[Jack M.]

Originally Posted by Quebequer

Which parts?!

The cog unit and the 2nd t-case which I have still not received.

[slo_335-e90]

really cool to see this. can't wait to see what comes of it!

[Kalud]

Originally Posted by Jack M.

Wow, I wonder what a metal analysis would find for that. I would be willing to bet it's not very well treated.

Looks like a lot of the grease flung away from the worm gear. Is it dry around the worm gear area as if the grease went away? I'm surprised that they didn't allow the gear oil from the t-case to splash into the unit and use that as lubrication instead.

It will be interesting to see what the used one looks like that I ordered too. Sounds like that is your t-case issue which needs to be addressed. Luckily that is something which can be easily removed if a modification were to be made.

Jack

I cleaned it to see the damages. It had enough grease for sure. Still not the TC oil but enough in my opinion... The worm gear is damaged but the gear it attach to is in very good shape, so the worm gear is metal but weak...

[Quebequer]

Originally Posted by Kalud

Early report, I've got a defective 2008 335xi transfer case motor in my hand and I checked it out. I will make a better set of pictures, but most importantly the worm gear is made of metal. It differs from the report of plastic worm gear on the X3.

This is what happened to mine. That worm gear doesn't look strong. Well, not enough.

[Quebequer]

Originally Posted by Jack M.

The cog unit and the 2nd t-case which I have still not received.

Sorry I did not see your post before, I should have checked.

[X.X.I.V]

Any news ?

[euro2fast4u]

Originally Posted by mykal335xi

Joining the group-buy guys, looks like it may fall short but I'm in anyway.

I ended up keeping my 335xi because the wife likes it so much. I doubt I'll race it again, but I will likely get the Cobb installed on it and a pro-tune for E85. If things don't progress much then I may get back into this myself when I get my second car (E39 M5), and run progressively more power and traction until something breaks.

A couple of notes for those non familiar with my car:
- Ran 490whp / 550wtq on nitrous + meth + race gas (no nitrous in 1st gear though, no point really without more traction)
- 350+ brake boost launches from 1st gear
- 100+ brake boost launches from 2nd gear, then the clutch packs for that gear were done, 2nd gear launches in the 335xi are NOT recommended by me for this reason
- Power transfer to the front wheels is a bit jerky when engaging at full power (rear wheels spin briefly before all 4 start spinning)
- Ran Pilot Sports initially, but just on tune only, all high power runs were done on Conti DWS, with this setup I hit a 1.57 60' time with copious amounts of wheelspin
- Wheelspin in my setup may be what saved my drivetrain from breaking, according to all the drivetrain experts I talked to traction is the #1 killer of drivetrain components
- No transfer case issues, or front diff issues thus far (knocks on wood)

Originally Posted by Jack M.

I'm sure it would be very easy to manipulate the motor which controls the LSD action in the t-case, but the problem is the ECU will very likely freak out if it was unable to control the LSD in they way it wants to. Is there a way to shut that OFF, so the ECU is not monitoring the unit? If so, I can very likely design and build a circuit which will allow the driver to control the LSD manually by either going full ON or full OFF.

Full ON would be nice for drag race use. Full OFF may be a bit tricky and I'll have to take a closer look at the clutches to be sure they will not be damaged if you were to run the car in a way where the front or rear wheels would move independently for extended periods.

I know the ACD unit in the EVOs will burn up the clutches if you have the wheels turn at a different rate for too long, even if the system is OFF and no pressure is applied to the clutches.

This was my thinking, If the ability to control the transfer case is capable through cobb or JB4 then i think alot of the warm gear issues will go away. Doing some research i see that as mykal335xi said, the rear wheels slip then all 4 slip. This to me sounds like (front/rear %) at a stop, the system is disengaged 0/100 when you accelerate and the system sees wheel spin it then uses the warm gear to transfer power to the front. Under heavy load (track launch) the gear cant handle it, and when you increase the tq thats more force that gear has to work against causing failure.

To me the easiest thing to do would to control the module like the evo 9's can do "snow mode" and sets a 50/50 delivery of power.

once you reach the middle of second gear or third you are able to transfer back to a less friction mode of say 20/80.


tldr; hack the transfer case module for 50/50 power delivery

[only_36]

Hi
Nothing new about this famous gear ???

[Ferruccio]

Hey, any updates with this? I'm running 400 at the wheels (from 259 baseline). Any news on what the weak spot is in the transfer case? It looks like mykal has not had any issues with his TC on much higher numbers than mine.

[Quebequer]

Any news?

[critical05]

Just adding my two cents, worm gears are very inefficient and produce a fair amount of heat. The heat is generated due to high sliding velocities characteristics of worm gears. The heat can quickly degrade the grease and also the high friction can will slowly abrade the worm gear.

Looking at the worm pinion from the pictures it looks like it has been worn thru abrasion not a brittle fracture of the teeth. The worm pinion gets thinned down to a point where there isn't enough material to support the load and then it strips the remaining portion of the pinion.

There are several options to address the abrasion, find a way to make these oil lubricated, which will help dissipate the heat. The parts look like there isn't any heat treatment to the pinion. Dependent on the base material used, a surface hardening ( induction) would make the surfaces harder to resist wear, however the teeth may get to brittle and fracture. Another option would be to nitride the parts, it creates a very hard surface that resist wear. Its a very thin layer so you maintain the ductility of the base material making it tough. The other option is PVD (physical vapor disposition) it puts a very hard, diamond like coating on the surface which increases hardness while also reducing friction. PVD doesn't care on what's its applied too, induction hardening and nitriding does care what steel alloy the pinion was made from. At work we use PVD on case carburized gears to fight wear, the sales guys always points out that it's used on NASCAR rear ends to increase wear resistance as well.

I also assume they chose a worm gear so the can set a position and hold it there. The friction aspect of worm gears also acts as a brake and doesn't allow the gear to back drive the pinion. If you redesigned something to remove this and incorporate all spur gears, the motor would then need a brake off some sort.

[X.X.I.V]

Bump

[X.X.I.V]

Bump..... is thing on ?

[Quebequer]

No news here? Seems like quite a long time...

[TeroRider]

Bump, is someone still working on that?

[aadum]

any updates?

[Carl Morris]

Probably makes more sense to talk to one of the shops that has offered to do it than pinging here. I think Jack is just waiting to see if it breaks often enough to justify developing any special parts. Until that happens I doubt we'll see him here, he's too busy with other stuff.

[Boosted-M]

I would love to get a 6AT trans solution, upgrade the transfer case and Vargas Stage 3's on my XI..!!!!

[Carl Morris]

It would appear that you guys with automatics are going to need nitrous if you want to come off the line hard with the big turbos. They're not getting full boost until over 4k rpm, which I assume is significantly above your torque converter stall speed.

[knissel]

So the consensus is that AT is no good for upgraded turbos? (and possibly not good for MT?)

I like the idea of treating the worm gear to make it harder (but not brittle)

[Carl Morris]

I don't think there's any consensus yet. There just aren't enough people with big singles and stage 3s yet. They are only going to have a problem with the AT if they want to come off the line really hard and can't get boost off the line, which I expect to be an issue with the big turbos. The MTs will work but will benefit a lot from a WOTBox or other 2-stage rev limiter. Especially if they use AWD or slicks.

[knissel]

I would like to get the discussion going on xi to get them breaking n54 records.

What kind of upgrades would have to happen to get something like Vishnu/FFTEC or VTT 700 hp (or even much more)?

Is the level 10 transmission enough or would something even better be needed?

How much would it cost to develop a better transfer case.

I feel like the xi has huge potential but I want to look at total cost or if it would even be possible.

20k USD or higher?

Thanks