X'es and R's

[PaulR]

Is it a waste of money to run 91 in my new 300 ProXS, I don't run it for performance, I was told all the additives in 87 is harder on rubber hoses, etc. I run 91 in all my 2-stroke stuff from my chainsaw to my 2.5 drag.

[Brad Zastrow]

i DID A dbr hood and the tune did not get close to a 300X

Paul is dead on with his post. The 300X is powerful reliable engine. I did not gain much speed switching to the R. However, the 300R does everything so much better. I am getting double the gas mileage and only need 87 octane compared to the X needing 91. Fuel savings are big. The 300R feels a little quicker with the extra torque. No stalling with R like the X. No smoke with the R which is a big deal when you have three two strokes blowing smoke out the back. In the no wake zones it would smell. The R weighs only 25 lbs more than the X. I will never own a 2 stroke again.

[skialot2]

Is it a waste of money to run 91 in my new 300 ProXS, I don't run it for performance, I was told all the additives in 87 is harder on rubber hoses, etc. I run 91 in all my 2-stroke stuff from my chainsaw to my 2.5 drag.

It's the ethanol in gas that is hard on the rubber parts of the fuel system. However, all engines manufacturers today use materials designed to handle today's corrosive fuels. Use whatever fuel the manufacturer recommends.

[hellbents-10]

are you going to program the ECU yourself?

Well yes as that is what I do for a living. I run 2 chassis dynos, and one engine dyno here. Motec is pretty popular on the long travel buggies around here.

[Wild Bill]

I wonder if one of the self-learning efi's will work. then fine tune from there.

[Lake rat Skater]

I have not been that impressed with the "self-learning" piggyback systems. They have a place for sure but there is a sled shop that does Motec and Maxx ECU systems and it seems to be much more advanced and allow endless options. Some of the sleds offer rolling launch control. I think a 300r with a standalone system like a Motec could see some solids gains. I would think the more challenging or expensive part would be to establish the wire harness.

[Speed Jr.]

Motec already released a plug and play for the 300R. It was at a boat show in Australia last year. It's on the AU website.

[David]

Well yes as that is what I do for a living. I run 2 chassis dynos, and one engine dyno here. Motec is pretty popular on the long travel buggies around here.

I did that briefly in the 1980's working on propane engines for the Canadian market for an OEM. I was unable to parlay that into a long term career, but I did fine anyway. Cool job, so I am a bit envious.

At any rate, will you put the 300R on a dyno to program it?

[hellbents-10]

With all the data logging capability of the Motec the boat in the water will be my dyno. I think they have a good base to start with on it so it would be no big deal to go from there.

[David]

Does the 300R have an air fuel ratio sensor?

[hellbents-10]

I would be willing to bet it does, if not it would be getting one!

[JPEROG]

It has an oxygen sensor but has limitations to the correction factor it will provide. The 300R needs more compression to make the steam we are going after. Tune will be minimum without it. Bigger throttle body and different cam grind will also come into play. This process is well under way as we speak and there is a 15" version coming soon.

Joe

[mikej]

What were the results ? That is great info.

MDS

The 250XS combo was obviously the slowest at 98 mph and then goes up from there. I ran out of prop and on limiter at 109 mph for my 30' Spectre with the 300R's. Waiting on some larger props now so hopefully goes up from there. Not bad for a setup on an older boat and love having a warranty!

[sick_nick]

there is a 15" version coming soon.

Joe

heard that years ago in palatka...

[JPEROG]

The project never stopped but there have been other projects that pay WAY more then what a 15" midsection ever will. When you are only as good as your bottom line, you do what brings in "instant cash".

Joe