Upgrading TM fps

Somnus

I have a TM Famas, haven't chronoed it recently but I think it's firing around 265-270. Not too sure. Basically I want to upgrade it.

The main thing I'm wondering about is if I get a stronger spring will it affect the rate of fire?

It has a high rate of fire which I don't want to lose. I'm a noob when it comes to the internals of Aeg's so I don't know how it will affect it.

Has anyone upgraded a TM aeg before? Any tips?

Dread-Lock

To be honest it doesn't matter what you think its shooting at, get it chrono'd first.
Yeah upgrading the spring will effect your RoF. It will slow it down a little as the motor has to compress a stronger spring.

Somnus

Dread-Lock wrote: »

To be honest it doesn't matter what you think its shooting at, get it chrono'd first.
Yeah upgrading the spring will effect your RoF. It will slow it down a little as the motor has to compress a stronger spring.

I will be chronoing it. Wondering how much it would slow it down though. That's why I'm wondering has anyone with a TM done it before,to tell me how much it affected the ROF.

Head_Hunter

Dr.Poca wrote: »

I will be chronoing it. Wondering how much it would slow it down though. That's why I'm wondering has anyone with a TM done it before,to tell me how much it affected the ROF.

A stronger spring will require more electrical current to compress, so you get less shots per charge. If your battery is capable of providing the amount of current required by the gun, then your ROF will remain the same, but number of shots per charge drops.
If the battery you are using is not able to provide the current required to compress the new spring, then your ROF will drop.
Most TM guns will use about 10A per shot, so a 1000mAh battery will provide 10A for 6 minutes. A stronger spring will increase the required current, thus reducing the run time/ number of shots.
Use a high mAh rating battery to overcome the new higher current requirements.

Dread-Lock

Dr.Poca wrote: »

I will be chronoing it. Wondering how much it would slow it down though. That's why I'm wondering has anyone with a TM done it before,to tell me how much it affected the ROF.

I can't say, as I don't know what condition your gun is in, what the RoF is like at the moment and a number of other things that would effect the outcome.
I downgraded a gun a little while ago and gained in and around 1rps (it got downgraded by about 40fps). I'm assuming you want an extra 40fps or so. So if you swap things around, you might lose around 1rps.

And sorry Head_Hunter but the spring will effect the RoF. A stronger spring will put more of a load on the gearbox, it doesn't matter if the battery can handle it, it will slow it down a little.

If you filled the boot of a car with bricks, its not going to go as fast as if it was empty. The car engine can still handle the load, but its not going to be as fast .

Edit: But you are correct in say the battery won't last as long and if you use a battery with a higher mAh it will have a higher RoF for longer.

Head_Hunter

I am correct about the stronger spring making no difference, if the battery is beefy enough. I've tested it myself using an 11.1v 1500mAh Lipo, M90 and M120 springs. I got 25 rps in both setups.

Puding

I am correct about the stronger spring making no difference, if the battery is beefy enough. I've tested it myself using an 11.1v 1500mAh Lipo, M90 and M120 springs. I got 25 rps in both setups.

then another aspect of your aeg is creating an artificial glass celling limiting your rps, a stronger spring will effect rof in most cases, the time when they do not is the exception not the rule

a high spring will mean the motor draws more from the battery, but again depending on components and type of battery this might not even be noticeable, if your running a 3000mha 9.6 the effect would be rather small at this level, where as if your running 1400 8.4v or lover end cells your going to notice the effect a lot more, but from .75j to 1j most people would not notice at all

real need the starting point to give solid advice so a chrono reading would be good put im going to work with a stock tm as a base line

i would throw in a m90 myself, when the gearbox is open swap out the bushings for bearings, this would counter the decrease in rof from the increase in spring strength, i also normal swap out the piston due to TM annoying spring/piston system

be aware that depending on the type of aeg and what you plan on doing in the futre you might want to be weary, if your thinking of throwing in a tight bore barrel you could very well have to drop down to and 80 - 85 spring depending on components and the version of the gearbox

Dread-Lock

No your right Head_Hunter, putting a "beefy" battery in the gun will bring the RoF back up. But a stronger spring WILL effect the RoF, if it didn't then why would you need to put a higher mAh battery in it?

Chances are if you put an 11.1v 1500mAh lipo battery in a gun its going to be firing at the max RoF that the gearbox can possibly produce with either spring.

And I doubt Dr.Poca is running a stock TM Famas (I assume its stock if its shooting at 270ish) on an 11.1v lipo battery anyway. So I was trying to give him an answer that might help him with the setup he has.

Head_Hunter

Dread-Lock wrote: »

But a stronger spring WILL effect the RoF, if it didn't then why would you need to put a higher mAh battery in it?

I just told you that I tried both springs and there was no difference in ROF.
I've also done the test with a 9.6v NimH, same ROF on both springs, just lasted longer on the M90 spring.

You use a larger capacity battery to increase the legth of time the battery lasts between charges.

defenderdude

Regarding upgrading a TM M16VN (or any similar TM), if I was to stick a MS90 spring into it (and new bearing bushings) - could one expect the gears/piston to last reasonably ok while still running an 8.4v battery

or are there any other upgrades (reasonably cost effective) you'd recommend?

