Questions about E36 Auto to Manual Swap: ZF to Getrag

[mpost3r]

Hi all, I got myself into a pickle but I knew this would happen (the car was such a great deal, I couldn't help it). My preferred budget is around 500 bucks. You may think to yourself, "this kid's psycho." Well, maybe to an extent. If you read on, you'll understand how it might be possible(with the exception of flywheel, clutch, etc)

WARNING: This thread will make your head SPIN. If you're not sitting down or are faint of heart, I would advise centering yourself. It's about to get more complicated than a 21st century marriage involving a mortgage. I will try my absolute best to make things as clear and precise, often by repeating things most of you guys would already know. Better safe than sorry. It involves lots of models and lots of years and lots of different transmissions all mashed up in one little neat, and, hopefully functional, package.

PREFACE: For those who actually take the time out of their own personal lives to read this mess, comprehend it, and then contribute help and knowledge, I would like to deeply thank you all. As a teenager with a love for E36s, I find it a blessing that forums like these exist, with members of it who are willing to help out beginners like myself. Hopefully this will be a learning experience for me, which I can then later pass on my recently gained knowledge to others who need it too. I was so excited when I bought the car. It's almost my perfect, ideal E36 with the exception of the stock suspension and automatic transmission. These two things, though, can be changed. And that's what I plan on doing. Thank you. Thank you for reading, for contributing, for understanding, for CLICKING on this in the first place. It really does mean a lot.

So,

Here goes. *deep breath*

I got a '99 328is, made 02/99. It's got an automatic, though. I knew I was going to manual swap this thing from the day I took it home, and July is my month for that. I plan on doing it by next week, or when I get all this compatibility sorted out.

I have some parts lined up for it:
-My friend is giving me a Getrag (240? 250? 260?) off of his 1998 323ic.
^I am fairly confident, if not sure, that this transmission will bolt right up to my engine and chassis. I was told that literally any transmission, ZF or Getrag, can bolt up to any engine, M/S50, M/S52. If this is wrong, please tell me. There's nothing to lose here, so it's alright if it doesn't fit - he's giving it to me for free.

-I'm probably gonna get this pedal set from a 1998 M3: https://denver.craigslist.org/pts/d/...616331214.html
^I'd assume that all the linkages and misc. parts (that I honestly don't even know the name of) that are listed on that craigslist ad are compatible with both ZF and Getrags, so I'm not worried there. If you happen to know if these 1998 M3 linkages and assorted parts are not compatible with my 1999 328is with a 1998 323ic getrag in it, please let me know before I waste my money.

-New slave cylinder: https://www.ecstuning.com/b-febi-par...521159045~feb/
^However, ECS says that part fits cars up to 01/99. I'm 02/99, but if I'm doing the getrag conversion off of a 98 323ic, I'd assume it would fit. If somebody knows WHY, exactly, it wouldn't work with 02/99 cars, please let me know. And, if that slave cylinder will not work with my 02/99, is there any that WILL? Even the genuine BMW one says it only works up to 01/99.

-Braided/steel clutch line: https://www.ecstuning.com/b-ecs-part.../009535ecs01a/
^This braided clutch line fits an E36 323ic(donor car's transmission) and a 328is(my car) so I'd assume any M52. If you think there's any compatibility issues, let me know. There is, however, the possibility that ECS thinks this is for a ZF trans, so I found the same exact cable, but for a 325is, which is more than likely a getrag: https://www.ecstuning.com/b-ecs-part.../009535ecs02a/
Which one do I get then?

