Its been a while - The E28 Lounge

The final configuration as follows:

Ported, decked 325i "885" head
274 degree, high lift, reground cam, from a stock 325i K cam
e30 323i intake manifold port matched to a 325i throttle body
325i idle control valve, air boot and brake booster feed lines
Super eta AFM and airbox
Super eta/325i exhaust manifolds
Super eta exhaust system
Alpina B3 2.7 chip w/ 325i fuel injection
Stock eta pistons, block, crank, rods, oil pump
Ireland engineering lightened flywheel
3.91 viscous coupling type limited slip diff (325ix only)
325i oil cooler and lines
Metric mechanic ultimate transmission
535i instrument cluster, late style from 86 on

The big thing with this setup is the 323i intake. When I put it all together the first time with everything listed but with a 325i intake, AFM and an early style eta exhaust system, it ran pretty well. The cam comes on harder, like it starts to pick up more agressively about 3500. It also stretched the powerband into the 5k range better. But, I was still looking for more. Much like I have been since I started with this same motor back in early 2004. I came across a few pages of an old racing dynamics catalog with pictures of thier 24 valve m20 head installed on a complete motor. If they decided to use the 323i manifold with a head like that, I figured they had a pretty good reason. So I got one on german ebay. After porting the hell out of the TB opening it was ready to go. With 325i injectors, 3 bar fuel pressure and an alpina chip, it detonated like mad between 4 and 5k under full load. It did seem to flow better on cam, as the computer was delivering the same amount of fuel it was with the 325i intake. After months of tinkering, the only way it will run right is with the O2 sensor unplugged, using a super eta AFM, 325i/super eta injectors, 2.5 bar fuel pressure and the alpina chip. It should run right at sea level with the 3 bar pressure, but without the O2 sensor input at ~5500 feet, it was too rich at idle and part throttle. Up here, its just right. The power is very good. One of these days it'll go to a dyno shop for the last word, but its safe to say its pretty quick. Faster than a nissan altima SE-R, neck and neck with a 3.5 liter maxima, faster than a 96 mustang GT. Its in that neck of the woods.

One thing thats easy not to think about is fuel injection. The stock, pre 1987 528e/325e injection will never make power. Its not that the hardware version isnt capable, its that BMW never made any variant of basic motronic that would support the kind of powerband we're talking about. You could take your fully built motor and everything to a shop and have a custom chip made, but if thats not an option, you're looking at a retrofit. Dont even try it without a copy of BMW's ETM, easily obtained on ebay in .pdf format. Anyway, I spliced a 1987 325i harness into my 1985 528 because I couldnt find a super eta harness. That involved fitting every single component that sent a signal to the ecu with that from a 325i. Every sensor, the AFM, plug wires, harmonic balancer and the corresponding pulse generator, ICV, O2 sensor, injectors, FPR. Everything but the coil and TPS. Just hit a junkyard and go nuts. Then you wire the fusebox connector from your old harness onto the new harness. The wires are pretty much common between the two harnesses. Both have an alternator charge warning wire, two oil level warning wires, a big coil power wire and so on. Just find every wire that goes through the old c101 fusebox connector and match it up with every wire in the 325i c101 connector. Its about 12 splices. You might need extra wire from your old harness, as the 325i connector doesnt quite reach. I used solder sleeves considering how much it would suck it one of those splices let go. The other connector that can get you is the c103 connector. Its the first one out of the harness from the chassis connector on the motronic control unit. It sends the engine speed signal to the tach, the fuel flow signal to the econometer and OBC, the A/C on signal to the ECU and the wake up signal from the ignition. Its only four wires, but if you miss them like I did the first time, it doesnt start, and you begin wondering which small detail in the whole major project you missed. Bad times. Its the same process as the fusebox connector. Just match em up and splice em. Other than that you'll need to move your new 325i ICV to between the throttle body and AFM, which means you'll need to be using a 325i throttle body, intake boot and the 325i vacuum booster plumbing. Lastly, you'll need to run some big red wires to the battery from the big red wires coming out of the harness that power the motronic control unit. That first start up is one of the most satisfying feelings in the world. Ahhhhh. If I could, I'd have a beer. If you have a super eta, consider yourself very lucky.

