Tuning FX Dreamline low powered German Version

[Hubertus]

Hello,

the FX Dreamline is now for a few months available in germany. i have waited for years and now im the proud owner of a dreamline classic .177 / 500mm barrel

we have a power level limit of 7,5J / 5,5 ftp 

in meter per second with a 0,547g / 8,44g exakt pellet 165m/s or 540 fps

my experience in generell with low powered converted pcp air rifles ? VERY bad done. did fx a better job ? lets find out!

german parts - fx made some changes! we can see a guide on the valve needle and a shorter spring

german transfer port 1,5mm / 0,059"

german reg ()()()()() adjustable down to 50 bar

left german valve cover - right full power valve cover

full power parts

german vs full power valve needle - german version has a different throat and is allready broken

german spring or also the full power spring ? wire 0,055" / length 2,23" / outer diameter 0,38"



fx made setup for 7,5J / 5,5ftp

max preload with one washer

60 bar reg pressure / 1,5mm / 0,059" transfer port size

very stiff to cock and after around 2000 shots fired the valve needle allready broke 



here are two videos about the performance:



https://www.youtube.com/watch?v=Bs3VQi-BKkE





https://www.youtube.com/watch?v=-J5dJdlne_A



thats not bad but i dislike the stiff cocking, allready broken valve needle and the small transfer port

what im not allowed to do ?

- of course not exceed the energy level of 7,5J / 5,5 ftp 

- change the barrel to a longer or shorter one

- modifications to the barrel and receiver: no drilling, no milling, 



im allowed to use the full power parts (they were all included) if the power level does not exceed 7,5J ! for example: i could use the fx valve adjuster if the energy do not exceed 7,5J when adjusted to the max setting



my idea's:

get rid of the small transfer port - even for 7,5J it's to small when max preload and a washer are needed!

using more regulated. plenum volume per shot with a lower regulator setting

using a weaker hammer spring



can someone explain to me what the different shaped needle does ? releases it with less travel more air ?

 

[TNT19]

Ouch man that sucks it broke already. Hope it gets fixed especially since you have worked so hard and waited so long.

 

[towle]

my idea's:

get rid of the small transfer port - even for 7,5J it's to small when max preload and a washer are needed!

using more regulated. plenum volume per shot with a lower regulator setting

using a weaker hammer spring



can someone explain to me what the different shaped needle does ? releases it with less travel more air ?

Please note I have no experience with the Dreamline but stiff to cock and the same hammer spring at 7,5J makes no sense to me

I own a the FX Typhoon in 40J with direct pull hammer, not side lever with gearing as the Dreamline and find that quite easy to pull, also to compare I have a Röhm Twinmaster with the regulator set up to go 150m/sec (with a much shorter barrel) with same 0,547g JSB pellet and I can cock the hammer with my eyebrow

Also the volume of the "plenum" of the twinmaster is next to nothing, so may guess is its about restriction in the airflow - that you could change the hammer spring for a much weaker one and open the air flow for the same result - and maybe a lighter hammer for faster lock time

Difference in valves - your version seems to have more mass in the stem and maybe that is was reduces the airflow? - again I do not know anything about the Dreamline so really not in position to give other than general advice

 

[Hubertus]

Hi,



i did some more testing and reduced the plenum volume and with a reg config of ()()()()( its possible to adjust below 50 bar

i have ordered some clear pvc aquarium hoses. the pieces of garden hose do look pretty ugly





https://youtu.be/kYkD9sXBeMs





transfer port on max / .30 cal 

~30 bar reg setpoint

full power hammer spring on max preload: 

185 m/s with a 0,547g jsb or 606 fps with a 8,44gr jsb

a few counter clockwise turns: 165 m/s or 541 fps = 7,5J / 5,5ftp (thats even much less preload vs the factory fx setting!!)

isnt that a good tuning to the knee of the power curve ?

fps spread looks pretty good - i will make a video later.

due to bad weather i cant shoot 25m groups with 7,5J