Better Fuel Burn Rate? Is it worth it?

[mrtopgun]

Ok the product is made by Dynojet. They build onboard computers for motorcycles and Skis so now they Build them for Boats. Basically I have used them on bikes since they were introduced, work great. The box is between the computer and motor.The box is programmable, fuel and timing. What they have found is mercruiser sets the motor rich by around 30% So Has anyone heard of it? Using it? Basically it would run off an O2 sensor, which would get installed and calculate in real time. So now you can see a lot of more problems before they get bigger. Also this only works on Fuel Injected engines.

http://www.dynojetcmd.com/cmd_marine_details.aspx

 

[jaywoodz]

Ok the product is made by Dynojet. They build onboard computers for motorcycles and Skis so now they Build them for Boats. Basically I have used them on bikes since they were introduced, work great. The box is between the computer and motor.The box is programmable, fuel and timing. What they have found is mercruiser sets the motor rich by around 30% So Has anyone heard of it? Using it? Basically it would run off an O2 sensor, which would get installed and calculate in real time. So now you can see a lot of more problems before they get bigger. Also this only works on Fuel Injected engines.

http://www.dynojetcmd.com/cmd_marine_details.aspx

I would love to know if this really works. I, too, would love to see if anyone has used it.

 

[PMC]

Sounds like snake oil to me. Boats are run hard and at a constant rpm. I just don't see a 30% increase in efficiency, especially that merc is over looking it

 

[GJarrett]

It should work in theory, if MerCruiser tunes its engines too rich across the rpm band and there is room to lean it out in cruise without overheating the engine or causing knock. I'm curious to know what air/fuel ratio Mercruisers are programmed to run on from the factory. Does anyone know? I notice the product claimed a 28% improvement at cruise - not wide open. If it works off closed/open loop technology with the O2 sensor and reverts to full rich mode under full power so the engine does not overheat or knock, it just might work. That would mean that MerCruiser must keep the a/f ratio rich all the way through the throttle setting though.

I run a device on my Harley that installs between the O2 sensors and the computer that fools the engine into enrichening the a/f ratio to help cool the air cooled engine and give it a little more power. It costs me a couple mpg but I figure it's worth that for a cooler engine in the summer. I would think you could reverse the process to give the engine a few more mpg at the expense of a leaner air/fuel ratio (which is sort of what this thing sounds like to me).

 

[mrtopgun]

Sounds like snake oil to me. Boats are run hard and at a constant rpm. I just don't see a 30% increase in efficiency, especially that merc is over looking it

I have seen it on a Bike. You calibrate the fuel at whatever rpm and throttle with the AFR. The afr is around 10.5 on the boats. You would want to be around 13.4 with the afr. Does the new 8.2 mercs have a 02 sensor? Ask any engine builder, its set up very rich on fuel.

Think about a warranty its made to either protect a manufacture or the end user. I would say that is why the motors are set up rich. Cant blow them up. Horrible fuel burn rate, doesnt cost them anything once it leaves the shipping dock. Just my thoughts.

 

[mrtopgun]

It should work in theory, if Mercruiser tunes its engines too rich across the rpm band and there is room to lean it out in cruise without overheating the engine or causing knock. I'm curious to know what air/fuel ratio Mercruisers are programmed to run on from the factory. Does anyone know? I notice the product claimed a 28% improvement at cruise - not wide open. If it works off closed/open loop technology with the O2 sensor and reverts to full rich mode under full power so the engine does not overheat or knock, it just might work. That would mean that MerCruiser must keep the a/f ration rich all the way through the throttle setting though.

I run a device on my Harley that installs between the O2 sensors and the computer that fools the engine into enrichening the air/fuel ratio to help cool the air cooled engine and give it a little more power. It costs me a couple mpg but I figure it's worth that for a cooler engine. I would think you could reverse the process to give the engine a few more mpg at the expense of a leaner air/fuel ratio (which is sort of what this thing sounds like to me).

I was told they were seeing around 10.4-10-6 on afr. 13.4 is optimum.

 

[Chris Nowell]

This may sound really old fashioned but I tend to leave things the way they come from the factory unless there are known issues. I've been boating for many decades with the Mercruiser 6 & 8 cylinder set ups and have never had any problems that were out of the ordinary. I think most of these rigs run a little rich from the factory but there must be a reason the engineers make them do this. I know, I'm old. The guys at work keep tryin' to talk me into "chipping" my truck for better fuel economy and performance too. I just don't trust these aftermarket gadgets to do what they're supposed to without creating some kinda adverse effect.

 

[GJarrett]

I was told they were seeing around 10.4-10-6 on afr. 13.4 is optimum.

That's really rich. If that's true then I could absolutely see how this thing could work. However I would have a hard time paying $599 for an item that I know is basically made from $30 worth of Radio Shack parts LOL.

 

[mrtopgun]

My thoughts on the fuel is that after 2-3 years its paid for. But I can see it as a tool to see the performance of the motor in real time. Afr tells alot in real time. AFR is off you ask why? Sensor bad? Oil pressure is the indicator after it has a problem. I think its just another tool for tuning and maintenance.