72 replies to this topic

[Steve Scheifler]

The ISC parts look OK but I don't like this "You need to open up the Delrin hole sightly to allow the metal sleeve to slide into the bushing."

They don't explain that at all and I'm not sure what one of the pictures is illustrating, but surely you don't have to enlarge the hole through them to get the bolt in?

[James York]

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

Not if defined at hub center, which it should be.  Anytime I have been checked for track, they do it by looking at my wheel offsets and checking for any spacers.  Granted that would not catch if I cheated up the suspension somehow.

[Johnny D]

I get it, some have more camber in shady ways...

Now you can too....?

But really ??

Make it legal with this bushing..??

Hmmm...

I guess it's up for discussion for this low cost class were in

J~

[Cnj]

I get it, some have more camber in shady ways...
Now you can too....?
But really ??
Make it legal with this bushing..??
Hmmm...
I guess it's up for discussion for this low cost class were in
J~

Sarcasm cloaked in naivete?
Anyway, yes people have been cheating up camber - and it's difficult to catch. So many have performance gain that can only be matched by engaging in cheating (but Mom, all the other boys did it!!!).
Yes, this will allow low cost Mazda parts (safely for those concerned about the spindle bending techniques) to be employed to gain additional camber.
Cost? Well it's really modest and presumably not much more than a current Mazda bushing. The savings will come in improved tire life, a financial bargin I am happy to accept.
Low cost class? Low cost racing is oxymoronic.

This is a good rule proposal. Low cost, long term tire savings, eliminates a common (hard to catch) cheat.

CNJ

[MPR22]

 Low cost racing is oxymoronic.

 

truer words have never been typed. 

[wheel]

I have had several conversations about the plunge cut and 1.5 mm clean-up of the short turn radius.  I want to be very clear that we have not added any weight or restrictors for the 1.5 mm de-burr because we currently have no data to support doing that.  But, if dyno data shows that the 1.5 mm de-burring has added power, there will a penalty to compensate.  This is part of the explanation that accompanied the REC from the CRB, so be forewarned.

 

Allowing the de-burr is only to keep many of the current heads in the game, (even though non-compliant to the old rules).  So, if I was building an engine for 2015, I would do the plunge cut to the rules and I wouldn't touch the short turn radius.  

 

wheel

[Chris70]

Wheel, thank you for keeping us informed.

The suggested rule seems correct up to the point of the 1.5mm de burr.

Either it is allowed permanently as is written or it is not. It makes no sense to allow something now and later penalize those who follow the rule.

Please chose your (our) poison and stick to it.

I have 11 heads waiting for a rule and a truck load of cars to get done and taken to Florida in less than 30 days.

Ademir Fedumenti

S.A.C. racing

[FastEddie]

This makes zero sen

 

Wheel, thank you for keeping us informed.

The suggested rule seems correct up to the point of the 1.5mm de burr.

Either it is allowed permanently as is written or it is not. It makes no sense to allow something now and later penalize those who follow the rule.

Please chose your (our) poison and stick to it.

I have 11 heads waiting for a rule and a truck load of cars to get done and taken to Florida in less than 30 days.

Ademir Fedumenti

S.A.C. racing

+1

Seems crazy to put in the rules and then 'perhaps" add a penalty later? It is either the rule or it is not the rule. 

[Jim Drago]

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

 

 

SMAC has kicked this around, CRB will talk about it at our meeting Thursday.  No promises, but no one seemed opposed to upper control arm bushings instead of lowers. We will discuss Thursday for BOD approval Friday.

[Bench Racer]

SMAC has kicked this around, CRB will talk about it at our meeting Thursday.  No promises, but no one seemed opposed to upper control arm bushings instead of lowers. We will discuss Thursday for BOD approval Friday.

Jim, talked with Whiteline Suspension and they instruct to install their offset busing in the upper control arm because there are less forces in the upper control arm. Per say never had an issue themselves with or custorme issue with a bushing rotating after press install. They also have a second part number with suffix "A" which has a split outer steel sleeve around the offset bushing which is less than a press fit into the control arm. 

 

Looking at ISC Racing, they press the offset bushing into the upper control arm because of less forces and they anchor the bushing to the control arm by drilling a thru hole and pressing a grease fitting thru the control arm. 

