Guibo - Proposed Motormount rule

[ECR]

Having arrived late to this discussion, i beg the forum's pardon for any redundancy in my reply. Having moved from VW to BMW a mere 3 years ago, with an E-36 in ITS, let's suffice to say that I've learned a few things about these cars when raced. The most important of which has been that the guibo, a new guibo, coupled to a fresh and balanced driveshaft assembly, can and will come apart at random, attempting to cut the car( and driver) in half. Therefore, and based on the fact that no performance gain is netted by changing it, when I find an aluminum replacement for my application I WILL install it, and take my chances at the tech shed, where the downside is far less harsh than the alternative. Until then, an oil change includes a guibo, and fingers & toes remain crossed.

Sincerely, David Leira

[Greg Amy]

Ah, the old "safety" canard...the more things change...

[Andy Bettencourt]

fresh and balanced driveshaft assembly,

???

[Flyinglizard]

I crewed a couple of DTM( pre sequential) cars that moved stateside. They had the stock rubber drivers.
The crucial point is to torque the bolts per book. That is to; not to turn the bolts ever, just the nut.(PITA)
FWIW the nose of the shaft engages the trans just enough to not allow the shaft to fall onto the ground upon failure. In theory..
Oh, if you have to buy a new U joint for a stock BMW?? You are supposed to buy the shaft assembly.

I dont see how this is any different than my 4130 axle cages, that all of you made such a big deal about. FWIW the cages appear the same as stock until you drop them on the ground from 5ft.

Maybe the rules should state " rotational equivalent."(mass and diameter) for drive systems.
That would cover Ujoints, axles, rag joints,Guibo, half shafts, drive shafts.

[Ron Earp]

???

New drive shaft. After my Jensen explosion I think it is a good idea and had a new one for the Z and will have a new one for my Mustang. It weighs the same as an old stock one, but it is just new, tested, and balanced.

[JeffYoung]

Well, we asked for comment and we got it...lol...

Andy, this discussion moved beyond just motor mounts very quickly after you guys left and the reasons for it to me make sense. All rule writing is arbitrary line drawing. The realization hit most of us I think after discussing the motor mounts rule that it made no sense to just say motor mounts and require crap rubber tranny mounts and diff mounts.

In fact, think about it. We are allowing the replacement at this point of basically all rubber in the suspension and driveline mounts. So, I would submit that allowing the change out of rubber in a guibo mount (no picking on Josh, but precisely in my view the type of cheap bolt on mod that Josh viewed as the future of IT) to be logically consistent with the overall class approach, and logically inconsistent to single this out and not allow it.

I just don't see a monster here. The rule can be written in such a way to make sure that CV joints and U-joints and dual mass flywheels and intake "rubber" doesn't get replaced. I admit "changing all driveline rubber" is too broad.

Andy I've told you before I like your wording of the rule and it is similar to something I drafted a while back. The problem is some on the committee are opposed to solid mounts. While I disagree with that position, I understand where they are coming from and the compromise we worked out is what you see now. With this committee, your rule won't fly.

I'm not adamant about this interpretation of the rule/making sure we cover guibos. I just think folks with guibos are getting a raw deal vis a vis what is a pretty consistent philosophy on bushings on the rest of the car. But if membership is opposed, I am fine with that.

Because you have created a monster. It's impossible to know where there is rubber in every driveline on every spec line. I again implore everyone to realize where we are in thread/proposed rule, based on a request to allow aftermarket motor mounts.

This is the stuff we have been warning everyone about. Lines in the sand...they will keep moving unless we stop trying to get cute with the rules, and stick to the simple stuff. I have always felt motor mounts should be able to be urgraded. I can even see the logic in transmission and differential but to allow every driveline bushing? Internal and external? Think of that for a second.

"Motor mounts may be substituted with units of alternate material. They may not reposition any component from it's stock location. They must be of stock external dimensions."

I don't care if they are made of metal or cotton candy as long as they don't exceed the limitations.

[Andy Bettencourt]

In fact, think about it. We are allowing the replacement at this point of basically all rubber in the suspension and driveline mounts.

Well, not yet actually. You are extending the line after the 'first extension' and it's getting out of control IMHO. It's not even theorhetical creep, it's just plain CREEP. Not needed, not consistant.

