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325is vs. m3 engine.....

7K views 34 replies 11 participants last post by  ZERO 
#1 ·
i am currently thinking upon which engine is a better buy...from ALL aspects of driving/racing, and which one outputs more than the other. I head the 325is is only slower than m3 because solely because of the fact of the ring-and-pinion ratio disadvantage of the 325is (i think it is like 3.75:1 and the m3 is like 4.75:1, i forgot). So what i'm tryign to get at is, which engine would be a better buy, in the aspect of performance, efficiency, and most importantly, MONEY?? and how hard would it be to cop me either engines??

also, would my 85 325e transmission work on these engines? i doubt it.

thanks in advance

peace.
 
#2 ·
the m3 is a better engine, you might as well spend the extra cash on it, more room to improve on an already improved engine, ones 2.5l ones 3.0l or 3.2l the engine work you would have to do for the performance numbers of the m3 with an 325 engine is probably more than you would have spent on an m3 all together.
 
#3 ·
if you want big power and are deffinately going the engine swap route look into a S50 engine from a 95 M3. its better all around than the M20 and S14. the US S14 (e30 m3 engine) is a 2.3L and the M20 (325i) is a 2.5L, both can be stroked to higher displacements though.
 
#5 ·
if you want big power and are deffinately going the engine swap route look into a S50 engine from a 95 M3. its better all around than the M20 and S14. the US S14 (e30 m3 engine) is a 2.3L and the M20 (325i) is a 2.5L, both can be stroked to higher displacements though.
It is true about the s50, i never excluded the s50, but what only worries me is that the pricing (i'm guessing for the whole works, including an obd I conversion, tranny, engine) is probably going to be around 10-15k. As a senior in high school and a college-bound student, i dont have the money, time and patience to do something like that (you never know, maybe i do...cuz we're all looking for a car that bones out right?). Am i right about the pricing on the s50 tho? lemme know.

also, i'm still considering the s14 engine as well as the m20 engine....only because i figure it will be cheaper and i STILL weill be able to perform well. Also :

the m3 is a better engine, you might as well spend the extra cash on it, more room to improve on an already improved engine, ones 2.5l ones 3.0l or 3.2l the engine work you would have to do for the performance numbers of the m3 with an 325 engine is probably more than you would have spent on an m3 all together.
i dont believe that is necessarily true, because from what i said earlier, the only disadvantage the s14 engine has over the m20 is the gearing. All a person would need to do is change their ratio to the same as the m3 and you will fairly beat it on a straightaway (compared to stock s14), although your top-end power would not be as great compared to s14 engine. So there ARE some advantages and disadvantages the m20 engine has, so i wouldn't be so quick to make that call.




Also, can someone tell me the pricing on s14 swaps, as well as the m20? Or even an m50 and/or s50 swap? :wink


thanks in advances




peace
 
#7 ·
the S14 is a better than the M20, its not just becuase of gearing. the 325is has a 3.73:1 final drive ratio and the M3 has a 4.10:1, but if you put a 4.10:1 in a 325is it wouldnt necessarily be faster than the S14, as the it does have a 20-25hp advantage and could slaughter a M20 above 4500rpm.

you can usually find a engine/tranny combo when looking for a S50, and it wouldnt 10-15k just for parts, probably around 6-9k. S14's are hard to find, and if you find one in great condition it could cost more than the S50, plus just because it came out of a E30 doesnt mean it will be less complicated to install than a S50. i think your best bet is to rebuild your current engine into a 2.8 or 3.0L stroker, which could turn out more powerful than a stock S14, and wont require any other modifications to the car in order to install it
 
#8 ·
indeed, i could do that with my engine, but i'm at the point where rebuilding my current engine will not satisfy my needs for power/performance. Thanks for the tidbit on the s50 engines, i hope it is around 6-9k because that's a price i could deal with (will take me about 1-2 years saving up that money :cry ). Plus, i would need to find a reliable and trustworthy mechanic to do such a job.


