torque at the flywheel not important (archive)

It is the rear-wheel torque that is important. The 325i has a 3.73 rear end and the 325e has a 2.79 or a 2.93 (depends on year) rear end. The 3.73 is 34% lower (higher numerically) than the 2.79 ((3.73-2.79)/2.79=0.3369). This means that the 325e would have to be producing 34% more torque at the flywheel to be producing the SAME amount of torque at the rear wheels.

I own an 89 325is, and previously owned a 85 325e, and there is a very big difference between the two. Because of the gearing, even at low rpm's the 325is out accelerates the 325e.

The problem with the 325e is that the head does not flow well. Displacement is crucial, but you need to be able to get air in and out of it quickly and efficiently. I would put a 325i head on your 325e short block. Use custom high compression pistons, or the 88 325 pistons that are not high-compression. A change in gearing is also very important.

I'm not knocking the 325e, they are very good cars. I think the 325i advantage is half gearing, and half horsepower. If you're racing, you are usually in a very high revs, so that is where you want the power.

Will Ott
89 325is

Hey guys when comparing the "e" and "i" don't forget about the torque difference. The e was built with big torque to pull the car easier without the motor having to rev to 6K. Not saying the e is better than the i but it will take serious ride in a bad "i/is" to convince me they are that much better.From what I understand the "e" head is changed because it has less cam bearings, and the cam will flex at high RPM, thus having a low limiter. However, the bottom end is said to be as good if not a little better than the "i". From this I have gathered that with the torque and HP of the "e" motor, with a bigger revlimiter and the larger cam of the "i" will ultimatly make a more performance oriented motor. I ask, Is this true?

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