M30 conversion thread. Q&A

[e21-Mark]

Does anyone have any idea of the spring rates that Hartge used with their 335 conversion or that Alpina used with their B6?

[Jason_323i]

I thought I would add few bits

Engines

Most comercialy aviable mounts are for the following engines and work with 6 cyl subframes

E12
E12 based e24
E24/e28

The e34 and later m30’s have a different engine mounts if you get lucky the highline e24 has the e34 spec engine ie bigger valves later motronic but the e24 engine mounts.

Fuel injection

The cost effective way is to use the fuel injection that come with the engine, but this limits the gear box choice as the e24/28 has the sensors for the ecu in the gearbox bellhousing.

The E12 injection runs a dizzy and is bosch L-jet it is not possible to chip this and is difficult to tune for more power

E24/28 injection is motronic 1.1 which can be chipped

E34 is motronic 1.3 which can be chipped and the ecu sensors are from the crank damper giving more gear box options.

A good upgrade is the motronic 1.3 to an e24/e28 engine.

Gear boxes

The main issue is the speedo drive if you want to retain the speedo

The options are e12 boxes which have the speedo drive or early e24/e28 boxes in which the speedo drive can be reto fitted

Most m30 boxes swap over but whatever ever box you use you need use a matching clutch and flywheel ie e28 flywheel and clutch not e28 flywheel e34 clutch.

You can retain the e21 m10 box, flywheel and clutch but clutch life will depend on how hard you abuse the car.

Weight

The extra weight is about 70kgs inc ancillaries

By using bits like a lighter e21 alternator, e34 starter motor, lighter flywheel, cone filter you can shed over 10kg. Moving the battery to the boot will offset about 15kgs and you can lose about another 15kgs using a good grp double skin bonnet.

Other weight loss bits are use a grp front spoiler, stainless 6 branch manifold, ditch the bumper etc

[rob0r]

Good advice Jason! I'm considering doing an M30 conversion for my black 316 (in my sig) and using the M10 gearbox. That way I can keep the speedo among other benefits. The only concern as you mentioned is the clutch, but surely there are stronger clutches out there since some people boost M10s to 350bhp! I'm not looking to do this any time soon though and I'm weighing up other interesting engines to stick in it

[e21-Mark]

We're looking at dropping my spare m30 into my 316 in the same way Rob. The plan is to shed as much weight as possible rather than worry about trying to boost engine performance. I'm guessing that there must be some e30 M3 clutch options available?

[murran]

after seeing a nissan s12 engine in a 2 door e30 1st hand.... id look into that in your 316 if i were you rob.
http://www.trampdrift.co.uk/Forum/TD/sh ... .php?t=125

[Jason_323i]

e30 m3 clutch and flywheel fits the m30 not sure if fits an m10 bellhousing

[rob0r]

after seeing a nissan s12 engine in a 2 door e30 1st hand.... id look into that in your 316 if i were you rob.
http://www.trampdrift.co.uk/Forum/TD/sh ... .php?t=125

That's a good idea, I've actually considered Nissan turbos before. I think my black 316 will stick with BMW engines, it's going to be a cool cruiser! I have a 535i manual arriving in a few weeks which maybe being broken since I need a new diff for my 735i manual. A 2nd hand open diff is £100, this 535i is £200 complete... It will probably end up getting fragged so I'll have the bits laying around, even the E34 manual box, but I'll choose to use the M10 box if I went that route. The other tempting option has double the amount of cylinders