Motor Mount Options?

[Z3_GoCar]

I've started purchasing parts to put the race car back togeather. One thing I've though alot about but haven't pulled the trigger on are the motor and trans mounts. I'll just go with stock trans mounts, but what about the group-N or equvalant motor mounts? I'd rather have a mount that hold up a little better and doesn't allow the motor to come loose and start banging around like it did. I've got to replace the trans-cross member and shift linkage, and maybe the oil pan because the mounts broke. Just how legal are the factory replacement motor mounts?

James

Btw, I was just kidding about loading up the spare tire tray with dirt....

[Greg Amy]

I'll just go with stock trans mounts...
You mean, the ones allowed by the rules...?


...but what about the group-N or equvalant motor mounts?
You mean ones that are not allowed by the rules...?

Hey, just sayin'...

[Knestis]

My engine stayrod is about 4" long and goes from where the rear engine mount bolts to the subframe, to where the rear engine mount bolts to the block.

K

[Z3_GoCar]

You mean, the ones allowed by the rules...?


You mean ones that are not allowed by the rules...?

Hey, just sayin'...

Acutally, since hardware is free, on the trans mount I was thinking about cutting off the stud thats welded to the steel plate on either side of the hour-glass shaped block of rubber, and drilling a through hole and using a bolt to hold the mount down. The real weekness of the stock mounts is that they're basically rubber bonded between two plates and we all know what happens to rubber when its stretched...

As for the Group N parts, they're made by BMW. When I did a search on Real-OEM there's like four part numbers listed. Is one of these better than the others? It seems to me if one wasn't filled with that silicon fluid, it might be stiffer.

As for a stay rod. I don't know where I'd connect it between the motor and chassis. There doesn't seem to be a good place to do that on either the BMW motor, or the chassis. Does anyone have pictures of this on a BMW?

James

[Greg Amy]

My point, James mah man, is that the rules do not allow alternate motor mounts. At all.

It's a point that's snagged more than a few folks, myself included (I showed up at the '03 ARRC *assuming* motor mounts were free...when my good buddy Tim pointed out that the red poly motor mounts were a bit much - and I re-read the rules - I recognized my mistake).

And don't you think the "cutting off of studs, re-drilling through the mount" bit is stretching the 'hardware is free concept' just a tad...? I mean, hell, if that the case, I should be allowed to drill and through-bolt my crankcase, right? I could also use a little bit more strength in control arms, too, now that I think about it... ;) - GA

[JoshS]

James,

My take is that if the BMW parts book (ETK, available online as realoem.com) shows a part as a valid part for your particular car, then it's a valid part for your car. I did a search and there are two different (three, but one has been superceded) part numbers for engine mounts for the 2.8L Z3. I have no idea what the difference is. What's the Group N part number?

Here's the realoem search for the Z3 2.8 roadster (yours is a CJ33, right?):
http://www.realoem.com/bmw/showparts.do?model=CJ33&mospid=48094&btnr=11_1296&hg=11&fg=10

In my opinion, any of the three listed part numbers would have to be ruled legal ... but no others. Is one of those the Group N part?

EDIT: looks like the Group N part number is 11 81 2 224 413. Not listed for any US car. Sorry, no go.

[Z3_GoCar]

Hey Greg,

Point taken, that's why I'm asking questions before pulling the trigger and buying non-alowed parts. None of these mounts that I'm researching are urethane, they're all solid rubber that remove the silicon gel damping fluid, and are built like stock mounts.

Josh, thanks for finding the part number for the group-N mount. I performend a google search looking for that and wasn't able to come up with anything. The cars a CJ33, build date of 10/96. As for aftermarket sources for parts, how about these mounts:

http://store.bimmerworld.com/shared/StoreFront/default.asp?CS=bimmerworl&StoreType=BtoC&Count1=410473048&Count2=327613472&CategoryID=68&Target=products.asp

James

[Greg Amy]

:017:

:giles:

[Andy Bettencourt]

I guess I am confused here. ONLY STOCK motor mounts are allowed. That doesn't mean stock in Europe, it doesn't mean 'made by BMW' - it means what came on your car from the factory.