Andy I've told you before I like your wording of the rule and it is similar to something I drafted a while back. The problem is some on the committee are opposed to solid mounts. While I disagree with that position, I understand where they are coming from and the compromise we worked out is what you see now. With this committee, your rule won't fly.

Without naming names, hit us up with a couple examples of where they are coming from. If you have limits on function, there is no issue with the material. The compromise is overly complicated and has opened up a HUGE grey area for people to exploit. Friggen HUGE.

I'm not adamant about this interpretation of the rule/making sure we cover guibos. I just think folks with guibos are getting a raw deal vis a vis what is a pretty consistent philosophy on bushings on the rest of the car. But if membership is opposed, I am fine with that.

Do me a favor and hold off on this position. The only bushings that are free are the suspension bushings. FAR from 'the rest of the car'. It's only being extrapolated in your mind based on the current wording out for member comment.

I honestly can't believe how much this has gotten out of control. "Please allow alternate motor mounts" -------> "All driveline bushings are free".

Somebody better sharpen their pencils and update the Glossery in a VERY careful way. See: 'Drive Train'

Maybe I'm nuts. Anyone else feel like this is bogus? Let me know before I send my letter.

[Knestis]

...or we could have left well enough alone.

THIS.

ALWAYS.

HAPPENS.

WHEN.

WE.

CHANGE.

RULES.

K

[Andy Bettencourt]

New drive shaft. After my Jensen explosion I think it is a good idea and had a new one for the Z and will have a new one for my Mustang. It weighs the same as an old stock one, but it is just new, tested, and balanced.

My point is that there is no provision that I can remember for an aftermarket BALANCED driveshaft unless the balancing is the same as the OEM spec. If that were the case, there would be no reason to call it out in a 'sales' way as something that was special.

[Flyinglizard]

Really Andy?? Balancing should be free. 99% of everything that spins is balanced at the OE.
I doubt that you can buy any rebuilt part, not balanced.
Even a 12$rotor is balanced

[Andy Bettencourt]

Even a 12 is balanced

Maybe so but if you were selling a car with an extra set of rotors would you advertise them as 'balanced'? No. Just asking the question here. If it's as delivered to OEM spec with no special customization, no issues...

[GKR_17]

Actually the flex disc mounts the driveshaft to the transmission & is made of rubber - when removed the driveshaft will hit the ground.

Nope. The tail shaft on the transmission has a shaft that engages a rubber bushing (also not a mount, and not replaceable except with stock parts) that keeps the driveshaft centered but does not transmit any torque. This also negates 99% of the safety concern of a failed guibo.

The E21 and earlier guibos were junk (so replace them more often). For the E30 and forward there's very little to worry about.

[shwah]

So now we get to test and develop lightweight driveline joints? Well that just reinforced my current opinion of the new rule.

If it goes through, I will definitely take the opportunity to make lightweight motor/trans mounts. I guess now I need to start looking at whether there are also smaller and lighter CVs that can work on my application...

[ShelbyRacer]

How about:

Mounts which attach the engine/transmission assembly to the chassis may be filled with alternate materials. This would include aftermarket "inserts". The geometry of the filled mount must be identical to a new, stock replacement (OEM-style) mount.


This way, you have to use the stock mount and can modify it from there. Permissive (what you CAN do) rather than restrictive. Thoughts?

[JohnW8]

John, where did you get that definition?

Got it from Turner Motorsports
http://www.turnermotorsport.com/BMW-...cs-guibos.aspx

I see little to no performance advantage other than adding durability to the part and possibly a miniscule faster response time. But I do see it stressing the driveline a bit more due to the urethane bushings stiffer material. Chuck might feel more vibrations through the driveline that he currently might not.

[JeffYoung]

Your input is noted...lol....

Seriously, having now taken a few cars apart, what bushings actually exist other than in the driveline and the suspension? Body on frame cars, they have some on the body mounts. Steering column maybe? I just don't see the monster in the closet on this one. Certainly not like the sphericals that came with the initial rule change, or ECUs, or "exhaust is free," or "traction bars are legal so redesign the whole rear suspension."

And it IS consistent. You don't seem to have read my post. There would be two "consistent" rules here. One says no bushings can be replaced, the other says all. We are somewhere in the middle with an arbitrary line that doesn't make a lot of sense.

