Part Three: The Transfer Ports

[Terry Syd]

The stratos are a superior intake system. When you take the intake port and then add in the strato ports, you will often find that the area of the 'intake' is more than 100% of the bore diameter. Not only that, but with the multiple ports they can open immediately as the multiple ports do not require a curvature to accommodate the piston skirt from hanging up. In other words, you can get 100%+ bore diameter intake that is INSTANT opening - that gives great time/area for intake flow.

 

[ChipsFlyin]

@Mastermind Thank you for compiling all of this information along with other builders!!! These threads are absolutely great!!!

There's so much info to review... I do have one question. I found another one of your threads on a 038 to 038mag build.
Can you explain what you did to the transfers and rational? I'm assuming better flow from or to the case ( mixed up with the cylinder upside down.) Thanks!

Before

After

 

[Mastermind]

@Mastermind Thank you for compiling all of this information along with other builders!!! These threads are absolutely great!!!

There's so much info to review... I do have one question. I found another one of your threads on a 038 to 038mag build.
Can you explain what you did to the transfers and rational? I'm assuming better flow from or to the case ( mixed up with the cylinder upside down.) Thanks!

Before

After

That's an old picture. LOL

I don't take as much out of the lowers as I did then.

 

[ChipsFlyin]

That's an old picture. LOL

I don't take as much out of the lowers as I did then.

Thanks! Old stuff is good stuff too.

 

[EvilRoySlade]

It’s been a while since I read through this but has enough been learned to bring up delayed scavenging? @tree monkey has figured out how to take advantage of it , has anyone else (publicly on the forum I guess)? The basic concept is simple, open the transfers just a hair early based really on top and bottom pressures, a tiny shot of combustion charge into transfers. Twofold reward here, tiny bump in crankcase pressure and using spent fuel to flush out the chamber. I have a multitude of questions about this but will wait.

 

[XP_Slinger]

It’s been a while since I read through this but has enough been learned to bring up delayed scavenging? @tree monkey has figured out how to take advantage of it , has anyone else (publicly on the forum I guess)? The basic concept is simple, open the transfers just a hair early based really on top and bottom pressures, a tiny shot of combustion charge into transfers. Twofold reward here, tiny bump in crankcase pressure and using spent fuel to flush out the chamber. I have a multitude of questions about this but will wait.

No expert here. But in my mind (theory) this could be accomplished through staggered transfer opening. The real trick that these pros know is exactly when to open them. I’ll wait with ya. Dot dot dot

 

[CJ Brown]

It's an interesting concept and I'm sure not a new one. I can see some problems to go along with the benefits. One is delayed transfer flow through the transfer(s) that opened early. Another is dirty hot gases flowing past one section of the ring(s) repeatedly. And third is heating of the transfer tunnel when you would like to keep it as cool as possible. All these problems could be avoided by drilling a port/hole through the cylinder wall and running an external transfer tube to the bottom of the crankcase. However, now the bearings would be exposed to the dirty hot gasses and I would expect that would reduce their life expectancy. In a play saw this might not be an issue.

Now who's going to try it and post the results?

 

[David Young]

I have no idea.

How do I make this my signature.

Can't believe no one picked up on this one yet...

 

[Lightning Performance]

How do I make this my signature.

Can't believe no one picked up on this one yet...

Rep

 

[Mastermind]

How do I make this my signature.

Can't believe no one picked up on this one yet...

I have no idea.

 

[huskihl]

How do I make this my signature.

Can't believe no one picked up on this one yet...

Quote his post, highlight the post including the quotes and brackets, copy it, click on your name to the left of the inbox, click signature, and paste it

 

[EvilRoySlade]

Quote his post, highlight the post including the quotes and brackets, click on your name to the left of the inbox, click signature, and paste it

Enabler.

 

[MustangMike]

So, are mufflers and baffles next??? I'll bet that would get real heated, especially since I'm in the camp that believes that more opening (or less baffle) is not always good.

Although a muffler mod has to be the easiest way to get initial improvements in performance, likely with some saws (not all, depends on lot of other factors) may reach a point of diminishing returns.

So if you open up your muffler so your saw can run 18,000 PRM, but your saw only does 16,000 RPM, are you giving up some low end and not getting any additional high end? I believe it happens sometimes, and is rarely identified.

 

[huskihl]

So, are mufflers and baffles next??? I'll bet that would get real heated, especially since I'm in the camp that believes that more opening (or less baffle) is not always good.

Although a muffler mod has to be the easiest way to get initial improvements in performance, likely with some saws (not all, depends on lot of other factors) may reach a point of diminishing returns.

So if you open up your muffler so your saw can run 18,000 PRM, but your saw only does 16,000 RPM, are you giving up some low end and not getting any additional high end? I believe it happens sometimes, and is rarely identified.

Gotta keep up around here...

http://opeforum.com/threads/part-six-the-exhaust-system.7372/

 

[EvilRoySlade]

That and I’m gonna spout garbage.
You are going to affect your cylinder maybe .1% by your muffler mod. In such a short distance/volume/ cone it is highly unlikely you had a measurable difference between straight exhaust port and muffler. Breathing is good. Resonance is better.

 

[MustangMike]

Gotta keep up around here...

http://opeforum.com/threads/part-six-the-exhaust-system.7372/

Thanks for that, and I'd read most of that thread, and forgot about it!!!

 

[Hedgerow]

Gotta keep up around here...

http://opeforum.com/threads/part-six-the-exhaust-system.7372/

Mufflers are overrated..

 

[Deets066]

 

[MustangMike]

What are the #s in that saw! Is the carb stock?

 

[cus_deluxe]

Probly stock on an 066 lol.