Any OEM piston compression boosters ?

[Eurotrash727]

Okay guys im trying to get a higher compression in my m20b25 & was wondering if there is any OEM pistons i can swap out to get higher compression ratios.

Anything to get me to around 11:1 would be Excellent & also does anyone know the max amount that can be shaved from a b25 head before you have clearance issues ?

Thanks James
Ps. iv tried doing research everything just comes back to the 2.7i builds not looking to go low comp.

[Cronopoulos]

http://www.iemotorsport.com/bmw/E30-engine/m20pistonf.html

[Eurotrash727]

http://www.iemotorsport.com/bmw/E30-...20pistonf.html

yeah not looking to spend 1000$ on a set of pistons, reason why i asked if there were any OEM piston tricks, Iv only built honda motors in the past & all there ish is interchangeable pretty much, just seeing if there was anything that i could do like that.

I wanna Run a decent cam profile & want the the correct compression pushing it.

[sayed ali]

2jz-gte pistons and m52b28 crank, 885 head

I'm not sure about the compression ratio but it's great combo ...

[Eurotrash727]

2jz-gte pistons and m52b28 crank, 885 head

I'm not sure about the compression ratio but it's great combo ...

ehh from the one guys thread that i could find that was gonna do this it was gonna be another boost setup.

[E30-325iS]

Mahle make 9.7:1 for the B25 but they'll probably cost you the same as custom pistons.
http://www.scribd.com/doc/12801628/Mahle-Pistons-M20

[Eurotrash727]

yeah iv been searching all morning & night can't find anything looks like ill be stuck dropping 900$ on a set of pistons if i want my CR goal.

[e30trooper]

euro eta pistons (2.7) mated with a 731 head.

[Eurotrash727]

With the b27 bottom end is everything just as capable as the b25 like rotating wise? I see the b25 is a more common higher reving motor seeing like 7-7500

[Eurotrash727]

euro eta pistons (2.7) mated with a 731 head.

iv been looking for a set of euro pistons haven't come across a set yet. Even with them i don't see my CR being reached.

Plan on running a 288/288 schrick cam so need a pretty high CR. I was just wondering if anything would get me in the 11:1+ area without having to drop the money on forged pistons.

[5Toes]

check ebay.co.uk

[KillaCam]

is this going to be your DD? .... if so you don't want 11.1... you're going to have to run race fuel everywhere you go or you'll have detonation. also.... SEARCH..... when i first started out i asked the same question and i found my answers by searching. Also, look on e30tech for some of your answers thy are there if not here..... but awyways.. the chance of finding this pistons is like trying to find a needle in a hay stack. they only made those piston for 1 year.. your better off just get a 731 and mating it to a early eta block.

[Yourmum]

The best you can do is shave the head and deck the block and it should take you somewhere in the 10s:1 but be warned that if you need a head rebuild someday you'll probably need a new head. Also, going this route you'll need to pull apart and rebuild your whole motor anyway which will be quite costly. Best bet would be an m50 swap.

Edit: you'll also need an adjustable cam gear to deal with timing issues that will arise. If you are also planning on running a 288 cam you will need to cut deeper valve reliefs in your pistons. In hindsight it will probably be cheaper buying custom pistons from the start.

[Eurotrash727]

Thanks guys yeah im really new to this stuff, i come from a long line of honda shit which iv done 12:5 compression safely on pump & daily. I actually have a local station with e85 at the pump too.

Thanks for the input guys , from this think im just gonna Say screw it & Go for a turbo setup. cause i already have a Eta motor in my car so ill prolly just pick up a 885 head & do a mild cam.

[Cronopoulos]

Thanks guys yeah im really new to this stuff, i come from a long line of honda shit which iv done 12:5 compression safely on pump & daily. I actually have a local station with e85 at the pump too.

Thanks for the input guys , from this think im just gonna Say screw it & Go for a turbo setup. cause i already have a Eta motor in my car so ill prolly just pick up a 885 head & do a mild cam.

I like where this is going, don't forget the megasquirt!