e vs. i

There are 4 types of e30 325. The 325, 325i, 325es, and 325is. The 325 is the 325e, they did NOT mark Es on the cars. If you have a plain 325 marking its a 325 e, or eta. The 325i is the exact same interior and electronic features as the 325(e). The 325es was a special model only made for 2 years which includes the sportier suspension, rear heckspoiler, trunk mounted battery, upgraded OBC, sports seats, and last but only best, Limited slip differential. The only thing it didnt have was the IS basketweave rims, just the 14" bottle caps. The 325is is everything just mentioned with nicer wheels, and of coarse the I engine.

Now as the engine differences... The E or eta (which means efficiency in greek) was a high torque low reving, fuel effiecient engine for the post fuel crisis era. It has 120 hp and 170 ft/lbs of torque and redlines at 4750rpms. It uses the same transmission but has small rear diff gears, 2.91:1. It uses slightly lower compression pistons (8.5:1 ??? i forget) , and the crank from a 528e, making the displacement 2.7 liters.

The I engine is a nice middle sized, middle rev band power engine. It is a 2.5 liter engine with 8.8:1 compression pistons. The redline is at 6000rpms and is paired with a larger 3.73:1 rear differential. This engine makes 168hp and 160 ft/lbs of torque.

Both engines are great, in my opinion the I is a much better all around engine. But the E is much better for tuning and upgrading. By chipping it the redline can be increased safely to 5000rpms. New diff gearing will be a major kick in the ass powerwise. Breathing characteristics are more important due to 2.7 liters. Cam will provide extra power go weee. Im spent.

Originally posted by Fox@Jun 26 2003, 05:37 PM

but my 87 325 DOES have a trunk mounted battery, as do most e30's

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as for the trunk mounted battery, perhaps american e30s are different to the rest of the world because i've never seen a trunk mounted battery in an e30.

all e30s use electronic fuel injection. l-jetronic (perhaps k-jetronic) or motronic.

the 1988 325 unbadged is not a 325e. The 325 uses Motronic 1.1 fuel injection and has 170 ft-lbs @ 3200 with 127 hp @ 4800 (comp 8.5 : 1)

however 1984 - 1985 325 unbadged are 325e. It uses Motronic 1. They have 170 ft-lbs @ 3250 with 121 hp @ 4250 (comp 9.0 : 1)

1987 - 1990 325i/s use Motronic 1.1 and produce 168 hp @ 5800 with a redline of 6500 and 164 ft-lbs @ 4300. (comp 8.8 :1 )

I'd recommend the 325i, i've driven an e and it felt like a pig compared to a 325i. A lot more can be done with the i motor also.

hope that helps.

oh just to show here is my 6 banger e30 with the batt in the front. Up there by the right suspension tower.

A lot more can be done with the i motor also.

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Not sure I'd agree with the above. The 325 eta motor is the basis for most strokers. Without the eta crank and rods (in some cases), you can't get the most out of a normally aspirated e30. The 1988 super eta is the most useful, but hardest to find. This model e30 came with what is almost a stroker - it has the pistons, crank and rods. However, its missing the intake and some of the head components. The heads are different between the 3 engines (325e, 88' 325, and 325i). However, the 88' 325 (super eta) is only missing the 'i' cam and second valve springs (325i's have double valve springs whereas all others only have single - this is needed to handle higher revs and lift).

Compression ratios between the super eta and 'i' are very close. I believe 8.5:1 and 8.8:1. However, if you shave the head to minimal specs, you can get the super eta to about 9.0:1. Do this, and add the cam and valve springs with the intake, and you've got an engine putting down about 190hp and 200lbs of torque in the 3000 rpm range. For the above, I'd almost rather have an eta if I wanted to do modifications. A super eta would be ideal. Luckily, I have both and will soon have a nice high torque 2.7l "i".