[shwah]

- it means what came on your car from the factory.
when the car was purchased new in the United States, OR a part that the manufacturer now supercedes in place of that one in the United States market.

[Ron Earp]

Point taken, that's why I'm asking questions before pulling the trigger and buying non-alowed parts. None of these mounts that I'm researching are urethane, they're all solid rubber that remove the silicon gel damping fluid, and are built like stock mounts.


If all the stock parts have silicon gel dampening fluid, then your replacements MUST have silicone gel dampening fluid. No way around that. Sort of like that dual mass flywheel BMW (and Porsche) used on a lot of cars - if it is stock you've got to use it, can't replace it with a conventional flywheel.

[Greg Amy]

when the car was purchased new in the United States, OR a part that the manufacturer now supercedes in place of that one in the United States market.
...noting that, "...Documentation of the superseding parts or assemblies must be supplied to the Club Racing Department and the appropriate part numbers listed on that particular model’s specification line."

Both in same paragraph, ITCS 9.1.3.C.

[Z3_GoCar]

...noting that, "...Documentation of the superseding parts or assemblies must be supplied to the Club Racing Department and the appropriate part numbers listed on that particular model’s specification line."

Both in same paragraph, ITCS 9.1.3.C.

9.1.3.C top of page 330 "Stock replacement parts may be obtained from sources other than the manufacturer provided they are the exact equivalent of the original part." So who says whats the "exact equivalent?" For anyone who can go down to NAPA to purchase such parts, do you run a frequency analysis spectrum to make sure the Chinese made part has the same polymer/cure ratio as your old part? Or do you just look at it and say, "Well it generally looks like the stock part, the holes are in the right spot, and it looks like it'll fit." If you were to even perform a simple test like a durometer on the rubber, what kind of value and more importantly what kind of error range would there be, and how does it change over time?

Remember, I'm not talking about orange poly's... I'd think the earlier list and documentation would only apply to the factory parts. On my car I could supply about a dozen or so of those superseeded part numbers, but they're not on the spec line right now.... Then multiply that across all the different cars, and our spec lines will grow much longer. I don't think the ITAC wants to get in the bussiness of part number management, not when you're getting ready to even get rid of the model (vin) numbers you have under your control now. I think the test is, "Does it look stock?" is about as close as we're going to get. Aluminum?? No, Orange/Yellow/Green/Black Poly?? No, These?? you tell me.

James

[Greg Amy]

Hoo-boy...here we go...

[lateapex911]

Well, ask yourself. You know the rule means stock. Do you think it's the same as stock. Really?

...on the other hand, replacement parts can easily fail a protest if they are deviant.

[Ron Earp]

James, in your case they need to have silicone dampening fluid and look stock. In my case they need to be made of rubber and look stock.

I'd like to use aluminum mounts get rid of the rubber ones that last 9 months. You'd like to get rid of the squishy BMW silicone filled ones and go to hard rubber, plastic, aluminum, or something like that. Neither of us can legally do these things the way the rules are written.

Ron

[JLawton]

9.1.3.C top of page 330 "Stock replacement parts may be obtained from sources other than the manufacturer provided they are the exact equivalent of the original part." So who says whats the "exact equivalent?" For anyone who can go down to NAPA to purchase such parts, do you run a frequency analysis spectrum to make sure the Chinese made part has the same polymer/cure ratio as your old part? Or do you just look at it and say, "Well it generally looks like the stock part, the holes are in the right spot, and it looks like it'll fit." If you were to even perform a simple test like a durometer on the rubber, what kind of value and more importantly what kind of error range would there be, and how does it change over time?

Remember, I'm not talking about orange poly's... I'd think the earlier list and documentation would only apply to the factory parts. On my car I could supply about a dozen or so of those superseeded part numbers, but they're not on the spec line right now.... Then multiply that across all the different cars, and our spec lines will grow much longer. I don't think the ITAC wants to get in the bussiness of part number management, not when you're getting ready to even get rid of the model (vin) numbers you have under your control now. I think the test is, "Does it look stock?" is about as close as we're going to get. Aluminum?? No, Orange/Yellow/Green/Black Poly?? No, These?? you tell me.

James

However you want to "try" and justify it...........


What do you think is the intent of the rule??

[dj10]

James,
This is pretty easy but let your conscience be your guide. 1. use the stock motor mount if you want to be legal. 2. Use something else and cheat. Honest, it's that simple.
I will say this, I don't like the rule. I doubt very seriously that you would win any races because of a better engine mount. I'm 99.9% sure I would never prostest anyone because of a engine or transmission mount. That said, I didn't write the rule, I just follow what is written the best I know.

[Z3_GoCar]

Thanks all, I will do the right thing. I think that BMW and aftermarket parts makers are not so wedded to what a stock part is. I don't know what the differences between the three parts listed in the ETK, but I can find what other vehicles that they go on so here's what I found:

The discontinued part: 11812228298
also is listed for:

E36 M3 CONVERTIBLE
E36 M3 COUPE
E36 M3 SEDAN


E46 325xi TOURING
E46 325xi SEDAN
E46 330xi SEDAN
E46 M3 CONVERTIBLE
E46 M3 COUPE
Z3 Z3 2.5 ROADSTER
Z3 Z3 2.5i ROADSTER
Z3 Z3 2.8 ROADSTER
Z3 Z3 2.8 COUPE
Z3 Z3 3.0i COUPE
Z3 Z3 3.0i ROADSTER
Z3 Z3 M ROADSTER
Z3 Z3 M COUPE

For both parts numbers 11817837985 and 11812283798:
are listed for:

E36 M3 CONVERTIBLE
E36 M3 COUPE
E36 M3 SEDAN


E46 325xi TOURING
E46 325xi SEDAN
E46 330xi SEDAN
E46 M3 CONVERTIBLE
E46 M3 COUPE
E85 Z4 M3.2 ROADSTER

E86 Z4 M3.2 COUPE

Z3 Z3 2.5 ROADSTER
Z3 Z3 2.5i ROADSTER
Z3 Z3 2.8 ROADSTER
Z3 Z3 2.8 COUPE
Z3 Z3 3.0i COUPE
Z3 Z3 3.0i ROADSTER
Z3 Z3 M ROADSTER
Z3 Z3 M COUPE

It seems to me that as BMW uses a mount similar to what was used in the past on a new model, they change the part number so that the new part is back-dated to be used on the older chassis, as can be seen with the adoption of the same part for the e-85/e-86.

James

[shwah]

If it really is a superceded part by BMW, and you want to run it - just follow the directions pointed out by Greg and get it added to your spec line. Then there is no grey area.

[JoshS]

...noting that, "...Documentation of the superseding parts or assemblies must be supplied to the Club Racing Department and the appropriate part numbers listed on that particular model’s specification line."

Both in same paragraph, ITCS 9.1.3.C.
That's what the rule says, but does anyone else think it's silly?

Let's see -- my car's motor mount is dead. I go to the dealer parts counter and I say, "I need a replacement motor mount for my 1999 BMW Z3". He gives me one which has a newer part number than the dead one (which was original).

Now, I go racing and someone hears that I just replaced my motor mounts and went 2 seconds faster, so I get protested for illegal motor mounts. They pull my motor mounts out of the car and read the part number off the side. They call the local BMW dealer and ask for the part number for a Z3 motor mount, and they get the same number. Pretty sure they are going to rule it legal.

Now, let's go the other way. My competitors misheard me in the paddock. What I really said was, "I'll bet if I replace these old crappy motor mounts with the new ones I just bought, I'll go 2 seconds faster!" So I get protested. They pull out my old, crappy, original motor mounts, and read off the part number. They call the local BMW dealer and ask for the part number for a motor mount. The parts guy reads off the new part number. No match. So the tech guy says, "Okay, then what's a 123456789?" Oh, that's the ORIGINAL part number. It's been superceded." Still legal.

Why do we need line item exceptions? There have been so many superceded parts on all the IT cars that the ITCS would quadruple in size. Not to mention that now, as James pointed out, we can use "stock-equivalent" parts that won't even have BMW part numbers on them.

Does anyone else agree that we should strike the rule Greg quoted?

[dj10]

That's what the rule says, but does anyone else think it's silly?

Let's see -- my car's motor mount is dead. I go to the dealer parts counter and I say, "I need a replacement motor mount for my 1999 BMW Z3". He gives me one which has a newer part number than the dead one (which was original).

Now, I go racing and someone hears that I just replaced my motor mounts and went 2 seconds faster, so I get protested for illegal motor mounts. They pull my motor mounts out of the car and read the part number off the side. They call the local BMW dealer and ask for the part number for a Z3 motor mount, and they get the same number. Pretty sure they are going to rule it legal.

Now, let's go the other way. My competitors misheard me in the paddock. What I really said was, "I'll bet if I replace these old crappy motor mounts with the new ones I just bought, I'll go 2 seconds faster!" So I get protested. They pull out my old, crappy, original motor mounts, and read off the part number. They call the local BMW dealer and ask for the part number for a motor mount. The parts guy reads off the new part number. No match. So the tech guy says, "Okay, then what's a 123456789?" Oh, that's the ORIGINAL part number. It's been superceded." Still legal.

Why do we need line item exceptions? There have been so many superceded parts on all the IT cars that the ITCS would quadruple in size. Not to mention that now, as James pointed out, we can use "stock-equivalent" parts that won't even have BMW part numbers on them.

Does anyone else agree that we should strike the rule Greg quoted?

Hey Josh!
Your making way too much out of this. Is everyone this hyper in silicone valley?:D Who ever you buy your mounts from, just keep the receipt with the part # on it. I you will get protested for your engine if you go 2 sec's a lap faster, not your engine mounts.;) Try and relax and go have a drink somewhere. Just don't drink and drive.

[JoshS]

Hey Josh!
Your making way too much out of this. Is everyone this hyper in silicone valley?:D Who ever you buy your mounts from, just keep the receipt with the part # on it. I you will get protested for your engine if you go 2 sec's a lap faster, not your engine mounts.;) Try and relax and go have a drink somewhere. Just don't drink and drive.
Hey, I'm just an ITAC guy trying to clean up and clarify the rules. I 'm fine. I probably have a bunch of superceded parts on my car already, and I'm sleeping just fine.

It's not even silly season for me ... I had my first race this past weekend (with NASA, not SCCA ...)

[Greg Amy]

Does anyone else agree that we should strike the rule Greg quoted?
The rule was created many moons ago to cover situations - such as the infamous VDub G-grind cam wars - where a lesser-performing part was superceded by the manufacturer with a better design. One can reasonably argue a performance advantage where a car is classified with one camshaft, yet when the cam goes out of production is superceded to one from another model that provides significantly more airflow.

While I highly doubt someone is going to protest a simple suffix change in a part number (it happens constantly, and changes with things as simple as a supplier change) it would be reasonable to protest a significant change in engine mount design. In that case it's the competitors' responsibility to work through the system to get it line-itemed.

There's no other reasonable way to cover it in the rules. Leave it to the competitors to prove reasonable supercession. Create a minor crack in the rules and we'll drive a truck through the resulting loophole. - GA

[Z3_GoCar]

Hey Josh!
Your making way too much out of this. Is everyone this hyper in silicone valley?:D Who ever you buy your mounts from, just keep the receipt with the part # on it. I you will get protested for your engine if you go 2 sec's a lap faster, not your engine mounts.;) Try and relax and go have a drink somewhere. Just don't drink and drive.

Hey Dan,

Yes... Yes we are. Just remember that about 80% of the people in California are from somewhere else:023: I guess you could call me a Carter/Reganomics Okie.

Back to this topic. Were are all the excepted parts, there should litterally be thousands of superceeded part numbers listed. Except looking at the ITCS, there are none listed. Greg, I bet you could litterally find a hundred on your egg alone.

James

[Knestis]

It should put the onus on the person opting to use a part not explicitly defined as "stock" on the car in question.

The "equivalent part rule" handles "equivalent parts" - if the engine mount in question is "the same" as what was delivered on the car when new, no change to the rules is required to cover that eventuality. If the part is DIFFERENT, then someone might try to rationalize it based on the "supersede" rule - as distinct from the "equivalent part" rule. THAT is when it should reasonably have been necessary for someone to get the clarity that results from a line-item allowance.

