235 replies to this topic

[Steve Scheifler]

 By design Mazda has put adjustment in the lower control pivot point to be able to get there factor settings. If what you were saying is true the would have been no need for cam bolts at all because all the parts are so perfect. The fact that Mazda has designed in a .470" slot for the cam bolts to take up the tolerance of the OE components when they built the car. There was so much variation in tolerance that a .470 slot was needed. 

 

I would amend that somewhat, they probably wouldn't need nearly that much adjustment for manufacturing variances alone, but it is an excellent point that MAZDA provides a way to compensate for minor damage of original parts without feeling that they must be replaced.  Read that again if necessary then throw out one of the arguments against.  Our problem is that we are starting at one extreme of their provided range, leaving ZERO compensation for the very same minor damage issues.  The time and cost to replace every slightly tweaked part seems an excessive penalty.

[38bfast]

An example of rules creep because someone or a lot were cheating was head gate with the short turn radius. It was clear it could not be done. It was not a tolerance issue. Mazda never produced a head that way. But because so many were cheating the rule was changed. Just for reference the SMAC did not recommend that rule change. The rule was adequate as written. 

[wheel]

As with all SCCA rule changes, the only posts that count are the ones that go through the crbscca.com letter log system.  Please express your opinion on the WDYT.

thanks,

wheel

 

PS, the CRB is looking for new SMAC members.  Please send in your resume, if you are interested.

[FTodaro]

An example of rules creep because someone or a lot were cheating was head gate with the short turn radius. It was clear it could not be done. It was not a tolerance issue. Mazda never produced a head that way. But because so many were cheating the rule was changed. Just for reference the SMAC did not recommend that rule change. The rule was adequate as written. 

Just to be fair, We amended the rule, because the reaction from SCCA was going to be stock heads and a huge cost to the class, and the potential of no parts. So that situation is not this situation.

 

As with all SCCA rule changes, the only posts that count are the ones that go through the crbscca.com letter log system.  Please express your opinion on the WDYT.

thanks,

wheel

 

PS, the CRB is looking for new SMAC members.  Please send in your resume, if you are interested.

We will get there, we have to beat each other up a little before we put pen to paper.

[Parity]

As far as variation between currently produced replacement parts and original parts, there may be something to that. I highly doubt Mazda changed the tolerances but automotive manufacturing is driven by process control rather than tolerances. It's entirely possible the current replacements parts have more variation that original parts. This is a total WAG by me but it could explain increases in variation. Send me 20 samples of both new and original parts and I'll run them thru a CMM and then we'd know for sure.

 

 

Added: I'll risk being anal but this is the sort of thing I deal with daily so here goes. A "tolerance" is a variation decided upon by the original engineering intent. If a control arm made of stamped sheet metal has a tolerance of +/-.020" it can vary up to .040". During production manufacturing the process is evaluated and if a normal distribution of 6 sigma is achieved then 99.97 % of parts made will fall into this range. However, 6 sigma is not considered very robust so process controls are tightened to bring the range well within tolerance limits. That means during model year production parts may actually be produced to something like +/-.010". Tolerance has not changed but parts are much more consistent. Now once the model design has changed and cost factors are more influential over quality the process capability may open up closer to the accepted tolerance range which means more variation and a higher likely hood of parts actually exceeding acceptable tolerance range. Maybe this is why Jim prefers "original" parts over new replacement parts? IDK but could be. Again if this is a concern I could setup a CMM run to inspect a batch of parts at my expense.

[Steve Scheifler]

As far as variation between currently produced replacement parts and original parts, there may be something to that. I highly doubt Mazda changed the tolerances but automotive manufacturing is driven by process control rather than tolerances. It's entirely possible the current replacements parts have more variation that original parts. This is a total WAG by me but it could explain increases in variation. Send me 20 samples of both new and original parts and I'll run them thru a CMM and then we'd know for sure.

 

Not necessarily specific to the parts in question here, but:

 

Productions jigs etc. can lose tolerance over their life and are often retired after a specified number of uses.  Get something from the end of that cycle and it may be marginal.

 

Where and by whom a given part is manufactured and/or assembled can change for a variety of reasons. Recall "factory" crate engines which were assembled in Canada and had some parts which were different than those ever delivered in a car but probably met whatever basic specifications they were given.  Example: valve springs.

