Transfer Port Thingy

[slivershooter]

What is the name of this part? The transfer port thingy?  Anyway, I read an article where a guy uses refrigerator water tubing instead of the stock thingy.  Is this something that's being done by others?     I tried making one from brass thinking it would conform to make a seal. getting the length right is critical.

[breakfastchef]

The Crosman term for that metal tube is a sleeve.


The poly port thing, from my reading on various forums, was developed out of necessity. Some fellow lost a sleeve (transfer port tube) and used ice maker tubing to replace the lost part. It was picked up by several early Crosman modders and hailed as something just plain phenomenal. Since standard sleeves work just fine, I never really paid much attention to the hoopla.


Fast forward to a few weeks ago when I received a .20 barrel and hopped up valve for a 22xx pistol. The valve and barrel were machined for the poly port. I understood during the installation of these parts when the poly tube really is needed. When you have a .22 caliber or larger barrel, pellet velocities can be enhanced by enlarging the exhaust port of the valve and barrel. This allows more gas to get behind the pellet faster. In order to not restrict flow of the air/gas, you need to use a sleeve with a larger internal diameter. The poly tubing is perfect for doing just that, plus it is somewhat pliable so a good seal can be made on the valve and barrel. Alternately, you could just machine a metal sleeve with a larger opening, but the tubing is inexpensive and widely available.

What is the name of this part? The transfer port thingy?  Anyway, I read an article where a guy uses refrigerator water tubing instead of the stock thingy.  Is this something that's being done by others?     I tried making one from brass thinking it would conform to make a seal. getting the length right is critical.

[BDS]

+1 to Larry's comment, much like hollow probe bolts and other 3 to 5 fps gadgets, the poly tube is over hyped IMO.

The little metal part is the transfer port, the small black seal is the transfer port seal.

Yes, frig tube or sprinkler drip tube can work, get a very flat surface and a brand new razor blade to make the cuts. Another fix is teflon tape layed into the tube side and the breech side (poke a small hole in each)and use the existing port and seal, the teflon tape builds up a few mil of sealing surface that conforms better than the bare steel without being too thick. I've done this to most of my 13XX and 22XX guns, never botherd with poly tubes.

[1377x]

crosman manuals call it a sleeve
we call it a transfer port
getting the length is critical to the seal
refrigerator/ice maker poly tubing can be used. i use a 5/32 id poly tube in my /25 disco and a micro irrigation line,nylon, .161 id/.25 od in my stainless steel 2260
long time ago a guy used brass tubing inside the poly tubing for a transfer port. the problem was the brass was thin and crushed usually after repeated dismantling. most worked if you put the gun together and left it alone after that
poly tubing inst necessary unless you are going for high fpe/fps its overkill in a 1377 or 2240
this guy named rsterne did a lot of testing with the 22xx and 13xx guns his threads can be seen on the caf forum or airgunhome.he posts on gta but you will not find these threads with his early experiments
.161 i.d. is optimal you can get that out of the stock metal sleeve it measures .140
if you have a lathe that makes for accurate fast work. but i followed the way of the dremel. chucked some 330 grit ,rolled tight, into my dremel bored out the sleeve to .158 iirc finished it up with some 1200-2000 grit

[onebaddj]

Ice maker line works and ice cheap but getting the length right can be a pain. To long and you run into me and my 1377's issues where the tube was too long and when everything was tightened down it cause my poi to be about 10 inches low at 10 yards. Put some nice dings in my dressor cause of that.    had to make 3 of them for that build cause i would take down a little then a little more then too much and get a leak. Its a frustrating process to trouble shoot a low poi down to the transfer port being to long and causeing your breech to flex every so slightly which cause the barrel to aim low. Ended up finding it by sliding a peice of paper under the breech at the port and forward but could not at the rear. So make sure you get the length correct if you do it. 

[breakfastchef]

.161 i.d. is optimal...

Optimal for what application?

[cherokeesteve]

I did the poly tube transfer port mod to my 2240. After fudging up the stock port seal I wanted to do a fix myself without having to wait on a part. If you go this route you should open up your barrel port to whatever size ID the tubing has (mine was .170).

