E30 M30 SWAP writeup.

[george graves]

Nice - THIS NEEDS A STICKY........

[Jean]

Wow, big props for this! Looks like I got a huge battle ahead of me since I got an early car and will have to research on additional items that will be affected.

If got a document and /or pdf with additional information or anything on this subject let me know. I'll be more than happy to get a copy.

Thumbs up!

[Garageaholic]

SPECIAL THANKS

Many thanks to the websites that I mentioned.
Thanks to all the guys on WWW.R3VLIMITED.COM, Jaredsquires.com





Now I know that this is similar to Jared Squires. i got alot of information from my swap from his website. I will try to get a better version that has the pictures that I have and all of the wiring diagrams that helped me immensely. Any questions, please let me know. Don't post simply to post on this thread. I want this thread to mainly be informational.

[Garageaholic]

TROUBLESHOOTING/ FAQ
Engine won’t even turn over
Check your Starter wiring.
Is your battery hooked up/ properly charged?
I have an E32 735i Battery in there and it gives me all the cranking amps I need.
My electrical system performs just fine.
Did you ground the engine to the chassis
Engine won’t start
Ignition coil hooked up
ECU hooked up
Fuel hooked up backwards
Need new distributor cap/rotor
Tachometer not working
Instrument cluster
Speedometer not working
Check sensor at differential
Car still overheats
Fan not “hugging” radiator
Car idles like crap
Too rich
Maybe your crank sensor is loose. Check on front flywheel.

[Garageaholic]

AIR INTAKE SCHEME
I had a cold air intake, but since I went turbo, I have this old cold air intake shortened specific for E30M30. It’s not K&N, but it worked great.

You can also use the intake from any stock E28,E23,E24,E32,E34 airbox. The E32,E34 boxes are much more aesthetically pleasing, however any of them will work. They look like this:

[Garageaholic]

FLUIDS
6.1 Qts of regular 10W30 oil
ATF for manual transmission
Anti-Freeze- blend with 50/50 ( I used regular water and never had a problem)
Steering/wiper/brake/etc…

[Garageaholic]

CARBON CANISTER
The carbon canister is mainly to there to maintain the pressure in the fuel tank when fuel is depleted to prevent a negative atmospheric pressure. Just trim the tube to a shorter length and hook up to the E30 canister that should already be there. Make sure M30 engine has it’s own valve, sensor, and tubing to hook up to the E30 canister. I think it has the tubing, not sure about sensor and valve.

[Garageaholic]

CRUISE CONTROL
If your car was equipped with cruise control before the swap, then the cruise control should still work fine after the M30 is swapped in. Just make sure that you connect the wire in the back of the instrument cluster. That wire reads the speed and adjusts as necessary. For me, the wire connects to the Green connector on the back of the instrument cluster. You will need to adjust the cable to make sure it’s taught. In the above picture, it’s the one on the bottom and it’s pretty loose, I need to tighten it.

[Garageaholic]

WIPER WASHER FLUID
The E30 ix reservoir will fit where the battery would go on a regular E30 car. If your E30 has the battery in the area by the passenger shock mount, then you must relocate the battery to the trunk for two reasons.

• In many states, you need a working windshield wiper system to pass inspection.
• You will be a fool to keep the battery in the front due to the weight distribution. Convertibles have their batteries in the front. I don’t know much about converting a battery to the rear. It can’t be too difficult.

Since my car has the battery in the rear, the front is a perfect place to store it. It will be a very tight fit, however, but definitely doable. Refer to picture:
The pump fits fine within the reservoir. If your reservoir fit on top of the passenger wheelwell, then you might have to get a different hose that is longer to accompany the extra couple feet of distance.

[Garageaholic]

THROTTLE MECHANISM
The E30 throttle cable and cruise control should mount right up to the Stock M30 linkage. Remember that you must use the M30 bracket on the intake manifold. Just bring the throttle cable around. Shorten or lengthen as necessary and install. The M30 throttle is simply at a different position, but works exactly the same as the M20 mechanism. As far as the cruise control computer cooperating with the rest of the car, please refer to “cruise control” section

[Garageaholic]

AIR CONDITIONING
Because the M30 is already heavier than the M20, I decided not to install air conditioning. Think about it. You have the compressor, all the plumbing, the condenser. It’s just cumbersome and if you’re going to ride this thing hard like the rest of us, you might want to consider not using it. Just keep the windows down! If you must, then be aware of the following things happening:
1. The extra power and torque you wanted, will be gone and going all to the A/C
2. If it’s that hot outside, your M30 is probably running on the hot side to begin with, Running the A/C will overheat it for sure.

