Am I crazy Trading "i" motor for an Eta?

[OD Green E30]

I have an interesting predicament I am in.

Let me start off my saying I have a 325is with worse than average rust issues and wiring from hell, so I bought a pristine 325eS (with working ac) to swap my good "i" motor into, as well as interior and suspension. The shell I bought (sight unseen) actually wasn't a shell at all, It's a running, driving 325es with a racing chip (unsure which chip but my buddy said it pulled really nicely with a 2.93)

My plan originally was to give the "e" motor to my mechanic in exchange for him helping me with the swap of everything good from my iS; engine, interior, and suspension to the new car. Aware that this would take alot of time, I started second guessing whether or not I should waste the time removing the 150,000 mile eta motor, and swapping in a 250,000 mile "i" motor. I also had a fleeting reservation that it would be pointless to bastardize a perfectly good 325eS with an old "i" motor when there is a perfectly running engine in the car. With this scenario, if i take the e motor, I would be giving my mechanic/friend the "i" motor as payment.

I intend to autocross this car from time to time, and I really do love the "i" motor, I'm just wondering if I would be totally filled with regret swapping to a chipped "e" motor just to save time and a small bit of the car's original equipment.

Am I crazy or is this a legitimate quandary? Discuss.

[e30m20TurbO7]

DONT TRADE IT , JUST BUY A eta bottom end and slap it on to the top end of your I . you will love it

I have an interesting predicament I am in.

Let me start off my saying I have a 325is with worse than average rust issues and wiring from hell, so I bought a pristine 325eS (with working ac) to swap my good "i" motor into, as well as interior and suspension. The shell I bought (sight unseen) actually wasn't a shell at all, It's a running, driving 325es with a racing chip (unsure which chip but my buddy said it pulled really nicely with a 2.93)

My plan originally was to give the "e" motor to my mechanic in exchange for him helping me with the swap of everything good from my iS; engine, interior, and suspension to the new car. Aware that this would take alot of time, I started second guessing whether or not I should waste the time removing the 150,000 mile eta motor, and swapping in a 250,000 mile "i" motor. I also had a fleeting reservation that it would be pointless to bastardize a perfectly good 325eS with an old "i" motor when there is a perfectly running engine in the car. With this scenario, if i take the e motor, I would be giving my mechanic/friend the "i" motor as payment.

I intend to autocross this car from time to time, and I really do love the "i" motor, I'm just wondering if I would be totally filled with regret swapping to a chipped "e" motor just to save time and a small bit of the car's original equipment.

Am I crazy or is this a legitimate quandary? Discuss.

[OD Green E30]

I already have an Eta bottom end, it's mounted to the "shell" I just purchased.

DONT TRADE IT , JUST BUY A eta bottom end and slap it on to the top end of your I . you will love it

[Holland]

Keep the eta, no need to swap a tired motor. Although a 2.7i would be the way to go.

[ButtJuice]

Like previously stated, Swap your i head over to your eta bottom end.

Rebuild/freshen up the top end and start the swap! There is plenty of info on r3v about this swap, use the search function.

[OD Green E30]

That does sound great, but I have heard swapping the "i" head onto the "e" motor lowers compression. do we think that the net horsepower gain would be substantial enough still to do the head swap? Obviously it is because people do it all the time, but I don't have the funds to do pistons or anything like that, at least not at the moment.

Keep the eta, no need to swap a tired motor. Although a 2.7i would be the way to go.

[OD Green E30]

I'll do that. thanks alot

Like previously stated, Swap your i head over to your eta bottom end.

Rebuild/freshen up the top end and start the swap! There is plenty of info on r3v about this swap, use the search function.

[Farbin Kaiber]

Yeah, just drive the eS while you part out the i, then do the i swap after you go through the i head.

[StereoInstaller1]

You also need to swap all of the "i" motor electronics and intake. If it were mine, I would grab the oil cooler and the entire cooling system from the B25 car, assuming it is late model. Either way, it would be foolish not to grab the 3.73LSD that should be in your iS.

And for fucks sake, get that cluster from the iS car!

Pull the B25 head, get it rebuilt, pull your motor out, re-seal the bottom end and swap heads. Do the electronics swap at the same time. You would have a fresh start, basically. A 2.7i properly done is great with a 3.73, shockingly quick. Add bewst later.

GL.

Luke

[jlevie]

Assuming all stock components, a 2.7i will make more power and have a broader rpm band than an ETA, but less power than an M20B25. But given what you have to work with that might be the best choice. Though what you have left (a high mileage M20B25 block and an ETA head) isn't worth much. You will also want to move the differential from the 325i to the 325es.

If it were me, I'd rebuild the M20B25 and use it in the 325es. Then you'd have a zero time engine.

[OD Green E30]

Assuming all stock components, a 2.7i will make more power and have a broader rpm band than an ETA, but less power than an M20B25. But given what you have to work with that might be the best choice. Though what you have left (a high mileage M20B25 block and an ETA head) isn't worth much. You will also want to move the differential from the 325i to the 325es.

If it were me, I'd rebuild the M20B25 and use it in the 325es. Then you'd have a zero time engine.

You also need to swap all of the "i" motor electronics and intake. If it were mine, I would grab the oil cooler and the entire cooling system from the B25 car, assuming it is late model. Either way, it would be foolish not to grab the 3.73LSD that should be in your iS.

And for fucks sake, get that cluster from the iS car!

Pull the B25 head, get it rebuilt, pull your motor out, re-seal the bottom end and swap heads. Do the electronics swap at the same time. You would have a fresh start, basically. A 2.7i properly done is great with a 3.73, shockingly quick. Add bewst later.

GL.

Luke

I think what I really need to do before I go balls deep into a 2.7i build, which I've heard will have lower compression, can have a rough idle, and slightly more trouble starting, is to check the health of my 250,000 mile "i" motor and see if it's really all that bad.

If its within the confines of what we could call "healthy" compression, say anything around 150, I feel like it would be redundant to go pulling the head off of one to frankenstein another, especially since if I keep the eta, I don't get to keep my "i" head from the other, that one goes with the motor to my mechanic as payment for helping me with the swap (I'd have to source an entirely new i head and pay for it). It sounds like I'll be doing the engine harness if I go with any option other than keeping the "e" and keeping it stock. If I do the I head swap I have to do the harness too, wouldn't it just be easier to put my i motor in? That way I don't have to get wrapped up in cracking this thing wide open and doing all this work to get the performance the old "i" motor already had.

I really wish I could have had a chance to drive the 325eS before my mechanic yanked the tranny. He said it pulled like an i, we later found out it "pulled like an i" while having a 2.93. with my 3.73 it could be better. who knows.

I will get back with you once I do that compression test on the old 250,000+ mile m20b25.

thanks again everyone.