Engine conversion; M20B25 or M50B25

[M.Directspares]

Hi all looking for feedback and opinion on the conversion, i have access to both engine M20B25 cameoff 325 sport and M50B25 single vanos bolt on to e30. have all the parts to pair with close ratio box and lsd. Which conversion is better in long run, experience and maintainance.Regards.

 

[Lionel_Koh]

If got extra budget , go for m50b25 instead ......

Newer engine with plenty of spared parts at very cheap price ......

Easy to maintain , reliable engine ......

Power wise 192 for stock and potential stroke to 3.0 or 3.2 using US M3 stroker kit or M54b30 direct fit for 3.0 or 2.9 high compression stroke .....

With the close ratio gearbox and lsd ..... sure fun to drive ......

 

[M.Directspares]

Hi Lionel, how are you. thanks for the opinion.

if so how about the weight ratio and balance. whats is the best suspension setup/rate? will be putting back my B8 shocks


Regards,

 

[Lionel_Koh]

Hi Lionel, how are you. thanks for the opinion.

if so how about the weight ratio and balance. whats is the best suspension setup/rate? will be putting back my B8 shocks


Regards,

can use back ur b8, monotube perform better than twin tube. . . . Spring make sure its for 6 potter. . .

 

[lightspeed]

i think it is all depend on what u want...
my verdict:
m20-if u want classical and mechanical driving feel
m50- smoother engine with higher power output and plenty of upgrading potential as pointed out by lionel.

parts wise i guess m50 is easier to source. m20 parts ain't cheap at all nowadays.
btw, im using m20b27 hartge, and have sit in buddy's m50.
So far im happy with my m20 and 'd like to keep the classical sentiment for the car. I can't handle high bhp in e30 anyway

 

[lightspeed]

can use back ur b8, monotube perform better than twin tube. . . . Spring make sure its for 6 potter. . .

im currently on b12. When my car speeding >150km/hr i feel the back not very stable, my ballz start shrinking indeed
i'm not sure it is due to e30 weight distribution design which mean for left hand drive? The car is higher (front & back) on the passenger side after lowered with b12. Could it be the reason for such unstability? im not sure.

If i have chance, i 'd like to try the adjustable setup to make the car same level, no more 'senget'. Not sure it would improve the handling?

 

[M.Directspares]

m20-if u want classical and mechanical driving feel
m50- smoother engine with higher power output and plenty of upgrading potential as pointed out by lionel.

2nd that, exactly what i feel about the conversion. Nyway the car will be my daily drive after the rebuild. maybe going to M50 route to be more practical?.

 

[Guest]

Was abuut to ask the same question, would like to ask the sifu's here is there a M50 2.3L, asking this is because I hv the m40 1.8L and JPJ allows and up side of 30% from the original engine capacity.
will there be any mounting, from the original M40.
is there a reference in this forum, for us to refer to.

 

[mizhan]

i once converted a 2 litre to 3 litre. it was approved by JPJ without hanky panky.

 

[Guest]

Oh thats a 50% jump, anyway thanks for the info

 

[Axle]

If got extra budget , go for m50b25 instead ......

Newer engine with plenty of spared parts at very cheap price ......

Easy to maintain , reliable engine ......

Power wise 192 for stock and potential stroke to 3.0 or 3.2 using US M3 stroker kit or M54b30 direct fit for 3.0 or 2.9 high compression stroke .....

With the close ratio gearbox and lsd ..... sure fun to drive ......

lionel memang sifu

 

[M.Directspares]

anyone here with 2.0 m20 upgraded to 3.2 evo engine? legal?

 

[E28driver]

If you go the M50 route, you can always swap out the M50 iron block (heavier) with an alloy (lighter) block from M52. Better weight distribution.

Rather than do a conversion from scratch, why not get an E30 that's already converted?

 

[M.Directspares]

im saving my e30, building from ground up. i think its more fun to build the car to suit your needs/taste.

 

[Daniel E30]

U will enjoy yr e30 regardless of which engine u choose. Ive been saying i wana sell it since a year ago, but its still here and am loving it.

 

[Guest]

If got extra budget , go for m50b25 instead ......

Newer engine with plenty of spared parts at very cheap price ......

Easy to maintain , reliable engine ......

Power wise 192 for stock and potential stroke to 3.0 or 3.2 using US M3 stroker kit or M54b30 direct fit for 3.0 or 2.9 high compression stroke .....

With the close ratio gearbox and lsd ..... sure fun to drive ......

Thanks Lionel for the input this info This is in far contrast with what one of the "BMW Specialist Centre" had to say. He points out that the engine is heavy and the car will not adapt well, lot of rollover.
The gear centre will be off alignment, and many others, those that have fitted the M50 had countless problems
His final conclusion is M42, which I beleive he must must be having the stocks available.
frankly I cant see what is the so called frightening impacts mentioned, virtually when u put in a half cut everthing is new.
my only concern is whether the mountings will need modifications, and also the LSD

I am really not interested in the M42 , might as well retain my M40 since they are both 1.8 engines,
I am opting for the M20B25 or the M50b25,

Appreciate inputs from all Sifu

 

[E28driver]

Dear bornfree

Your "specialist" is talking through his A**hole.

The M50 into E30 route is a well trodden path for many people on the forum. Do your research and check out the many examples running around with few issues.

Please consider changing your "specialist".

Respectfully.

Thanks Lionel for the input this info This is in far contrast with what one of the "BMW Specialist Centre" had to say. He points out that the engine is heavy and the car will not adapt well, lot of rollover.
The gear centre will be off alignment, and many others, those that have fitted the M50 had countless problems
His final conclusion is M42, which I beleive he must must be having the stocks available.
frankly I cant see what is the so called frightening impacts mentioned, virtually when u put in a half cut everthing is new.
my only concern is whether the mountings will need modifications, and also the LSD

I am really not interested in the M42 , might as well retain my M40 since they are both 1.8 engines,
I am opting for the M20B25 or the M50b25,

Appreciate inputs from all Sifu

 

[Guest]

Bro E28driver,

Thanks for sharing, it so happened that the "specialist" i mentioned was located from this forum, at least I know for sure now that the M40 can be swapped with the M50 engine.
Thanks

 

[Lionel_Koh]

Thanks Lionel for the input this info This is in far contrast with what one of the "BMW Specialist Centre" had to say. He points out that the engine is heavy and the car will not adapt well, lot of rollover.
The gear centre will be off alignment, and many others, those that have fitted the M50 had countless problems
His final conclusion is M42, which I beleive he must must be having the stocks available.
frankly I cant see what is the so called frightening impacts mentioned, virtually when u put in a half cut everthing is new.
my only concern is whether the mountings will need modifications, and also the LSD

I am really not interested in the M42 , might as well retain my M40 since they are both 1.8 engines,
I am opting for the M20B25 or the M50b25,

Appreciate inputs from all Sifu

About the engine weight .........

M20B25 is 117kg
M50B25 is 136kg
M52B25/B28 is 118kg
M42B18 is 100kg

If u look at the figure, original E30 M20B25 engine weight is 117kg and upgrade to M50B25 only extra 19kg for the engine . Of cause when u do the conversion u need to upgrade ur suspension set up as well like bilstein B12 with thicker ARB and strut bar etc ..... Dont see any problem as ur specialist mentioned . If u afraid about weighting issue...... Go for M52 engine which is aluminium block which is only 1kg extra compared with M20B25 ...... Im using M20B25 as comparison cos this engine can be found at E30 chassis.

Hope this will clear some doubt for u .....

 

[mizhan]

And for every extra 40kg, you need one additional bhp to contra the weight gain, in a straight line.