Author Topic: M47 crank and pistons (Read 3563 times)

ANtiX25 · « **on:** October 16, 2012, 09:27:00 AM »

I am considering doing the M47 crank, but want to do FI if i get lower compression pistons say 8.5:1 will this defeat the purpose of the project?

wazzu70 · « **Reply #1 on:** October 16, 2012, 03:00:02 PM »

Why would it defeat the purpose?

If you dont go FI 8.5CR will be a more lethargic engine. You will still have more torque though from the added crank stroke.

romkasponka · « **Reply #2 on:** October 17, 2012, 10:11:24 AM »

Quote from: wazzu70;116854

Why would it defeat the purpose?

If you dont go FI 8.5CR will be a more lethargic engine. You will still have more torque though from the added crank stroke.

As I know in Lithuania nobody goes for lower than 9:1 with FI especiali if they use E85.

wazzu70 · « **Reply #3 on:** October 17, 2012, 11:38:12 AM »

Agreed, I would use 9:1 on pump. 10:1 on E85.

Thats just me though. 8.5 is somewhat popular because people believe it gives them a small margin of safety.

rob_e30 · « **Reply #4 on:** October 22, 2012, 06:31:10 PM »

I have a complete set of LC pistons for this setup that I will let go cheap. We ran them with our turbo M42, M47 crank, stock rods. 8.5:1 CR. I've actually got 2 sets of pistons, some of which are brand new. Our setup put down over 330rwhp and was 1.95L.