NOW, the minimum conditions necessary for the ITAC to approve such a line item variance are not entirely clear. I would think that it would be necessary to demonstrate that the stock/original part is truly NLA from any source, including through "equivalent part" aftermarket. But that's a lot of supposition on my part.

K

[JoshS]

Makes sense to me.

[dj10]

Hey, I'm just an ITAC guy trying to clean up and clarify the rules. I 'm fine. I probably have a bunch of superceded parts on my car already, and I'm sleeping just fine.

It's not even silly season for me ... I had my first race this past weekend (with NASA, not SCCA ...)

To Josh & James,
1st thing, I'm glad to hear you guys aren't going to have a nervous break down. :D I have loaded the BMW parts CD on my laptop. There should be no complaints or questions if you have the data for support.

Did you win the nasa race? What class were you?

[JoshS]

I did win both NASA races. I was racing in PTC. No one runs in GTS out here, it's totally non-existent.

[dj10]

I did win both NASA races. I was racing in PTC. No one runs in GTS out here, it's totally non-existent.

Good way to start out the year! Congrats:happy204:

[lateapex911]

Hey Josh!
Your making way too much out of this. Is everyone this hyper in silicone valley?:D.

OK, let's get this straight...Josh might fantasize about the comings and goings in Silicone Valley, but it's hundreds of miles south....he spends his days herding electrons in SiliCON valley.....

Interesting how the two valleys have become so interdependent on each other, LOL.

[Gary L]

OK, let's get this straight...Josh might fantasize about the comings and goings in Silicone Valley, but it's hundreds of miles south....he spends his days herding electrons in SiliCON valley.....
Now that there's funny... I don't care WHO you are! :happy204:

[jjjanos]

NOW, the minimum conditions necessary for the ITAC to approve such a line item variance are not entirely clear. I would think that it would be necessary to demonstrate that the stock/original part is truly NLA from any source, including through "equivalent part" aftermarket. But that's a lot of supposition on my part.

K

Cannot be done. Simple statistics. I can reject the null hypothesis that the part is unavailable but it doesn't go the other way.

[Greg Amy]

"I can reject the null hypothesis..."
Damnable economists...

;)

[jjjanos]

Damnable economists...

;)

Actually, having done the analysis, I can say that with a 95% confidence interval that we can reject the hypothesis that economists are damnable. I am unable to reject the hypothesis that we are contemptible.

[spnkzss]

Actually, having done the analysis, I can say that with a 95% confidence interval that we can reject the hypothesis that economists are damnable. I am unable to reject the hypothesis that we are contemptible.

You need to go pick up your new car.

***shaking head*****

[Z3_GoCar]

Maybe some pictures of the damage will get me some sympathy:

http://49thaero.tripod.com/sitebuildercontent/sitebuilderpictures/twisted_racer5.jpg

The bar hanging down on the left connects the shifter to the tail of the transmission. It's completely twisted in two and was jammed into insulation on the drivers side of the tunnel.

http://49thaero.tripod.com/sitebuildercontent/sitebuilderpictures/twisted_racer6.jpg


http://49thaero.tripod.com/sitebuildercontent/sitebuilderpictures/twisted_racer7.jpg

I was thinking the through bolts would at least stop the flop with out making the mounting stiffer. I highly suspect that part of the spin had to do with loosing one of the nuts on the right side motor mount, as it's the only mount not torn in half, the nut is no where to be found and the threads on the top stud is buggered like the braket rubbed up and down on it several times.

James

[JoshS]

I think that rolling the car over had something to do with the extreme damage. There is no evidence that compels me to believe that you'd shear the stock engine mounts with "normal" use.

[Z3_GoCar]

It's a good thing that you said "normal," because there's nothing normal in how we use these cars. All I can say is that in about 12-16 days of hard use I could feel something was going soft :shrug: Did the nut already vibrate off the right mount? I wouldn't know, except I did check it before I went out for the weekend. But I do know that the shifting was getting sloppier, and shifting while cornering was less and less a good idea. I'd say maybe 3-4 weekends is the limit on the mounts. Probably part of the problem is the desert conditions are hard on rubber, plastic, and wood.

