My DCR is 9.26

4.310 bore
4" stroke
Canfielde 310cc 119cc heads.
Comp XR292 Streetroller 292/297 110 lobesep

Stall in a 2800lbs car is 3500 N/A and 4500 on 300 shot.

4.33 gears and 33" tires.

Can it be done on 93 octane gas?

Are you sure 9.26 is the DCR and not the SCR? To get 9.26 DCR with your cam and heads, you'd need domes about 46cc, giving a 12.3 SCR. If 9.26 is the DCR I don't think you can run 93 octane.

With a zero deck and 0.62 gasget.

47cc ;) Mayby ill mill them down a bit.

I will start under 170 deg every run. On n20 ill use 108 octane.

There will be a fully mapable EFI on it. So i can adjust timing curves.

I ditched my 062 gasket for a 032 to get e tight quench.

SO i ended up @ 10.00 DCR and 13.00 Static.

Can it be runned with 108 Race gas?

I don't know, that's up there. David Vizard only mentions 9:1 DCR for race gas. I guess you'll have to experiment. Start with the highest octane you can find then go lower. Keep a sharp eye on the plugs. Don't ever let it go lean or get hot. I don't think there is any chance of using 93 octane.

So i went with buying a third gasket and shipped it to sweden even before i got my first here ,)

Now its a 043 gasket. Lowering DCR a bit.

And the only gas it Get is AG 108 nitrous race fuel.

Im also running an EFI on it so i hope ill newer lean it out.

Now its a DCR of 9,71 and 12.61 Static.

People always talking about running 12.5 slugs on 93 octane when using Alu Heads. And i got a pretty stout cam. Perhaps they cant run their old school machinery ;)

Godsend,

I don't put a lot of weight on dynamic compression ratios. Sure, you can run the numbers, but what does it really mean? It doesn't mean it will or won't run on a given fuel.

Sure, it will provide a qualitative number for comparison, but heck, you can guess that!

I would just build what you've got and step down the octane until you have a problem with your specific combination. There are some key variables that influence detonation that override your intake valve closing timing event :rolleyes: like weight, gear, and altitude. There is also a lot of variability in what the actual octane of 93 fuel is also.

I'm sure I'm on the upper end of what's acceptable for 93 octane, and I'm going to throw in a BUNCH of nitrous on top at the PGD's and we'll see what happens.

Will someone calculate my DCR for me with a few hundred of nitrous? LOL just kidding.

David Vizard only recommends 9:1 on race gas? I wonder how much DCR a 15:1 CR static engine with 2 foggers has? They are pretty common.