P90 shooting low FPS after spring upgrade

[SG1-EVERETT]

Need Serious Help

I just got a Chrono and a M120S Spring so I put my 120s in and checked the FPS 385. Is the right or is something just plan wrong below.

The Parts

Deep Fire - Reinforced Half Tooth Piston
Systema Metal Bushings Set for the P90 w/Anti reversal Latch
Systema Metal Shim Set
Systema Helical Genuine Ratio Gears Hardened Steel
Guarder Aluminum Piston Head With Bearings
TM Tappet Plate for P90
Guarder Enhance Cylinder
Guarder Double O-ring Cylinder Head Stainless Steel
Guarder Air Nozzle
Prometheus P90 247mm Barrel - 6.03mm Tight Bore
Stock Motor


The Springs and FPS using Guarder Chrono Speeder 2000


Systema M100 = 334 FPS most of the time
Systema M120 = 363 FPS most of the time
Systema M120s= 385 FPS most of the time

1.
Thought may be it’s the HOP UP switch barrels with new stock P90 drop 10 FPS.
The stock 90 is shooting a steady 271 FPS and 281 FPS with 6.03 barrel.
2.
Switched nozzle from Guarder back to Stock no change.
3.
Switched piston head from Systema 1000 with clogged ports and still no change with Guarder Aluminum.
4.
I even put the stock TM stock piston, piston head and spring 234 FPS.
5.
I put my finger over the nozzle and the piston will not move so no leaks there.
6.
Posted this message looking a answer.

[Skladfin]

I'm pretty sure that's quite normal

[ILLusion]

Those numbers are pretty much on par.

[McKee]

That sounds normal for all your upgrades but kinda low when you put all the stock parts back in. Usually a stock marui should be around 270 or so, 234 is on the low side. Maybe spring fatigue? How long were you using stock internals?

[SG1-EVERETT]

The thing that gets me is the stock spring is new only used during one game.
I have access to another brand new stock TM P90 that does shoot 270 FPS.
You would think its the Hop Up but have switch barrels back to the stock I get a 10FPS reduction..

[Airmax]

I have an stock TM P90 Spring and also getting around 250 -260 is close to the same as your resaults. I will be changing the spring out to get a close 330 fps for my club field.

[SG1-EVERETT]

I had some success today after taking my mechbox apart about ten times.
I found two issues causeing FPS loss.
My DeepFire Halftooth piston was rubbing on the sector gear!
From the shine in the space beteen the gears it acting like a brake.
I swap back to the stock TM Piston and was shooting 372 FPS.
Also I have been using Radio Shack lube gel and start thinking it was too thick. Reading through the forums someone mentioned that cylinder lube can reduce your FPS.
I cleaned my cylinder and applied ceramic grease to the cylinder.
I also polish the piston guides with steel wool and applied ceramic grease.
Another tip from the forums.
I didn't have the bearing on in the piston so I put it back in.

Now my P90 is shooting a steady 390 FPS perfect.

[Skladfin]

congratulations!

but only 5 FPS gain?

[wilkinwk]

what are the specs of yr battery??

[damage]

Originally Posted by SG1-EVERETT

Deep Fire - Reinforced Half Tooth Piston

Systema Helical Genuine Ratio Gears Hardened Steel

That does not sound right.

Half teeth piston is for Infinite torque up gearset. You need full teeth piston.