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Thread: E30 Mile High Tune
11-24-2004 08:12 AM #1
01-14-2005 08:18 PM #2
it's tough with an e30 (long)
As you know, HP gains for the eta engine (or any bimmer for that matter) are expensive. I have an '87 325e and it's the slowest 325 ever made. If you want a lot more power, sell the e and get an i. The eta is designed for good gas mileage with a little more torque to compensate for less HP (compared to the i). Limited Slip Differentials do a lot too, but those come stock on some 325i and all 325is. Search the e30 board on here....all your questions have been discussed in depth by people with much more knowledge than I have. Hope this helps.
p.s. The first thing I am getting is a chip (only about $60 off of ebay). I am also getting a new O2 sensor this weekend cause my gas mileage is terrible-20mpg around town with conservative driving.
02-08-2005 01:04 PM #3
go to a local junk yard, pick up a "i" head for
then shave a tit off the head. -don't forget the intake manifold and TB. -you should also get a front-mount distributor and toss your stock dizzy. get these off any 87-91 325i/is and it will be chomping at the bit. the motronic EFi will allow a chipped rev-limit around 7K, plus it'll be more efficient.
....the only other thing, if you shave the head for the killer c/r, you should have a machine shop cut dimples in the stock piston heads so they won't kiss.
that setup alone will slap an M3 around,... until you get into a corner ;)
a good 272+ cam would make that a non-issue though!
06-27-2005 11:03 PM #4
- Rio Rancho, NM, United StatesMember No: 124000
- Join Date
- Apr 2005
- Rep Power
What are you talking about
The eta has a front mount distributor, just like the i. The problem with decking the i head is valve clearances. I took .040 off of mine, which brought the compression ratio at least to where it used to be. But in doing that you leave the valves only the thickness of the head gasket before they hit the pistons. Especially on the intake side, where the intake valve actually peeks out below the surface of the decked head, its terribly close. With a 274 degree reground cam and used dual valve springs, its seen 6600 without grenading, though anything more than 6500 or so is more noise than power. Such is the nature of a 12v head. You are correct on your choice of fuel injection. The "i" adaptive injection is very good. Its better with an Alpina chip, but those are hard to come by. I've seen two on ebay in the last few years, I got one of em. The only other thing most people dont know they're missing power from is the intake manifold. The 325i manifold is pretty much the best we have over here. It works well enough. But if youre adventurous enough to source an e30 323i intake manifold out of germany you will be pleasantly suprised. Its part number 1-278-080, usually says 1-278-081 on the manifold. Thats from the e30 323i and non catalyst e30 320i. 320i's with a cat got a wimpier manifold. The e30 323i makes for a killer powerband, about the same down low, comes on like the 325i manifold by around 4000 but keeps picking up till about 5k, where it maintains good power till about 6k. Peak torque feels like its about 5k with the 274 cam, 323 intake and head porting. Thats a sweet motor to drive. The only hitch is porting the 323i intake to fit the 325i throttle body. Its a lot of grinding, and if you dont do it right you wont make as much power as you could have. Other than that theres the standard 325i exhaust manifolds, which work fine for me, though I had to use two front manifolds to fit my early 528e exhaust system. Thats what I've got and its really quite fun, even at almost 6000 feet on the west side of rio rancho, new mexico.
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