Ohhhh here we go again.

What's the big difference?

Snappyness. The B27 engine doesn't give that 'jolt' to the car until around 3500RPM and coughs out at 4750. The B25 does it at like 1500 and lasts until 6500.

The i comes alive above 3000 and loves to rev, while the e is shy and tranquil. The e makes its torque down low and has no problem pulling out of 5th at 25mph with a 2.79 diff. The i can do it around 30 with a 3.73 LSD.

Fuel economy? Not that different. The e makes around 27-30mpg (my best was 35) on a level flat highway, at 65mph. At 55mph it gets around 40, at 45mph it chimes in at around 55mpg.

The i, on level highway, makes around 33mpg on a level highway while the e makes 35. Overall downtown the my eta made around 22, best was 24.5. But the i, currently, is making 25mpg with very conservative driving and the best overall made was 26.7mpg***8212;most likely due to the eta has old crusty injectors while the 325is has new 19# injectors.

The overall real difference? The 325i is much snappier and loves to rev. The eta is shy and not very interested.

 

Thanks. I'm on the verge of bringing an 88 IS into the stable. I never even knew there was a difference between six cyclinder engines. I thought all E30 six cylinders were the same, although I knew the M models had some engine differences. So it seems like the ES (which is what I have now) is more of a cruiser than the Is.

 

Any eta model, stock, is more of a beater car than anything else.

There were quite a few six cylinder engines fitted to E30s: M20B20, M20B23, M20B25, and M20B25. And then there's the M21D24. And then there's the Alpina and (South Africa had the 333i) Hartge kick offs, including shoehorning the big M30 engine in, starting at 3.2L up to 3.5L. No ///M E30 had a six cylinder engine, the ///M3 models had 2.3L four-cylinder engines with 200bhp, all the way up to 2.5L in the Sport EVO models with 240bhp.