Recommendation for upping the ROF and FPS in stock mp5

[canabubba]

So, I'm in my twilight years of airsoft - sold off a dozen guns, and almost all of my gear. Plan to play 4 or 5 times a year with one nice, simple gun.

I've got a stock CYMA MP5 that I've thrown a swordfish rail onto. I'm running a 7.4v LiPo in a small battery box.

The gun itself is great - never had an MP5 before, and love the platform - but I'd like to bump to ROF and FPS a little, as I play outside. I've never had the gearbox out of it.

It's currently shooting sub-300fps, the rof is pretty low - probably less than 10rps with the 7.4v.

So, my options for rof are to go with a faster motor, or some higher-speed gears.

At the same time, I'll probably bump to an m110 spring.

I'm thinking I might be looking at just a BETTER motor to handle the spring and boost rof a little, plus some higher speed gears to further boost rof, and the spring.

OR, a powerful high-speed motor, new spring, and stock gears might work, too.

I'm very comfortable going into the gearbox - in fact I need to make sure she's shimmed properly anyway.

The challenge is finding a good balance without intimate knowledge of every motor and gear ratio combination out there.....while staying with the 7.4v battery.....that's where YOU guys come in

Yeah, I could go with a higher-voltage battery, but I'd rather not get into a mosfet.......I've been down that road before and built some very high-end guns......but I'm just looking to keep this one simple.

My goal - a nice, quiet gun that won't need much maintenance, decent rof (10-15 rps), decent fps (375-ish).

Cost isn't an issue, but keep in mind this is a $200 gun - let's not get silly.

Suggestions? (and please feel free to be specific as to motor rpm and gear ratios......)

[lurkingknight]

go motor. going faster gears requires a stronger motor, in most cases the stock motors have issues pulling faster gears efficiently. Run that until the gears break, then go faster gears then.


One of the reasons you're seeing poor performance is because mp5s generally have 2 sets of tamiya connectors stock and a fuse. There's an extension in the rear of the lower to route wires either to front or rear for full stock. These extra elements add a lot of power sapping resistance and lower your rof.

You could benefit from eliminating that or both and switching to deans, or a complete rewire, but at that point if you are rewiring you might as well go faster gears cause you're in the gearbox at that point.

I would recommend an shs motor, reasonably low price for a lot of added performance over what you have.

To me the cost of the gun is irrelevant. You can drop the same 400$ into a 200$ cyma or a 600$ vfc and achieve the exact same results. The only difference is that the 200$ gun might have some manufacturing tolerances that are suspect or it's heavier than nicer guns.

[canabubba]

Thanks knight - sound advice - and yeah, I already got rid of all the extra wiring when I went to a deans connector. Once I'm in the gearbox, I'll check out the air seals.....who knows what's going on in there......

For the motor - are you talking about a stock speed motor? or High Speed?

[lurkingknight]

shs only come in 2 different varieties, speed or torque. both should be neo magnet driven so both will be a substantial upgrade over stock cyma. The magnets alone will account for both rpm and overall torque, but the torque motor would be more power efficient. airsoftparts will sell the most widely used one, which is the torque motor.

The torque or speed naming convention doesn't mean as much when dealing with neo magnets.

[8bitninja]

That sounds awfully low. I'm getting higher than 10rps at 330 FPS on a stock CYMA MP5K with the included 9.6v NiMH. I've since gone to the Marui MP5K HC but kept the CYMA around as a loaner.

[canabubba]

Originally Posted by 8bitninja

That sounds awfully low. I'm getting higher than 10rps at 330 FPS on a stock CYMA MP5K with the included 9.6v NiMH. I've since gone to the Marui MP5K HC but kept the CYMA around as a loaner.

That probably makes sense, as I'm running a 7.4v LiPo.....

[freshblake]

Be sure to add an air seal nozzle if you haven't already!

[Styrak]

Originally Posted by canabubba

That probably makes sense, as I'm running a 7.4v LiPo.....

No it doesn't make much sense. 7.4v lipo is similar to a 9.6v NiMH, maybe slightly less powerful. Less than 10rps is very low though, have you put it through a chrony to confirm?