With cylinder heads, you'll hear a lot of things about how the eta heads dont flow and the 325i heads dont fit without super eta pistons or something custom. Then theres the special 731 head that fits the eta pistons and flows well enough. I hear its good for 190 HP. Given the scarcity of the 731 heads and the abundance of the 325i heads, its really not worth trying the oddball 323i head. To fit a 325i head to an early eta, just deck it .030 or .040. I went .040 on mine with a stock head gasket and a high lift, longer duration cam and I havent had any problems. I'm even using stock 325i dual springs. Its gone as high as 6750 rpm and it hasnt grenaded. I usually shift at 6500 just to be safe. But, I still dont think .040 is absolutely necessary. .030 or .020 would probably do just fine.

Another thing worth considering is the limitations of the stock 325i cam. I wouldnt put one in my Moms car. Its just not a great performer. A schrick 272 is great of you can afford it, but I had great results from a regrind from Top End Performance in california. It was cheap and it runs like crazy. I'm sure most other regrinds offer similar results.

The no brainer is the super eta exhaust system. e30 guys can fit the 325i exhaust, which pretty much grows on trees. e28 guys either need a custom system or a super eta system. It really uncorks things over 4k and keeps it going to about 6k. It actaully gave me some trouble with detonation initially. I hadnt yet worked that out at the time, and I needed to massage it a little bit more to keep it under control. It got enough dirty old exhaust out that it pulled more air in on the intake stroke. Thats a good flow improvement.

The driveline is pretty striaght forward. When the flywheel went in I used a 325i clutch kit. The 325i pressure plate is noticeably lighter, both in clutch effort and clamping force, than the eta clutch assembly. It slips a little once in a while on hard upshifts, but its not really a problem. The 325ix diff has special output flanges, which means you cant just slap the ones from your old diff in like you do on any other diff swap. So you need the dust caps from the 325ix half shafts to mate your output shafts to the 325ix diff. The viscous coupling type limited slip beats the hell out of the clutch pack type mechanism in every other BMW LS diff until the shear pump equipped e46 M3's. It doesnt wear out and the locking action varies up to 100 percent depending on slippage. Especially considering the mileage on most used LS diffs, I like the alternative to the old busted limited slips from 535 and 325is models.

The 535 instrument cluster is an easy retrofit. The late style gauges are more refined than those of the pre 1/86 models. The hardware is also much more condensed and better built. All you need to do is swap in your old speedo if youre concerned with mileage. The tachometers and center gauge pods are not interchangeable, but you should be able to find a tach that fits your motor, as the eta and 535 both come in either cluster version. I like the way the needles seem damped on the later clusters as opposed to the jerky early hardware. e30 guys can just swap tachs. If you have an early coding plug type cluster, fit a 318 tach. Coding chip guys can use a 325i tach.

The oil cooler refrofit was actually pretty difficult. I had to cut off the big sheet metal box that comes down from the engine support to run the lines around the A/C lines through to the front valence. But it does fit and if you drive hard or you live in a hot climate, its a good idea. It does crowd that side of the engine, so for turbocharged cars it might complicate plumbing issues. e30 cars, for which my cooler and lines were designed for, probably have fewer fitment issues.

And thats about it. Its a different car compared to the 85 528e it used to be. Started off with 238 thousand miles and a peice of metal inside cylinder #5. The old block has gotten new pistons and rings and rod bearings. And thats it. The car has about 312 thousand miles on it now, stock main bearings, rod bearings, oil pump. If you keep the oil clean, you can drive it as hard as you want. If it gets over 80 degrees outside, and if you can find it, a fully synthetic 10w40 or 20w50 is ideal. If its chilly in your area or you drive it gently, full synthetic 10w30 works. Just wait until the oil gets up to temp before you wail on it and it should run forever. A good five minutes after the gauge shows operating temperature is a good rule of thumb.

Stay tuned for the turbo super eta project. I should be running well before christmas...
1985 528e
312,000 miles
0 to 60 in 6.8 seconds
T3 Super 60 trim, coming soon...