OS muffler

Has anyone try a os muffler off the 21xm vII outboard motor on a os max-21xm outboard and does it give you more speed . Thanks for your input .

I know you can not do that IMPBA i was just going to just play in my back yard pond with it just did not want to go buy one if it did not work .

you probably can if you swap the head too!!!!

The muffler from a V2 will make a V1 motor faster. Been there tried that.

It would be great if we could swap parts within class and manufacturers. If it comes up for a vote, I for one and a lot of others will vote to pass it. However, this subject can not be discussed on this forum without causing a huge crap and urination battle and always ends up accomplishing absolutely nothing. Same people...same fight every time.

I am surprised just you mentioning it hasn't brought out the keyboard campaigners and peanut gallery. If I were you, I would just experiment with the idea at your home pond and see what works for you and maybe one day, maybe some day soon, you will be able vote on the rule to have that changed.

What ever the majority wants is how it will be in the end. Some will like it and some won't. Just like now. Some like the rule as it stands now and some don't. If it gets changed some will quit over it (or at least threaten to) and others will join because of it. I have learned over the years that I could get up tomorrow morning and start throwing one hundred dollar bills off my roof top and somebody will be mad at me because they had to bend over and pick theirs up off the ground. You just can't make everybody happy.

What is important? Having fun running your model boat. When you come to a sanctioned IMPBA race, you have to follow the rules that are in place no matter what. Right now the "If I can't see it, it's okay to do it" rule is in place.

-Carl

Carl,

Just let me know when you are going up on your roof next?

I could use a few extra Franklin's, and I will bend over and not say a word.

What you said is very true.

Enjoy Testing The Thor,

Mark Sholund

My testing was different to what has been said above. Fitted the first style muffler to a V2, switched props and saw a gain on the Stalker.

Ditto with Mr Duggan

Tim_Duggan said:

My testing was different to what has been said above. Fitted the first style muffler to a V2, switched props and saw a gain on the Stalker.

Click to expand...

So just to be clear a V1 is a water cooled muffler without the spacer and the V2 is the aircooled muffler with the spacer?

bzubee said:

Tim_Duggan said:

My testing was different to what has been said above. Fitted the first style muffler to a V2, switched props and saw a gain on the Stalker.

Click to expand...

So just to be clear a V1 is a water cooled muffler without the spacer and the V2 is the aircooled muffler with the spacer?

Click to expand...

Yes Bill, you are "clear."

Jerry

A regular header and your choice of tuned pipe will cost a little more but give you more power than either of the OS pipes. As was stated just getting the prop correct is your first step to performance.

Mic

On my boat with the V1 muffler I have to go 1/4 turn leaner and its down 2 - 3 mph. V2 muffler 1/4 richer and 2- 3 mph faster. Switching heads made no difference

however my water cooled head was restricted.

There is More RPM in the V2 Muffler. I have tested back to back to back to back and the same result was repeated every time.

fyi Most guys over prop their OS Outboards. I run a cut down 40x53 with a lot of back cut and less than stock pitch

Jim,

Reduce the propeller diameter to 38 mm and keep the trailing edge cup to 3.21" or less

on any O.S. Outboard engine. You will hear the pipe work much better no matter what

version. We have had the water cooled motor faster than the air cooled motor in recent

test results.

Have Fun,

Mark Sholund

Mine are round 37.8 - 38.2 mm dia

and vary from 3.0 -3.3 I have been mainly playing with LE pitch since I found what my setup likes

I can't imagine bolting on the V1 muffler and going slower. just can't see it on mine at all but then again

I am a long ways from Box Stock internally

Could also be that you guys are going much faster ? . I have nothing to compare to apart from the Stalker Pro. My best speeds have been in the

56 - 57 mph range with the boat on the looser side and 54 - 55 mph locked down

I have been absent from IMPBA 15 years. Hello I am Kevin Burns question IMPBA don't have a modified B Tunnel class? Every time I raced my Tunnel before it had a tuned pipe. Am I missing something here?

The muffler on the version 2 OS Max OB is the same as the 1st version except the addition of the center section, just order the center section. The center section is how to tune the muffler. it has very thin walls easy to cut and shorten.

Someone in this thread said something about the 1st gen muffler being water cooled? Where is the water cooling on the 1st generation OS Max outboard muffler? There is a fitting for tank pressure, a fitting for lubrication to the aft lower unit, another fitting for the lubrication of the top lower unit. I do not see any place water is cooling the muffler. Am I missing something?

One other thing to increase the pressure wave that throws un burnt fuel back into the engine before the piston closes is to plug off one of the mufflers exhaust ports/stingers at the very rear of muffler. This we used to do a similar thing to the tuned pipe stingers, we would put a tube inside the stinger to reduce the ID of the stinger to increase pressure inside the tuned pipe.