[Garageaholic]

DIFFERENTIAL

There are many different options for picking the right differential. Some of these differentials are too high for highway speeds. Some are too low for fast acceleration. Many of these differentials (bolded) are featured in E30’s. Many of them can be grabbed from E28, E24, E32. Just swap the output flanges and the rear cover from that of your current E30. It’s as simple as that. I do not know the entire differential compatibility between BMW’s in the 80’s-90’s. Not to mention, it’s out of the realm of the M30 swap, so here is a brief overview.
4.10 Doable, but way too high and might lose first gear
3.91 Drivability on the highway will be tough. Compromise top speed
3.73 Perfect for a lightweight flywheel operation. I agree with Jared on this one.
3.64 In between. If you can get your hands on it, go for it
3.46 Probably a real good all around gear. Kind of rare to get though
3.25 I have in my M30 turbo. I love it. I cruise around highway at 2500rpm at 70mph
3.15
3.07
2.93 Better for higher turbo M30’s <12psi
2.79

[Garageaholic]

BRAKES/BRAKE BOOSTER
Hooks right up. The master cylinder is not a problem and is in the way of nothing in the engine compartment. The brake booster vacuum hose that comes from the intake manifold of the E32 engine hooks right up to the brake booster of the E30. Another very simple modification, but very important.

[Garageaholic]

SHIFTER MECHANISM
You have many choices here with the shifter mechanism. This depends on the transmission you get. I will talk about the option that I went with. Since I got the E28 transmission, I had to use the plate style shifter. I have heard that if you use a newer tranny, from an E32 or E34, you can use the E30 shifter and arm. It’s simply different hookups on the transmission itself. Like I said, many ways to skin a cat. I’m going to cover the way I did it, and I think it was the harder of the two, so that should benefit anybody reading this
Pictures of my setup:

As you can see, I had to shorten and weld NOT ONLY the shifter plate, but also the shifter selector arm. This was very tricky because I kinda had to feel how long to make it. Word to the wise: Do this I the engine/tranny has been dropped in. I can’t imagine how you would do it without any frame of reference.

• Cut the plate in half
• Have a friend sit in the driver seat. You under the car with both halves. Attach the one half to the transmission via the two hex bolts. Forget about the shift rod for now. Line up the other half of the plate overlapping the first half. There will be about an inch or two (depending on engine position) of your shifter plate. Have your friend in the driver seat tell you when the shifter would be in the center of the hole. Then, make a mark, take it apart. And weld it together. I bolted them first, then welded, just for security.
• Now for the selector rod. This is very important how you do this because if it’s not right, you will have problems shifting.
  • Too short – 2nd and 4th gear will hit the console
  • Too long – 1st, 3rd, 5th gear will hit the console
  • Just right, the neutral position of the shifter will be right in the middle of the console and all gears will shift perfectly, including reverse.

I replaced all nylon bushings. They are yellow and look like thin plastic washers. I replaced 4 of them. It was tight, but then again, tight is good. It means minimal play in the shifter.
I also used AND highly recommend a short shift kit to prevent any scraping of the shifter in the console, ruining my shift boot. 40% reduced throw, so I was happy.

Now in order to retain the shifter mechanism to the frame of the E30, you must think smartly about it, lol. The first iteration of this, I had no rubber bushing in between the shifter mechanism and the body (highlighted by Yellow circle in first picture) . I bolted it tight! Bad idea. Turns out that under coasting conditions, I could shift fine, but hard acceleration or turning situations I forgot that the tranny/engine DO MOVE, so having the shifter practically welded to the frame was a bad idea. That’s why you can see in the first picture that I decided to put a rubber bushing. That allows about ¼” to ½” of play for the tranny to move around under hard acceleration. Now I can easily shift under any circumstances. I will leave this to your imagination. It’s not difficult if you can be creative and have a lowes or homedepot near you. I initially ruled out using the actual BMW part. I just didn’t think it would be compatible, but it most definitely could be.

[Garageaholic]

IGNITION/STARTER
I used a starter from an E28 535i. I got lucky and found one lying on the ground at a junkyard underneath the car. The bolts are difficult to get on, particularly the obvious one. I don’t remember if it’s 17mm or 19mm, but it is one of those. I highly, highly recommend installing the starter prior to dropping the engine/tranny in the car.

Don’t forget about starter wiring. You can do this after the engine/tranny has been dropped in the car. You will need the obvious power wire. You can use the one from your E30 if you like, or get a 2 gauge wire from homedepot or something. Make sure that the loop on the end is clamped on bigtime if you do the homedepot route.
Now on to the other wire for routing. You will take the black wire with the yellow stripe and wire it to the starter. Remember that the starter is already grounded. You already hooked up the power. Now you need that “switch”. That ignition switch wire is the black with yellow stripe and you will see on the starter, there are two tabs to attach that wire on the solenoid. Read carefully as I show you which one to mount it on. If you properly install the starter, and you look at the driver side of the engine, you will mount the wire on the tab that’s on the top of the solenoid.


The E30 ignition coil is fine for the swap. No need to use the E28 coil. You can change out the spark plugs and wires if you wish to as well.