-Guibo(and full driveshaft?): https://www.ecstuning.com/b-uro-part...111227410~uro/
^This guibo is for a '98 323ic. It's confusing, but I'm pretty sure I got it down: If I run this getrag transmission out of a 98 323ic, I need a getrag guibo, but bolt it up to my 328is' driveshaft and diff flange. (once again, if this is wrong and you know better, correct me.) Also, if I'm bolting up a 328is driveshaft to a 323ic guibo, would I need different hardware? I don't know if I want to do this, however. I would much rather get a complete getrag driveshaft, so I don't run into balancing issues. This is the route I'm pretty sure I'm gonna go with:

Getrag trans-->325/323 front driveshaft-->325/323 guibo-->325/323 rear portion of driveshaft

Then, it gets more complicated. The differential flanges are different. I was told by someone whose really handy with e36s that there are 3 different differential flanges: M3, 328, and a 325/323. However, the diff flanges are easily interchangeable. If this is the case, it would most likely be easiest (but more expensive, since I have to ditch my current driveshaft and flange) to run:

Getrag trans-->325/323 front driveshaft-->325/323 guibo-->325/323 rear portion of driveshaft-->325/323 differential flange-->328 differential

Then, we run into the NEXT issue on the laundry list, and that is gearing.

I cannot find, whatsoever, the gear ratio of the differentials between the auto and the manual, and it's 100 degress outside so I'm not gonna look. If one of you guys knows the differential ratios of E36 automatics and manuals, let me know so I can plan accordingly; I'll see if I need a new differential to accommodate for the different transmission gearing (good time to install an LSD, if I can find one for cheap). If I don't I'd rather keep the stock diff right now, because I'm on a tight budget (hence swapping a free getrag instead of buying a ZF to make it more plug and play).

Hopefully, those are all the conflicting issues between a ZF and Getrag in terms of putting the power to the wheels. If I missed something and find it, I'll update it. If I miss something and don't, let me know.

-Flywheel/Clutch Installation: Up for debate. I'll find one, this shouldn't be hard. It doesn't really have to do with the swap either, just like any flywheel and clutch job.
^Feel free to leave suggestions. My budget is $500.

NEXT UP: The install:

Preface: My car was wired with an aftermarket security system and remote start. The security system shouldn't conflict if it were on a manual, but the remote start sure does. I never use it anyways, as the radio frequencies from the stock security system conflict with the aftermarket. If I lock with the aftermarket FOB, and unlock with the OEM key, the alarm goes off, and vice versa. So, I only use the key; screw the aftermarket system. The battery is dying in the FOB so I never actually use it. If, however, the wiring of this system would conflict with the manual swap (my guess would be detecting if it's in park or the brake is pressed), let me know as well. I don't see why though, since I don't use it and am fine without it.

WIRING:
I've spent a pretty decent amount of my life researching this, and know that the park safety switch, or whatever it's called, needs to be bypassed in order to actually work. This guide I'm using is pretty handy:

http://www.e36-tech.com/DIY/5speedswap.htm

However, cruise control works perfectly on my car, and I don't know if I want to part with it. Anyone know anything about how to keep cruise control, or where it's wired? I'll refer to that guide I just linked, because it talks about it but I cannot find out exactly how it works.

Hydraulics:
Hopefully the friend that's helping(more like doing 80% of it because he's a lot more competent with E36 transmissions and drivetrains than me) understands and comprehends the hydraulics within the manual transmission to a greater extent than I do. I do know, however, that the master cylinder reservoir, even on the automatic, has a nipple already on it for the clutch slave. There's also plastic plugs in the carpet next to the brake pedal to install a clutch pedal. Going back to the partial parts list, however, I run into the issues I foreshadowed to above. I'm not sure which steel clutch line I should run: the one ECS says fits a 325is (getrag?) or the one ECS says fits a 328is (ZF?)
Also, when comparing pictures, you can see a noticeable difference:

ECS SAYS THIS FITS A 328IS AND 323IC:
https://gyazo.com/6fd6d1f50dd04b5e4136ec181256a89b

ECS SAYS THIS FITS A 325IS:
https://gyazo.com/a46ec9594c41a482ab2f9651345f3a3f





Other than that, the transmission and driveshaft install seem like what I like to call "precision grunt-work." Everything has to line up, but it's mostly just heavy lifting and lots of swear words. My friend who offered up his time and help with this knows the rest on how to set up the little things, and that guide I found should do most all of it as well. This, to me, is similar to many other E36 auto to manual swaps, except mine has a extra touch of German engineering in it, since I have to do a ZF to Getrag swap.

