"Eta" to "I" Head swap questions

[Quinn Sivaivai]

Can I use a 87-91 525i ecu for my 88 325i

[MR 325]

I'm building one right now for my track car. I have everything I need to get it all back together but decided to hold off untill I can afford a 272/274 Cam and HD Valvesprings, as well as some Headwork. Really feel like those extra things will REALLY make this setup shine.

The Cam and Springs alone are looking to be around 550-800. So just getting ready to jump off that cliff here soon. Fun fun fun.

Really no need for performance springs with that setup. Good (tested) used valve springs are fine. Maybe brand new stock spec springs if you really feel the need!

Does his head come with a cam?

Yes our heads come with a performance cam. Click link in my sig for info. :)

Can I use a 87-91 525i ecu for my 88 325i

All M20B25 ECUs will interchange. The E34 M20 was made in 1989 and 1990.

[JasonBates]

Yet another question.

I was thinking of running I.E. Headers and was thinking of just running two pipes all the way back. I was talking about it with a friend, he said I would need to run an x or a y pipe at one point. Something about equalizing pressure or something.

Would I actually need to do something like that?

[digger]

Yet another question.

I was thinking of running I.E. Headers and was thinking of just running two pipes all the way back. I was talking about it with a friend, he said I would need to run an x or a y pipe at one point. Something about equalizing pressure or something.

Would I actually need to do something like that?

dont need to but seems to improve performance and help keep things quieter

[JasonBates]

So, just run an x-pipe from the headers to resonators, then straight out?
Or
Y-pipe to a resonator to y-pipe and out the back.
Or
Should I run a muffler at the end of either one of those?

[MR 325]

I would just run single 2.5" exhaust personally. Y it in to a single pipe after the downpipes.

[JasonBates]

That does sound a bit cheaper.
These are just ideas I'm bouncing around.

[Pdxseth]

I'm forced to do this this weekend. I cracked my head and have a complete m20b25 conplete with a bad rid bearing in my garage so I think I have all the parts(even the cluster) my question is: do I need different radiator hoses and are b25 water pump different from the b27 I'm gonna go buy gaskets,head studs, water pump and timing belt Tomorow. I just don't want to buy the wrong parts

[MR 325]

I'm forced to do this this weekend. I cracked my head and have a complete m20b25 conplete with a bad rid bearing in my garage so I think I have all the parts(even the cluster) my question is: do I need different radiator hoses and are b25 water pump different from the b27 I'm gonna go buy gaskets,head studs, water pump and timing belt Tomorow. I just don't want to buy the wrong parts

The water pump difference is between early model and late model. If you're swapping the 885 head on to your Eta block and keeping your original cooling system you'll want to order a pump for an 87 or older.

[e30trooper]

If using the eta water pump , get a belt 1" shorter or find a late model water pump pulley and matching belt

[Pdxseth]

So either water pump will work I just have to use the pulley off the late model b25

[MR 325]

So either water pump will work I just have to use the pulley off the late model b25

NO. The water pump needs to match the cooling system (radiator and hoses).

If you're running the early radiator and hoses get the 87 and older pump.

[JasonBates]

More questions

I have more questions.
I just got an 'i' cluster from a just yard out of what I think was an 89, my question is, will this one work for the swap as a bolt in cluster?
And is there any way to test it outside of the car to make sure everything works in it?

This is more of a trans question, but if I plan on running an AKG shifter or some other short shifter, what all would I need to pull form a parts car?

[Pdxseth]

NO. The water pump needs to match the cooling system (radiator and hoses).

If you're running the early radiator and hoses get the 87 and older pump.

Ok so I'm keeping the 85' cooling system but all the swap parts are coming from a late model. So I want to use an early model pump an late model pulley? Or I can use a belt that 1" shorter? And I also need the "I" crank pulley?

Sorry for so many questions I'm just trying to get all this right so I don't run into too many problems after I purchase my parts

[MR 325]

I have more questions.
I just got an 'i' cluster from a just yard out of what I think was an 89, my question is, will this one work for the swap as a bolt in cluster?
And is there any way to test it outside of the car to make sure everything works in it?

The cluster will work but you'll need to swap in your early model fuel gauge.

Ok so I'm keeping the 85' cooling system but all the swap parts are coming from a late model. So I want to use an early model pump an late model pulley? Or I can use a belt that 1" shorter? And I also need the "I" crank pulley?

Sorry for so many questions I'm just trying to get all this right so I don't run into too many problems after I purchase my parts

Run all of the pulleys from the M20B25 engine and buy the belt for that engine.