Stroker Questions

[wakeking989]

Hey all!

First off, I'm new here, but not new to E30's. I've owned mine for about 7 years now so I know the ins and outs of them pretty well. I've also lurked around on the forums for quite some time but just never made an account.

Anyway, I have a few questions about stroking the m20. I'm thinking of going with an 84.5mm bore and some 0.5mm oversized pistons from mahle, an eta or super eta crank (81mm stroke) and stock 325i 135mm connecting rods. I'm pretty sure this will give me a 2.8l, correct? Also what will the compression ratio be? Eventually I will turbo the car, but that will not be until next year around tax return time and when I can get a second car and make the E30 a dedicated project.

I understand that there is a search function and I have been using it a lot but am having trouble finding build with people using 84.5mm pistons; usually its an 85 or 86mm piston set. Any insight is much appreciated. Thanks fellas.

[downforce22]

http://www.e30zone.net/e30zonewiki/index.php/M20_Stroker_Info

[wakeking989]

Thanks Downforce! That's a huge help. Do all of those options use 135mm connecting rods?

[redlightpete]

Thanks Downforce! That's a huge help. Do all of those options use 135mm connecting rods?

Uhh, no. The custom piston arrangements allow some flexibility for rod length, but if you're using 325i pistons, the rods have to get shorter with longer stroke.
If you're planning to buy new Mahle pistons anyway, you may want to check out Ireland Engineering's 85 mm Mahle pistons designed for the eta crank.

[wakeking989]

Uhh, no. The custom piston arrangements allow some flexibility for rod length, but if you're using 325i pistons, the rods have to get shorter with longer stroke.
If you're planning to buy new Mahle pistons anyway, you may want to check out Ireland Engineering's 85 mm Mahle pistons designed for the eta crank.

Thanks. I'll definitely check those out!

[redlightpete]

Sorry, I just looked and those pistons I referenced are for the 84 mm M52 crankshaft.

[digger]

budget strokers all use 130mm rods

[wakeking989]

budget strokers all use 130mm rods

According to this thread: http://www.r3vlimited.com/board/arch...p?t-74095.html

In order to get 2.8l of displacement though you can use 85 or 86mm pistons, 135mm "i" rods (or 135mm s50 rods in nando's case) and an eta or super eta crank (81mm stroke). Is this not considered a budget stroker?

[digger]

According to this thread: http://www.r3vlimited.com/board/arch...p?t-74095.html

In order to get 2.8l of displacement though you can use 85 or 86mm pistons, 135mm "i" rods (or 135mm s50 rods in nando's case) and an eta or super eta crank (81mm stroke). Is this not considered a budget stroker?

yeah i personally define budget as using OEM m20 pistons