 

There seems to be a growing issue with Mazda sourcing parts for older cars from non-Original Equipment Manufacturers and slapping them in Mazda packaging.  Other than the markup often seen as being for an "original factory" part I don't really have an issue with it overall if they vet the source adequately for the typical consumer, but it certainly can become an issue in our game. Possible examples: Valve springs, Valves.

 

Interestingly, I once bought front control arms from Rock Auto to see how they compared with originals, and what arrived appeared to be genuine Mazda parts including the labels glued to the arms.  Later I tried this again and got something very conspicuously different.  Perhaps someone just picked up a bunch of NOS somewhere and dumped them through Rock, but when I ordered they were being listed as from a recognizable aftermarket brand.

 

Anyway, point being that relying on comparison to "original from Mazda" is an increasingly risky proposition.

[Steve Scheifler]

Speaking of aftermarket control arms, someone (Bench maybe?) save me the trouble of digging through the current rules and tell me why they would not be compliant if critical dimensions are the same yielding the same alignment ranges etc. of a stock part.  Are they any different in terms of the rules than brake calipers, master cylinders, hoses, ball joints, etc? My only complaint with them back then was that they were heavier than the 1.6 arms but so are the newest superseded parts from Mazda.  If a budget racer wants to try them to ensure a new undamaged part at a lower price, can he? Heck, they even came with the ball joint.

[Todd Lamb]

IMO, this is the ONLY valid argument for this proposal. 

 

But... If the slotting rule is allowing enough for those poor SOB's who cant get there "legally"  and we think people are getting there illegally by tweaking parts.. You really don't think that will stop do you?

 

Let's say the new slots allow all to get to 3.75 degrees at 4.5 in ride height.. 

 

What if we test and the cars like to to 4.75 and 4.2 degrees rear camber?  Guess what.. the guys cheating now and getting 3.5 plus at this height will have no problem getting 4.2 now. And no, tech likely will not be able to catch them.   

 

So I ask, what is this accomplishing? We help a very small few that cant get to a decent number for whatever reason but we give more adjustment to those who are already cheating and more options..  It also adds lots more testing for all of us to see what really works best.  I would prefer not to do it and I better equipped to do it than 95% of the class.

 

To all those who say, well there is a limit to how much negative camber is a gain.. You are correct.. But I remind you.. 5-6 years ago 99.9% of us were saying.. "it's not like people will start showing up with 4 Plus degrees of camber".. Guess what   

 

The slot will allow about .2 - .25 deg more camber. You've gone on record saying 3.5 is the max with stock parts. So at most 3.75deg would be achievable. That's at a given ride height, so you can take that out of the equation.

 

5-6 years ago we were on Toyos and they didn't have the grip level that the current Hoosiers do, so we didn't need that much camber. Not really sure your point has any validity.

 

There's a vast amount of misinformation in this entire thread. Rich and Ralph have very succinctly explained the reasons for the slotted control arms, and none of them have to do with Danny or wanting to get more camber. Dave Wheeler has very succinctly explained why he is against (if you read between the lines he wants to sell his gauges). Steve, who it pains me to agree with , has pretty well debunked the rest of the arguments.

[Johnny D]

5-6 years ago we were on Toyos and they didn't have the grip level that the current Hoosiers do, so we didn't need that much camber. Not really sure your point has any validity.

 

Any update on the tire testing making this subject a moot point ?

 

J~

[Jim Drago]

The slot will allow about .2 - .25 deg more camber. You've gone on record saying 3.5 is the max with stock parts. So at most 3.75deg would be achievable. That's at a given ride height, so you can take that out of the equation.

5-6 years ago we were on Toyos and they didn't have the grip level that the current Hoosiers do, so we didn't need that much camber. Not really sure your point has any validity.

.

5-6 years ago we were on Hoosiers
If the proposed slotting only allows .25 degree it makes even less sense to allow. No one is winning or losing races on .25 degree. If we accept my 3.5 max with out slotting as close to legal max and feel that somewhere around or over 4 is being run by front runners.. The proposed slotting rule does not get us to the perceived “ sweet spot’ .Therefore we will still have competition wondering why they can only get to 3.2, 3.5 when others are able to get to 4+. Either do away with slotting as it really doesn’t accomplish much if anything or allow to slot until your hearts content. This really solves no problem an just creeps the rules IMO

[Todd Lamb]

I believe that was the era of the Toyo 888's

 

You've chosen to ignore the entire point of the slotting that has been put forth already several times. It has ZERO to do with allowing more camber than we currently have. That may or may not have been why Danny did it, but that's not why the SMAC approved it.

 

There's no reason to spend hours and hours and hundreds of dollars in parts to get to the maximum 3.5deg because something moved a millimeter and you're stuck at 3.1deg.

 

You and many builders have free/cheap parts at their disposal, and labor is a money maker, so I can see why you'd be against it. As a shop owner/car builder I would love for the slotted control arms to not be allowed so I can charge customers for new parts and lots of labor, but it is simply not good for the class and adds unnecessary expense for the racer. Wearing my SMAC hat, this decision was a no-brainer.

[Bench Racer]

First we went with Hosier sticker tires, improved drivers capability immediately.

 

Then we went with off-set front bushings. Same arguments as with this rear control arm slut.

 

Then we went with the AFTERMARKET  front hubs. How they working out.

 

Now SMAC is trying to sell upper rear control arm sluts. 

 

SMAC, measure some parts and post some data of raw OEM parts to support you posts.

 

If the parts are as fucked up tolerance wise as some of you are posting, the parts will never fit Dave's gauges.

 

Talking about why the Mazda engineers designed in the cam bolts is way out of some of your pay scale.

 

Transfer to some not so sticky tires and many of our issues would disappear.

 

Put a maximum negative camber on front and rear (I could care less about who has off-set bushings) and let people learn how to drive. 

 

A bunch of you need to back track to the production class car rules pre 1997 and after 1997. In the 50's and 60's there rules were very straight forward as our rules were when we started. Keep on sliding the rules for what ever reason and there will be a day you'll regret, when new folks shy away and the SM numbers start shrinking. Todays Production class rule are so messed up, only those that continuously sift the rules for what they believe the intent of the rule is reach the pointy end frequently. Is that where we want to be, I don't think so.

 

 

A. PURPOSE AND INTENT The Spec Miata (SM) class is intended to provide the membership with the opportunity to compete in low cost, production-based cars with limited modifications, suitable for racing competition.

[Steve Scheifler]

...
If the proposed slotting only allows .25 degree it makes even less sense to allow. No one is winning or losing races on .25 degree...

 

Probably true, though maybe not in some of the very close battles we've seen over the years.  But here is a simple question requiring a simple Yes/No answer.  If you found that your own car maxed out .25 degrees less on one side than the other, and less than you are typically running, would you fix it?  I'm going to be presumptuous about the answer and jump to, "enough said". 

 

But then you went on to make what I think is the very same point I was getting at in my own literary masterpiece when I said:

 

" And frankly, if after all that the guy with a slightly compromised subframe can't attain the new ideal camber and height combination, what have we gained? "

 

Because IF 3.75 really is sometimes better than 3.5, or a height of 4.75 inches really is better than 4.5 so long as you can still get 3.5 camber, then the poor schmuck is right back where he started.  OK, at some point he may benefit from slightly more even tire wear and more heat cycles so that's not nothing if true, but you haven't solved the original problem at all.  And that's exactly why I went with in for a penny in for a pound, give us the front ball joints, a much longer slot if there is room and if that does the trick, shake hands with NASA, and send Jim off to do the testing for us.

[ChaseH]

As far as variation between currently produced replacement parts and original parts, there may be something to that. I highly doubt Mazda changed the tolerances but automotive manufacturing is driven by process control rather than tolerances. It's entirely possible the current replacements parts have more variation that original parts. This is a total WAG by me but it could explain increases in variation. Send me 20 samples of both new and original parts and I'll run them thru a CMM and then we'd know for sure.


Added: I'll risk being anal but this is the sort of thing I deal with daily so here goes. A "tolerance" is a variation decided upon by the original engineering intent. If a control arm made of stamped sheet metal has a tolerance of +/-.020" it can vary up to .040". During production manufacturing the process is evaluated and if a normal distribution of 6 sigma is achieved then 99.97 % of parts made will fall into this range. However, 6 sigma is not considered very robust so process controls are tightened to bring the range well within tolerance limits. That means during model year production parts may actually be produced to something like +/-.010". Tolerance has not changed but parts are much more consistent. Now once the model design has changed and cost factors are more influential over quality the process capability may open up closer to the accepted tolerance range which means more variation and a higher likely hood of parts actually exceeding acceptable tolerance range. Maybe this is why Jim prefers "original" parts over new replacement parts? IDK but could be. Again if this is a concern I could setup a CMM run to inspect a batch of parts at my expense.

