M30B35 Swap FAQ

[Anjey1989]

What custom exhaust specs do you guys suggest for the m30b35? I have an e23 and am still using the b34 exhaust manifolds as well. Should I got Y pipe --> 2.5" piping --> Magnoflow muffler?

if you can get your hands on exhaust from 2.8 m30 then it will be enough (their cheaper than m535i)(it is what i did when i was looking for exhaust for my e28 , http://www.realoem.com/bmw/enUS/partxre ... series=E24 ) if you are concerned that the narrower ends of the manifold can reduce your hp, then I suggest you watch this video: https://www.youtube.com/watch?v=azPKIjxmmdU

i suggest that you use two pipes all the way (better fitment) with a H-pipe somewhere in the middle (in front of stock resonator, google: e28 exhaust)

[Oujee]

I have m30b34 in my e28 518i 1986 euro. Engine is from 1988 e32 735ia. Engine mounts are from 1984 528i e28 and they fitted straight to e32's block.
So..
Do I have "rare" m30b34 block? Because it has 2 place for engine mounts?

[BuzzBomb]

If it's an '88 735, it will be an M30B35. Yes, the early B35 e32 has the correct mounts for an e28 chassis. Rare? I don't know, but I would say sort of yes.

[LOMELOX]

Helllo!

What kind of instrument clusters could I use on my e28 with M30B35 swap? Does other M30s cluster work also? Or could I use E34 ones maybe or are they different?

I have the same question. i know the e34 cluster is a bit smaller than the e28 but i just want to know if it will work and if so i will worry about the sizing later.

Thanks!

[BuzzBomb]

E28 clusters are specific to the e28 chassis.

[DMorgan]

I cant wait to take a b34 block/crank/rods with relief cut b35 pistons and a b34 head (using a big cam) ported polished to a b35 intake and a megasquirt ecu. We've got local tuners that want some business.

From there we'll add a turbo- over 10:1 compression running e85. I bet we'll make a fat powerband around 400 hp from a basic built hx35 turbo kit and junkyard engine build that cost $1200. If we blow it up oh well.

[LOMELOX]

E28 clusters are specific to the e28 chassis.

Obviously.

The question be asked is simply will it work in an e28 with the motor swap and ECU from an e34.

[BuzzBomb]

E28 clusters are specific to the e28 chassis.

Obviously.

The question be asked is simply will it work in an e28 with the motor swap and ECU from an e34.

The answer was given very clearly. If you don't like my answer, let me be more verbose by adding that the e34 cluster is specific to the e34/32 chassis. If that still isn't clear enough, look up "Specific" in the dictionary.

[jhh925]

Mhh... but how does the ECU know to adjust the idle when there is no signal from the A/C switch???

Judging by the schematics, I'm going to say that m1.3 ecu does use the a/c compressor signal as input at pin 40. So you can try connecting pin 4 of c103 to pin 40 of the ecu.

Actually both 40 and 41 are tied together and take their signal from the A/C switch power on wire. Just tie them together at the DME, pull the radio, and run a wire to the back of the A/C switch (pin 3, GN/Yl). Done.

So I just want to make double-sure I'm following this part of this discussion. I've re-done my B35 wiring harness as instructed in Brad D's initial post on page 1 so that at present, I'm going from (i) C101 pin 1 to DME pin 6 and (ii) C101 pin 3 to DME pin 32.

As I understand this thread on the AC power on condition signal to the ECU:

1. DME pins 40 and 41 relate to the AC power on condition. (Mapping for DME pins is here.)
2. I can leave those two DME wires (pins 40 and 41) totally alone if I want to
3. Or I can tie DMW pin s 40 and 41 together and jump from there to my AC power switch in the dash

Questions:

- Is #3 above correct?
- Has anyone tried to connect DME pins 40 & 41 to their AC power switch?
- What is the result if you make that connection? What's the result if you don't?

And to confirm, in the picture below, is the "AC power on" switch wire that I'm looking for correctly circled (the GN/YL wire shown at pin 3)?

[BenGerman]

Can anyone tell me if the harnesses from a B35 E24 are the same for automatic and manual transmission?
If not, what would need to be changed to use the auto harness in a manual car?

Thanks!

[BuzzBomb]

Can anyone tell me if the harnesses from a B35 E24 are the same for automatic and manual transmission?
If not, what would need to be changed to use the auto harness in a manual car?

Thanks!

There are differences, but for a manual car, there's nothing you need to add or change to make it work besides including the auto TPS. It's a lot more work to use a manual harness in an Auto car. Also, since it is from an e24, see my post about halfway back about the additional wire in the fusebox connector (pin 8).

