AKG Transmission Mounts. Flex Disc Questions

[coreyw]

I have these on my car currently, but will they work with the E36 M3 ZF tranny?

http://www.akgmotorsport.com/catalog/catalog.php?item=32

Also, for a daily driven, 90% street car, would you recommend a Revshift guibo/flex disc or just OEM?

Thanks.

[jamesthebikeguy]

Just oem.

Proven race cars, 600+ hp bmws, and established tuners with the likes of Turner Motorsports, and Bimmerworld all use OEM guibos in their race car drive lines.

[treff-7]

This is from the description of your mount:
"For BMW e30 (318 323 and 325 only), e36 (318 323 325 328 M3) and e46 (323 325 328 330 M3), Z3 and Z4"

M3 only came with ZF so it should be good.

I would say the RevShift guibo is more for abused cars for track to handle excessive power. OEM guibo should do just fine.

[coreyw]

Just oem.

Proven race cars, 600+ hp bmws, and established tuners with the likes of Turner Motorsports, and Bimmerworld all use OEM guibos in their race car drive lines.

Oh good to know. Thanks!

This is from the description of your mount:
"For BMW e30 (318 323 and 325 only), e36 (318 323 325 328 M3) and e46 (323 325 328 330 M3), Z3 and Z4"

M3 only came with ZF so it should be good.

Right, but since the tranny is going into an e30 chassis, I didn't know if it would still work. But if that same part fits alla those applications then I guess it really shouldn't matter. Thanks.

[treff-7]

if it's good for the e30 325 and e36 M3 then it should work with s50/52+zf in e30 chassis. the only thing i can think of is the height of it that might be a problem. if you could measure it i can compare it to the one that's used for this swap (e21 i think). i have a brand new one.

[treff-7]

i measured mine and the rubber part is 32mm (1-1/4") high. if yours is the same it will be fine.

[RobertK]

This is from the description of your mount:
"For BMW e30 (318 323 and 325 only), e36 (318 323 325 328 M3) and e46 (323 325 328 330 M3), Z3 and Z4"

M3 only came with ZF so it should be good.

I would say the RevShift guibo is more for abused cars for track to handle excessive power. OEM guibo should do just fine.

I wouldn't install a RevShift guibo on any car. The guibo is designed to flex for a reason, because your car also flexes so the driveshaft needs to have flexibility.

Installing a RevShift guibo deflects vibration and required flexibility to the u-joints, transmission mounts, and engine which will eventually destroy said u-joints and mounts.

The only thing I would install a solid guibo or driveshaft into would be a drag car that races in straight lines.

[John@Revshift]

It's not a solid guibo. It has polyurethane bushings which provide a proper amount of flex. There are tons of people with them installed on their cars. It's a proven part. No debate/discussion necessary.

[dsobering47]

I'm a BMW master tech and I wouldn't install a revshift Guibo in anybody's car. The OEM one is more than sufficient and it's not always required to remove all flex out of a car. I'll be using an OEM guibo in my turbo m52 in my e30 and I have no second thoughts about it.

[RobertK]

It's not a solid guibo. It has polyurethane bushings which provide a proper amount of flex. There are tons of people with them installed on their cars. It's a proven part. No debate/discussion necessary.

You're product hasn't been on the market long enough to prove anything and those uneducated about the issue will continue to blame bad center bearings or transmission mounts when they foul up. There is a comment on your website were a user says the rubber guibo is the weak point on a BMW when in fact 99% of the time the reason your guibo shreds because your u-joints have gone bad and the lock up kills the CSB and guibo.

The bushings might provide some cushion but the solid aluminum frame they are seated in does NOT provide an adequate amount of flex. Our cars are meant to being driven around curves not straight lines and to this day BMW continues to use rubber guibos for this purpose.

[Thizzelle]

agree bushings are ok to have stiff, guibo not so good. My center support bearing was shot for a long time and the guibo still didn't shread just cracked. if it was solid the u-joints would have been toasted.

