super eta head to i head

[318i sTiLL FLy]

Ok, I'm doing it today.. a head off a 89 325i with 127k on it.. putting it on my 88 super eta with 81k on it.. will this be good for hp upgrade.. if i only do the head is that ok or do i have to do injectors or anything else, ect...

any ADVICE!!!! ANY!!! please!!!

[Julien]

I would do intake as well (as long as the electricals are the same.. anyone?)

[JGood]

To get any real benefit you need to do the entire top end swap, with the wire harness, ecu, everything.

[c0rnfl4k3]

What are the benefits of this swap?

I have an 88 seta aswell, and have heard of the swap, but not much on the pluses.

[JGood]

What are the benefits of this swap?

I have an 88 seta aswell, and have heard of the swap, but not much on the pluses.

Well, look at the hp/tq curves of both engines... should be self explanatory.

50 more peak hp and a higher redline (longer usable power band).

Do a search, you'll find everything you need to know.

[bimmer2288]

I did this swap on my car and would suggest just swapping out ECU's than the head. I put in a 325i ECU long before I put in a new cam, intake, throttle body, performance chip, etc. I noticed more of a difference in the ECU than the other mods I just mentioned.

[Jonathan M3]

IIRC the seta's head is the same as a 325i's, its the cam and springs that need to be swapped along with the manifold, TB, ECU, and harness.

[nando]

are you guys certain the harness needs to be swapped?

[Van Westervelt]

are you guys certain the harness needs to be swapped?

On the 88 seta, my harness is identicle to the 325i harness. Just head, injectors, intake mani, and ecu. Those are the things I would swap if I went this route. There might be a couple more little items, but I doubt it.

[StereoInstaller1]

I did this swap on my car and would suggest just swapping out ECU's than the head.

This is DUMB. Do NOT do this, no matter what wonderful success someone else had with it.

Here is why: It all comes down to cam and valve springs and rev limits.

Stock I head has 7 lubricated cam journals. Supports the cam in 7 places, in other words.
Stock SETA head only has 4 lubricated cam journals, because the E cam only has 4 journals, thus is much less stable.

If you were to change to "i" valve springs, it would add enough additional stress to possibly break the cam...which would suck beyond all belief.

None of this matters if you can't spin the motor over 4500RPM...but that 173 ECU WILL allow that high RPM power...of course you won't make that power unless you have airflow, thus the manifold swap, and you won't continue to make that power if it runs lean, so you need to swap injectors and FPR...etc.

Just someone else got lucky and did not break their shit does not mean you will.

Do it right or you might pay the consequences.

Luke

[Jonathan M3]

The part # for a seta head is the same as a 325i head. The seta's cam is different than a regular eta's. All you need is a 325i cam and springs.

Chris is correct though, you don't have to swap harnesses, just ECUs. I forgot about that.

[Jscotty]

This is DUMB. Do NOT do this, no matter what wonderful success someone else had with it.

Do it right or you might pay the consequences. Luke

Well I am glad you said something. I was getting ready to tell him to drill a 1/4" hole in each piston and then add a bottle of that 2-cycle oil to the gasoline that's used in chain saws and lawn trimmers.

[bimmer2288]

This is DUMB. Do NOT do this, no matter what wonderful success someone else had with it.

Here is why: It all comes down to cam and valve springs and rev limits.

Stock I head has 7 lubricated cam journals. Supports the cam in 7 places, in other words.
Stock SETA head only has 4 lubricated cam journals, because the E cam only has 4 journals, thus is much less stable.

If you were to change to "i" valve springs, it would add enough additional stress to possibly break the cam...which would suck beyond all belief.

None of this matters if you can't spin the motor over 4500RPM...but that 173 ECU WILL allow that high RPM power...of course you won't make that power unless you have airflow, thus the manifold swap, and you won't continue to make that power if it runs lean, so you need to swap injectors and FPR...etc.

Just someone else got lucky and did not break their shit does not mean you will.

Do it right or you might pay the consequences.

Luke

The SuperETA head has 7 oil journals. Do some research and you'll find that out. There is nothing wrong with swapping ECU's. I had more of a kick in the pants difference doing that than the other mods I mentioned.

Stock injectors are fine, FPR is fine, etc. I have no qualms about the 325i ECU in a SuperETA.

[backtrail69]

You can't rev past 5500ish RPMs without the valve springs and there is no power up there without a i or better cam.