1.3 Motronic Up-Grade & 2.7i How To

[EtaSport]

My ES goes strong as well. Jeff's was quick but then again at the time I think he had a 4.10 in it for auto-X two summers ago.

Yea, i rode in it with the 4.10s and he was grabbing 3rd in it :D. Something about his car still seems off though. When I go from his to my buddy josh's, jeff's seems lacking.

[kenika65]

Yes please show pictures!

I did not put my domed i head on my flat top pistons because of the different in chambers also.

The low compression will cause long cranking to build compression before it will start and will have a rough idle, but other then that the combination is strong and great for turbo.

But I still prefer to have piston to head match and that is why im waiting to buy domed pistons for the i head.

[SchnellerVert]

My ES goes strong as well. Jeff's was quick but then again at the time I think he had a 4.10 in it for auto-X two summers ago.

[EtaSport]

You're welcome for the input. I have not put an I head on a regular e block with flat pistons. I wanted to see what I could do with all eta castings. Since the combustion chambers are designed for the piston domes and the i combustion chambers aren't, I think there might be a turbulence issue, and it would just be unefficient. Then again, many would say the eta head is unefficient. I do have a few pictures of the latest head I put together showing off the chamber and the intake side.

The best way to go would be to use larger valves in the e head, but then everyone will say it is a waste.

I built my 2.7 for around 500 bucks including the motronic swap. You should only start with an eta in a good running state. Higher mileage engines wont respond quite as well. I had solid compression numbers on all 6 for a good 15k miles or so with the i set-up (around 165psi) A few weeks before pulling the m20 I did a leakage test as the final head swap indicated a slight ridge on number 1 and more piston pin play than i liked. The results showed 40 percent leakage through the rings on cylinder 1 and 30 percent on cylinder 4. After pulling the head which was only installed for a month or two, there was a lot of carbon build up on my shiney combustion chambers. My motor had almost 400k miles on it though.

cowden's eta block had around 100k miles on it and runs great. e30_325es' car has well over 200k but it still goes strong.

[scabzzzz]

Dang. I'm running back and forth with whether or not I just want to swap an M50 family motor in my car based on the compression results I get next week on my motor. Seriously considering this jazz. Will save me a buttload of money doing this instead of buying an E36 M3 for my performance woes.


Thanks guys

[kenika65]

You do not need to swap all of the parts listed in the first post. The coils are universal, (im still using my original fuel pumps even with my m50), the exhaust manifolds are almost identical. The only things you really need are:
AFM
TPS
FPR
thermostat housing with all sensors (only 2)
crank position sensor with reluctor wheel (front crank pulley)
spark plug wires for the pick-up on wire #6
injectors
ICV
and thats about it if i remember.

Etasport Thank you for your post! I have been looking for more insight.
(thanks for the advice on cams)

Etasport is right about what you need to upgrade to run a i ecu.

I was emphasizing on a total i 1.3 upgrade.

Your experiences with cams have all been on 82-87 eta flat top piston heads right? If So have you put an i head on your flat top pistons?

[EtaSport]

Well, since I have built several of these set-ups i guess i can post my results here. I started off with no real info or support of the eta 2.7i build. I started with my 350k mile m20b27. I have built 2 eta heads. Both used I cams, I also used a 274 regrind, and a 283 catcam.

Both heads were ported on the intake and exhaust. I have found that enlarging the intake to i head inlet specs is a waste because the volume of air coming in is bottlenecked by the smaller valves. Mid range torque jumped with the bigger ports, but top end seemed to die out over 5k. My previous head had a less extensive port job and made very linear power. I had both of these heads on my m20. I used m20b25 springs and drilled the cam journals for the 7 bearing cam.

Out of all the cams I tried, I feel the most worthwhile for a small valve eta head is the I cam. The 274 was okay, but lacked low end punch, and the 283 was another waste as the car never felt like it was ever in a powerband even at 6k+. Needless to say that cam was swapped out quickly, yet made its way back into the same head after I sold it, and I still think its holding that car back.