Anyone know a good mechanic that is experienced in these swaps, also that is reliable and trustworthy, particularly in the Souther California/Los Angeles area???




thanks in advance





peace
 
#9 ·
do a 2.7i.... ei, buy an m20b25 (325i engine) and COMBINE it with your eta engine (m20b27)... it'll make for a 2.7 liter m20 w/ about as much HP as a stock s-14, but more torque...

here's what i'm hoping do to in the spring/summer

find a 325i beater car for cheap... pull the entire engine... from the airbox to the exhaust tips.... as well as the wiring harness & ECU

rebuild that m20b25 w/ the addition of your 2.7L ETA crank, eta connecting rods and either Super Eta or Euro Eta pistons. install that allong w/ all the electronics (ecu & wiring harness) into your car... oila, ~190hp & 210-220 ft/lbs of tq

http://www.strictlyeta.net will have even more info about modding the m20 (Fred Kim took what i said above a step further & did a 1mm overbore & custom pistons for a 2.8i)
 
#10 ·
Originally posted by 1985bmw325e@Dec 3 2003, 04:40 PM
if you want big power and are deffinately going the engine swap route look into a S50 engine from a 95 M3. its better all around than the M20 and S14. the US S14 (e30 m3 engine) is a 2.3L and the M20 (325i) is a 2.5L, both can be stroked to higher displacements though.
It is true about the s50, i never excluded the s50, but what only worries me is that the pricing (i'm guessing for the whole works, including an obd I conversion, tranny, engine) is probably going to be around 10-15k. As a senior in high school and a college-bound student, i dont have the money, time and patience to do something like that (you never know, maybe i do...cuz we're all looking for a car that bones out right?). Am i right about the pricing on the s50 tho? lemme know.

also, i'm still considering the s14 engine as well as the m20 engine....only because i figure it will be cheaper and i STILL weill be able to perform well. Also :

the m3 is a better engine, you might as well spend the extra cash on it, more room to improve on an already improved engine, ones 2.5l ones 3.0l or 3.2l the engine work you would have to do for the performance numbers of the m3 with an 325 engine is probably more than you would have spent on an m3 all together.
i dont believe that is necessarily true, because from what i said earlier, the only disadvantage the s14 engine has over the m20 is the gearing. All a person would need to do is change their ratio to the same as the m3 and you will fairly beat it on a straightaway (compared to stock s14), although your top-end power would not be as great compared to s14 engine. So there ARE some advantages and disadvantages the m20 engine has, so i wouldn't be so quick to make that call.




Also, can someone tell me the pricing on s14 swaps, as well as the m20? Or even an m50 and/or s50 swap? :wink


thanks in advances




peace
my god im an idiot, lol i was thinking e36 engines. sorry fellas, let mrm3 field this topic hes your man
 
#11 ·
First of all there is more then one m3 and 325i motor. Which were you reffering to? Second, what is your sole goal? I know you said over all and if that is the case then I would go with the e30 325i motor. They have gotten over 400hp out of them. You can squeeze around 1k hp out of an s50 ('95 e36 m3 motor) but it will through off your weight distribution which will in turn affect your handling. So if you truely want something that is best over all. That would be the way to go. 400 hp is more then enough hp for the e30. Now if you just want to go fast and you dont care to much about handling then by all means go with the s50. The big problem with the s14 is $$$. Plus it is only 2.3l where as the e30 325i motor is 2.5l. I havnt seen an s14 with 400hp. I thin the most I have seen or heard of is 300 something hp. Another good thing about the e30 325i motor is it is fairly common, and it is a strong motor. Therefore parts will be less expensive compared to a s14. I hope this helped. Feel free to comment on anything.
 
#12 ·
I have a few more things to add. Correct me if I'm wrong but wasnt the m3 limited so that it could be eligable to race? I mean other wise BMW would have made it a 2.5 or even a 3.0l. Also is the m20 the e36 325i? I thought it was. What is the name of the e30 325i motor? That is the one I was reffering to in my post above.
 
#13 ·
First of all there is more then one m3 and 325i motor. Which were you reffering to? Second, what is your sole goal?
the m3 motor i was talking about is the s14 and the m20b25(correct me if i'm wrong but i believe that is the 325is engine?). As from the previous posts, you guys have persuaded me to single out the s14 engine because of the fact that you guys said that it is an expensive process to maintain an s14. My sole goal is not to just say "forget handling, i want all power" - no. I want my car to handle just as well (preferably even better) as the performance. I dont want a car that has a lot of power but yet can't even harness its power around the apex. Basically i want a car that i can go on closed race tracks and have fun with the car, and not to have a sluggish car that takes turns like a freakin jollopy. So yes, performance and handling is a must, but what i'm concerned more about is performance because engine wise, i pretty much dont know jack.

