'2.7' vs '2.8' stroker

[The Humjet]

If putting in an eta crank into a 325i block will create issues with pistons smashing into the head I dont think longer 137mm rods with eta crank will help :P

[98turbo]

Don´t use eta pistons for your 2,7. With those you can´t get a really good performing engine.

Use your eta crank and rods.
Then get some 325i pistons. With that combination you need to mill off your block for 2mm.
Because of this modification, you need to get a adjustable cam gear, to get the right timing again.

If using non-cat 325i pistions you will get a CR of 10,3
If using cat 325i pistons you will get a CR of 9,4

either way this combination will give you way better performance than any eta-piston combination can do.
(Thats the typical way the 2,7L engine is built in europe)

Sorry noob question what is a non cat piston? With a 10,3 compresion ratio can I run 91 octane?

[1craze30]

I would urge others in this thread to place correct information in here. Either that, or op USE THE SEARCH FUNCTION!!!!!! This has been talked about to death, and this is turning into a bad thread

[mkcman17]

Actually, agreed...i can do eta reasearch on my own. No need for a swordfight up in hurr

[The Humjet]

I'm actually liking this thread cause I'm learning something new even though I have researched about this swap for quite a while

[323iNathan]

The non cat pistons are from the early euro m20b25's, they had no catalytic converter, but also a higher CR.

[Pedaaa]

the adjustable cam gear is that used to re-tighten the loose cam belt due to shaving the block? sorry if its a dumb question I don't know how adjustable cam gears work.

Yes, after shaving the block, the camshaft would be on a lower position. But that would mean your belt is a little bit too long now. So your timing could be wrong now or the belt will not fit at all, for about a 1/2 thooth.

So you need to place a adjustable cam gear. Which is good for fine-tuning your timing also.
See a photo of mine below:
(you can either make your own, or get one from e.g. dbilas)

[Pedaaa]

Sorry noob question what is a non cat piston? With a 10,3 compresion ratio can I run 91 octane?

No, you would need 98 octance, if using this setup.

what about custom 137mm rods? I've driven turbo m20s, and they're absolutely bonker...just not what I'm looking for at the moment.

it would work with 132mm custom rods. But i never came across something like this.

[The Humjet]

Your setup sound like the solution to gettin a high comp good flowing stroker without ordering expensive custom pistons, thanks for sharing your knowledge Pedaaa

[nickflic3]

http://strictlyeta.net/technical/328i_1.html

Good read for anybody thinking about doing this.

Mike hurry up and buy my eta bottom half before I use it lol

[mkcman17]

What the hell you gonna do with it? thanks, lot of good info here guys.

[Eecen]

Use your eta crank and rods.
Then get some 325i pistons. With that combination you need to mill off your block for 2mm.

If using non-cat 325i pistions you will get a CR of 10,3
If using cat 325i pistons you will get a CR of 9,4

It definitely will works this way.
(i know what i am talking about, i have such an engine 186rwhp, 214hp)

What are you running for management with this setup?
Cam specs?
Intake changes?

[Pedaaa]

Thats my current engine setup:
- Basic Engine: 325i 88
- eta crank
- eta rods
- non-catalyst 325i Pistons from KS (original 9,7:1 CR for the 2,5L)
- Block milled off for 2,2mm (10,5:1 CR)
- adjustable cam-gear
- 284/272 Schrick cam shaft
- Schrick valves
- valve seats modified and matched to the ducts
- ported ducts
- throttle body ported and with bigger flap
- air inlet manifold matched to the increased head ports and bigger throttle body
- Flywheel machined to 5,5kg
- Exhaust headers
- Alpina B3 2,7L ECU

Planned mods:
- MAF Conversion
- high flow cone filter with cold air intake
- 200cpi metal-catalyst
- ??lbs fuel injectors
- well tuned engine management

Photos:

[mkcman17]

^
wow, great write-up!

[MonkeyMadness]

Wooo

small question got way out of hand...
guy wants stroker for little money
2.7 is cool but gets pulled by nice b25
so I would go 2.8..
885 head (you have)
325I pistons (you have)
eta rods (you have)
m52 crank 84mm (you can get cheap) sell eta crap...
totaly pull on b25 and smoke 2.7 convertions...

2.8 duh..