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BMW M51 questions from California
NapaBavarian Offline
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#1
BMW M51 questions from California
I know there are a few Europeans on here, perhaps a speed Finn or two. I have an e34 in the yard..actually my BMWs range from 68 2002 project to a 97 M3 parts car, but they all have the same problem, they requird some sort of slovent in the fuel tank...nasty and the thought of the stuff causes me to have epileptic seizures. I have seriously contemplated importing either a couple complete engines or perhaps if it makes shipping easier they could be broken down into individual components, ya know, to repair my bmw because those parts are so hard to find over here...

It seems there are turbo and turbo intercooled models, td & tds. I find references to two models of each, and some refrences to chiping, is there a mechanical and an electronic injection pump? Can anyone shed light on the differences? I find little information in english.

What transmissions were used? I have a couple (not sure, a few?) S5D 250 G from M50 gas and can affordably get a complete S5D 310Z from 91-92 525i a d just about any other common us model in the 15-30 year old range.

Will m50 flywheel work? I have bolted an m20 flywheel to an m50 with minor clearancing.

How much power can I get from a basically stock engine, no major modifications? I want something I can drive every day and while power is fun I'm more interested in getting it together.

Thanks in advance.
12-22-2013, 04:02 PM
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F.R.A.S Offline
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#2
RE: BMW M51 questions from California
The diesel gearbox is ZF S5D 320Z or ZF S5D 310Z, that's the same as 328 and M3 5spd. M50 flywheel will work, but M20 och M30 solid flywheels are better. M20 is only for a 228mm clutch (Sachs 618 pressure plate) so the M30 is better and allows for a 240mm clutch (Sachs 765 pressure plate).

Easy power is mechanical pump from the 324-diesel (all 325/525td and tds are electronic). Then the normal, exhaust manifold, turbo intercooler and so on... You can run about 350hp, just keep track of the old EGT.

To make MORE power, wait for our m51 rotor pump delete ---> om603 inline pump conversion.

BMW has it all worked out and almost everything fits across. The crank fits from m20 --> m50 and m51 and vice versa. Now the only crank with a longer stroke than the m51 is the m54b30 with 0,01mm longer stroke witch is nothing... But to make it a bit more interesting one can machine down a s50b32 crank to fit and get the volume up in the old m51d25 =) But that's not cheap easy power.

I hope you have some usable information here any how.
F-tune Performance [Image: V-band_om606.jpg] [Image: GTX3582R.jpg] [Image: gs6-53dz_gearbox.jpg]

I can help you out with all your manual transmission, clutch, flywheel, intake and exhaust manifold issues.
01-15-2014, 03:18 PM
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NapaBavarian Offline
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#3
RE: BMW M51 questions from California
Thanks, that helps with several questions. The 310 or 320 (one or the other) gearboxes were also offered in the 91-92 525i so driveshaft isn't too hard to come by, now all I need is to get some parts to california.

Do you know anything about how much needs to be changed to get the factory intercooler into an e34 or e36?
01-16-2014, 10:44 PM
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F.R.A.S Offline
Holset
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#4
RE: BMW M51 questions from California
Factory intercooler is just shit, throw it as far as you can and buy an aftermarket one.

We can offer custom chiptuning for the m51d25, but the safest bet is to go mechanical on the fuel side and using a m21d24 pump. Just as you know.

(01-16-2014, 10:44 PM)NapaBavarian Wrote: Do you know anything about how much needs to be changed to get the factory intercooler into an e34 or e36?
F-tune Performance [Image: V-band_om606.jpg] [Image: GTX3582R.jpg] [Image: gs6-53dz_gearbox.jpg]

I can help you out with all your manual transmission, clutch, flywheel, intake and exhaust manifold issues.
01-17-2014, 06:06 AM
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muuris Offline
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#5
RE: BMW M51 questions from California
E28 524td has mechanical pump, too. There are two types of flanges in tds pumps, the other is different to mechanical. Both the tds and mech. pumps have 10mm distributor head which is sensibly enough for 170hp, so pump mods are necessary in either case. Even with 12mm distributor 350hp is not realistic, 250hp is. Some heavy mods should be made so the head or head gasket wouldn't fail when using high boost and lot of fueling. I know that 300hp tds engines have been built but I know none that has lasted long..

Merc inline pump would solve fueling issues (6cyl ve & high rpm = nit good) but the head/gasket problems remain..
02-13-2014, 03:48 AM
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NapaBavarian Offline
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#6
RE: BMW M51 questions from California
I've been thinking more about this, I'm wondering if I could build a mechanical m47 4 cylinder for my e30 cabriolet
11-11-2014, 02:40 PM
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whitey1986 Offline
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#7
RE: BMW M51 questions from California
This is all great information as I have just bought my tds :-)
04-20-2015, 05:24 AM
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whitey1986 Offline
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#8
RE: BMW M51 questions from California
So what about this om603 inline conversion? I would be very interested in this or more information!
06-08-2015, 02:07 PM
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