James

[Greg Amy]

Maybe some pictures of the damage will get me some sympathy...
I'm sympathetic that you're gonna have to buy OE-spec motor mounts on a regular basis to keep this from happening in the future...

;)

[Andy Bettencourt]

I feel for you too. If my car had 'weak' motor mounts, you can bet I would be taking advantage of the stayrod allowance.

[mbuskuhl]

James,

Your sig says ITE. It's my understanding there are no national rules for ITE but are rather division/region specific. What does your division/region have in place forITE rules?

In the SOWDIV, ours are pretty basic and listed below. As such, I can do pretty much whatever I want to my ITE car, including non OEM motor mounts. We have MX-5 cup cars that run ITE, some NASA GTS cars and a few others.We just have to meet minimum safety specs and have a maximum engine displacement.

Just a thought.

Improved Touring E (ITE) Cars eligible for ITE are production based cars with fenders and doors that are not currently eligible for any other SCCA club racing class. Cars entered in ITE must meet minimum safety standards of the 2008 GCR and Improved Touring Category Specifications, ITCS, including all items in Section 9.1.3, ITCS. Suitability of any car for ITE is subject to the approval of the Chief Steward and Chief Scrutineer.
The maximum engine displacement for normally aspirated cars is 3,500 cc. Turbo-Charging or Super-Charging is allowed with a maximum displacement of 2,500 cc. Rotary engines are limited to two (2) rotors.

[Gary L]

Hmmm... going off on a tangent here, not because I really care, but because I'm just ornery. I'm deducing that you folks must be interpreting the phrase "...including all items in Section 9.1.3, ITCS" in your ITE ruleset, to mean just the safety standards? That's kinda the way it's written. If that's the case, what's to keep you from running something that resembles, for instance, a 3500 cc powered Daytona Prototype car in ITE? With a showroom stock roll cage and no fuel cell, BTW. :D

If that's not the case (and you must meet more than just the safety portions of 9.1.3), how do you get around the infamous IIDSYCYC caveat that's part of the ITCS and install non-OEM motor mounts?

[mbuskuhl]

If that's the case, what's to keep you from running something that resembles, for instance, a 3500 cc powered Daytona Prototype car in ITE? With a showroom stock roll cage and no fuel cell, BTW. :D


Here's what stops it... "Suitability of any car for ITE is subject to the approval of the Chief Steward and Chief Scrutineer."

....and the fact that who in their right mind would run an expensive prototype car in ITE with all us? :) BTW, it would have to have a fuel cell, I don't think they have "gas tanks"....maybe you could put a Honda Accord tank in it for fun ?

I'm just saying, ITE rules are loose, at least in the SOWDIV - just meet safety standards and maximum displacement - that's the way the rule is interpreted and enforced. I understand it's called ITO/ITU in other parts of the country? If James is running ITE, and depending on his divisions rule set, he may be able to solve the motor mount issue real easily.

[Z3_GoCar]

There are several reasons why I started out in ITE, but it's not really where I want to be. When I purchased this car ITR was still in the works, the motor is running a TECII standalone, and I still need a real steel hood. Reasons I want out is we have some very built ITE cars here. Joe Hall has a 300zx which is a closet GT car. We also have a WC Roush Mustang that shows up sometimes and even blows Joe away. It runs a custom double a-arm rear suspension with lever shocks, like it was pulled from a formula antlantic. No, I'd rather live with the limits than go even more wild.

James

[Z3_GoCar]

I just receved the new mounts. I ordered the motor mounts from Bimmerworld, listed as e-36 M3 stock mounts as we share the same part number. There's not any pat number on the mount, but it is listed at about half the price in real-oem, so I'll save the money.

The transmission mounts I ordered from Bavarian Autosport. The part number is on these mounts. Also, they're so soft that I can squeeze them between my thumb and fore fingers and compress them 1/16" I bet if I yanked one them I could rip it in two. It's no wonder it failed like it did and I'm suprised I didn't rip them during an off course excursion.

James

[GKR_17]

Are those OEM parts from Bavarian? From my experience they've been using a lot more aftermarket junk lately, and for that reason I've started limiting what I buy there.

[Z3_GoCar]

Thanks for the tip Grafton, I'll check them out, but they do look like oem and there's a part number molded on them.

James