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DISCUSSION => Swaps, Turbos, Buildups => Topic started by: ANtiX25 on October 16, 2012, 09:27:00 AM

Title: M47 crank and pistons
Post by: 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?

Title: M47 crank and pistons
Post by: wazzu70 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.

Title: M47 crank and pistons
Post by: romkasponka 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.

Title: M47 crank and pistons
Post by: wazzu70 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.

Title: M47 crank and pistons
Post by: rob_e30 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.