Recipe for 2.7l i engine

[OreoGaborio]

that i can't answer for ya.. but if you have super eta pistons in there... it shouldn't be too bad

[rs4pro3]

Think of it this way a Machine shop will only charge about $30 to shave the head or at least my local shop charges $24. You will probally see 1-2hp but will also get a better throttle response, as the higher the Cr ratio(within reason) the more responsive the Engine is. Most of the time BMW heads are warped any way when they come off the engine and have to be resurfaced, so you might as well have them shave it the rest of the way. Don't shave the head though untill you actually have the pistons in hand that you will be ussing as once it's shaved you can't go back.

[OreoGaborio]

very good points... nice tip bro :up:

[Super Eta]

i have some eta parts laying around such as a crank and so basically my question is how much money or we talking with this rebuild?

If i need parts i might be able to pick off of the engine in my car now wich will only be done out of desparation.

[KevinM]

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

Pete, when you actually get around to doing this I wanna be there. My super e will most likely undergo the same thing once I get some funds.

[Erick]

Now a 2.7i is something I would like to look foward to.... cheapest hp gains.... I like the idea.

[808BMW]

I want to go turbo, and I figure, what lower CR by getting a thicker HG, when I can lower CR by upping the displacement :twisted:

[JPbmw]

the lower the CR the better for a turbo set up, right?

[OreoGaborio]

Pete, when you actually get around to doing this I wanna be there. My super e will most likely undergo the same thing once I get some funds.

you got it bro... hopfully you'll be around & hopefully i'll actually get to do it ;) i may end up concentrating on rebuilding the suspension first though... so i dunno if i'm gonna do it this summer or next.. we'll have to wait & see

[slammed_e30]

does anyone have any specs on a 2.7i, like hp and tourqe?

[nitro325is]

lots of good info guys.

about the motronics on my brothers 88 super.He has been using my old 153 ecu with bavauto chip that i had on my 87 325ic with no problems. Well till he overreved.The engine did not ping or hesitate...could only spin to about 6200 though before the head started to make noise.Due to single springs i assume.Told him to not spin more than 5900.But how many 16 yrs old listen to older bros.
So is his car some weird exception or just nobody else tried this before? He had it on their for like 2 months....again no problems..even gained a few MPG.He had a 154 ecu in there before.So i think the rewire does not apply.Looks like this will be a very easy swap then.
On the same token I have run a 154 on my dads 90 325 with no problems either for about a year now.Dads ECu was dead so this was a free replacement.

On more question....i am giving him my head..since im going m3 cam m50.It is a completely new head with BMP 282/272 cam with BMP heavy duty valve springs. The cam is high lift 11.5 mm..does this have to be taken into consideration when shaving the block/head?

Thanks again for this very informative thread...We'll do a tech article when we get this done.

[rs4pro3]

Yep your cam choice needs to be taken in to consideration when shaving. As with a higher duration came the valves are open for longer which means you need to allow more squise room so the pistons don't hit the vavles. If you want the exact amount post a message here. http://autos.groups.yahoo.com/group/mod_m20/
And yes the lower the cr ratio the better it is for a turbo but remeber you still want enough cr ratio so the Engine will Idle :D

[808BMW]

the lower the CR the better for a turbo set up, right?

AFAIK, lower CR will help raduce detonation (as will intercooling and higher octane gas).

My plan: I want to run 8 lbs of boost on a 2.7i on 92 octane.

[rwh11385]

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

hey, i have a question? What CR can you reach on a 325i engine by shaving the head (safety that is). Can one get 9.8 CR by shaving the head??

p.s. I want to run a 278 x 10.4 intake at least and 272 duration on the exhaust.