Year end build

[Red97]

Have you run other 359 hybrids on the dyno?

No, this was the first on the dyno. Not had any ported 359/357 on the dyno yet.

 

[davidwyby]

No, this was the first on the dyno. Not had any ported 359/357 on the dyno yet.

I got 3 or 4 that need dyno’d…

 

[Maintenance Chief]

I think the carburetor is holding you back on Horsepower.
Just my opinion ( so take it for what it is), could be the intake is too smooth also, as in your getting droplets instead of vapor in the fuel charge.
Got any regular 272s data from the dyno?

 

[Red97]

I got 3 or 4 that need dyno’d…

Send em in...

I think the carburetor is holding you back on Horsepower.
Just my opinion ( so take it for what it is), could be the intake is too smooth also, as in your getting droplets instead of vapor in the fuel charge.
Got any regular 272s data from the dyno?

Could be the carb for sure. I bet it would like more. I'll have to see what can swap in sometime.

Never had a 272 on the dyno.

 

[Maintenance Chief]

Send em in...



Could be the carb for sure. I bet it would like more. I'll have to see what can swap in sometime.

Never had a 272 on the dyno.

I mean honestly looking at the curves ,that looks exactly like the type of saw I like to use ,wide band of power a plenty of torque.
I absolutely hate peeky saws that constantly bog and hunt for the magical power rpm .

 

[davidwyby]

Send em in...



Could be the carb for sure. I bet it would like more. I'll have to see what can swap in sometime.

Never had a 272 on the dyno.

Me n Kevin are workin on a 272

 

[Maintenance Chief]

Me n Kevin are workin on a 272

Cool , I have a 625 Jonsered that has an OEM top end I got from Bobs retirement sale. I'll look forward to your advice.

 

[davidwyby]

Cool , I have a 625 Jonsered that has an OEM top end I got from Bobs retirement sale. I'll look forward to your advice.

Ima build it, he’s gonna make the holes bigger. I bet @Onan18 has a build thread for that chassis.

 

[Red97]

Me n Kevin are workin on a 272

Send it lol

 

[huskihl]

No, this was the first on the dyno. Not had any ported 359/357 on the dyno yet.

1 357 at least. Tim’s

 

[Red97]

1 357 at least. Tim’s

That is correct. But I want to say that was back in the first round of dyno stuff. Before the new system that saves the runs lol

 

[huskihl]

That is correct. But I want to say that was back in the first round of dyno stuff. Before the new system that saves the runs lol

Yep could’ve been

 

[farminkarman]

1 357 at least. Tim’s

Any recollection as to what that 357 put down Kevin?

 

[huskihl]

Any recollection as to what that 357 put down Kevin?

I don’t. I just remember it being flat-ish and not rounded up high.

 

[pbillyi69]

i would very much like to know what a ported 357 puts up for numbers. more so i wonder what the one that scott ported for me puts down.

 

[Woodpecker]

That is correct. But I want to say that was back in the first round of dyno stuff. Before the new system that saves the runs lol

Yeah it was the first gen unit.

 

[Wolverine]

i would very much like to know what a ported 357 puts up for numbers. more so i wonder what the one that scott ported for me puts down.

 

[drf256]

Awesome thread. @Red97, you do super cool stuff.



Do you think an OEM cylinder would make a difference?




I wonder how much affect the 359 case has on performance. Would more case volume be helpful?
Chainsaw Jim extended the transfer lowers on his down to the case feeds. That had to add a lot of case volume.

I’m working on a 359/272 hybrid and was considering going the other way: filling the 359 case feeds with epoxy. Not really because of volume, just because they create a dead space. But it does reduce case volume. Do you think that will be a mistake?

I think it’s a mistake.

Tight case-More Vacuum/Compression. So it’s gonna pull more charge in and spit more back. There’s no reed valve.

It’s like when guys make full circle cranks. To the best of my knowledge they reduce intake duration and powercurve gets shifted up in the rpm range.

I think he needs more carb too, but Joe does monster 590/52mm 046 Hybrids that do great with the stock modded 590 carb (unless I am mistaken).

I also hate AM jugs. There is a finesse in the OEM transfer tunnels that’s not always readily apparent.

 

[Red97]

Joe,

I am wondering about case volume mismatch. Have you considered adding some JB weld to the intake floor? Easily reversible and you have that awesome Dyno.

My bet is that the 272 cylinder can’t fill. Very tight cases need less intake duration.

Hmm less intake and more case compression? Guess it would be easy to try. Fill it up to 70* and see how it responds.

I do believe it has some sort of carb issue. I'll have to try the one from my 357 to see if any change.

 

[davidwyby]

i would very much like to know what a ported 357 puts up for numbers. more so i wonder what the one that scott ported for me puts down.

A little less than a 6100