Another chainsaw dyno...

[Red97]

The 2 top performing hybrid's today.

Red Hp, Blue Tq

Yellow Hp, Green Tq

 

[jacob j.]

View attachment 242280
The 2 top performing hybrid's today.

Red Hp, Blue Tq

Yellow Hp, Green Tq

54mm vs. 52mm?

 

[MustangMike]

I was going to ask if you knew why one was so much stronger in the higher RPM range???

 

[Red97]

54mm vs. 52mm?

Yes, one of each.

I was going to ask if you knew why one was so much stronger in the higher RPM range???

Yes.

 

[MustangMike]

And … which one did better??? Did the larger bore run out of case capacity fuel before the smaller bore???

It does seem a bit stronger in the low end.

 

[Red97]

Yellow/green are the same saw from above.

Red/blue is a 3rd hybrid build.


Next week I'll try to get that pile of saws on the dyno.

Interested to hear some thoughts.

 

[mdavlee]

View attachment 242291
Yellow/green are the same saw from above.

Red/blue is a 3rd hybrid build.


Next week I'll try to get that pile of saws on the dyno.

Interested to hear some thoughts.

52mm made more peak HP but a sharper curve?

 

[Bigmac]

View attachment 242291
Yellow/green are the same saw from above.

Red/blue is a 3rd hybrid build.


Next week I'll try to get that pile of saws on the dyno.

Interested to hear some thoughts.

I would be cool to see what jug won, I know you had high hopes for one...
That one jug peaked hard at 10.5k that would be a runner!

 

[Bigmac]

And … which one did better??? Did the larger bore run out of case capacity fuel before the smaller bore???

It does seem a bit stronger in the low end.

Usually a smaller case area increases rpm, like stuffers on the Mac’s

 

[Bigmac]

It’s am excited to see what muffler worked best too! And the 440 big bore vs 460 52mm.

 

[Red97]

It’s am excited to see what muffler worked best too! And the 440 big bore vs 460 52mm.

I will say 440 big bore is not the way to go.

Just couldn't hang,

Also let you know
All 4 (3 with graph) saws are within 3* on all the port time.

Only 440/044 i use from here on will be 50mm. And can normally find one cheap.

Would really like to find a non d chamber...

 

[TreeLife]

This is very interesting. So the smaller bore saw made better power? Which lines represent what saw?

 

[MustangMike]

I think all of the 044/440 cylinders were D chamber, only the 046/460s had hemi chambers.

I am familiar with the smaller case acting like case stuffers, but I'm also familiar with a lot of big bore saws not living up to expectations. Sometimes a little more is good, but too much is too much!

While 440/460 hybrids often run well, using a 460 big bore cylinder on one usually results in a flop and big bore 460 and 660 saws rarely are stronger than their standard bore counterparts.

 

[Bigmac]

I think all of the 044/440 cylinders were D chamber, only the 046/460s had hemi chambers.

I am familiar with the smaller case acting like case stuffers, but I'm also familiar with a lot of big bore saws not living up to expectations. Sometimes a little more is good, but too much is too much!

While 440/460 hybrids often run well, using a 460 big bore cylinder on one usually results in a flop and big bore 460 and 660 saws rarely are stronger than their standard bore counterparts.

Mike I feel that is mainly bad quality castings and smaller transfer area, along with a piston skirt that is the same width as stock, limiting intake and exhaust area, Stihl’s have narrow pistons to start with. I don’t think is because of case volume. But have been wrong before! Lol

the interesting thing is these are all aftermarket casting and are running quite well, he has a lot of work into them to make them runners! If they were left alone I am sure they would be disappointing

 

[Philbert]

The 2 top performing hybrid's today.
Red Hp, Blue Tq
Yellow Hp, Green Tq

Looks like a map of Lake Superior to me!

Philbert

 

[Red97]

This is very interesting. So the smaller bore saw made better power? Which lines represent what saw?

79,86,79 the power in those 3 graphs

I think all of the 044/440 cylinders were D chamber, only the 046/460s had hemi chambers.

I am familiar with the smaller case acting like case stuffers, but I'm also familiar with a lot of big bore saws not living up to expectations. Sometimes a little more is good, but too much is too much!

While 440/460 hybrids often run well, using a 460 big bore cylinder on one usually results in a flop and big bore 460 and 660 saws rarely are stronger than their standard bore counterparts.

These are 5,7,9 mm bore over stock

Mike I feel that is mainly bad quality castings and smaller transfer area, along with a piston skirt that is the same width as stock, limiting intake and exhaust area, Stihl’s have narrow pistons to start with. I don’t think is because of case volume. But have been wrong before! Lol

the interesting thing is these are all aftermarket casting and are running quite well, he has a lot of work into them to make them runners! If they were left alone I am sure they would be disappointing

The saw with the most power has the smallest exhaust port.

Looks like a map of Lake Superior to me!

Philbert

It does.

 

[Terry Syd]

79,86,79 the power in those 3 graphs

I don't understand that quote, are you referring to intake timing?

 

[mdavlee]

I don't understand that quote, are you referring to intake timing?

CC

 

[Terry Syd]

OK, displacement. Crikey, this site is getting more obtuse every week. First it was BGD - at least I understand GFY.

 

[Bigmac]

What muffler was stronger? Pipe or deflector?