M20 or B25
Moderator: martauto
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Colin
- E30 Zone Newbie

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- Location: South Bucks
I will need a new engine for my 325i soon as it has been to the moon and back. What is the difference between the M20 and the engine fitted to a new 325. Is it a lot more economical and will it fit?
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jmc330i
- Engaged to the E30 Zone

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The M20B25 is the engine you have now.
I take it you are thinking about fitting the M50B25 from the E36/E34??
Theres a few M50 conversions about. Its not a straight forward conversion but its not overly difficult either.
The M50B25 engine is 2.5 24v with just over 190bhp. I think they are actually a bit worse on fuel than the M20 is, but I dont know if its a lot. The M52B28 2.8 24v (328i engine) is meant to be better on fuel. About the same power as the 2.5 24v but has more torque.
I take it you are thinking about fitting the M50B25 from the E36/E34??
Theres a few M50 conversions about. Its not a straight forward conversion but its not overly difficult either.
The M50B25 engine is 2.5 24v with just over 190bhp. I think they are actually a bit worse on fuel than the M20 is, but I dont know if its a lot. The M52B28 2.8 24v (328i engine) is meant to be better on fuel. About the same power as the 2.5 24v but has more torque.
James
'91 325i Sport
'93 318i touring 16v
'91 325i Sport
'93 318i touring 16v
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Colin
- E30 Zone Newbie

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What is the normal fix when the engine finally goes bang? is a normal recon better on a more modern lump?
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rickk
- E30 Zone Newbie

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I've been asking myself the same a while ago...
Cost will be about the same (recond M20 vs. low-mileage M50), but ofcourse the M50 will give you some more headaches to fit in.
That said, the M50 is probably the 'sensible' choice, more power, more economical (AFAIK), more torque, better idle all in all more modern technology.
But in the end I chose for the M20 because I think it looks (I really don't like those plastic covered engines, altough the M50 isn't that bad) and sounds much better, it just 'fits' the car.
FWIW: weight is about the same (M50 a little heavier, M52 a little lighter).
- Rick
Cost will be about the same (recond M20 vs. low-mileage M50), but ofcourse the M50 will give you some more headaches to fit in.
That said, the M50 is probably the 'sensible' choice, more power, more economical (AFAIK), more torque, better idle all in all more modern technology.
But in the end I chose for the M20 because I think it looks (I really don't like those plastic covered engines, altough the M50 isn't that bad) and sounds much better, it just 'fits' the car.
FWIW: weight is about the same (M50 a little heavier, M52 a little lighter).
- Rick
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Brianmoooore
- E30 Zone Team Member

- Posts: 49360
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Latest engine is the M54 - just aquired one. Looks like it's going to be an electronic nightmare!
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Jhonno
- Homo Hair
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- Location: FLAT, FLAT, FLAT!!
M50 - 136kgs
M52 - 118kgs
M20 - 117kgs
M52 - 118kgs
M20 - 117kgs
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LOOPYLEE1965
- E30 Zone Regular

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LOOPYLEE1965
- E30 Zone Regular

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Dan318-is
- Married to the E30 Zone

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my mum had a 328i e36 was bloody quick i must admit, i cant really say tho cos i never been in a 325i
iv done 155 in a tvr tho, i can assure u it aint safe. it aint safe
iv done 155 in a tvr tho, i can assure u it aint safe. it aint safe
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chu346
- E30 Zone Addict

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318-is wrote:iv done 155 in a tvr tho, i can assure u it aint safe. it aint safe