[1377x]

Optimal for what application?

pressures 850psi and up
rsterne has graphs and all the info on airgunhome of the testings he has done with co2 and hpa which basically a 1377 uses
all the icemaker tubing does is creates more turbulence and wastes air/co2 until you get into using larger/heavier projectiles
he calculates how much air is used for each shot with the .161 sleeve and poly tube
lots of info over lots of threads . if you look at his threads/post he uses the sleeve instead of poly tube
this also has something to do with streamlined ports and porting that is not streamlined
going from a .156 port to a .170 port back to a .156 port is never optimal in any application. turbulence turbulence turbulence. streamline your ports

[breakfastchef]

That .161" number refers to his latest work with the QB79 Ninja build. His work with Disco transfer ports did not include .161". Each HPA gun can be tuned to the shooters needs and wants. The transfer port diameter is only part of the equation that also includes valve and barrel porting dimensions, stroke, hammer spring tension, etc. I am not sure that saying that .161" is optimal is totally accurate for all applications.




 

pressures 850psi and up
rsterne has graphs and all the info on airgunhome of the testings he has done with co2 and hpa which basically a 1377 uses
all the icemaker tubing does is creates more turbulence and wastes air/co2 until you get into using larger/heavier projectiles
he calculates how much air is used for each shot with the .161 sleeve and poly tube
lots of info over lots of threads . if you look at his threads/post he uses the sleeve instead of poly tube
this also has something to do with streamlined ports and porting that is not streamlined
going from a .156 port to a .170 port back to a .156 port is never optimal in any application. turbulence turbulence turbulence. streamline your ports

[1377x]

That .161" number refers to his latest work with the QB79 Ninja build. His work with Disco transfer ports did not include .161". Each HPA gun can be tuned to the shooters needs and wants. The transfer port diameter is only part of the equation that also includes valve and barrel porting dimensions, stroke, hammer spring tension, etc. I am not sure that saying that .161" is optimal is totally accurate for all applications.




 

wrong
the .161 comes years before the qb build
i think i built my disco pistol in 2010 it was based on rsternes full sized disco built before i did mine,well, it had to be i read his threads before i did my build. thats when rsterne gave me all the details on the porting
you might want to check out his old posts the one you can not find on gta. rsterne was helping me with builds long before he was on gta. he was on airgunhome and caf. so was gippeto. both of them have been a big help


the rest of what you said does depend on the tuning of the gun
what doesnt change is that in the mid to low powered guns .170 transfer ports are to large. streamline your ports

[onebaddj]

So if i read this correctly basically match your port to your caliber. Small caliber smaller port. Also you mention turbulance this makes me think about the parts for cars that spin the air going into the carb to stream line the air flow and reduce turbulance. Would putting rifling in the transfer port to spin the air do anything?

Also what are the real gains from smoothing out the air? .5% increase in efficiency or 10% increase? My basic thought was bigger port = more air faster into the barrel. May have to rethink some stuff.

[1377x]

when you have the time read some of rsterne's posts on airgunhome or caf. he explains all of this. i have a pm from him also explaining this. i have shared this pm with a few other members here and it helped them.
the bigger the port the more you waste
there gets to be a point when the gains turn to waste
there are others out there that can explain this too, but rsterne is the first one i chatted with before he became a member of gta

[breakfastchef]

Sorry fella, I'm not buying this. Your blanket, all-encompassing statement was that a .161" transfer port diameter is optimal. Well I cannot find any information that confirms your statement. I find it highly unlikely that a .161" transfer port diameter is optimal in all calibers above .177 and across all makes of PCPs. There are just too many factors involved in tuning a PCP, many beyond my comprehension, that affect performance. And, this does not even touch on valve and barrel porting which is equally important as the transfer port size.

Maybe you meant to say that in the Disco/MRod platform, .161" is an optimal transfer port ID for a .22 caliber gun. That I could understand, but only if I knew what optimal meant to you. You did not define optimal. Is it optimal efficiency, optimal shot count, optimal fpe? [/size]After reading this comprehensive post comparing 11 different transfer ports in an MRod, there is obviously not a universal optimal size.



http://www.network54.com/Forum/79537/thread/1305313653/Benjamin+Marauder+P-Rod-+Performance+Results+With+Various+Transfer+Port+Diameters


Perhaps you can dig out some references and share them with everyone so we can be better informed.

wrong
the .161 comes years before the qb build
i think i built my disco pistol in 2010 it was based on rsternes full sized disco built before i did mine,well, it had to be i read his threads before i did my build. thats when rsterne gave me all the details on the porting
you might want to check out his old posts the one you can not find on gta. rsterne was helping me with builds long before he was on gta. he was on airgunhome and caf. so was gippeto. both of them have been a big help


the rest of what you said does depend on the tuning of the gun
what doesnt change is that in the mid to low powered guns .170 transfer ports are to large. streamline your ports

[1377x]

i have look around!

[cherokeesteve]

http://www.network54.com/Realm/CFTech/Bioportupdate.htm

This is what I followed.   Also while angleing valve port, opened up to .170 as well.    Just wanted to match up with ID of tubing I had.