Let's Talk Transfers

[Deets066]

Transfers are where a lot of the gains are IMO. Too big and the saw seems to get lazy. But where it gets tricky for me is if that is true, then adding fingers shouldn't help. But they do, so is directional flow more important than velocity?

 

[Moparmyway]

Transfers are where a lot of the gains are IMO. Too big and the saw seems to get lazy. But where it gets tricky for me is if that is true, then adding fingers shouldn't help. But they do, so is directional flow more important than velocity?

I think they are both important, and relative to esch other.

I heard about a saw that lost its edge with the addition of fingers, but gained it back when the runners were narrowed with epoxy

 

[Mastermind]

So is it considered best to hit the chamber with fresh charge then flush from the intake side 2nd, or open the intake side then charge the rest of the chamber?

Tricky question to answer.

I like to open them all at the same time in most cases. If I do open one before the other, I open the mains first.

 

[paragonbuilder]

I get confused with this. Mains open first, on exhaust side. Then secondary's on intake side.
But when you add fingers they seem to always be on the intake side and open first.
Anyone care to explain?


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[smokey7]

Proper sized carb, all casting flash removed, exhuste raised half the gasket transfers raised gasket thickness, exhuste widened and shaped, intake shaped, squish around .016-.025 tune it and run it. Always been very happy with that setup.

 

[Mastermind]

I get confused with this. Mains open first, on exhaust side. Then secondary's on intake side.
But when you add fingers they seem to always be on the intake side and open first.
Anyone care to explain?


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I'll take a stab at it.

You are talking about two completely different designs. A four port engine rarely ever gets fingers......

The two port engines have big open transfer passages that are sort of slow flowing. Adding fingers, and opening them a few degrees before helps purge the exhaust.......or so I've been led to believe. I'm actually rethinking the whole process.....

 

[Moparmyway]

Proper sized carb, all casting flash removed, exhuste raised half the gasket transfers raised gasket thickness, exhuste widened and shaped, intake shaped, squish around .016-.025 tune it and run it. Always been very happy with that setup.

Thats a good start, but I got machines to play with, so I am going to spin something in my lathe, and grind somethings on my bench, might as well be a saw

 

[Keith Gandy]

I'll take a stab at it.

You are talking about two completely different designs. A four port engine rarely ever gets fingers......

The two port engines have big open transfer passages that are sort of slow flowing. Adding fingers, and opening them a few degrees before helps purge the exhaust.......or so I've been led to believe. I'm actually rethinking the whole process.....

Im interested in the rethought process

 

[Deets066]

I think they are both important, and relative to esch other.

I heard about a saw that lost its edge with the addition of fingers, but gained it back when the runners were narrowed with epoxy

I think part of the problem with that saw was that there wasn't enough case capacity for the amount of transfer I had.

Sure a hybrid makes more velocity, but it loses it fast when you add a lot of transfer area

 

[paragonbuilder]

Im interested in the rethought process

I am as well!


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[Mastermind]

I read a post by Terry in OZ.....

He said that boost ports on some engines opened after the mains. The idea was to get under the main charge and lift it into the chamber.

Really got my head to running some ideas....

 

[Keith Gandy]

I am as well!


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I see the fingers as purging and adding flow. On a quad the secondary sidewall can be angled more toward the intake but they r still lagging in time to what fingers accomplish IMO. Maybe on quads the secondary could crack alil early progessively and simulate fingers?

 

[Keith Gandy]

I read a post by Terry in OZ.....

He said that boost ports on some engines opened after the mains. The idea was to get under the main charge and lift it into the chamber.

Really got my head to running some ideas....

So r u contemplating lagging fingers behind the mains?

 

[drf256]

You have your terminology reversed Al. The mains are closest to the exhaust port, secondaries next to the intake.

Thaaks for the clarification. I havent explored a quad yet

 

[drf256]

Great discussion. Lets keep it going

 

[Mastermind]

So r u contemplating lagging fingers behind the mains?

You know I gotta try it.

 

[Keith Gandy]

You know I gotta try it.

Well its reversible at least and worth a shot !! That will be interesting. 2° or needs alil more time before pushing?

 

[Moparmyway]

I think part of the problem with that saw was that there wasn't enough case capacity for the amount of transfer I had.

Sure a hybrid makes more velocity, but it loses it fast when you add a lot of transfer area

Do you think you would have had the same results if you added crank stuffers or found a different way to lose case capacity ?

 

[Mastermind]

I'm building a new jug for the pipe saw.......I'll do a thread.

 

[Keith Gandy]

Do you think you would have had the same results if you added crank stuffers or found a different way to lose case capacity ?

I like that idea Deets was using in the transfers