[TimS]

I hooked up those 2 wires to the ac, not at the switch but out by the compressor. it is a single wire round plug. So it will only have power when the compressor has power ie pressure in the ac system , not when it is turned on.

[teahead]

Can someone tell me what this plug goes to? Surrounded in red, top right.

It's in the same general location where the DME and relays are?

Wiring diagram (E34) not helpful.

[teahead]

Is that plug the same thing as this shown here ("not used")???

[Soundstorm]

I have a European 1982 528i with L-Jetronic. I'm now doing a M30B35 with M1.3 swap.

My wire harness has a 3-pin connector for C103. Pin 1 and 3 match this how-to. Pin 2 is GN/YL and is connected to pin 15 on the fuel relay (Bosch 0 280 230 001). As it's connected to pin 15, I assume it's basically ignition-on supply. Ignition-on is also provided through the C101 connector at pin 12 (GN).
Can I just ignore pin 2 on C103? I guess it's ok, as there are now 2 relays (main+fuel) instead of one, and the ECU takes care of the fuel relay. Ignore

I also have quite a few cables left over on the M1.3 C101.
Pin 3: WT/BK, ECU Pin 32. Signal to instrument cluster. Unsure
Pin 12: GY, ECU Pin 15. Signal to instrument cluster/check control. Unsure
Pin 14; BK/WT, ECU Pin 29. Signal to instrument cluster, vehicle speed output. Ignore
Pin 15: BR/BK, ECU Pin 49. Unsure
Pin 16: WT/YL, DIAG Pin 15, ECU Pin 13. Data receiving line, E28 is not intelligent enough. Ignore
Pin 17: WT/VI, DIAG Pin 20, ECU Pin 55. Data transmission line, E28 is not intelligent enough. Ignore
Pin 19: GN/BL, DIAG Pin 18, ECU Pin 39. Labelled as not used. Ignore
Pin 20: BN/YL, OBC Temp sensor pin 1. I guess this is ground for the sensor, and not needed on E28. Ignore

So can I just ignore all 9 loose ends? Or do they need to be connected somewhere?

[Sector9]

I'm so glad I came across this thread as it helped clear up a lot of questions I had in thinking about this swap. (I originally wanted to do the m20 e2i conversion, but I think the m30 would be a better platform to begin with for my purposes.)

I'd like to swap in the M30b35 but I'm getting confused between all of the links I've searched for and bookmarked. Thanks to everybody who contributed to the faq, It's pretty clear what needs to be done from the firewall forward, to include the ecu. None of it is too confusing for me. I just want to get some things clear and organized in a list before I start scavenging parts.

I have an 87 528e with the original manual transmission (I think its the g260/5). I don't mind using the e24 b35 or the e34 b35, it's really up to whatever I can find first. I can work around the engine mount discrepancy on the e34 b35. I don't mind using the e24, e34, or E28 SETA harness either, again that's pretty much whatever comes first.

What I can't find out if the original transmission in my 87 528e bolts to the b35. If it does, that's great. If it doesn't bolt up, I don't know if the bellhousing on my transmission can be swapped out with some other bellhousing to bolt up to the b35, (and if so, I don't know if I'd then need a different driveshaft.) < this is the most confusing and reading multiple links with conflicting info is making it worse

If my original transmission is too weak, but it'll bolt up somehow, im going to run it until it explodes while I find the better option which I understand to be the e34 g260/6, or g265? I haven't looked too hard on finding the info to swap in another transmission into the 528e because it didn't seem like something that had to be done out of necessity. If my transmission just won't work without a pointless, and likely custom adapter, would running the e34 manual transmission require a different driveshaft?


I'm sure this is covered somewhere too, but since I just thought of it this second, I'm sure I can get an e28 535i tachometer working in the cluster, or get a whole 535i cluster and somehow set the mileage to what my mileage is currently.

[BuzzBomb]

"I have an 87 528e with the original manual transmission (I think its the g260/5). I don't mind using the e24 b35 or the e34 b35, it's really up to whatever I can find first. I can work around the engine mount discrepancy on the e34 b35. I don't mind using the e24, e34, or E28 SETA harness either, again that's pretty much whatever comes first".
I realize that you "don't mind" using e34/32 engines and harnesses, but if there's a chance that you might be able to hold off and secure an '89 e24 setup, it will save you a lot of work.
What I can't find out if the original transmission in my 87 528e bolts to the b35.
It won't.
If it doesn't bolt up, I don't know if the bellhousing on my transmission can be swapped out with some other bellhousing to bolt up to the b35,
You can't, it's a one piece transmission
I don't know if I'd then need a different driveshaft.
All e28/24 models used the same drive shaft in manual cars '86-88.
If my original transmission is too weak, but it'll bolt up somehow, im going to run it until it explodes while I find the better option
Nope.
which I understand to be the e34 g260/6, or g265?
You need a 260/6. A 265 is considerably more expensive and will require a different drive shaft.
If my transmission just won't work without a pointless, and likely custom adapter, would running the e34 manual transmission require a different driveshaft?
Yes

[1st 5er]

What I can't find out if the original transmission in my 87 528e bolts to the b35.
It won't.
If it doesn't bolt up, I don't know if the bellhousing on my transmission can be swapped out with some other bellhousing to bolt up to the b35,
You can't, it's a one piece transmission

Where's Sammy when you need him?

