44 replies to this topic

[Bench Racer]

Had the CaveMan diff. previously in other races/qualifying been involved in bump drafting?

[davew]

For those of you worried about legality, this has been legal for many years. I wrote a letter and requested a definitive answer. That is when the words about trans and diff housings was added to the rule quoted above.

 

Been legal since begining of SM by "industry standard repair"

Specificly made legal by my letter and change in wording many years ago.

Not a performance advantage.

Not a slippery slope to prod rules.

Many of you just did not know about the rule or the problem. 

 

Jim, being a business man, is simply making the part available to those of you who can not weld aluminum. And at a reasonable price. Look up a new one, close to $1000. Even used are in the $300 range.

 

Dave

[Diller]

Any reason that the subframe plates had to be sourced from Mazda and these do not?

 

Not that I am complaining because the front braces are extremely well priced but there is some inconsistency.

 

Also, reliability is a performance advantage weather you like it or not, ask any IMSA or endurance team. It does become a slippery slope when the argument for any cheater part becomes "reliability". If it's unclear I do support this modification (even though I just rebuilt a diff without welding in the brace) but think it should be spelled out similar to how the front braces were.

[FTodaro]

Dewey. Normal bump drafting does not break the diffs. This is less likely to happen when you have your foot on the gas more likely when you are off the gas or miss a shift and get nailed hard. In my experience.

[Jim Drago]

For those of you worried about legality, this has been legal for many years. I wrote a letter and requested a definitive answer. That is when the words about trans and diff housings was added to the rule quoted above.

 

Been legal since begining of SM by "industry standard repair"

Specificly made legal by my letter and change in wording many years ago.

Not a performance advantage.

Not a slippery slope to prod rules.

Many of you just did not know about the rule or the problem. 

 

Jim, being a business man, is simply making the part available to those of you who can not weld aluminum. And at a reasonable price. Look up a new one, close to $1000. Even used are in the $300 range.

 

Dave

Dave

I really think we did a disservice when we did this, not sure if you were on SMAC then or not. So it was likely SMAC and me as CRB rep at the time.  We left the rule vague for all the reasons you listed. But IMO, if I was asked to inspect and rule on what I have listed.. I would rule it non compliant.  Many of the housings that I have seen are butchered up nasty looking examples of plating housings that were broken in half. The plating in that example "could" be justified as industry standard repair as plating a broken piece is "normal"  Taking a nice virgin housing and plating it like we did to hopefully guarantee it doesn't fail in hard bump draft or stacking in first few corners...  I would think that is a tortured interpretation.  I feel confident that I could likely win an appeal, but I think it needs to be spelled out to alleviate any concerns. I would hate to have to make up a story(why everything in original post is in quotes) in order to do what makes the most sense. I have no intentions of pulling mine out at this point, I have no intentions of welding it all the way around to "look" more like a repair and  I would quit racing  before I would put one of those frankenstein looking POS repairs in my car.  Hopefully the SMAC will "repair" (pun intended) the rule. However I won't change what I am doing now regardless of the the rule. 

I will take my chances. 

[Jim Drago]

Any reason that the subframe plates had to be sourced from Mazda and these do not?

 

Not that I am complaining because the front braces are extremely well priced but there is some inconsistency.

 

Also, reliability is a performance advantage weather you like it or not, ask any IMSA or endurance team. It does become a slippery slope when the argument for any cheater part becomes "reliability". If it's unclear I do support this modification (even though I just rebuilt a diff without welding in the brace) but think it should be spelled out similar to how the front braces were.

 

 

Pretty simple.. 

The fear was front pick up points could be moved and hidden under the front subframe braces.. Pretty hard to move anything without changing the diff housing and welding a piece on the inside of the perimeter of the original housing.   

Jim

[dickcdawg]

Have 1.6 diff housings experienced similar breakage, benefit from same gusseting? 

 

Dick H.

#39 ITA - '92 Miata - SeDiv North

[Danica Davison]

It would be a weeny protest. 

 

hmmmmmmmmm.  never make another bet with me Jimbo  

[Jim Drago]

hmmmmmmmmm.  never make another bet with me Jimbo

You want to make another bet this will be addressed and resolved by runoffs

[Bench Racer]

Dewey. Normal bump drafting does not break the diffs. This is less likely to happen when you have your foot on the gas more likely when you are off the gas or miss a shift and get nailed hard. In my experience.

Frankie no matter how the words are packaged, it's an a$$ packing which STARTS the crack or breaks the diff. How many diff's. from street cars/never on a track have you found with hairline cracks or fractures? 

 

The Wheeler's, Drago's and others who view lots of diff's. from never tracked diff's. to race tracked diff's. know the facts.

 

It would appear one fact (Jim's prepped diff. housing) is only the passenger side breaks. Question, why does only the passenger side have OEM notches and or get beefed up? Diff. pinion rotational direction/speed? 

[Caveman-kwebb99]

Had the CaveMan diff. previously in other races/qualifying been involved in bump drafting?

 

I wasnt sure what you were asking till you replied to frank.  my car goes up on a two post rack after every race for nut and bolt and inspection of parts like diff carier subframes etc.  I have never found a crack even a slight one in the diff carier or my subframes other then a cleanly broken diff carrier those two times I mentioned... it actually kind of suprises me on the diff carrier as I have been the recipient of some hard ass bump drafts... Maybe I have just been lucky??? No idea...

[Caveman-kwebb99]

You want to make another bet this will be addressed and resolved by runoffs

 

 

If only you had done your damn job! No bets would be neccessary!!!! XOXOXOXOXO

[Danica Davison]

I wasnt sure what you were asking till you replied to frank.  my car goes up on a two post rack after every race for nut and bolt and inspection of parts like diff carier subframes etc.  I have never found a crack even a slight one in the diff carier or my subframes other then a cleanly broken diff carrier those two times I mentioned... it actually kind of suprises me on the diff carrier as I have been the recipient of some hard ass bump drafts... Maybe I have just been lucky??? No idea...

 

It has actually happened a couple of times within the last two years or so at Daytona. Daytona being probably one of the most bump draft dependent tracks in the country.  You have the guys that get driven away from coming out of either the bus stop or turn 6 and they get sucked back in from a little too far back.  If they don't ease off before hitting bumping in to the car in front, it can break the diff housing.  That's the only track I know of that really has an issue with breaking diff housings because of people not knowing how to bump draft

[dstevens]

While we are at it...lets make it ok to keep or remove anything under the dash! We are beyond show room stock...we don't need heater cores or fans or anything related. We need to eliminate the "non performance argument" from peoples minds and just let things that don't matter go!  

 

[Jim Drago]

If only you had done your damn job! No bets would be neccessary!!!! XOXOXOXOXO

and we would be missing out on all this fun

[Caveman-kwebb99]

and we would be missing out on all this fun

 

 

this is fun?????   Nobody is even making fun of Danny!

[Jim Drago]

Here you go..  take a look at 7:25 to 8:00

Thats all it takes

Jim

 

http://www.ustream.t...orded/100564920

[Caveman-kwebb99]

Here you go..  take a look at 7:25 to 8:00

Thats all it takes

Jim

 

http://www.ustream.t...orded/100564920

 

Seemed like alot fo brake checking before the broken diff just sayin!   

[FTodaro]

Jim when you go in and fix the "Diff Rule" go ahead and get rid of the two gasket requirement on the restrictor plate also, if you want to clean a few things up.

[EMatoy]

Have 1.6 diff housings experienced similar breakage, benefit from same gusseting?

Dick H.
#39 ITA - '92 Miata - SeDiv North

The 1.6 housings don't have the notch. I don't know of any of them breaking.