Recipe for 2.7l i engine

[nitro325is]

My younger bro broke a rocker on his 88 super eta.I have several e and i parts cars that he can take parts from to get his car going again.He is now interested in doing the 2.7i conversion while he drives my eta.

Back on e3s someone went into detail on doing the supereta 2.7 liter....the other boards only discuss regula eta to 327i conversion.So does someone have the info available..I already checked Freds site ...its the regular eta to 2.7 i conversion discussion there.

Specifically of interest was the shaving of the block or the head to raise the compression ratio to at least 9:1.


Thanks,

JP

[rs4pro3]

Basically you want all the 325i manifold and wiring and probally the head since a rocker broke. Then you'll want to shave the head a couple mils, I can get you the exact numbers or PM tricked 323i on this board as he knows. this will bump the cr ratio up. other than that there isn't much to using the super eta to make into a 2.7i

[Super Eta]

Im condidering this sorta also as i have the Eta block and a B25 block, the B25 block needs work and i may just do a rebuild.

I also would like more info on how to do this like how much will need to be shaved and so on.

[rs4pro3]

ok I'll try to find the info for your guys and let you know.

[PatNy]

how much hp can be found by doing this to an eta? im interested in learning!

[rs4pro3]

with a full I head and I wiring and senors you can get close to 200hp but you'll need to bump up the cr ratio a little.

[rs4pro3]

ok here is the info on shaving the head http://autos.groups.yahoo.com/group/mod_m20/message/590

Note: those numbers are for Eta pistons and since the super eta has a little less cr ratio I believe the numbers can be adjusted as nessicary.

[Tricked 323i]

SInce the super and i are the same cast all you would need to is have your head rebuilt with an " i" cam and dual valve springs. I am not sure what you can do about your rev limiter since there is no chip made for the super. You could always switch to a 1.1 or 1.3 ecu and harness and have a chip burned as well. Here are the tolerances and specs bellow from a friend of mine Jack Roberts...........
Decking the block 0.020" (0.5mm) and milling the head 0.040" (1.0mm) will raise the compression ratio of an otherwise stock 2.7 super-eta from 8.5 to 9.6:1. The resulting squish/quench clearance will be approximately 0.031".ecs

[808BMW]

What is required to do this if you are starting with an i motor?

[OreoGaborio]

aight guys... there's a few different ways to do it, so here we go (and these AREN'T all of em)

2.7i # 1 - m20 block... either one... w/ the eta crank, eta connecting rods, supereta pistons, the rest 325i (head (inc. camshaft, double valve springs etc), ecu, wiring harness, intake manifold, TB, exhaust etc)... this will probably net you around 190-195hp & 215 ft/lbs, but don't quote me on that.. that's just a guess

2.7i # 2 - m20 bock... again eitehr one... w/ eta crank, eta connecting rods, EURO eta pistons, the rest 325i (head (inc. camshaft, double valve springs etc), ecu, wiring harness, intake manifold, TB, exhaust etc)... this'll give you a few more HP & tq, since the euro pistons ahve a higher compression ratio.... but those are pretty damn hard to find

2.7i # 3 - m20 block... again either one... w/ eta crank, 325i connecting rods, custom pistons, the rest 325i (head (inc. camshaft, double valve springs etc), ecu, wiring harness, intake manifold, TB, exhaust etc)... personally, if you go custom pistons, i don't see why you wouldn't wanna bore the block out 1mm & make it a 2.8i... i dont think it'd be much more in cost

if you go custom pistons, you can just give all the info of the rest of the engine to the shop that's making em & you'll be all set... no shaving of the head necessary... even if you go w/ #1 or #2, you don't HAVE to shave the head... the CR isn't too horribly low that you'll have to do this AS FAR AS I KNOW............ HOWEVER... if you use the regular ETA pistons... the CR would be pretty low & would be worth shaving the head...

just realize that if you use the eta block, i believe you'll have to drill an oil journal to get oil up to the 325i camshaft that's sittin in that 325i head

anything here that needs to be corrected?

[808BMW]

Looks like option #1 is my best bet... eta crank and conrods are easy to find, but supereta pistons or not likely to be local... how much would they run on ebay?

[OreoGaborio]

not a lot... couple hundred at the MOST, or so i would think

[slammed_e30]

So let me get this right, if you use the super e pistons and the i head you should get the head shaved? I have the complete i swap but i haven't had the head shaved. what are the effects of not shaving the head?

[OreoGaborio]

So let me get this right, if you use the super e pistons and the i head you should get the head shaved? I have the complete i swap but i haven't had the head shaved. what are the effects of not shaving the head?

a slightly lower compression ratio.... no biggie... you're better off w/ supereta pistons than regular eta pistons

eta pistons would net you a super low CR... w/ supereta, shaving the head is not really a necessity from what i've heard

just so i can be perfectly clear... i don thave any personal experience in building a 2.7i, but i've done a shitload of research (like... almost a year now) and i HOPE to have one by the end of next summer.... but first i'm gonna get my suspension & other needed maint. items sorted out

[slammed_e30]

how much am i loosing by not shaving the head, i mean is it worth the performance money wise?