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Discussion Starter · #1 ·
The proposal to specify that only production car-available active center differentials are allowed is intended to put a cap on costs to be competitive in Open class (according one PRB member). I appreciate this effort. I don't have all the answers, but I have a few questions.

Would this mean that all homologated Group N active center differentials would be allowed in Open class? If so, I don't have a problem with that, I just want to know if that's what is meant by the proposal.

Are Subaru and Mitsubishi the only manufacturers that have homologated Group N active center differentials? I hear that the latest Group N active center differentials are fabulous.

Are there other production car-available active center differentials out there that would be much good for rallying?

What sorts of center differentials did 5+ year old WRC cars from Ford, Peugeot, Toyota, etc. use?

Is old WRC center diff technology better than current Group N technology?

Are there any unintended consequences of this proposal?

Enlighten me.
Dave
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Pat will jump in and correct me here :), but my gut is that the the STi active center (the production road car one) is not much of an advantage over a VC.

I've driven it a lot on loose surfaces (snow & ice, but not much gravel) and the stock TCU (gearbox brain) has "issues" when being run flat out on very loose surfaces.

The "static" EMCD -- which is on one of the Grp N variants ( forget which one, prob the 15" one), ie the 6speed, but just a manual knob, no computer, would be much more suitable. It has better power handling than the old 5MT electric one, and you can adjust the static amount of center diff lock you need. Same gearbox guts, just a "non-active" control knob that varies the PWM to the diff.

The way I read the proposed rule (which could be wrong) is that you'd need to keep the entire production active center diff intact, including controller.

So, still waaaaaay better than a 5 speed, but you're in open so you could just run the 6 speed any way you want it (VC or static EMCD), just no aftermarket controller.

The road going Evo ACD does have a gravel map, but if Leon says there are reliability issues....

Glenn
 

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I see it as any active center diff used in a production car.
i.e. if Audi had an active diff on their cars (even though they do not rally and have homologated cars) that diff should be allowed on any OPEN car. If we just stick with "homologated" then we are stuck with 2 diffs to choose from.

-george
 

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thread hijack alert!

Mustafa,
I would like to think the differences would be in sweat equity vs. checkbook.
If someone wants to put an Audi under an Imprezza body? That's Open.
If someone puts who-knows-what under a Fox Wagon? That's Open.
But buying one expensive electro-mechanical device after another that can't be duplicated by someone in his garage, that serves no other purpose than to raise everyone else's budget, is kinda dumb. This sport pays zero, has no hope of breaking even in the next 10 years, has very few accomplished drivers and no cost-no-limit teams.
Most are VERY limited by costs. Why would anyone want to kill all hope of competeing before the season even started? That is not the way to welcome newcomers that may, by their individual participation, elevate the sport someday.
If we got on better footing running ex-WRC cars would be nice but the factories can't afford them either (and they have limits too).
rz
 

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RE: thread hijack alert!

I believe putting limits on what can and what can't be used in Open Class will be taking away from the spirit of Open Class.

If the bill is too high to pay, there is no shame in switching to a less expensive rectricted class.

Are we trying to bring Open Class in line with Group A ? Is that the motive ? If so let me know, I can bring/build a Group A car with all homologated goodies, but if it's not the case, leave Open Clas alone, last I checked it wasn't QuasiOpen or KindaOpen or OpenButRestricted Class.

Randy, if I concoct an active diff in my garage and slap it under my car how can anybody else duplicate it ? The same thing goes to fancy schmancy expensive WRC diffs aswell, it's very ridiculous to try to ban something because you don't have access to it, regardsless of the reason, financial or technical.

If it ain't broke don't fix it, and I don't believe we need to fix Open Class. That's all I have to say.


M.Samli
 

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RE: Here's Open

Your right that is wide open. Wow! Someone had way to much time on their hands. I have the utmost respect for that. But in all reality I can appreciate why they said no. You can't even begin to justify putting plates on that thing I am sure they did as home built or something but... You have to take into account what they are doing with the series here and in Canada and I think you can appreciate why they don't want it. However I haven?t looked recently but the rules use to say something like run what you brung as long as you can convince tech its safe you just won't get points. I don't know if its still in their or not. My guess is it wouldn?t take much exploitation to do away with that too.
 

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RE: Here's Open

>If you think Open really is unrestricted, here's what is NOT
>allowed right now...
>http://www.bishop.ab.ca/CSCC/rocky/2003/rocky_winners.htm
>and look at the picture on the right of the 1996 winners.
>"Tim Bendle / Art MacKenzie
>1996 Rocky Mountain Rally"
>Now THAT'S Open.
>rz

i want one of those. that would be a blast on the farm!
 

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RE:

banning active center diffs with the exception of those avaiable in production cars would mean that 2 disctinct brands of open class cars would have an unfair advantage over the others

banning them altogether would mean that group N and production GT cars can have things in them that open cars cant (lame)

leave it like it is, or else put a technology cap on them (i.e. the maximum allowable pressure in a hydraulically activated differential is xxx bar)

-Pat
 

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RE: Here's Mitsu

Good info on the Mitsu ACD system can be read here http://www.btrprep.com/e7_qa.htm , anyone wanting to understand what it is and how ACD works should have a look. ACD comes standard on all USDM 2005 Evolutions.

I do not know much about the Subaru system, maybe Pat can shed some light. I think it's wise we understand what we are talking about banning.


Personally I think banning OEM systems would be unwise. Allowing aftermarket systems can get expensive, but I doubt anyone would make the effort. I think electronic centerdiffs should be left open(the rules, not the diff;) as they can be a liability as much as an advantage.

What would we do with a Hyundai using a evo box and ACD, since it's OEM and "off the shelf" would it be ok? Or make the rule "if came equippped with"

Active front and rear diffs are what we should stay away from, a bit over the top.


Peter
 

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RE: Here's Mitsu

Hence, let me repeat in plain old English;

Stop screwing with stuff that needs not be screwed with.

Leave Open Class Open. Open is not GrA. But if you would rather play the GrA game get ready to lose whatever competitive edge you had the illusion of having.

M.Samli
 

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Discussion Starter · #15 ·
RE: Here's Mitsu

Mustafa,
Most likely nobody on this thread thinks they have a "competitive edge" in the diff department. Pete and Pat have active center diffs that are widely available and that won't be banned. My center diff is not active, not adjustable, not electric, not very special. This is simply intended to be an information sharing session.
Dave
Car # 207
 
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