Will it work? High speed.

[Montesa77]

Looking to do a complete over haul(again, sort of) of my MP5. Have heard many things about setups not running a fast as possible due to lack of starting(torque) up power.
List:
10.8v 3300 mAh battery by vapextech
Element 9mm Gb Inc. bearings
"" "" 13:1 gears
"" "" Polly carb piston
"" "" Polly carb piston head
"" "" High speed motor
SP 85 spring
Deans
16 AGW wiring
Basic MOSFET


Would this run ok? Or would I be better off with a torque motor?

[sj_asc]

Re: Will it work? High speed.

I would say no, the ultra low ratio set will demand more torque, but pulling such a light spring you probably wont have any problems in that area, the problem you will run into will be piston timing.
An SP85 will not be able to return the piston assembly in time paired with that battery, no amount of weight reduction will fix the issue, the resistance of compression in addition to the variables of bb weight and hop setting will cause problems sooner rather than later.
I would run an M100 at least, and shed some weight off the piston assembly, a slightly mis-matched cylinder (half port) will also help the piston to retun in time in trade for a small amount of muzzle energy (dependant on how long your barrel is, half ported cylinders won't steal anything noticeable from a 229mm barrel).

[Montesa77]

Re: Will it work? High speed.

So would a torque motor be more down my street?

[guard-sniper87]

Re: Will it work? High speed.

i agree ,

as the 85 spring would need a spacer ontop to actually make up for the lack or power behind it to return the set up faster,

so going for either the m100 or even a 105 spring would be perfect as you would not get any rattle from the spring indicating it is too loose and also will not be to stiff to slow the gear set down

[Montesa77]

Re: Will it work? High speed.

Well the piston head and guide both have big bearings which is why I have the SP85 in there.

[Clot]

Re: Will it work? High speed.

I think the question is.. just how fast do you want to go ?

There are a fair few of us on here who can give you detailed parts lists and necessary mods to achieve most rates of fire.

[guard-sniper87]

Re: Will it work? High speed.

it still not matter mate, as the spring would need a spacer of some sort put in first before it will have enough releasing pressure to be able to return the piston fully before the next cycle

so be better to have a 95 , 100 or 105 ...

as your not increasing the ratio of spreed as your sticking with a 13:1, so only a slight increase because of the mosfet better wiring and bigger battery ??? stick with 9.6 or even 7.4 lipo


damn clot being a ninja :p

[Montesa77]

Re: Will it work? High speed.

But the M100 and a light'nd piston will bring it over site limits. What about short stroking?

[guard-sniper87]

Re: Will it work? High speed.

what is your site limit,

if 328 , put in a m95 or a 1j spring

and info the piston wont make FPS difference its the air seal's

[sj_asc]

Re: Will it work? High speed.

The bearings in the head typically add no spacing advantage over the stock base, as for the spring guide bearings, those add a little advantage but i can assure you it will not be enough to increase the tension to the required rate. Once the motor starts cranking the revs with that gear set you should be well into the low 30s, particularly with that spring, the piston simply will not return in time before the sector attempts to re-engage. If you have a typical hard polycarb piston you can say good bye to the initial pickup tooth as they are too brittle to withstand even the minor timing issues that occur with high speed setups, why do you think the softer stock TM piston is a favourite for many high speed enthusiasts?
The real issue is that we will be looking at much more severe timing errors, ones that could potentially catch the wrong tooth on pickup and create a lock up.

The setup you have is potentially pretty good, maybe if you optimized the piston assembly and dropped a cell from the pack you could probably run that no problems, but if you are intent on the 10.8v high discharge pack then i highly recommend you step the spring rate up to at least M100.

[Montesa77]

Re: Will it work? High speed.

The piston will drop/ raise FPS if it is short stroked as not all the spring is being compressed. Forget about Element piston, think I will go with TM. Site limit is 350 max.

[guard-sniper87]

Re: Will it work? High speed.

ok , the 350 limits will be with m100 mate,

short stroking the piston's teeth mate is ROF , only changing spring and making air seal better will effect FPS,

the M100 spring with above stated set up will be fine, but reduce the 10v pack to a 9.6 after installing the mosfet mate or you'll tear the piston to bits very fast

[Montesa77]

Re: Will it work? High speed.

Just think for a second. Short stroking DOES reduce FPS. But thanks for the advice.

[Ominous Slayer]

Re: Will it work? High speed.

I think the question is.. just how fast do you want to go ?

There are a fair few of us on here who can give you detailed parts lists and necessary mods to achieve most rates of fire.

^ This
Dont forgot to answer this, could make it easier to answer if we know how fast you want to go

[guard-sniper87]

Re: Will it work? High speed.

doubt he even knows Lee