The basic position (as I understand it) of the guys who do not want metal/solid mounts is that they can be used to create stress points on the chassis and make the motor or the tranny or the diff essentially part of the "stiffening" structure of the car. I don't know enough about it to say one way or the other. The reading I did suggests that doing this is generally a BAD idea on a production based car with a limited cage and no tube frame.

Since input so far has been overwhelmingly negative on something that I view as a non-core IT value, I would oppose this despite the inconsistency I mention above.

One last comment on Kirk's post (as always, good to see you this weekend). We need to have "anchors" like Kirk and Lee and others who make sure we don't move too fast or in many cases move at all.

At the same time, IT does have to change to keep up with the times. If we were running that ruleset from 1985 we'd be dead. And we have tough competition now from NASA. Over and over again every time I go (infrequently) to a NASA event or see pictures of one, I'm shocked and amazed at how young the paddock is compared to ours.

IT should be the leading class in SCCA attracting young drivers (along with SM), especially ones who want to build their own cars (along with STL -- Greg and his team have done a great job with that). Things like the washer bottle rule and this bushing stuff seem like such huge end of the world issues to us, but to a 25 year old kid (or even sometimes the 40 year old kid) it's a lot of hot air over what to them is nonsense.

I agree we need to find a balance between no changes, and changes that don't change the core of the class and make it more attractive to others, and changes that DO change the core of the class and eventually kill us. Not easy to do, but necessary.

Well, not yet actually. You are extending the line after the 'first extension' and it's getting out of control IMHO. It's not even theorhetical creep, it's just plain CREEP. Not needed, not consistant.



Without naming names, hit us up with a couple examples of where they are coming from. If you have limits on function, there is no issue with the material. The compromise is overly complicated and has opened up a HUGE grey area for people to exploit. Friggen HUGE.



Do me a favor and hold off on this position. The only bushings that are free are the suspension bushings. FAR from 'the rest of the car'. It's only being extrapolated in your mind based on the current wording out for member comment.

I honestly can't believe how much this has gotten out of control. "Please allow alternate motor mounts" -------> "All driveline bushings are free".

Somebody better sharpen their pencils and update the Glossery in a VERY careful way. See: 'Drive Train'

Maybe I'm nuts. Anyone else feel like this is bogus? Let me know before I send my letter.

[Knestis]

Got it from Turner Motorsports
http://www.turnermotorsport.com/BMW-...cs-guibos.aspx

I see little to no performance advantage other than [performance advantage] and possibly a [performance advantage]. ...

Edited for clarity.



K

[DavidM]

IMO flex-disks are not part of the mount rule nor should they be and the rule should not be rewritten to somehow include them. There's my input.

David

[Andy Bettencourt]

Jeff, can you let us know what the opposition is to solid mounts? Some worries? Avoid 'stressed member; stuff because simple wording avoids that issue.

And PLEASE, just because there is overwhelming objection to the proposal as written, doesn't mean the ITAC should throw out the entire idea. The membership wants alternate motor mounts. They don't want a Pandora's Box.

Give them what they want, in a simple and restrictive way.

[tnord]

as the actual author of the rule (with some edits from chip)...

i did not write it intending to include them.
i do not believe the "allowance" wording includes them.
i do not believe the "intent" wording includes them.

furthermore....i am one of the "objectors" to solid mounts. i've said time and time again on calls that i don't like them, but i'm sure as shit not going to hold up getting an alternate mount rule through if we can't all agree on a wording that we think that is reasonably successful. since i objected, i was voluntold to come up with some wording. i took my best crack at it which is what you see in fastrack, and it went through unanimously.

the reasoning i don't want it is partially because of what jeff mentioned with the stressed member arguement, and the other is a matter of perception. fucking bullshit like those custom bearing mounts that schaafsma has posted has no place in IT just like spherical bearings don't have any place in IT either. do they make any significant performance difference? no. but it's just another item on the list current drivers or prospective drivers see as a hurdle to being competitive. it's a bunch of little crap like this that has at least contributed to the decline in SM.....shock mounts, AFPR, torsen, subframes, etc.

the criticizm of this particular wording is that it's ambigous on whether or not it allows bricks of aluminum on mounts (i don't think it is but whatever....people that want to be pricks and intortutate will do so regardless), while simultaneously saying that there's no advantage to the solid mounts and you wouldn't want to do it anyway. if we at least put the doubt in somebody's mind that they're legal, and that a tech inspector somewhere could DQ them for having the parts.....and keep them out of 99% of cars i think we've done well.