325i motor, 325e electronics

[superj]

well, we had to do it. we had to use 325e electronics on a 325i motor because my son pulled his 2.7 even though we didn't have a complete harness, an afm, or an ecu.

luckily, the car runs like a freaking champ now. I figured that the ecu doesn't care what motor its on, it just provides fuel according to sensor readings, especially the 02 when it warmed properly. the cam actually is the picky part.

when we first put it all together, I had to custom make a number of hoses because the eta has a lot more vacuum related stuff than the I does. it looks totally stock though and started up better then the long crank the eta motor always did, which is weird, but whatever. anyways, at first it idled like a drag car, bump bump bump, all lumpy and sounded awesome. once it warmed up and everything was reading properly, it mostly smoothed out but idles at about 900, a little high to me but it could be a vacuum leak at the dipstick because it feels loose to me. but when my son drove it, he said its super fast compared to the eta motor and he can do 100 on the highway, with room to go on the tach, whereas the eta was maxed out at 65ish. and at the autocross, it cut 5 or 6 seconds off his previous times.

so, for future reference, if you have the engine but not the electronics, you can run it all until you get the stuff you need so if you are tight on time, like we were, knock out the engine/trans when you can and just do the electronics later. you will enjoy the change.

sometime this week, we do suspension. I still have to figure out which wires go where since the c101 was cut off the harness

[msservices]

What do you think was wrong with the eta motor for it to not run on the highway?

[bluptgm3]

I was under the impression the the Eta ECU limited the redline to ~4500 rpm.


Sent from my iPhone using Tapatalk

[superj]

the eta motor was just rev limited because of the single valve springs and lower red line. the I motor doesn't have the valve float issue and a chip raised/removed the red line so it can rev up now.

really, the eta motor was fine but my son wanted to be able to race his friends and feel faster off the line. he put a 4.10 to make it quicker from a stop but it limited his highway speeds, like we all know happens when you do that. since the I revs higher and is cammed differently, it works at normal highway speeds. he is pulling a 3.73 at the junkyard though. we found one a few hours from here so I told him to grab it and we can put the 4.10 in the garage or put it on his friend's automatic 325e so he can be quicker off the line

[msservices]

Thank you for the write up. Now we know how an I motor works with chipped e electronics, now it would be interesting to see how the e motor would do with just the I electronics swapped over. The sons friends car could be the guinea pig for that write up

[superj]

Actually, our other car is a 2.7 block and a 2.7 head with all i electronics but it has the i intake, throttle body, afm, and exhaust so i guess its not a good comparison. Its faster than this car but we bought it already swapped so i have to see what cam it has

[msservices]

Can a 2.7 head have an I cam if it’s not an 88?

[bluptgm3]

Actually, our other car is a 2.7 block and a 2.7 head with all i electronics but it has the i intake, throttle body, afm, and exhaust so i guess its not a good comparison. Its faster than this car but we bought it already swapped so i have to see what cam it has

I’m surprised you have not floated a valve or two…


Sent from my iPhone using Tapatalk

[superj]

msservices: I am not sure about the cam deal? I know there are more cam bearing surfaces on an I head for the cam to ride in so I would think that as long as the I cam hits the ones in the e head than it would fit? but, I have no idea, I am just speculating on that.

bluptgm3: I hear that's possible but in the 12 or 15 years of owning eta powered cars, and driving them like they are made for speed, I have never floated a valve. I have heard of it, just never done it.

[bluptgm3]

bluptgm3: I hear that's possible but in the 12 or 15 years of owning eta powered cars, and driving them like they are made for speed, I have never floated a valve. I have heard of it, just never done it.

There is a difference between early and late model Eta and Super-Eta engines.
Super-Eta uses the “I” head (and electronics)
“I” head uses dual valve springs and allows higher red line.



Sent from my iPhone using Tapatalk

[superj]

This an 87 and the block numbers and head numbers show 2.7 in realoem. But the elctronics are all i model. I thought it was a super eta till i ran the vin in realoem and it showed it to be a regular eta. The diagrams show it should have the cold start valve and the trans sensors but doesn't have any of those on it.

- - - Updated - - -

And i keep forgetting to pop the oil cap and see if i can see the valve springs. I told my youngest son to move the camry out from in front of the garage tomorrow so we can get going on it

[msservices]

It would have the cold start valve deleted if it has i electronics, so maybe they had the blank cover handy. Also on your other car that has the I motor with the e electronics, which injectors is it running on?

[superj]

since I am running the eta ecu, I have to run the eta injectors. the I and e injectors are different impedance so I read that if you put I injectors with the eta ecu then it will burn out the drivers on the eta ecu because of the higher resistance.

the missing cold start valve is what made me immediately think it was a super eta when we first looked at it when we went to buy it. and it took like a rocket. my oldest son immediately volunteered to drive it home, ha ha ha. normally I drive all the cars when we pick them up so I can see whats wrong with them

[superj]

Ok, after a number of days of driving, we have learned some stuff.

1: this is totally doable for someone who has the motor but not the electronics, yet.

2: the car is noticeably quicker then an eta car.

3: you will feel some odd vibes at a range of rpms, like from idle to 3800ish.

I think that since the ecu is set up for cam on the eta head, its firing the plugs at where it thinks the eta is, not the i cam, so its not firing at the best time for ignition.