And that's it! That wasn't too bad now, was it? Oh. It probably was.

I'm eager to get this show on the road, so I will respond to comments fairly quickly!

If you need any more clarification or details/plans, let me know and I will do my best to provide.

THANKS!
-Sean

TL;DR:
I want to manual swap my ZF '99 328is with a 98 323ic Getrag. Help me with the swap, such as compatibility issues with guibo and driveshaft and differential flanges. Also feel free to pass knowledge down about the rest of the swap!
Please, read the whole thing for all the details. Or, if you'd prefer, I sectioned off the post to make it relatively easy to pick out little details.

[ed323i]

I think there must some FAQs on this forum or experiences from people who've done this before..
No experience doing this myself, but I can help you with the diff ratios.
Check them here (look below final drive): http://www.bokchoys.com/differential/GearRatios.htm

A stock 328i (and 323i) manual have 2.93 diff, which, at least for the 323i is a bit too long. For the 328i it's okay, but a little shorter will make it more fun.
The 325i (M50) has 3.15 and that would have been great for my 323i. Both 325i and 323i have a 2.5 liter engine, but because of the added torque down below of the 323i M52 engine, BMW decided to use the long ratio differential, which, especially in areas with lots of hills, make it slower than necessary accelerating from a stand still.

A stock 328i auto, on the other hand, has a very short ratio diff, 3.91 .
You can drive a manual 328i with that diff, but you will loose a LOT of comfort and there will be a lot more noise on the highway. It will be really fast accelerating, but you'll need to shift twice to get to 60 mph instead of once with the stock 2.93 diff. For a comparison, the 318i(s) has a 3.45 diff, and that's already quite short ratio. So 3.91 with a manual transmission would result in very high rpm's at highway speeds.

So, you can give it a try with the original diff, but, especially if you drive it a lot on the highway, you'll want to buy another one.. I think a 3.15 would be a nice compromise between acceleration and comfort. There is also a 3.15 LSD version, which would be the perfect upgrade I think..

[jc43089]

That trans would be a G250. They are ok for stock power, 2nd gear synchros can wear out. Mine has 290k on it and a 1-2 shift is ok if you don't ram it but a 3-2 usually needs double clutching.

realoem.com is your friend when trying to determine what parts fit together.

The slave cylinder would be the part called out for any 325 or 323 e36.

Most manual e36 cars have a 3.15, some have 3.23. There might be other options but those are typical. I have a 3.15 and it is good with the G250. The gear ratios between the ZF and G250 are not significantly different, both have 1:1 5th gear. Ignore differential advice from e30 guys as the G260 has 5th gear as an overdrive gear to bring the revs down on the highway.

That pedal set looks like it will work great, the pedals and master cylinder should be picked to match your late model car so the right switches mount for the pedals. The slave should match the transmission. Use realoem to see if the hardline section of the clutch tubing is the same from early/late. That will help you figure out which flex hose to use. It is likely the same because it ends at a bracket on the body and the length of the flex hose is probably different to reach the different location of the slave cylinder on the ZF. I am not positive on that though.

The driveshaft: the rear section of all driveshafts is the same length up to the center support bearing. It is ideal to keep the driveshafts as an assembly because that is how they are balanced when new, however you could just get the front section and if you notice vibration take it out as an assembly and have a driveshaft shop balance it. I am making a custom driveshaft for my M50 swapped Toyota van and that is kinda what I am doing with BMW front section and Toyota rear section.

Wiring, I didn't look at the link you posted but the BMW Electrical troubleshooting manual (ETM) is your friend. Most swaps make a complicated mess of wiring because people just follow the internet DIY from somebody that didn't read the ETM to begin with. What you want to do is find the page showing the start interlock and compare what is different for auto vs manual. I can help with that when you get there, I'm an industrial electronics tech so wiring diagrams and multimeters are fun for me