Hello,
I am planning to swap the M10 in my 1982 E21 to an M20B25 stroker as part of its overall restoration project. Looking to build a CA SMOG legal M20 using stock intake, injectors, ECU, new cat... This is for a fun to drive reliable street E21. I am not chasing peak horsepower.
Option 1: 2.9L Mahle (2860cc)
885 head with 272 cam (remember SMOG compliant)
IE Mahle 2.9L Ultimate Street Stroker Piston (85mm bore)
10:1 compression (new to work with 91 octane CA gas)
84mm stroke crankshaft (M52 crank and 135mm rods)
Option 2: 2.8L (2823cc)
885 head with 272 cam (remember SMOG compliant)
86mm bore with Custom Pistons (probably via Top End Performance)
10:1 compression ratio
81mm stroke crankshaft (325e crank)
Anybody with any thoughts or opinions of these two options? I seen a few post indicating Option 2 works for SMOG with a properly rebuilt engine, ECU w/tune, and a new CAT (not one at its end of life from the donor E30). Option 1 probably similar.
My E21 blog is here (just at the start of this project):
All the best,
Ricardo
I am planning to swap the M10 in my 1982 E21 to an M20B25 stroker as part of its overall restoration project. Looking to build a CA SMOG legal M20 using stock intake, injectors, ECU, new cat... This is for a fun to drive reliable street E21. I am not chasing peak horsepower.
Option 1: 2.9L Mahle (2860cc)
885 head with 272 cam (remember SMOG compliant)
IE Mahle 2.9L Ultimate Street Stroker Piston (85mm bore)
10:1 compression (new to work with 91 octane CA gas)
84mm stroke crankshaft (M52 crank and 135mm rods)
Option 2: 2.8L (2823cc)
885 head with 272 cam (remember SMOG compliant)
86mm bore with Custom Pistons (probably via Top End Performance)
10:1 compression ratio
81mm stroke crankshaft (325e crank)
Anybody with any thoughts or opinions of these two options? I seen a few post indicating Option 2 works for SMOG with a properly rebuilt engine, ECU w/tune, and a new CAT (not one at its end of life from the donor E30). Option 1 probably similar.
My E21 blog is here (just at the start of this project):
All the best,
Ricardo
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