bradi65 4 Report post Posted June 22, 2015 What are the cons of getting the 2.3? I see a few around cheap and i would like to get one to build up the engine out of the car then place it in once finished, I ask about the 2.3 because i hardly ever see a 2.5 around for sale.??? any out there !! Would it be a wast of time compared to just getting a 2.5? I think the 2.5 has more torque and the the 2.3 lacks a bit until about 4k RPM. Would it be cheaper in the long run just getting the 2.5? Quote Share this post Link to post Share on other sites
E30 325i Rag-Top 2959 Report post Posted June 22, 2015 Pretty sure the 2.3 was only available with L-jet injection, whereas the 2.5 is the Motronic. So if you are swapping a 2.3 into your 325i it might make things a little bit more interesting in terms of getting everything hooked up and working. Some early 2.3s would also have things like the extra "cold start" injector in the inlet manifold, so you might well require the loom and ECU, etc to go with it and make it work properly, then there is the crank sensors and where they are, etc.... You might be able to bolt the Motronic bits, inlet manifold, from the 2.5 onto the 2.3 to make it work?? 2.5 definitely has a bit more power, 171hp v 150hp as standard figures. Don't know on the torque figures, sorry. 2.5s do come up now and again, and I would say it is worth trying to get one for the reasons above. 1 Quote Share this post Link to post Share on other sites
bradi65 4 Report post Posted June 22, 2015 Well you have just made my decision easy! I think i will stick with what I know will be easier in the long run and just keep a look out for a 2.5.... Thanks for help =] Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted June 22, 2015 both the B23 and B25 have no balls below 4000rpm so thats not a reason to rule a b23 out 1 Quote Share this post Link to post Share on other sites
duvey 245 Report post Posted June 22, 2015 I had trouble finding a 2.5 to swap into mine, too, but found one in the end. If it makes any difference, the B25 has all sorts more torque than my old B20 below 4K rpm. Motronic is a much more modern fuel injection system too. 1 Quote Share this post Link to post Share on other sites
bradi65 4 Report post Posted June 22, 2015 Cheers. My first E30 was a 320i, then the next was the 2.5 and i loved it wont ever buy a 2l again. i think ill stay with the 2.5 much more fun Cheers guys Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2132 Report post Posted June 22, 2015 a manual 2L is not too bad, but auto 2L is the worst E30. you got all the fuel consumption and weight of the 325i with the go of a 318i pulling all that extra weight. Quote Share this post Link to post Share on other sites
DeadlyPixels 6 Report post Posted June 23, 2015 Amen to that. My sisters old 318i auto box E30 felt just as quick as the 320i auto we are tidying up. Sure they had different diff ratios, a taller final drive in the 320i but that made it slower which kind of negated the point of the extra displacement. Manual anything fixes that right up though - have driven a 316i with a manual and a 4:45 diff and although it was never that rapid it was so much more fun that either of the automatic cars. On topic though, a M20B23 wont be as powerful as the B25 but that's no reason to avoid it. If you are building it out of the car you could use Megasquirt or some other standalone system which would negate any off the old tech issues in jetronic or motronic. Also if you have the B23 it should have the old school side driven distributer which makes it easier to go standalone ECU because the ignition is purely mechanical so you only have to worry about fueling - and it makes converting to coil setup easy later too. Making the whole setup with more power and efficiency than you could ever get out of jetronic. If you were planning on keeping jetronic though I feel a lot more "meh" about picking a B23. You can probably tell that the idea of a standalone ECU to play with on an M20 has been an interest of mine. On the pros for the M20B25 it makes more power out of the box which is nice and the added torque is nice. Motronic 1.3 is a decent system although I'm less a fan of the earlier 1.0 setups (have helped dad with one and was a bit of headache to diagnose compared to a 1.3 car). I think it all depends on what your goals are on the build. I would pick what you think is cool - the couple hundred dollars difference at most in price difference ins't likely to be very consequential when you consider the whole project. You could spend that much just on maintainance parts for the new motor regardless (new hoses, filters, fuel line etc). Just my $0.02 Quote Share this post Link to post Share on other sites
louistan3 1 Report post Posted December 10, 2015 Sorry to resurrect a thread but was interested with the B23 as well. I was able to grab a semi decent one for cheap and was wondering if anyone knew if the B23 is a drop-in replacement for an L-JET B20? I've got a PFL B20 and so far it seems that I can drop in the B23 without any changes to wiring, etc. Would the ECU for the B20 work as well? or would I need an L-Jet B23 ECU? I'd prefer not to redo the electronics and such, which is why I wasn't really considering an upgrade to Motronic or anything else. Quote Share this post Link to post Share on other sites
reggid 0 Report post Posted December 12, 2015 323i m20b23 are pretty cammy engines, but they arent a hell of a lot slower than a 325i because of the weight difference of the early vs late models Quote Share this post Link to post Share on other sites
louistan3 1 Report post Posted December 13, 2015 From what i read they seem pretty close in hp and torque which is why it seems like a good idea. Would the ecu work or will need a b23 ecu? Sent from my SM-N9100 using Tapatalk Quote Share this post Link to post Share on other sites
