Super ETA w/ "I" swap -any reliable figures on increase in HP & torque?

[Yogawrench]

I have a stock 1988 Super ETA with 5 speed transmission. Love the torque, but the car cries out for the full "I" top-end swap. It is my daily driver, so reliability and driveability are paramount. While I have hazy plans that some day I might do a modest turbo set-up, I'm not yet ready to do a head gasket/ARP stud job just yet. The first step is to do the "I" swap with a 173 DME with a Mark D chip.

My question is, does anyone have any reliable numbers for the estimated increase in HP and torque by going with the "I" swap? I've searched here but don't seem to find any hard numbers. Anyone out there with some info on this?

[Wschnitz]

Im also interested in this. My SETA would love a full I swap

[SmokeE30]

I can't speak to actual Hp increases but it should essentially put you at the stock m20b25 power rating. Plus a bit more if you use a chip, different intake, ect. I did this to my seta and I enjoy it but I really need to swap the 2.93s out for 3.73s, the gears are now long as hell and its nice for the highway cruises but the power band is all wrong for spirited driving anywhere else. As is it is only slightly faster in a straight line than my buddies ETA with a chip , 3.25 gears, and muffler delet. But then again when we run each other I never get out of third by aisle I can hit 100mph without using 4th now.

[bmwstephen]

i have yet to see a stroker seeta on the board has been completed. specifically, without ongoing troubleshooting, unexpected idling issues, etc... so if reliability and drivability are your concerns, you might want to connect with other members here and they will give you their 2 cents.

[Gary Horneck]

If you have a '88 ETAS, you already have the 885 head most likely. Just the cam and valve springs would need to be changed out, and a 173 ECU. My i conversion was on a '87 325e, so my numbers would not be representative of you conversion, but its a substantial bump on the e.

[jlevie]

The DME (and possibly a chip) aren't going to get it. You need the change the SuperETA cam for one from an M20B27. I can't remember if the intake and AFM also need to change. And you will need a tune optimized for that combination.

[SmokeE30]

You need the cam, valve springs, intake manifold, throttle body, intake boot, afm, fuel injectors, fuel pressure regulator, DME, among other things, that's assuming your head has all the oil holes in it to support the m20b25 camshaft.

[the.other]

ive been running a '88 327i for the better part of 8years now without any issues. you need:

DME from an late model i (i think its x173 iirc)
intake from an i
cam from an i
double valve springs from an i
throttle body from an i

fwiw when i did it i just straight up swapped a head out of an 325i instead of dealing with replacing valve springs/ cam etc.

if you can get your hands on a chip for 327i its good but not strictly nessasary.
(i might be forgetting something as it was a while ago).

I never dynoed it, but I was consistently faster in a straight line than my buddies with m20b25's. the top end leaves something do be desired, but it is definitely night and day compared with eta. Ive always loved this engine as it has just enough more low end grunt than the m20b25 but enough top end to keep up at highway speed.

[MR 325]

i have yet to see a stroker seeta on the board has been completed. specifically, without ongoing troubleshooting, unexpected idling issues, etc... so if reliability and drivability are your concerns, you might want to connect with other members here and they will give you their 2 cents.

Are you serious? It's one of the simplest swaps in the world. Done 5 or so of them over here with NO issues.

I can provide dyno numbers on a rebuilt Super Eta engine with Myster-E head next month.

[Yogawrench]

If you have a '88 ETAS, you already have the 885 head most likely. Just the cam and valve springs would need to be changed out, and a 173 ECU. My i conversion was on a '87 325e, so my numbers would not be representative of you conversion, but its a substantial bump on the e.

My thought was to avoid cracking open the engine to replace the cylinder head. I'm not looking to track/race the car, nor am I contemplating getting maximum revs from the engine. I'm looking for increased power but only if it doesn't compromise reliability. Don't want to break down constantly.


I thought the Super ETA head was essentially an 885 head minus the stronger valve springs and the "I" cam. Will swapping out the "I" intake, TPS, AFM, throttle body, crank sensor etc be sufficient to make it a reliable swap?

[Yogawrench]

Are you serious? It's one of the simplest swaps in the world. Done 5 or so of them over here with NO issues.

I can provide dyno numbers on a rebuilt Super Eta engine with Myster-E head next month.

If you could share your numbers I know we'd all appreciate it. How easy is the Super ETA to "I" swap?

[MR 325]

I thought the Super ETA head was essentially an 885 head minus the stronger valve springs and the "I" cam. Will swapping out the "I" intake, TPS, AFM, throttle body, crank sensor etc be sufficient to make it a reliable swap?

Yes you are correct and yes it will.

The crank sensor and engine harness are the same so no need to swap those. Just the intake manifold, injectors, throttle body, TPS, FPR, and AFM.

[e30Rooster]

When I went to the hpf dyno day there was a eta block with I head car it made about 145hp/145tq on a mustang dyno.
Eta was 99hp/130-140tq and the b25 I car was 135hp/135tq
Sent from my C771 using Tapatalk 2

[603Racing]

The I swapped Eta should always perform better than a b25. It's not because of the peak hp/tq, it's because of when the power is delivered. The Eta will deliver more torque sooner.

Would be cool to see this on a dyno comparison. "Stock" I swapped eta vs. stock b25.

[einstein57]

mckman has a dyno graph floating around. Although his has a cam regrind.