BMW automatic transmission

Hey guys, not sure everyone knows (or cares), but I ended up grabbing Jari's rally car. Flew down to Florida on Friday and drove the car home to Denver, hand controls and all...and yes my arm is still a bit tired! I've now got a real appreciation for how well Jari flogged that car given the transmission.

I'll start out by saying I was 99% sure I'd be swapping the car back to a manual. I bought it with the intention of using it as a teaching car and hillclimb rental in the Denver area, but I've gotten a few messages that if it was kept as an automatic with hand controls there were some folks interested in having some fun in it. Don't worry Jari - I will pull these out this weekend and get them headed back to you, but will take lots of pics so I could replicate the setup.

Some folks had ideas about how we might be able to get around the issue, so I was just wanting to re-start the conversation. Currently it needs a new torque converter but before I toss more $$ at it, I'm wondering what it might take to really fix it and get this thing running in a rev limiter punishing fashion. Here's a quick recap on what it's got:

• Transmission is a ZF4HP22 from an E30
• Shifter can move whenever (key doesn't need to be in or car to be running)
• Won't shift back into 1st gear even if the lever is in 1st until speed is low enough.
• Jari did mention a lockup of the wheels may be enough to trick the transmission to allowing shift into 1st.

With the noise the TC was making, I took it easy on the 2200 mile drive and just left it in full automatic mode, so I don't have much experience with shifting it manually. Here's what I did notice with it in full auto mode

• Up-shift happens ~3800-4000rpm regardless of throttle input.
• Down-shift happens when revs drop to the ~2200-2500rpm range, possibly gearing dependent.
• Wondering if down-shift brings it right back to the 3800-4000rpm in the next lower gear?

Thinking about trying to take it out to CORE this weekend once I get a regular throttle cable installed, but not sure if I'll be able to pull that off or not.

Thanks guys!

Dave



Edited 1 time(s). Last edit at 04/08/2013 11:44AM by DaveK.

Here is the solenoid operation chart:


With this info, someone could easily build module to operate. Looks like it has 2 main solenoids, a TCC lockup solenoid, and a reverse solenoid.

GM 4L60 uses a 2 solenoid system with PW controlled pressure solenoid. Looks like the solenoid logic is the same, so you could possibly use an aftermarket 4L60 controller!

http://bmracing.com/?wpsc-product=shift-plus-2-electronic-overdrive-transmission-control-for-gm-4l60e4l65e



Edited 1 time(s). Last edit at 04/05/2013 12:31AM by phlat65.

Look at the TCI bits. We did a thread earlier on this. Here: http://www.rallyanarchy.com/phorum/read.php?5,78553,78622#msg-78622

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"Talk about drugs. Driving a car like that, going that fast, it’s like all the drugs at once." - Tommy Byrne

"Now, Pinky, if by any chance you are captured during this mission, remember you are Gunther Heindriksen from Appenzell. You moved to Grindelwald to drive the cog train to Murren. Can you repeat that?" - The Brain

Or possibly manual control of the box with something like this built for Toyotas, Nissans and Jeeps.
http://www.radesignsproducts.com/Home.php
-Jon

Manual swap.
Ps. For any of you thinking of doing a rally school, you could do four days here, two school days with Dave and two days of actual competition at a hill climb for probably around same amount as four days at the other place...

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Grant Hughes

Dave, it´s NOT electronically controlled... And like said, no way you can drive it on full auto mode... at lest fast anyway.. =)
Here you can see that it´s not really THAT bad... how many would even guess that it´s an automatic without knowing it...






Edited 1 time(s). Last edit at 04/06/2013 11:12AM by bttmotorsport.

So didn't get a chance to take the car out testing this weekend, but did run to the junkyard and pickup a new throttle cable (and got a manual pedal set for $20!), only to find out that the OEM throttle cable was still installed but not connected to the gas pedal. If I'd have taken a 10 second look under the dash when back in Florida, I'd have been able to drive home with a normal gas pedal. In the words of the great Homer Simpson...D'oh!

I did get to drive around the block and the car seems nice and peppy, and shifting it manually as Jari suggested works great...except for the ability to drop it back into 1st gear. I didn't have a chance to see if there were any shifting 'locks' in the higher gears, but it wouldn't complete the downshift to 1st until the revs in 2nd were right about 2000rpm (can drop shift lever into 1st whenever, transmission just won't actually make the shift till speeds are deemed low enough).

Been slammed during the week with too much work, but appreciate all the suggestions and help here so far and will try to dig into it further as time allows. Have tech for our hillclimb series this weekend, first race of the season next weekend, Chumpcar race in a yet to be completed BMW the following weekend, and another hillclimb two weeks after that. Time to actually do anything is going to be scarce for another month or so.

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bttmotorsport
Dave, it´s NOT electronically controlled... And like said, no way you can drive it on full auto mode... at lest fast anyway.. =)

You're right that it feels like a totally different car when shifting it manually. When you say its not electronically controlled, are you meaning that there's no external "ECU" for the gearbox like the E36 automatics have?


Thanks!

Dave

No ECU.... Oldschool..

Quote
DaveK
Been slammed during the week with too much work, but appreciate all the suggestions and help here so far and will try to dig into it further as time allows. Have tech for our hillclimb series this weekend, first race of the season next weekend, Chumpcar race in a yet to be completed BMW the following weekend, and another hillclimb two weeks after that. Time to actually do anything is going to be scarce for another month or so.

I have to finish analysis, write, and defend my thesis before Chumpcar also. Cage is almost done, probably will be done or really really close to it tomorrow.

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Grant Hughes

Quote
NoCoast
I have to finish analysis, write, and defend my thesis before Chumpcar also. Cage is almost done, probably will be done or really really close to it tomorrow.

OffTopic: I just had an hour long very positive interview with the prof I might be working with if accepted. I may be moving to Alabama after all.

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Kirk Coughlin
Woodbury, MN and River Falls, WI

Quemadmodum gladius neminem occidit, occidentis telum est.

Does the BMW 4HP22 have the throttle kick down cable for the transmission or??

Peugeot's use the 4HP22 as well, and it has a kick down cable attached to the throttle linkage. With some fine tuning it should pull 6000rpm on shifts, and kick down to 1st when you floor it and the speed is low enough. If you pull it too far then the cam over centers into WOT mod and it will ONLY upshift at ~6000 rpm...

Lots on line with rebuilding them, but I've never seen much on modifying them. Early Peugeot 4HP22's you had to make sure not to rev in neutral or park over 1500 rpm - there was a fix in later years and when rebuilt - but lots of cars got scrapped.

Apparently a pretty easy fix now however if you're handy and willing to rebuild it yourself.

Rabin

There´s kickdown wire... but that doesn´t solve the downshifting problem. Also, it is not possible to drive, or yes, it´s possible to drive, but not compete while driving on "D"... For example, when starting on 1st gear tires start slipping, it will throw 2nd in, on 10mph... slipping stops, goes back to 1st and so on... 30 years of competing with at:s, that much i have learned already... =)

Sorry - I should specify that it should downshift when you floor when manually shifting. I agree driving it in D is crappy, but if you manually shift the auto and it doesn't drop into 1st, it *should* downshift when you floor it.

That's how I had to do it with my Peugeot anyway as that was the only was to get it into 1st at speed, and it only did it when I set the downshift cable just right.

No idea if it'd work on the BMW version however - just a suggestion.

Rabin

Kickdown wire is not connected to throttle, it´s "on " all the time, tightened to max tightness..