As far as components I used, I went with the 325i intake, throttle body, exhaust, and complete motronic 1.3 (no chip). The car was quick for what it was even with 2.93 gears it would run. I swapped in a 3.25lsd and it would max out around 140 on a flat road. 0-60 times were probably in the mid 7s and it was about as quick as an svt focus and stock civic si.

You do not need to swap all of the parts listed in the first post. The coils are universal, (im still using my original fuel pumps even with my m50), the exhaust manifolds are almost identical. The only things you really need are:
AFM
TPS
FPR
thermostat housing with all sensors (only 2)
crank position sensor with reluctor wheel (front crank pulley)
spark plug wires for the pick-up on wire #6
injectors
ICV
and thats about it if i remember.

When my m20 kicked the bucket from the high mileage and high rpm running, I parted it out and sold 2 'kits' made up of the heads I built and 2 complete motronic conversions. Both cars are still running and if I may say so are complete beasts. One belongs to e30_325es on here and e30tech, the other belongs to cowden_12 on here.

e30_325es's car now has a mark D chip, 283 cam, m30 afm, bav auto headers full exhaust, fan delete, 8mm wires, and a 3.73lsd. He put down 146hp/146 torque (i believe torque is so low because of the 283 cam). His car ran a 15.4 before he blew the small case 4.10

cowden_12's car is an 84 318 with full m20b27 swap, motronic 1.1 with jim C chip, turner intake, single 2 inch exhaust with no cat and magnaflow muffler, 325i flywheel, small case 3.91. His car feels stronger than e30_325es's and I think it will run with my m50.

Both cars are running proof that high performance from an eta is possible. Also look at rs4pro's car who has the same set-up, now with an mas air conversion and a supercharger. I hope to shed confusion on this subject well into the future, as there are becoming more and more threads asking questions that have already been answered in the past. Yes, it has been done, and has been proven.

[eyagel]

Oh it is, keep us updated with your progress on your 87 325

i will, jordan will be helping me, need to get my head hot tanked, and some upper gaskets, than its time to tear apart the beat to shit eta.

[kenika65]

im gonna do this soon, i head, 1.3, I intake mani., i exhaust mani, fuel rail, injectors, harness.

gonna be good.

Oh it is, keep us updated with your progress on your 87 325

[nineohfour]

here are a couple quick engine piscs. nice and dirty for ya. id like to do this to my car. but its not going to happen till the start of the new year. it eases my mind that i wont have to hack the harness at all.:D

[eyagel]

im gonna do this soon, i head, 1.3, I intake mani., i exhaust mani, fuel rail, injectors, harness.

gonna be good.

[kenika65]

forgive me for beating a dead horse, on an 88 super eta is the i ecm compatible without swapping the engine harness?

Your 88 super eta already has 1.1/1.3 Motronic wire harness and sensors.

Yes you can click in a 325i,is,ix ecm and it would have a higher i rev limit.

But all it is needing is double valve springs to survive the higher rpms or something may break.

And if you are wanting more power or higher power curve then install a bigger cam and you will be happy.

Do you have engine pictures?

[nineohfour]

forgive me for beating a dead horse, on an 88 super eta is the i ecm compatible without swapping the engine harness?

[kenika65]

whats the advantage in the upgrade? better fuel economy? power? and i wish i could find a $100 325i car around here lol

thanks

What you are doing is making an old m20 82-87 newer with updated electronics, intake and fuel system.

All eta engines used Bosch Motronic engine management systems that were calibrated for maximum fuel economy. The result was a very conservative spark advance curve and fuel delivery curve. In addition, the Motronic had a built-in rev limiter that engaged at about 4750 rpm. This very low redline was the result of the four bearing cam, soft valve springs, intake manifold and camshaft design. Due to the very low overlap and short duration of the cam and the intake manifold tuning, the motor does not make any power over about 5,000 RPM.



For the 1988 model year, the eta cars got a refresh from the factory with Bosch Motronic 1.1/1.3 Adaptive fuel injection a modification that adjusts the idle speed of a cold engine and a 6200 redline.

[Bimmerboy91]

whats the advantage in the upgrade? better fuel economy? power? and i wish i could find a $100 325i car around here lol

thanks