rev limiter when jumping type system??

larby · 13-10-2009, 06:06 PM

Hi all,

I'm sure I've touched on this idea before, was thinking about it all day today... I'm trying to think of everything i can to help keep my drive alive with the supercharger.

From what everyone has said, it seems the most damage is done by over revving and not matching re-entry revs to speed.

Is there any system in existance designed to limit the revs during 'air time', keeping them at the point they were at on leaving the water, until back in the water? I'm considering chatting to my old boss (a very good electrical engineer) about constructing such a system, but if it's already out there, or a totally useless idea, i could save myself a few bob!

Cheers, James

Paul E · 13-10-2009, 06:12 PM

It's called your right foot isn't it?

Techteam · 13-10-2009, 08:44 PM

The problem with what you describe is that when the boat jumps there is no load and therefore a lot of rev limiters miss the over rev. However, MSD make what they call the Marine Engine Protector which is specifically designed to get around the no load problem. Unfortunately it only works with their ignition system, although I would recommend that for your application too. $$$$$

larby · 13-10-2009, 10:31 PM

Well I'm already going to be running MSD, does their 'Marine engine protector' do what I'm asking then? (I'll look it up now!)
I was thinking about referencing it from either a tacho signal or water pressure via a dedicated pickup on the cavitation plate.

Cheers, James

larby · 13-10-2009, 10:32 PM

Quote:

Originally Posted by Paul E

It's called your right foot isn't it?

my right foot has a limited number of settings, and isn't always that accurate!!

larby · 13-10-2009, 10:35 PM

Hmm, yeah I've had a look at it now... Does what i want it to, but only limits to the specific revs you set it to. I'm hoping for something that holds revs at whatever they are at when you leave the water as I'm guessing having the revs too low could be just as damaging as too high?

James

Techteam · 14-10-2009, 02:58 PM

You would need to ask MSD but it should work closer to how you want it than you would imagine cause of how it works. If you read carefully how it limits ie misses cylinders then refires it next rotation the engine should maintain very close to the throttled rpm only limiting when essential because when the boat jumps things happen very quickly.

larby · 14-10-2009, 06:39 PM

This is true, I noticed on the MSD site this unit can actually be used on any motor even if it doesn't have MSD ignition.
I see what you mean about it having the right effect due to the jump happening quickly... If i set it to say 4k or 4.5k revs then i doubt it'd have time to limit the revs to that extent, could play around with it to get it right.
Cheers for that link...

James