2.7 l hybrid turbo

[fat325]

hay all
new to this forum and doing a lot of searching but couldn't find exactly what i wanted to know.
I'm doing a turbo setup. 350rwhp+ is my goal. Ive got a 325is with a m20 b25 engine. Ive just pulled the engine out to rebuild the engine. Ive herd a lot of people talk of this 2.7 l hybrid but need some things cleared up. From my understanding all i do is swap my 2.5i crank with the 2.7e and use the e rods with custom pistons. is that right?
One other thing. If that is how it works, while I'm at it would it be worth wild boring it out to a 3l with over sized pistons? are you able to do that?
thankyou

[CorvallisBMW]

You can only bore out an m20 an extra 1mm, that's all there is room for. With an 'e' cranck, that will get you 2.8 L. if you want to get 3.0 L you will need a longer stroke crankshaft from (I think?) an S52. Go with the 'i' rods though, they are generally regarded as better suited to the task.

However if you are going to try and get 350 rwhp out of a turbo car, you will not want a high compression ratio; you may not need custom pistons. By simply placing the 'e' crank in you 'i' engine, you will get 2.7L with an 8.4:1 CR. If you had the bores honed/polished and got a new/refurbished set of stock pistons, it would be cheaper than going to full custom pistons. However if you do want to bore the block 1mm to get the 2.8L, then you will need custom pistons.

[fat325]

This s52 crank what work is involved in fitting this? do you need to machine anything. with the turbo setup would it be better to go 3litre or stick with the 2.8 setup?

[echothreezero]

I was under the understanding that the i rods meant the piston ended up proud of the block and that the e rods plus approx a 1mm skim was the way to go for a 2.7. N/A setup at least.

[CorvallisBMW]

This s52 crank what work is involved in fitting this? do you need to machine anything. with the turbo setup would it be better to go 3litre or stick with the 2.8 setup?

I'm not sure what you need to fit the s52 crank, you may need to do some work on the block for clearence of the rotating assembly. I would recommend just going to www.bmw2002.com and checking out their stroker kits. You can get any CR you want.

[fat325]

thanks champ

[kissinger]

2.8 stroker

I used I rods, custom ross pistons from IE, 2.7 e crank, 272 cam, m30 injectors, m30 027 afm, IE Afpr, and Patients. Really happy with outcome but still want more power. I also plan to turbo in near future, Multi Layered Steel Head Gasket .024" up to .140" from Vac motorsports, ARP M20 Head Stud Kit, and megasquirt engine management. I might run turbo under car like STS Turbo Systems. I dont like extra weight up front kills handling keep it light thats my two cents.
Dont forget larger injectors, i would search here from others that have turbo.

[nando]

You can only bore out an m20 an extra 2mm, that's all there is room for. With an 'e' cranck, that will get you 2.8 L. if you want to get 3.0 L you will need a longer stroke crankshaft from (I think?) an S52. Go with the 'i' rods though, they are generally regarded as better suited to the task.

However if you are going to try and get 350 rwhp out of a turbo car, you will not want a high compression ratio; you may not need custom pistons. By simply placing the 'e' crank in you 'i' engine, you will get 2.7L with an 8.4:1 CR. If you had the bores honed/polished and got a new/refurbished set of stock pistons, it would be cheaper than going to full custom pistons. However if you do want to bore the block 1mm to get the 2.8L, then you will need custom pistons.

fixed that for you

to use the S50/S52 cranks you need a sleeve on the front for the oil seal and you have to clearance the intermediate shaft. I'm not sure what block clearancing needs done, but that can be taken care of when you have your block machined.

also, IE sucks. :p