Difference between the 325 12v and 24v engines

Post Thu Feb 10, 2005 2:51 pm

Just wondering what the differences were between the engines in the E30 325 and the E36 325. Has anyone ever tried changing the old one for the new 24v engine or is it a waste of time?
Not that Im thinking of doing it or anything, was just wondering really.

Post Thu Feb 10, 2005 3:16 pm

yes mate e30adam has a 2.8 and there is another chap with a red e30 with e36 engine in it, someone will tell you who and the pros/cons

Post Thu Feb 10, 2005 3:17 pm

e30 325i 12v is 171 BHP - m20
e36 325i 24v is 190 bhp, - m50 (not sure please feel free to correct)

general difference i think is the m20 is more revvy engine than the m50 since the m50 is 24v , also there is a later version which include Vanos (variable cam lift/timming similiar to Vtech form honda etc etc).

an m50 powerplant into a e30 is most certainly possiable, check out this site http://www.e30m50.com/E30/mym50swap.htm,

a couple on here have a m50 e30 (wil6pot i think).

all i can think of, but defo not a waste of time.

has anybody thought of putting the 328 engine in the e30 (bbtb and intake manifold should be about 210 ish? would this be a similiar swap to the m50?

Post Thu Feb 10, 2005 3:46 pm

Yeah, the E30 325i is the 12v M20 and the E36 325i is the 24v M50.

The E36 328i 24v is the M52 i believe. About the same power as the 2.5 M50 but more torque. The swap is pretty much the same as the M50, except for the EWS security.

Ive seen a 2.8ltr 24v in an E30 and it was nice. And I think there is someone on here with just that conversion.

Then ofcourse there is the S38 and S50 conversions

Post Thu Feb 10, 2005 3:53 pm

I own the Red M50 conversion! I think the main difference is the power delivery, the DoHC 24v engine in my car is a rev monster it'll just climb and climb the revs, the power it gives is progressive and gets stronger the closer you get to the Redline. The M20 i drove recently was incredibly smooth (felt like it had one cylinder) and had more lowdown torque but didnt rev as freely as my own.
Its a stunning engine imo altho i think the better fuel economy of the multi-valvers is a bit of a myth, mines a bit better than its M20 counterpart but you still feel the thirst come fill up time!

Post Thu Feb 10, 2005 4:02 pm

ive driven wil's car and its an awesome machine

it revs waaay more than an m20 and the torque is also good although not as good as a 2.7, so getting it sideways is a bit harder.

it makes sense as a conversion before as to get a m20 to bequicker than a stock m50 is very expensive- prob about 3-4k for a proper 2.7 with all the goodies like headwork etc and ecu mods

ive driven in convoy with wil many times and it seems although mine is more powerful he still remains in my mirror!

the engines are also cheapish due to the huge no's of cars with these engines out there!!

im looking into this conversion for another e30 some time in the future, prob the 2.8 with some intake mods as was described earlier in the thread. 220hp is not a problem and is about what my 2.7 is currently producing with a lopt more money spent on it!

Karan

Post Thu Feb 10, 2005 4:08 pm

do the M52 328 engine over the m50 325, as although there is 1 BHP difference, 325 192 v's 328 193, the torque difference is amazine.

Check out performace stats of 328 e36 V's 325, then think about that engine in a E30, yeah baby!

328i e36 is Much quicker than e30 325 and revs build pulling you all the way, whereas my e30 325 cab had a definate power band, just not as linear.

Sound = m20
power = m52

in standard form i'm talking about.

Post Thu Feb 10, 2005 5:17 pm

Im not sure what an M52 would be like installed, i do know theyre easily modded to nice bhp levels for cheap but the one i drove didnt rev as hard as my M50! Altho it did have way more mid range it lacked the top end surge. It might be cause of the VaNOS or something?
Id debate the sound part tho cause mine has a 2/4 branch manifold which gives it a noise unlike any other straight 6 you'll see!

Post Thu Feb 10, 2005 6:31 pm

2.8 engine with 325i single vanos engine management and exhaust along with intake manifold = 220hp area

Post Thu Feb 10, 2005 6:31 pm

my mate has a e36 325i 24v and my e30 is a 325i 12v and we had a massive race on the a12 and they where totally the same nither of us could pull away from each other, but my car has a zone chip,bbtb,induction kit,and powerflow exhaust on it but i dont no how much difference all that makes. but there deffinatly wasnt no difference between the two. when my car was standard and had not touched the engine it was rolling roaded at 167 bhp and 171 touque. but now it could may be about 175 bhp???? ill have to get it on the rollers again.

Post Thu Feb 10, 2005 8:18 pm

6potWil6pot wrote:Im not sure what an M52 would be like installed, i do know theyre easily modded to nice bhp levels for cheap but the one i drove didnt rev as hard as my M50! Altho it did have way more mid range it lacked the top end surge. It might be cause of the VaNOS or something?
Id debate the sound part tho cause mine has a 2/4 branch manifold which gives it a noise unlike any other straight 6 you'll see!

its cause the non vanos m50 has wilder cams than the vanos ones!

Post Thu Feb 10, 2005 8:42 pm

Hap wrote:yes mate e30adam has a 2.8 and there is another chap with a red e30 with e36 engine in it, someone will tell you who and the pros/cons

My engine is a 2.8 M20 not an M50 from an E36

Post Thu Feb 10, 2005 9:14 pm

6potWil6pot wrote:Im not sure what an M52 would be like installed, i do know theyre easily modded to nice bhp levels for cheap but the one i drove didnt rev as hard as my M50! Altho it did have way more mid range it lacked the top end surge. It might be cause of the VaNOS or something?
Id debate the sound part tho cause mine has a 2/4 branch manifold which gives it a noise unlike any other straight 6 you'll see!

I'll have to have a listen to that next meet!

Dunno what it is bout my old 325 cab, but maybe the exhaust note was good due to it being a rag top? ... i.e. you dont normally hear the note like that in a coupe?

also, maybe yours sounds good as it might not have a cat?

Post Thu Feb 10, 2005 11:55 pm

interestring read here,

might be a bit off topiic, but if the m50/52 engine can be had for say 600-800 region woudlnt it be better to go m50 rather than the m20 2.7 route and cam, manifold head work etc? cost wise as well as performance?

is the m50 a striaght in drop? no mods? g.box, sport diff?

Post Fri Feb 11, 2005 12:06 am

Yeah there could be a number of things contributing to the sound my car makes, but im almost certain you can hear an uneven burble from the manifold!
From what i know about my own, its physically a straight drop in but i dont think you can use an M20 gearbox, the E30 brake servo will be too big for the engine block and you'll need a custom exhaust manifold as any other one will foul the steering rack.

Post Fri Feb 11, 2005 6:35 am

hey i'm from Australia... heres a site that might intrest you all on this subject... alot of these type of conversions

http://www.bmauto.iinet.net.au

Post Sun Feb 13, 2005 3:12 pm

An E30 with a good standard M50B25 engine is going to be a match for any M20B25 engined E30, unless it's had shedloads of money thrown at it's engine.
The M20 gearbox can be used with the M50 engine, but it's rotated a few degrees, which causes problems with the gear linkage. Problem with using the E36 box is it's 1:1 5th gear, which means sourcing a suitable diff of around 3.4:1.
E36 328 engine should fit the same as the M50, but to unleaseit's potential power, IIRC, you need to use the 325 inlet manifold.
Sump will need changing to E34 5series to fit E36 engine in an E30,or use a E34 engine instead.