72 replies to this topic

[Bench Racer]

Might the load condition be better if the eccentric bushing is used on the upper control arm inner end???  

[Mike Babcock]

Might the load condition be better if the eccentric bushing is used on the upper control arm inner end???  

 

That's what was requested...

[FTodaro]

Because?

One concern I have is that they are one more thing to slip out of adjustment, and the loads are significant. They are also different from the stock approach in that they directly impact other aspects of suspension geometry by moving the pivot point vertically. That can be good or bad, and you need to pay attention to which way you turn them. The combination of both may be asking for something to slip, but it's worth a try for those struggling to get camber by the rules.

Is NASA on board?

If your going to allow these bushings, why not just allow Camber to be open so to speak and let people use these or other bushings to come up with their set up. Once everyone is allowed extra camber, does it matter how you get there from a rule standpoint?

 

I am for it since the tires we are running call for more camber, much easier to now just make it open.

[Bench Racer]

Per FasTrack:

 

2. #15634 (Michael Babcock) Camber for SM

Thank you for your request. Add 9.1.7.C.3.p:p. Inner bushing(s) on the front lower control arms may be

replaced with the Mazdaspeed offset bushing (part number 0000-04-5409).

 

When checked MazdaSpeed the specified part number is for inner upper control arm.   ???

 

[wheel]

RE: My post #4, above, I am not certain that all of the heads would be non-compliant under the 1.5 mm de-burr measurement.  I did not actually measure them all and cannot swear that they were all more than 1.5.  One or two might have actually made it in under the 1.5, but I'm not sure.  One head did not have any de-burring, but was non-compliant for another reason. 

wheel

[Bench Racer]

[Charlie Hayes]

How is it planned to keep the bushing fixed in the correct "offset" position? We are playing we 3 very big alignment variables up front and it already is hard enough  to keep things where they belong with eccentrics on a racecar. Its also a task to get people to correctly set up the current loaded bushings. People screw that up all day long already. Now giving someone another variable to further dial them out from the front? What material will be used? Who will be testing them? 

 

I have never had a set of offset bushings work. In the early Spec E30s that was the hot ticket. I will not set a rear end up with them because the time spent is lost the first time the driver hits the track. 

[Parity]

Just received my copy of Sportscar mangazine. Article on page 56 by Jim Wheeler states, " The plunge cut...will no longer be allowed in Spec Miata." I'm hoping this is a case of it went to print before the final decision was made. ?? Wheel?

[Bench Racer]

Mike Babcock requested per his words, eccentric bushings for the inside of the upper control arm.

 

ISC Racing out of FL is one of several providers of eccentric delrin bushings intended to be used in the inner of upper front or upper rear control arms, because of less loading in upper control arms and they do anchor the eccentric bushings.

[Don Browning]

As a new comer to SM it is nice to see the ruling made that calms things down.  Does much have to be done at this point to have everyone in compliance?  Are most of the heads that competed in 2014 compliant and ready to compete in 2015?

[wheel]

Paul,

I love the printed media.  I still read paper books, subscribe to magazines and take the daily paper.  However, the printed media presents a problem when it comes to something like the SM head debate.  I wrote that column more than a month ago and things have changed since it was written.

wheel

[Mike Babcock]

This will be a four bushing kit for the LOWER control arm. Uses the same eccentric bolts. AFTER(if) this is approved by the BOD, Mazda will have this kit made, this will take 30-60 days. These are not on the shelf at Mazda now, a part number was put in the system in order to get it in the book for 2015. 

 

This is what was recommended to Steve Sanders and what i believe they are pursuing after BOD approval. Whiteline is making a new style, so these may/may not be the final version, Mazda may chose to have them made elsewhere.  But this is what it will look like and what was recommended. 

 

http://www.whiteline...CFRAF7AodsS4AEg

 

Jim

 

Jim, are you able to comment on the reasoning behind the recommendation to implement this solution on the LCA's, rather than the uppers?

[ChrisA]

It would seem that the upper control arm would be a less problematic location for an eccentric bushing/bearing to go, provided it doesn't cause the tire to rub the springs (I wouldn't think the offset would need to be that extreme.) It would need to be a staked or sleeved press fit unit to prevent it from rotating. Don't know what kind of material would be best used. I've had polys before and they were a PITA. Poly does not make a good bearing for the inner sleeve, so they needed to be lubricated annually to prevent stiction and even then were marginal. Perhaps a true roller bearing for that location..? Set and forget.    Also, the lower control arm really doesn't want a stiff bushing material. It needs some compliance to allow for alignment adjustments.

[38bfast]

The upper arms have a larger diameter bolt passing through the bushing. This will alow less offset than the lowers with the smaller diameter bolt.

[Mark]

ISC Racing makes an offset bushing for the front upper control arm. They claim an additional 1.5 deg of camber from these. They are pinned in place to prevent movement. Installation guide:

 

http://www.iscracing.net/bushinst.html

[Marc Cefalo]

ISC Racing makes an offset bushing for the front upper control arm. They claim an additional 1.5 deg of camber from these. They are pinned in place to prevent movement. Installation guide:

 

http://www.iscracing.net/bushinst.html

had these exact bushings in my ITA car.  they worked great and NEVER shifted regardless how many curbs i launched the car off of.....

 

[Johnny D]

Paul,

I love the printed media.  I still read paper books, subscribe to magazines and take the daily paper.  However, the printed media presents a problem when it comes to something like the SM head debate.  I wrote that column more than a month ago and things have changed since it was written.

wheel

 

Can you disclose your current point of view?

J~

[wheel]

The system is working perfectly.  There is a recommended rule change for 2015 that came through the SCCA system.  The BoD will vote on it next week, and the class rules will be clear for 2015.  When any new data comes in to the SMAC and the CRB, we will consider it with regard to any additional changes to the class.  I am a big supporter of using the system to work through these types of situations.  Thanks to Bob Dowie, my mentor in this job and a ten year member of the CRB, for teaching me how all this should work.  

Not sure if that is an answer to your question.

wheel

[Bench Racer]

Jim Wheeler, it would seem that Miake Babcock asked for the eccentric bushings to be used in the inside of the upper control arm and the FasTrack words indicate they will be approved for ues in the inside of the lower control arm. Agree the cam bolts are a smaller diameter, if there are no other issues, how about tweeking the rule a bit so we could turn the upper bolt to a same diameter as the cam bolt to get the full value of the eccentric bushing. On the nut end of the smaller upper bolt we would require a stepped flat washer inserted into the sub-frame hole to hold the smaller bolt diameter.

 

Or if  desired camber can be gained by using the OEM original sized long upper control arm bolt all would be good. 

 

Mark Cefalo, when using the ISC Delrin eccentric bushings with the OEM upper control arm long inner bolt how much negative camber could you get and is/was there any issue with the tire hitting the coil spring? Any other issue? Your picture shows a NA chassis.

[Ron Alan]

In theory...wouldn't messing with the lower arm require a track width clarification? Not so much with the uppers?