[John@Revshift]

The bushings might provide some cushion but the solid aluminum frame they are seated in does NOT provide an adequate amount of flex. Our cars are meant to being driven around curves not straight lines and to this day BMW continues to use rubber guibos for this purpose.

Actually, today BMW uses a guibo that is very similar to the Revshift guibo on the 335i and some other cars.
Apparently, BMW doesn't think its a bad design/idea. Can't argue with that.

You're product hasn't been on the market long enough to prove anything

Our first test guibos that we made are currently on a couple daily driven e30's. They have been holding strong for over 2 years now. No broken drivetrain parts have been reported.


FYI, I will only post facts on the forums. I will not debate or participate in any discussion that strays away from the facts.

[jrdeamicis]

Actually, today BMW uses a guibo that is very similar to the Revshift guibo on the 335i and some other cars.
Apparently, BMW doesn't think its a bad design/idea. Can't argue with that.





Our first test guibos that we made are currently on a couple daily driven e30's. They have been holding strong for over 2 years now. No broken drivetrain parts have been reported.


FYI, I will only post facts on the forums. I will not debate or participate in any discussion that strays away from the facts.

Rubber bushings loaded into a aluminum frame. Similar idea to yours but poly and rubber are very different materials. FACT

I like your mount, you should find a press in rubber bushing with sleeve to work with your guibo and then you would have a perfect blend of adapter and guibo.

I like my rubber guibo, it takes all that abuse from my driveline. I would prefer to kill my $100 dollar guibo over my $1400 transmission or my driveshaft.

Do you have your guibos balanced after machining? I always wondered.

[RobertK]

First of all that is a picture of an automatic transmission. Look up the part number for a 335i with a MANUAL transmission and you will see that it is a rubber flexdisc. BMW does not use this design on any of their cars with MANUAL transmissions.

Second look very close to that picture on the right hand side of that guibo and note the crack / stress damage to it.

Like it has been mentioned before, I would rather replace a $40 guibo than an entire drive train or even just the drive shaft for that matter.

This thread on Bf.c reaffirms that your product deflects drive line vibration elsewhere throughout the drive train.

http://forums.bimmerforums.com/forum/showthread.php?t=1817727

i'd say these guys know a thing or two about BMW drive shafts.

http://www.driveshafts.com/pages/bmw_ujoint.html

Most BMW driveline designs use a rubber flex disc to connect the transmission to the drive line. This flex disc absorbs torsional vibrations from the engine/transmission and reduces shock load to the driveshaft and rear axle. The driveshaft is supported by a ball bearing, encased in a soft rubber cushion. This cushion also dampens unwanted driveshaft vibrations, and to some extent both the flex disc and the support cushion can be "tuned" to the specific arrangement of chassis, transmission and rear axle.

[John@Revshift]

i'd say these guys know a thing or two about BMW drive shafts.

http://www.driveshafts.com/pages/bmw_ujoint.html

They do know a lot about BMW drivelines. Here are some interesting points from the page that you linked.

The front half of a BMW driveshaft, (excepting early 1600's) is connected to the rear driveshaft with a universal joint and either a fixed or sliding spline. A universal joint is a precision bearing, which allows for small angle changes from engine/transmission movement. BMW driveshafts use an extremely precise design of universal joint with considerable torque carrying capacity for its size.

This means that the u-joints are what compensates for any drive shaft misalignment and that they are well capable of handling the load.

Another interesting feature of the most common BMW driveshaft design is that the front driveline is usually centered directly off the transmission main shaft. This driveline design causes BMW driveshafts to rotate with the smallest amount of radial run-out possible. Additionally the rear part of a BMW driveshaft is centered with the next most accurate means, a precision piloted fit flange.

This means that there is no axial difference between the transmission flange and the front part of the drive shaft. The flex disc does not and is not intended to make up for axial misalignments. The flex disc's sole purpose is to dampen rotational forces.

FACTS!