First of all there is more then one m3 and 325i motor. Which were you reffering to? Second, what is your sole goal? I know you said over all and if that is the case then I would go with the e30 325i motor. They have gotten over 400hp out of them. You can squeeze around 1k hp out of an s50 ('95 e36 m3 motor) but it will through off your weight distribution which will in turn affect your handling. So if you truely want something that is best over all. That would be the way to go. 400 hp is more then enough hp for the e30. Now if you just want to go fast and you dont care to much about handling then by all means go with the s50. The big problem with the s14 is $$$. Plus it is only 2.3l where as the e30 325i motor is 2.5l. I havnt seen an s14 with 400hp. I thin the most I have seen or heard of is 300 something hp. Another good thing about the e30 325i motor is it is fairly common, and it is a strong motor. Therefore parts will be less expensive compared to a s14. I hope this helped. Feel free to comment on anything.

I'm also thinking about the s50 motor, it seems like a tempting thing to do. But as whata OreoGaborio has mentioned, finding a good 325i motor and combining with the present motor i have right now. Although, i'm concerned about the pricing of the s50 swap, even if it's really tempting to do. People say it will probably be around 10-14k, others say 6-9k. I dont know who to believe? Any feedback on this topic please will be greatl appreciated.

Also, what would you guys do? swap an e30 325is engine and replace with ETA parts?

Or go with an s50 engine swap?

What seems more practical in use, in the interests of time, money, maintenance, complications, performance, handling?



Thanks in advance




Peace
 
#14 ·
a mild 2.7i would cost you like.... 2 grand or less if you did it all yourself
 
#15 ·
there is a company where you can buy just about every bmw car motor made.....ill have to find the link unless someone knows it. It is like bavarian motor exchange or something....
 
#16 ·
Originally posted by RollinOn24s@Dec 5 2003, 06:54 AM
First of all there is more then one m3 and 325i motor. Which were you reffering to? Second, what is your sole goal? I know you said over all and if that is the case then I would go with the e30 325i motor. They have gotten over 400hp out of them. You can squeeze around 1k hp out of an s50 ('95 e36 m3 motor) but it will through off your weight distribution which will in turn affect your handling. So if you truely want something that is best over all. That would be the way to go. 400 hp is more then enough hp for the e30. Now if you just want to go fast and you dont care to much about handling then by all means go with the s50. The big problem with the s14 is $$$. Plus it is only 2.3l where as the e30 325i motor is 2.5l. I havnt seen an s14 with 400hp. I thin the most I have seen or heard of is 300 something hp. Another good thing about the e30 325i motor is it is fairly common, and it is a strong motor. Therefore parts will be less expensive compared to a s14. I hope this helped. Feel free to comment on anything.
bmw did make 2.5L S14's, and you could easily find what you need to build your own 2.5L S14. you will not get 400hp out of a n/a M20B25 (e30 2.5i), but could get over 300 with a n/a S14, and who knows what it could be under boost. the M20 is a 12v SOHC which isnt ideal if hp is what your after. a M50 may effect handling, but a later alluminum block M52, (51lbs lighter), will not change handling, you can get them at 2.8L's and probably stroke them to 3.3L (like alpina did).
 
#17 ·
im not sure but i think that the s14 2.5 is just a bored out version of the 2.3, not sure, just my guess, if so, i dont know how much more boring it could take, the i4 prob could handle a lot of power but doubtfully more than a i6 unless the sohc is really thatbig of a factor and i just dont know....i would go with turboing what u already have, if u dant have anything, id turbo a i6 just cause it seems a little safer in terms of the power that it could handle...again u should check what amount of power each motor can handle without fucking with it too much, if ur the diy type learn about forced induction and go turbo, thats my current goal, swaps are always cool, but unless ur doing urself, dont take it to someone ur not 100% sure of dont be a gunnie(?) pig with 5-12k, as for swap info, go here if u live on the east coast: schneller, an s14 motor, to my knowledge prob would be alittle $$$ to mantian
 
