CMB 91 VAC

[Ian Inverarity]

It's probably also been said that raising exhausting timing or making the pipe shorter robs low end power too. And rightfully so, because it does....but we still raise and shorten!

Trading off low end torque for more power or higher RPM is fair enough, if that suits what people are trying to get. But if sub piston induction costs torque, are there corresponding benefits or is it just a loss?

 

[Tom Foley]

I raised my Exh timing , went to a larger volume pipe , head clearance at a generous .015" with stock button , 60 % fuel and opened up the drum housing exit into the engine and the engines will accelerate from a crawl with pipes at 11 - 1/2 " . These are great engines for ease of tuning and overall performance . The OD - 99 plugs have been the best so far for my boat anyway .

 

[dwilfong]

What's wrong with sub piston induction?

Have always bin told that it robs low end power.

Never tried to run one with it so can only go with what I have bin told.

So come on spreed some wisdom for us. Whats the scoop.

David

It's probably also been said that raising exhausting timing or making the pipe shorter robs low end power too. And rightfully so, because it does....but we still raise and shorten!

Got it. losing some thing you don't need is not a loss at all.

David

 

[Anders_Martinelle]

Tom, how is the bearings??

Have you put the gun at your boat and checked the speed??

How much did you raise them?

Anders

 

[Tom Foley]

Tom, how is the bearings??

Have you put the gun at your boat and checked the speed??

How much did you raise them?

Anders

Hi buddy , heading to the garage to put the bearings in after I finish this beer while on IW !! I will check the timing in a few and report back .

 

[Tom Foley]

Looks like 190 - 191 deg of duration on my exhaust timing .

 

[Glenn Gates]

I raised my Exh timing , went to a larger volume pipe , head clearance at a generous .015" with stock button , 60 % fuel and opened up the drum housing exit into the engine and the engines will accelerate from a crawl with pipes at 11 - 1/2 " . These are great engines for ease of tuning and overall performance . The OD - 99 plugs have been the best so far for my boat anyway .

What pipe are you running Tom?Thanks,

Glenn

 

[moe1117]

wow!!!!! every one I cant understand All the comments HOW ABOUT WHAT THAT (FOUR LETTERS) ARE YOU DOING RUNNING A BIG (THREE LETTERS) TWIN WITH TWO GUYS STILL IN THE RETRIVE BOAT IT'S RIGHT THERE ON VIDEO YOU SHOULD BE BANNED!!!!!!!!!!!!