Once I get this TP issue resolved, yes I am going to drop the reg pressure and start again with a tune.
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Can you lose performance with a larger Transfer port?
- Thread starter Vetmx
- Start date
Air guns are systems. IF you change one thing, and dont account for that change through out the rest of the "system" you can see this kinda thing.
make the changes suggested, and slowly change and test one portion of the system till you get the performance you're after.....
make the changes suggested, and slowly change and test one portion of the system till you get the performance you're after.....
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There are two topics going now about the Huma TP in Dreamlines. Glad I am not the only one. I am more accustomed to giving advice than asking questions but every now and then something dumb has me scratching my head. I thought it would be resolved when I discovered I didn’t clean up the back of my probe good enough. It got better but still lacking behind the oval port. The Huma is probably an improvement over the older Dreamline round ports though.
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No experence with the Huma TP, but do with stock TP. When I opened up the TP on my DL .25 Classic to 6.5mmx5.5mm oval, leaving the guns tune stock with only a plenum added, I also got a decrease in FPS, small, but it was measurable.
The plenum alone with no adjustments gave me a 3-4% FPS increase with JSB 25g and 34g and the porting decreased it by only .25% respectively. After spending countless hours and ton's of 34g pellets adjusting reg. pressure up and down from 120- to 150bar and HS from factory 2 turns in and out from bottom, my SD was in the upper single and lower double digits and couldn't get it to stabilize. Factory settings gave me SD of 1.6 w/25g @905fps and 4.8 w/34g @777fps. My goal was to shoot the 34g @860-865 at the same SD and still be the 1 hole shooter it was at 50yd. I figured the probe was the last piece to modify between the tank and the pellet so I cut out a 3.5mm piece on the front of the cup and shaped the rest to match my new port size. Adjusted my HS to "Max" which is about 1/4 turn out from bottom, and adjusted reg pressure up until I reached 885fps, then backed off my HS to reach my desired 3% de-tune for efficiency hitting 860ish.
I did do the "dry fire" for 5 shots after the reg adjustment, but there was just something that didn't feel right about that process because the reg still "settled' after a couple shots of 34g. I then started shooting a 5 shot mag of lighter pellets and then started the 34g strings. Much better results for me, reg was settled in with no change.
All said and done with my FX set to 140bar and 3% of my plateau it shoots the 25g @1005fps w/ 1.4SD and the 34g @859 w/ 4.4SD. My shot count has remained the same and is as accurate as ever.
Details, details...
My friend Rick just got a new lathe and will help make me a SS pin probe, I think this is a fantastic next step upgrade for smoother airflow. Looks like you already have the tools and I can tell you know how to use them , I saw your handy work with your shroud extension for the plenum addition. Smart.
The plenum alone with no adjustments gave me a 3-4% FPS increase with JSB 25g and 34g and the porting decreased it by only .25% respectively. After spending countless hours and ton's of 34g pellets adjusting reg. pressure up and down from 120- to 150bar and HS from factory 2 turns in and out from bottom, my SD was in the upper single and lower double digits and couldn't get it to stabilize. Factory settings gave me SD of 1.6 w/25g @905fps and 4.8 w/34g @777fps. My goal was to shoot the 34g @860-865 at the same SD and still be the 1 hole shooter it was at 50yd. I figured the probe was the last piece to modify between the tank and the pellet so I cut out a 3.5mm piece on the front of the cup and shaped the rest to match my new port size. Adjusted my HS to "Max" which is about 1/4 turn out from bottom, and adjusted reg pressure up until I reached 885fps, then backed off my HS to reach my desired 3% de-tune for efficiency hitting 860ish.
I did do the "dry fire" for 5 shots after the reg adjustment, but there was just something that didn't feel right about that process because the reg still "settled' after a couple shots of 34g. I then started shooting a 5 shot mag of lighter pellets and then started the 34g strings. Much better results for me, reg was settled in with no change.
All said and done with my FX set to 140bar and 3% of my plateau it shoots the 25g @1005fps w/ 1.4SD and the 34g @859 w/ 4.4SD. My shot count has remained the same and is as accurate as ever.
Details, details...
My friend Rick just got a new lathe and will help make me a SS pin probe, I think this is a fantastic next step upgrade for smoother airflow. Looks like you already have the tools and I can tell you know how to use them , I saw your handy work with your shroud extension for the plenum addition. Smart.
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My compact came new with an oval port. It will be staying on because it performs best. The Huma will be back in its bag until I build a pin probe. If I build a pin probe. I am happy with where my gun is at right now. I don't even want to look at my lathe for a week.
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Has to be turbulence being created somewhere. Inhibiting potential velocity of air charge.
I keep wondering why people are running the huma transfer ports. I know why. But the factory single port with port job seems to work better in most all cases. If the huma is massaged, it should perform equally as well. But basically requires the same amount of work...?
FYI all my ports on my FX barrels have been bell-mouthed to .30" the middle of the port is untouched, and inside is elongated towards the barrel.
I keep wondering why people are running the huma transfer ports. I know why. But the factory single port with port job seems to work better in most all cases. If the huma is massaged, it should perform equally as well. But basically requires the same amount of work...?
FYI all my ports on my FX barrels have been bell-mouthed to .30" the middle of the port is untouched, and inside is elongated towards the barrel.
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FX Impact MK2 PP 25 cal 700 mm pellet liner, Huma dual port enlarged and FX pellet probe elongated, Edgun gauge showing 120 bar on Reg, JSB MKII 34 gr pellets.
Here are my tuning results, showing also each power wheel speed with spreads, see my pictures on second page:
https://www.airgunnation.com/topic/fx-impact-mk2-pp-25-cal-how-to-start-tuning-for-power/page/2
Here are my tuning results, showing also each power wheel speed with spreads, see my pictures on second page:
https://www.airgunnation.com/topic/fx-impact-mk2-pp-25-cal-how-to-start-tuning-for-power/page/2
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