tibbs.james 1 Report post Posted July 21, 2007 Hi guys I have a few questions about cylinder heads and blocks for m20 engines. My car is a 1990 E30 2.0 , motronic ECU and it has the later style 89" head and manifolds with the better ports/exhaust manifold. would there be any reason i could not simply bolt my head and manifold onto a 2.5 block and keep my current ecu inlet manifold and other accesorines? Reason being my exhaust manifold has been surfaced to perfect flatness, my head has been rebuilt,skimmed and valves seated. and my rocker gear is also in nice condition. I believe all i would need to do is fit the correct size injectors and perhaps fit the air flow meter from a 2.5 and i would be good to go providing these will work with the existing ECU.( which they probally won't what issues are there with doing that ?) i don't see 2.5 engines on trademe often what are they worth roughly ? any feedback appreciated. I'm pretty handy rebuilding engines, so ive no worries to do the work. I really just want to know if it does work and what other people have done. Quote Share this post Link to post Share on other sites
Hartage 0 Report post Posted July 21, 2007 As i understand it no. Combustion in 2.0lt is in the cylinder head. 2.5 is in piston, you would end up with a VERY low comp motor Quote Share this post Link to post Share on other sites
tibbs.james 1 Report post Posted July 21, 2007 hmm, stuff Perhaps i will come across a later type complete 2.5 engine at some stage whats it like on the electronics side of things running a 2.5 in a 320 body/injection gear. I know there is at least one member on here with that setup but ive forgotten the user ID Quote Share this post Link to post Share on other sites
hotwire 352 Report post Posted July 21, 2007 hmm, stuff Perhaps i will come across a later type complete 2.5 engine at some stage whats it like on the electronics side of things running a 2.5 in a 320 body/injection gear. I know there is at least one member on here with that setup but ive forgotten the user ID Different ECU, AFM, injectors, throttle body sizing, at least Sold a good M20B2.5 recently at $700 Quote Share this post Link to post Share on other sites
parriehunter 0 Report post Posted July 23, 2007 Hey i have just done a complete swap with a '90 525i m20 motor and the ecu that came out of that car was the same that was ready in the '90 e30. So i guessed it didn't need to be swapped. Quote Share this post Link to post Share on other sites