 

Seems from two providers, the upper control arm is the first choice for the offset bushing. And both companies use the steel inner sleeve that the OEM long bolt fits through.

 

Thank you

David Dewhurst

[pitbull113]

I have the ISC upper offset bushings in the front of my ITA car and I'm very happy with them. 

[Jim Drago]

Jim, talked with Whiteline Suspension and they instruct to install their offset busing in the upper control arm because there are less forces in the upper control arm. Per say never had an issue themselves with or custorme issue with a bushing rotating after press install. They also have a second part number with suffix "A" which has a split outer steel sleeve around the offset bushing which is less than a press fit into the control arm. 

 

Looking at ISC Racing, they press the offset bushing into the upper control arm because of less forces and they anchor the bushing to the control arm by drilling a thru hole and pressing a grease fitting thru the control arm. 

 

Seems from two providers, the upper control arm is the first choice for the offset bushing. And both companies use the steel inner sleeve that the OEM long bolt fits through.

 

Thank you

David Dewhurst

Thank you for your input I had to get a last one or two in there

[Marc Cefalo]

 

 

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.

 

we were able to get over 4.5 degrees of negative camber with them.  the car ran on 205 50 15 goodyear eagle RS's and never rubbed the front springs.  also keep in mind that was with a 40mm offset wheel with no spacers so i doubt there would ever be rubbing with the more aggressive offsets we run in SM.  there were no known issues we had with them.

[Steve Scheifler]

Sold.

Now can they or Mazda guarantee timely supply or do we need specs to avoid any shady stuff while allowing others to produce them?

[Ron Alan]

Not if defined at hub center, which it should be.  Anytime I have been checked for track, they do it by looking at my wheel offsets and checking for any spacers.  Granted that would not catch if I cheated up the suspension somehow.

Thanks for agreeing with me

My guess is the original maximum track width was figured with the lower eccentric bolts maxed out. That and the other parameter of wheel patch straight down from the fender has given the 25mm wheel the nod for maximum track width. 

So if offset bushings are speced for the lower arm...this will move the hub outward which will widen track width. Not sure if this would be measurable but it could amount to a couple MM's for sure?

If done on the upper arms...this would move the hub inward if anything.

 

What is the claim on the measurement difference in some of the offset bushings mentioned?

 

So if this was an open item...we were allowed to replace stock with offset, I would do the lowers in the front(at the eccentrics) and the upper(upright)or uppers(control arm) in the rear. This may improve the stock stagger a little(shrink the difference) still running 25mm offset wheels. I know some like to run 30mm offsets with 5mm sacers in the front to help this.

[Steve Scheifler]

I don't know. I guess if you just pin them in place maybe lowers would be fine, it's just that I've heard too many stories of them moving. It would be nice to reduce the deflection of the stock rubber (you are running the stock ones, right??) but not if it compromises reliability.

[ChrisA]

I don't know. I guess if you just pin them in place maybe lowers would be fine, it's just that I've heard too many stories of them moving. It would be nice to reduce the deflection of the stock rubber (you are running the stock ones, right??) but not if it compromises reliability.

 

Depends on the design of the bushing and inner sleeve. If the inner sleeve is the is the off set mechanism, as it was with my former polys (SuperPro), than it is difficult to ensure all the eccentrics are aligned properly in the arms. Even if we had no problems with them moving under load, the ride hight changes we make will effect them, along with all the alignments. Too easy to get something off and them handling & alignment issues arise.

[Bench Racer]

Thank you for your input I had to get a last one or two in there

[ner88]

I for one think the eccentric bushings are a bad idea.

These will cause excessive wear to tires, bearings and more.

These cars don't need 3' or more camber.

Simple rule at no cost to anyone would be limit camber.

We all know what is max based on the cars adjustment limitations so pick a number and be done with it.

This is rules creep!

[Bench Racer]

I'm sure the rule will be written, one MAY install offset bushings in the upper control arm. Don't want the offset bushings, don't install them. My take on this, allowing offset bushings is that folks were obtaining more negative camber illegally, therefore make getting there legal.

 

I do agree with your thoughts on excessive tire wear, bearings and more. If we used harder tires those excessive wear issues would go away.