CNC Machined Carrier Bearing GB Feeler

[Brandon12V]

Having solid motor, trans, and diff mounts, something always has to give. I rebuilt & replaced everything on drivetrain a couple yrs ago (guibo, carrier bearing, driveshaft, halfshafts, etc..) and still manage to destroys seals, guibos, and CB's. I want to eliminate the main point of flex that can cause destruction of these parts. it would be easy have a custom one-piece driveshaft made, but this may be a bit more inexpensive than that route.

I have a car buddy who works for a reputable CNC shop and may be willing to do this, given the business. This part would basically replace the entire cast housing(including that shitty rubber) that surrounds the bearing between the two pieces of the driveshaft. Stainless steel will most likely be used to save money. Think of it like a housing that you press your existing bearing into. I must forwarn that incorporating a part like this can cause stress to your guibo(which in my case is the only point of flex) but will help get power to the ground with quicker response. it will create more vibration in the cabin as well. I DO NOT recommend this for those of you still rocking out OEM mounts. This is basically a race modification but "streetable, given, you have the mounts to support. OEM mounts will create too much play in shaft and may cause the bearing to back out of the housing. it will be almost like having a one-piece driveshaft while still maintain some "play". Even though your guibo will be taking more stress, it will be the only weak point between the differential and transmission. anyone who has ever been under their e30 knows that it is much easier to look up and check your guibo than checking your CB, let alone replacing it. This will make it much easier to diagnose a problem when you start getting vibrations coming from the drivetrain.

With all that being said, how many of you would be interested in purchasing such a part and let me get an idea of what you guys would be willing to pay. I know "cheaper the better" but what would consider reasonable?

Thanks,

-Brandon

[Massive Lee]

Great. Report after 100,000 miles of combined testing.

[Brandon12V]

Sarcasm...? I'm sure there are people, other than I (at least racing), looking for an alternative solution to a one-piece driveshaft. this IS one of biggest weaknesses of modified e30's prone to failure. r&d cost money that I don't have but if you're willing to put up the CNC, I'll pay and test it on my car. Otherwise, I don't I don't see what the point was of your input, and quite frankly, I found it slighty rude. I may be misinterpreting the attitude of your response though. is this something you're interested or do you have a better solution mr. lee? please don't take my response the wrong way, just a genuine reply.

[Massive Lee]

... I don't I don't see what the point was of your input

And I think that is exactly the problem. Offering a solid center bearing GB without having done any prototyping nor testing. You claim that the center bearing is failure prone. Considering that a car will see perhaps two or three in its lifetime, I don't consider it as such.

So, I suggest you make your own prototype. Then test it and report. You will discover several side effects (I will let you discover what they are). But asking people to do the testing for you in a GB is not fair. And I am actually saving you a lot of money. Because when you start refunding for a non working part, it becomes quickly costly.

Basically, there's a reason why the center bearing is on a quite loose suspension...

[Brandon12V]

perhaps you only read half of what I stated..? They ARE failure prone on race e30's. three in it's lifetime? I know mine has seen 3 since I've had it + 1 prior to my ownership. And like I said, this is a race application and this IS a feeler. how does the suspension dynamics have anything to do with this? if you have solid and/or delrin mounts, shit should not be moving under there. what are not telling me..? have you actually tried something like this?

[Massive Lee]

I haven't said a word about the car's suspension. The center bearing is suspended for a reason. It can move up and down, side to side and back and forth.

I have no time to educate you on the inter relations of a car's components with others. Therefore, I suggest you make a unit and test it as suggested. You will then see why the center bearing is soft mounted. If yours is failing repeatedly, then it is a sign that something is wrong with other components.

Who said the guibo is failure prone on a race car? Never saw that.

As an instructor tracking an e30 M3, I do 25 track days per summer with an average of 6 sessions per day. One track day is most likely the equivalent of a race weekend for you. 25 track days = 25 weekends or perhaps 4 seasons. My guibo has 6 years or 24 of your seasons and it is still like new. I have no problem whatsoever. So, if you keep on breaking them, then check somewhere else.

BTW The two parts of the driveshaft are not 100% aligned and are curved up at the guibo. For a reason. Movement is needed, which you loose with a solid mounted bearing.

[StereoInstaller1]

I wanna see this "one piece driveshaft" idea that comes up every couple years.

I just wanna know how you are going to install it

[OrganicMechanic]

hi I am a machinist as well--I have made a billet center support carrier--I drove it down the driveway then right back on the lift to pull it out--

there is a reason why it has float--if you are going though so many then you need to check out your solid mount geometry.

--Side note--

there really needs to be a vetting for these group buys.

[calz4m]

I haven't said a word about the car's suspension. The center bearing is suspended for a reason. It can move up and down, side to side and back and forth.

I have no time to educate you on the inter relations of a car's components with others. Therefore, I suggest you make a unit and test it as suggested. You will then see why the center bearing is soft mounted. If yours is failing repeatedly, then it is a sign that something is wrong with other components.

Who said the guibo is failure prone on a race car? Never saw that.

As an instructor tracking an e30 M3, I do 25 track days per summer with an average of 6 sessions per day. One track day is most likely the equivalent of a race weekend for you. 25 track days = 25 weekends or perhaps 4 seasons. My guibo has 6 years or 24 of your seasons and it is still like new. I have no problem whatsoever. So, if you keep on breaking them, then check somewhere else.

BTW The two parts of the driveshaft are not 100% aligned and are curved up at the guibo. For a reason. Movement is needed, which you loose with a solid mounted bearing.

+1

I am also an instructor and do 25-30 days a season in my E30 as well. In two years there is NO noticeable wear on the guibo or center bearing. There is something wrong with your setup which is causing premature failure of these parts. Pre-loading the bearing during install is very important. Just double triple check your setup. Even with solid mounts all around there is still considerable movement of your drivetrain under a load, btw.