Looking for some input on front control arm bushings for the FC. I'd like to go with the AWR units but at $715 it's a bit much.

Has anyone tried to make their own needle bearing units and have a machine shop make up some sleeves? I just bought an extra set of arms to mess around with and was looking at bearings online.

Would the AWR units really do that much more than Delrin or UHMW bushings in the front? Can the cost be justified? Right now I just have some Energy Suspension ones, anything is going to be an improvement.

I already have the AWR spherical bearings in the rear with aluminum DTSS eliminators, that end is taken care of...need to add toe link kit is all. I am looking to change out my subframe, diff, tranny and engine to Delrin/UHMW as well from stock and Mazda Comp stuff. Probably will go with http://www.mmr-direct.com/ as the prices are incredibly low unless there is consensus not to use these.

Thanks for the feedback.

 

I won a lot of races with the standard urethane bushings.

 

I made some offset bushings for mine in delrin before is was headed for EP(not legal in limited prep or whatever they call it this year) I'll see if I can find them and take some pics for you if you want. I have other delrin ones in the car right now that I made. The amount of sticktion compared to bearings is noticable when you move things by hand but I doubt I'm a good enough driver to notice on the track. There are enough other things I can blame besides bushings, like I really need those $6000 shocks...

 

Thanks John. I don't follow the need to make them offset though? I wouldn't make my own if using Delrin/UHMW, the one's below are only $80. I would consider trying to make needle bearing units if there was a benefit.

I hear people talk about potential binding on the rear control arm mounts and that's why the bearings are supposedly better than Delrin in that application (makes sense with how camber is adjusted), but does it make a difference in the front between Delrin/UHMW and a bearing? AWR is pretty respectable, they did them for a reason I assume.

Chris, people win on urethane but there is better. I want the best, plain and simple. There is always room for improvement and I always strive for more with everything in life.

http://mmr-direct.com/Pictures/RX7/F...FC3SSB100A.jpg

 

to duplicate the AWR setup you need to machine the control arm to fit the off the shelf bearings. this is why they cost so much. it could be copied if you have or are a machinist.

 

The offset bushings can help your geometry if you aren't allowed to change the outerball joint location. You can raise the pivot point by about 3/8" within the stock subframe limitations.

 

I'd go Delrin and save the change. Most of the fastest cars in Florida over the years used it with no troubles.

I first installed the ES kit but was very unhappy with the result. I could get the suspension to move but I still thought that there was too much bind present. I installed the Delrin and now everything articulates very nicely with almost no effort. Smooth articulation with no deflection is what you're after. Delrin did the trick.

 

Are you using delrin for your rear trailing arms also? Did you like the delrin bushings more than polyurethane for the rears. I keep hearing about this binding issue, so I was thinking about going with polyurethane

 

Im using the Mazdaspeed delring bushings both front and back, as well as the subframe bushings, and they seem really great. They are pricey, but I havent had any suspention issues at all with the car.

 

Delrin on the front, delrin on the rear sub, and delrin on the diff mounts.

ISC Racing control arms with spherical bearings for the rears. The car was built with those so I've never used them on my car. I have raced other ITS RX7s using delrin in the rears with no drama. I'd have to spend more time racing the cars back to back to say that I could tell the difference.

 

I think you mean Mazda arms with spherical bearings from ISC as they have to be stock arms. I just glanced at the ISC site and see they do the work for you (exchange), same bearing kit I would presume you just buy from AWR.

This is interesting ... "Holds Toe Adjustment Better." How? The factory cam washer is still used, that's what controls toe. Is it because you can tighten down the nut more than with Delrin or stock bushings? Wouldn't think so. The spherical bearing kit is designed to be used with the adjustable toe links that AWR sells, use those and you can put a custom washer in place of the cam washer, thereby eliminating the ability of it to rotate. - That is what holds toe adjustment better, not simply using the spherical bearings... but toe link kit is not IT legal, therefore IT cars have to keep the stock cam washer and it's still easy to knock toe out of place.

 

good arguement.

 

On the front, if you're using urethane and it's causing excess friction or binding, it may be because the bushing at the rear of the control arm is sticking up past the top of the bushing mount. If you shave it off a bit that should free it up a somewhat. Same goes for swaybar bushings, and I know there that this is a common problem and that fix works.

I'd much prefer spherical bearings in the rear, because when you use individual camber adjusters, they twist the control arm relative to the subframe, where the mounting bolt is, so this twists the bushing relative to the bolt. This can lead to binding (I've heard from people who this has happened to) and it'll only be worse with stiffer bushings, because they hae less flex in them.

 

Exactly. I can't vouch for the "holds toe better" arguement, so I won't. But as I described the results of my delrin install in the front, the same thing is true in the rear. Much better articulation with virtually no bind. Disconnect the shock and move it up and down: near zero bind; all you feel is the weight of the arm.

This is the key to consistent, repeatable setup changes, as well as dialing in the initial setup. As long as there is bind, you'll be fighting it trying to get your setup to work. Different temps will result in different levels of bind, and your whole setup goes out the window.

The reason I don't support the added expense of the sphericals on the front arms is that the same result is achievable for much less money. Since the arm pivots on a pair of fixed points, all you need is some well-lubed delrin to get the same effect as spherical bearings. On the rears, the arm movement is not fixed around a single pivot point depending on the camber settings. As was mentioned above, different camber settings in a non-spherical arm can introduce bind relative to the mounting bolt. The SBs eliminate this.