Never really messed with my TM stuff - always been good enough for me as-is. But this thread has me thinking about the 90 spring...:)

Somnus

Dread-Lock wrote: »

I downgraded a gun a little while ago and gained in and around 1rps (it got downgraded by about 40fps). I'm assuming you want an extra 40fps or so. So if you swap things around, you might lose around 1rps.

That doesn't sound too bad. It's a stock Famas with nothing changed as far as I know, I picked it up second hand but not skirmished with. When I get it chronoed I'll post and let you know what it's firing at.

So if I did get a stronger spring you'd recommend a different battery too?

I suppose you need to know what it's firing at before you'd have an idea what spring or battery would be best.
I haven't got a clue when it comes to the mechanical aspect of airsoft.

Dread-Lock

Dr.Poca wrote: »

That doesn't sound too bad. It's a stock Famas with nothing changed as far as I know, I picked it up second hand but not skirmished with. When I get it chronoed I'll post and let you know what it's firing at.

So if I did get a stronger spring you'd recommend a different battery too?

I suppose you need to know what it's firing at before you'd have an idea what spring or battery would be best.
I haven't got a clue when it comes to the mechanical aspect of airsoft.

Well if you're using the stock battery I would suggest getting a better battery regardless of any other upgrades you have in mind. As the battery that comes with the gun is pretty low quality.

And while we're on the subject of batteries, you should also get a good quality charger. As those cheap chargers that come with the gun can sometimes damage your battery.

defenderdude wrote: »

if I was to stick a MS90 spring into it (and new bearing bushings) - could one expect the gears/piston to last reasonably ok while still running an 8.4v battery

or are there any other upgrades (reasonably cost effective) you'd recommend?

I wouldn't worry too much about putting an MS90 spring into a TM gun. Especially if your only running it on an 8.4v battery.
If you put new bearing bushings in it and shim it properly, it should be fine. Of course the stronger spring will put more wear and tear on the gearbox, but it wouldn't be anything drastic.

Head_Hunter wrote: »

I just told you that I tried both springs and there was no difference in ROF.
I've also done the test with a 9.6v NimH, same ROF on both springs, just lasted longer on the M90 spring.

If it doesn't effect the RoF why are you suggesting Dr.Poca get a better battery? Surely if it didn't effect the RoF, then there would be no need to change anything.

And when I downgraded one of my guns and I gained roughly 1rps, I'm running an 8.4v mAh1500 battery in it. Care to explain that for me please?

Chuck the Buck

defenderdude wrote: »

Regarding upgrading a TM M16VN (or any similar TM), if I was to stick a MS90 spring into it (and new bearing bushings) - could one expect the gears/piston to last reasonably ok while still running an 8.4v battery

or are there any other upgrades (reasonably cost effective) you'd recommend?

Never really messed with my TM stuff - always been good enough for me as-is. But this thread has me thinking about the 90 spring...:)

Depending on if you've done anything to it (tight bore, better airseal and the like) a 90 spring (depending on the brand) could push it over the limit. I've a tm m4 that with a 90 spring was doing around the 350-360 area. I put the original spring back in with a king arms bearing spring guide, 6.03 barrel and guarder bucking and it runs at 310-315fps and at about 13-14rps on a 9.6v battery (needs reshimming). Been running it on the 9.6v for over a year with no problems other than the cheap and nasty element bearings exploding ($6 for 6mm bearings from ebaybanned wasn't a good idea). I use metal bushings now and wouldn't touch bearings for a 6mm gearbox shell with a barge pole.

For cheap and cheerful chuck a bearing spring guide in with the stock spring (to compress the spring more and give a bit more power) and metal bushings (because the stock plastic ones are fail). Depending on the power increase you get you could also try the 'ptfe trick' to get a better airseal.

As for the piston and gears all should be fine, I've had mine since April last year (and used it nearly every weekend) and other than the il crapo cheapo bearings exploding after a years use everything is fine with it.

Head_Hunter

Dread-Lock wrote: »

And when I downgraded one of my guns and I gained roughly 1rps, I'm running an 8.4v mAh1500 battery in it. Care to explain that for me please?

Because the battery was not able to provide enough burst current for the original spring. Ever wonder why a cheap battery with the same mAh rating performs worse than an intellect battery of the same rating? It is because the cheap battery produces less burst curent than the intellect one.
By downgrading the spring, you brought the gearbox load current into the range that the battery could handle.

Dread-Lock

Head_Hunter wrote: »

Ever wonder why a cheap battery with the same mAh rating performs worse than an intellect battery of the same rating?

No, because I already know about the burst rate of a battery...

And as you clearly ignored this:

If it doesn't effect the RoF why are you suggesting Dr.Poca get a better battery? Surely if it didn't effect the RoF, then there would be no need to change anything.

I'm going to leave this little debate where it is. As I feel it just proves me right . And anyway we're boarding on thread spoiling at this point (if we haven't already passed that point).

Head_Hunter if you still have a deep urge to prove me wrong, PM me.

Head_Hunter

I'm not going to the trouble of explaining this further. Believe what you will .