To echo want Parity said, I could help with an “original” vs “new” inspection of a batch of parts if the SMAC or someone really wants to see variation. Writing a part program on my CNC CMM wouldn’t take me much time.

Chase

[Jim Creighton]

Bench Racer hit it on the head. I started in Production in 1971. It was very simple. Now, nothing is simple. If that's what you want, keep drifting and you'll be there sooner than you think. And for a real treat, read the complete production category rules in the current GCR. Then, reread it. Then, figure how many things you can no change on your SM to make it a limited prep prod car in EP.  That's about how far production has come since it started.  

[Steve Scheifler]

The comparisons to the production classes are not new, and they certainly are not altogether unjustified.  But, wouldn't it be reasonable to say that a very significant difference is the number of very different cars in a given class and that a lot of the requests for changes are to equalize between them?  We certainly have had our share of that but nothing compared to what is necessary in the multi-car classes with vastly different platforms across many generations.  Surely that accounts for a lot of it, no?  So while there are cautions worth taking from their experience it is far from the same scenario.

[Jim Creighton]

Steve, I'm actually referring to items such as allowing coil over suspensions, alternation carbs, brakes, fiberglass panels, single side roll cages, spoilers, ignition systems, roller rockers, and the list goes on.  None of these items were truly necessary. Most adjustments can be made by weight. Sure, some cars just don't fit and that's too bad. But, the CRB decided to allow things that cars never had to balance it out. Once an item appeared, everyone had to have it.

 

That's what so great about SM. And as such, why do you need more rear camber if almost everyone can get the same?  Sure, a bent sub frame might get more or less. But, it's going to give up something elsewhere. Otherwise, Mazda would have made all the Miatas with bent sub frames!!!

 

I'm on the outside looking in and have no dog in the hunt. I'm just trying to keep you guys from going down the same path the production class did. I watched our cost to race the same little Austin Healy Sprite go up each year. We changed the roll cage three different times so we could keep up with the Jones. I still have a shelf full of cylinder heads each with the latest, greatest trick. And don't even mention camshafts. Sure, we got faster, but so did everyone else.

 

Is this what SM needs?

[Caveman-kwebb99]

I completely understand the caution in allowing things, but it this case taking a Dremel to a rear control arm is no where near the level or letting us put in new cams or pistons on tubed control arms and poly of metal bushings etc.

I would be against any of that, but to make a way for the have nots to have something for little to nothing. This is on par with allowing the 1.6 to take out a blinker and wrap an air tube and grind a few welds in the headed imo!

[Bench Racer]

I would be against any of that, but to make a way for the have nots to have something for little to nothing.

 

This is on par with allowing the 1.6 to take out a blinker and wrap an air tube and grind a few welds in the headed imo!

Your point A., rule a maximum camber, done deal.

 

Your point B., had the SMAC/CRB paid attention day 1 when they allowed the 99 plus cars they would have equalized the cars at day 1. Your mixing apples and lemons.

 

Take your 1.6 to FL and make ALL 1.6 owners proud. Hopefully your 100% prepared. If not there'll be a bunch of $hit flying your way.  

[Caveman-kwebb99]

Your point A., rule a maximum camber, done deal.

Your point B., had the SMAC/CRB paid attention day 1 when they allowed the 99 plus cars they would have equalized the cars at day 1. Your mixing apples and lemons.

Take your 1.6 to FL and make ALL 1.6 owners proud. Hopefully your 100% prepared. If not there'll be a bunch of $hit flying your way.

I can assure you I am not 100% prepped. I found a quarter quart of oil in the air tube when I wrapped it. The engine is at least 3 seasons old.

I am not going to be whining like other 1.6 owners when my less then top.prepped 1.6 can't win. Nor will I be talking about how my top prep nb cars are both faster than a car that is clearly not at the top of it's game.

How did the partiy of the 1.6 and prep level of a car that I have spent about 8 hours total on since the purchase of a garage queen even enter into this conversation????