Let's Talk Transfers

[tree monkey]

I feel if you need to add fingers to a work saw that your transfer aren't right.

 

[jmssaws]

Have you tried after mains?

If I put fingers in this cylinder I'm working on they will be after the mains.

 

[jmssaws]

I feel if you need to add fingers to a work saw that your transfer aren't right.

I believe you are correct, I've seen fingers gain and not change a thing.

They did nothing to my 066 but it ran as good as I can make it before so the transfers were right,very little blow down for a 066 I thought but I was wrong.

 

[czar800]

What about piston Windows? The Charge starts out exiting through the piston windows in to the lowers. The piston windows are the first restriction the mix hits.

I'm totally just thinking out loud, but the mix is restricted at the piston Windows then kind of dumped into the lower transfers which are wider and more open than the piston Windows. Then it's redirected and compressed more before the upper transfers/fingers opens.
I built a 024 and opened the piston Windows. I was thinking at that time the benefit would be the windows were open to eliminate the first restriction.

I was thinking let the velocity increase come at the last point which is the upper transfers shape and size.
Think about it like a garden hose leave the end open the water doesn't go very far but put a small nozzle on the end and at It will spray far.
You would not put a nozzle internally mid hose and then expect the water to spray out of the end as if it was placed on the end.

Another benefit I thought about when I did this was being able to shed a lot of weight off of the piston.

I could be all wrong... But the saw runs great!! It seems to hang with the 026 I build.. I can't explain why??

 

[czar800]

I forgot to mention on that 024 I widened the transfer so far towards the intake I have to run to piston 180°.

 

[Barneyrb]

Has anyone ever tried to put a "peak" in the top of the transfer. I built a 028 and instead of a flat roof I put a peak in the center of the port and then tapered down to the sides. That saw run damn good but I haven't built another one like it.

My thinking was it started opening where I wanted it but retained a higher velocity for just a few degrees before the port was fully open. Maybe I'm wrong

 

[czar800]

Maybe this isn't the right thread to discuss this, but why it that if you run 10 of the same model saws one will just seems happier than others??? That's my 024 it's just a happy little saw!

 

[jmssaws]

Maybe this isn't the right thread to discuss this, but why it that if you run 10 of the same model saws one will just seems happier than others??? That's my 024 it's just a happy little saw!

I've ported hundreds of 066/660's and there are saws that I can remember.

 

[awol]

fingers should be looked at as boost ports, angled up and open last.

This is very true. I think the mains need to be responsible for shaping and delivering the "main" charge, while the fingers augment this delivery.

 

[paragonbuilder]

fingers should be looked at as boost ports, angled up and open last.

So this is why on the quad jugs the mains open first and flat, then the secondaries open aimed at the intake and toward the roof?


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[drf256]

So this is why on the quad jugs the mains open first and flat, then the secondaries open aimed at the intake and toward the roof?


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They don't exactly do that Dan.

On the ones I've seen, they open Exhaust main lip first, intake secondary lip second, then both uppers start to fully open. They look like a "V" if the shape were to be exaggerated with the cylinder upright. A longer leg on the exhaust side of the "V". The mains open at a flat angle and the secondaries angled up, like you've said.

 

[paragonbuilder]

They don't exactly do that Dan.

On the ones I've seen, they open Exhaust main lip first, intake secondary lip second, then both uppers start to fully open. They look like a "V" if the shape were to be exaggerated with the cylinder upright. A longer leg on the exhaust side of the "V". The mains open at a flat angle and the secondaries angled up, like you've said.

Ok. I've got to go look at some jugs again...[emoji23]


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[drf256]

I get the true boost port theory, but after the mains open, what pressure is there to drive any flow in the tiny cross sectional area of a finger port?

 

[Moparmyway]

I get the true boost port theory, but after the mains open, what pressure is there to drive any flow in the tiny cross sectional area of a finger port?

The piston is still pushing mix out of the crankcase

 

[jmssaws]

I think once the mains open there's nothing left for a finger

 

[tree monkey]

how much case pressure do you guys think a saw has?

it's just a few pounds, maybe 10. any more and the impulse hose and pump diaphragm won't hold up.

velocity means very little, volume mean more, direction is key.

 

[super3]

I think once the mains open there's nothing left for a finger

Still have 55°+ of piston traveling down.

 

[jmssaws]

Still have 55°+ of piston traveling down.

To do what though? When a port cracks open it shoots it's wad.

 

[tree monkey]

it happens a lot slower then you think

 

[jmssaws]

how much case pressure do you guys think a saw has?

it's just a few pounds, maybe 10. any more and the impulse hose and pump diaphragm won't hold up.

velocity means very little, volume mean more, direction is key.

I think 10 is optimistic.

Velocity is direction that's why u lose when velocity is lost.