Mastermind Meets The MS661 Again

[Mastermind]

Sup B'Rad?

 

[User Name Here]

That'll work for me! I was dreading either a 30 min drive or using ethanol gas. I guess I'm as bad as most others about over thinking stuff.

Randy - I meant to ask you the other day when you called but I was going about 3 directions at once and it slipped my mind.

Thanks guys!

 

[Ron660]

Bring it down ole buddy. Down South

Yes I remember when Chad used high and low on the dyno the 87 produced more power but Mustang is more interested in temperatures. Im thinkin on mtronics it will adjust for either and run the same temp but on a reg. Carb saw if not adjusted for it will make a difference?

Here's the dyno testing Chad did on my 660, 212 psi, with 92 and 110 octane. At 10500 and 11500 the 110 showed a slight HP advantage. At 9500 and 11000 the 92 showed an advantage (most of the rpm range the 92 showed an advantage). At 9000 and 10000 both were the same.
I've only conducted one octane test with my 660 with 93 and 110. The 110 was an average of 11.6% faster in dry 25" wood. Both were 4-stroking well at carb tune. I wouldn't disagree with someone if they said that 93 or 87 was faster in their saw compared to racing fuel. I would like to conduct more field tests myself.

 

[Mastermind]

Now that's what I'm looking for.....

 

[TK]

On my snowmobile I have a custom boost bottle, it's a tube that connects the intake boots, after carb and before cylinder. This will equalize pressure, but more importantly store atomized fuel mixture. Wonder if this could be used in a saw?

I think that's for linking two carbs on two cylinders, equalizing the two. I don't think you can do anything with that in a single carb/single cylinder situation. Those were also used only on reed valve setups if I remember correctly.

 

[Deets066]

Yes you are correct to equalize pressure and store atomized fuel. When you are running full throttle and let off there is fuel mix that is unburnt and blown backwards, this is why you get fuel/oil on the air filter. If you have a chamber to store that atomized fuel the next time you hit the throttle you have instant throttle response. But that is all you will gain throttle response, no hp

 

[Ron660]

Now that's what I'm looking for.....

View attachment 395178

200psi has to be better than 180....more torque? Any bridge ports planned for it?

 

[spencerpaving]

The suspense is killing me...he probably waiting for his heart to calm down...or looking for broken pieces in the dark! Lol

 

[MustangMike]

Ron, I think your graph confirms what Brad said, and I think it would be even closer if it was 87 & 93.

OK, I just cracked my owner's manual for the 362 C: "Use mid-grade unleaded gasoline with a minimum octane rating of 89 and no more than 10% ethanol content. Fuel with lower octane rating may increase engine temperatures. This, in turn, increased the risk of piston seizure and damage to the engine."

Keep in mind, all these recommendations are with the 50:1 mix ratio. Changing the mix ratio to 40 or 32 to 1 will also increase the octane because oil will not burn as fast as gas.

 

[Mastermind]

I just got home.

Took my lovely wife out for her birthday.

 

[Chris-PA]

View attachment 395166


Here's the dyno testing Chad did on my 660, 212 psi, with 92 and 110 octane. At 10500 and 11500 the 110 showed a slight HP advantage. At 9500 and 11000 the 92 showed an advantage (most of the rpm range the 92 showed an advantage). At 9000 and 10000 both were the same.
I've only conducted one octane test with my 660 with 93 and 110. The 110 was an average of 11.6% faster in dry 25" wood. Both were 4-stroking well at carb tune. I wouldn't disagree with someone if they said that 93 or 87 was faster in their saw compared to racing fuel. I would like to conduct more field tests myself.

Realistically, that graph tells me the two are virtually identical. I have no doubt that the differences between those two curves is several times less than the error/variation of the values - that is not a shot at Chad's dyno at all, rather there is always error in everything, and plenty of possible sources here.

 

[Mastermind]

We all know that gut feelings, how something sounds, etc, are poor indications of how something will really run......but this MS661 sounds freakin mean. My gut tells me that it's gonna be something really special.

 

[Deets066]

So is this a poor indication of how it's really goin to run

 

[Mastermind]

Who knows?

I just pulled the jug to check everything.......all is well.

We shall see tomorrow.

 

[treeslayer2003]

I just got home.

Took my lovely wife out for her birthday.

happy birthday to her she gets a spinning loop and a coffee......no cake lol.

 

[Mastermind]

Have you ran that 064 yet Mike?

 

[treeslayer2003]

yes sir but not falling yet. blocking 12" wood in the yard ain't a good test lol. it is sloppy here......freeze thaw, freeze thaw.......works slow.
it starts with one pull, can ya believe it? old bing still is good. that coil and fly wheel combo works well..... however i wonder if it still has the same timing........sure cranks easier lol.

 

[spencerpaving]

My gut feeling is telling me I have to go to the bathroom....

 

[Deets066]

Who knows?

I just pulled the jug to check everything.......all is well.

We shall see tomorrow.

This is the epoxied jug we are talkin bout correct?

 

[Mastermind]

Yes sir.