#18 ·
#19 ·
Originally posted by ehlpitel@Dec 7 2003, 04:27 PM
im not sure but i think that the s14 2.5 is just a bored out version of the 2.3, not sure, just my guess, if so, i dont know how much more boring it could take, the i4 prob could handle a lot of power but doubtfully more than a i6 unless the sohc is really thatbig of a factor and i just dont know....i would go with turboing what u already have, if u dant have anything, id turbo a i6 just cause it seems a little safer in terms of the power that it could handle...again u should check what amount of power each motor can handle without fucking with it too much, if ur the diy type learn about forced induction and go turbo, thats my current goal, swaps are always cool, but unless ur doing urself, dont take it to someone ur not 100% sure of dont be a gunnie(?) pig with 5-12k, as for swap info, go here if u live on the east coast: schneller, an s14 motor, to my knowledge prob would be alittle $$$ to mantian
yeah of course the 2.5 and 2.3 are the same engine with different bore sizes and maybe stroke, but the S14 is a true racing engine and has recieved much more praise than the M20 for being race bred and a true performer. however, imo, it wouldnt be worth it to go with a S14 if you dont have a m3 since the S50's or Al block M52's are great alternatives. the S14 can handle more power than a M20, and can achieve more power than a M20 while having a decent life span for a racing engine. having 6cyls isnt everything
 
#21 ·
Originally posted by MrM3@Dec 7 2003, 05:08 PM
the S14 can handle more power than a M20, and can achieve more power than a M20 while having a decent life span for a racing engine. having 6cyls isnt everything
No dissrespect but could you show me an s14 with 420 hp? If not then the m20 can handle and achieve more power.
 
#23 ·
Originally posted by 1985bmw325e@Dec 8 2003, 04:01 PM
i would say the s14 engine. I have seen a few with 285hp N/A. I know where you could do this if u wanted. 
where can i get this engine? is this place reliable?
yes the place is reliable..its a known company....msg me and ill give u details
 
#24 ·
hey u know wut i think, ur not tryin to spend money right, get either A ur engine, and rebuild it for turbo, or all motor performance applications. or B get a beat up m50 engine, rebuild, get that head triangulated, port polish, custom pistons, turbo or all motor ur choice again. i say go with the m50 cuz its all for the most part the same engine as the s50, just differant internals and head. then look online and get some euro M3 parts. a good part i have seen is the intake and multi throttle bodies. makes ur car look and im sure feel like a formula car. i have an e30 325i and yes i have a topic in here, if anyone can help me out its much appriciated. i hope i have elped u out there and good luck to u
 
#25 ·
the 2.5L s-14 is both stroked AND bored out (in other words... $$$$$$$$$$$$$$$$)... and s-14's cost a SHITLOAD to buy, maintain and upgrade... that's why even some e30m3 owners have done the m50 swap instead of modifying their s-14... and contrary to popular belief, the m50 isn't going to affect handling as much as people think... i believe it's only about 20-30lbs heavier than an m20... remove stuff like a/c & you lighten it up further

the s-14 is an awesome engine... but not something that's exactly affordable... converting an s14 from a 2.3 to a 2.5 would cost around 4 grand... and that's AFTER you buy one... for another 4 or so....

so... you pickin up what i'm puttin down?... don't swap in an s14 unless you're friggin loaded

:deal
 
#26 ·
Originally posted by RollinOn24s+Dec 7 2003, 06:27 PM--></span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (RollinOn24s @ Dec 7 2003, 06:27 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-MrM3@Dec 7 2003, 05:08 PM
the S14 can handle more power than a M20, and can achieve more power than a M20 while having a decent life span for a racing engine. having 6cyls isnt everything
No dissrespect but could you show me an s14 with 420 hp? If not then the m20 can handle and achieve more power. [/b][/quote]
if the 420hp M20 is force fed then your missing the point, theres no doubt in my mind that a turbo S14 could go beyond 420hp, but even if some how the 420hp M20 your referring to is n/a then it will probably have a short life and be unreasonably expensive
 
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