[LeiseyJr]

"I have an 87 528e with the original manual transmission (I think its the g260/5). I don't mind using the e24 b35 or the e34 b35, it's really up to whatever I can find first. I can work around the engine mount discrepancy on the e34 b35. I don't mind using the e24, e34, or E28 SETA harness either, again that's pretty much whatever comes first".
I realize that you "don't mind" using e34/32 engines and harnesses, but if there's a chance that you might be able to hold off and secure an '89 e24 setup, it will save you a lot of work.
What I can't find out if the original transmission in my 87 528e bolts to the b35.
It won't.
If it doesn't bolt up, I don't know if the bellhousing on my transmission can be swapped out with some other bellhousing to bolt up to the b35,
You can't, it's a one piece transmission
I don't know if I'd then need a different driveshaft.
All e28/24 models used the same drive shaft in manual cars '86-88.
If my original transmission is too weak, but it'll bolt up somehow, im going to run it until it explodes while I find the better option
Nope.
which I understand to be the e34 g260/6, or g265?
You need a 260/6. A 265 is considerably more expensive and will require a different drive shaft.
If my transmission just won't work without a pointless, and likely custom adapter, would running the e34 manual transmission require a different driveshaft?
Yes

He's wrong. You don't NEED a new working trans, just find any G260 for an M30 that's in bad condition internally.. Than swap the front case off that onto you're G260/5. It's in my build thread for "Fubar" and was proven on track multiple times.

[1st 5er]

"I have an 87 528e with the original manual transmission (I think its the g260/5). I don't mind using the e24 b35 or the e34 b35, it's really up to whatever I can find first. I can work around the engine mount discrepancy on the e34 b35. I don't mind using the e24, e34, or E28 SETA harness either, again that's pretty much whatever comes first".
I realize that you "don't mind" using e34/32 engines and harnesses, but if there's a chance that you might be able to hold off and secure an '89 e24 setup, it will save you a lot of work.
What I can't find out if the original transmission in my 87 528e bolts to the b35.
It won't.
If it doesn't bolt up, I don't know if the bellhousing on my transmission can be swapped out with some other bellhousing to bolt up to the b35,
You can't, it's a one piece transmission
I don't know if I'd then need a different driveshaft.
All e28/24 models used the same drive shaft in manual cars '86-88.
If my original transmission is too weak, but it'll bolt up somehow, im going to run it until it explodes while I find the better option
Nope.
which I understand to be the e34 g260/6, or g265?
You need a 260/6. A 265 is considerably more expensive and will require a different drive shaft.
If my transmission just won't work without a pointless, and likely custom adapter, would running the e34 manual transmission require a different driveshaft?
Yes

He's wrong. You don't NEED a new working trans, just find any G260 for an M30 that's in bad condition internally.. Than swap the front case off that onto you're G260/5. It's in my build thread for "Fubar" and was proven on track multiple times.

Thank you sir.

[BuzzBomb]

Why would you suggest someone seek out a bad trans to Frankenstein something when there are plenty of good ones out there? You're just creating more work. I'm not wrong, I just work smarter, not harder like some of you.

[Sector9]

Yall are a godsend. Thank you for the additional info. I'm going to find either a broken m30 g260 and swap over the front case, or if I can score a working manual m30 g260 I'll do that (more than likely.)

Once I have an m30 g260, which driveshaft would I use?

[mrvedit]

First, this is an incredibly useful thread which single-handedly is make the M30B35 swap a realistic option. Thank you to all that contributed.
I found this thread a month ago and it encouraged me to buy a M30B35 from a '89 735i and get both the harness and 1.3 ECM.
I'm confident that a month ago the images on Page 1 were all/mostly visible, but now many Photobucket images throughout the thread are no longer visible.
While I did find the C101 wiring diagram as a table, might the images become visible again?
Thank you.

[Spencer L.]

I found this FAQ posted on another website trying to figure out my wiring last night, and the pictures are visible.
Here is the link:
https://www.diyauto.com/manufacturers/b ... -by-brad-d

[tig]

High-speed, low-drag way of mounting the 179 ECU in an E28: