NA DOHC EJ Engine Build?

[GEE-OTTO]

This thread smells of awesome :-)

[Underdog]

Ran some rough numbers this morning on a 2.35L destroked long-rod setup and it looks like you will need about a 7cc domed piston to achieve 12.5:1 CR with a 50cc chamber (like the D/V/W heads). Theoretically 12.5:1 approaches the knock threshold limit for 93 octane, but that is a very generalized approximation. The big question is whether you can fit that piston without really screwing up the cylinder quench, and whether there will be enough clearance for the valves, particularly if you are using a high lift profile and DAVCS.

[Sgt.Gator]

Ran some rough numbers this morning on a 2.35L destroked long-rod setup and it looks like you will need about a 7cc domed piston to achieve 12.5:1 CR with a 50cc chamber (like the D/V/W heads). Theoretically 12.5:1 approaches the knock threshold limit for 93 octane, but that is a very generalized approximation. The big question is whether you can fit that piston without really screwing up the cylinder quench, and whether there will be enough clearance for the valves, particularly if you are using a high lift profile and DAVCS.

 

Thanks.

I run Premium Oregon Pump 92 octane + Torco Accelerator in the race wagon now to a mix of around 103 Octane. I have no problem continuing that mix. If it could be run it at 96 Octane that would reduce my consumables cost.

 

http://www.torcousa.com/7-docs/Torco-Bleding-chart.jpg

 

So how do we solve The Big Question? What combo of crank/rod/piston gets us there? I don't really want to have custom rods and pistons made if there is a combo of OTS parts we could use.