing greasing a few times a year. Delrin is like 4 times as expensive and is better than poly but only lasts a couple years. Cheap sphericals are better than delrin but are doubtful to last a year and are going to be a custom solution. Expensive sphericals are even slightly better and should last many years but again you're looking at like 10 times the price of the poly and custom. What matters to you? For me, poly is a cheap stop gap measure before getting quality sphericals.

 

Ive tried many different ways to zerk them. grease never goes where its needed unless you dissasemble it. grease zerks simply don't work on Poly bushings. freekin wast of time to put them in.

 

Agree to disagree, 95% of my polys are pre-split from the factory, and the zerk sits right over the void. Pre-cast grease channels bring it straight from the slit to where it needs to be. Mine can and will squeak, and immediately shut up once I grease them. Must be doing something...

The stock rubbers are ten times as stiff as even ungreased poly bushings. I'd bet a nickel my arms would drop under their own weight were I to remove the spindles/coils with the poly bushings. On stock rubbers, no way.

Lots of guys swear poly bushings lower their car 1/2" or so, because of the friction "spring rate" lost over stock.

 

can i ask how specifically you accomplished this? every implementation ive seen on a miata was set up to fail, and didnt direct the grease to where it needed to be. not saying you did it wrong, but im curious if even done correctly that its still an uphill battle.

 

looks like deezums answered my post in an offhand way.

 

did that still dosnt work. As a mater of fact Ive found much more consistant and lower friction with the surface between tha ARM and the bushing being the sliding surface instead of between the bushing and the pin. even with the slots and carfull handleing of how the zerks are installed thats where the grease ends up if using zerks anyway on 10 out of 14 of the bushings. And the greas might stay in place for a single autocross at best then it goes back to taking 40+ lbs of force just to get the A-arms to pivot. Ive measured up to 90 lbs if compleatly left alone for a season. That amount os stiction is a huge detrament to suspension performance. With the V8-roadster arms it seems to be better than stock arms but still sucks.

 

I don't think it’s possible to do correctly even if you think your scheme might work it won’t. Poly simply won’t stay greased and it has a high friction coefficient by itself. Makes a horrible bushing material if you desire low sliding friction. or at least an amount of friction that stays the same week to week.

Delrin at least has a low sliding friction

 

im trying to find pics of how i did my truck. im curious what you think, although im not sure the miata bolt size affords the ability to do it that way.

 

I wish sombody made Delrin ones for my V8-roadster arms.

 

Give me dimensions and I'll make whatever you want.

Thoughts
http://www.s10forum.com/forum/showthread.php?p=7533641
86' s15 ext cab v8 corner carver, 56k beware

 

The V8R arent delrin? And they dont use normal miata bushings? Why the dick would he do that? Normal miata bushings fit perfectly in a common off the shelf tubing size (1.75x.065 I think).

 

The V8r use common off the shelf tubing size but I haven't found off the shelf bushing for them. something Im going to look at this winter.

I might even go back to stock arms and modify the front lower to get the Camber I need. Or convert the V8-r to run sphericals some how.

I still question the strengh of the V8-R front lowers. I've cracked one set. I think the replacements they sent me used a much thicker tube in one critical spot because they got heavyer even though the outboard end has been lightened.