Spring Comparison Chart - Updated April 1st, 2006

[glankel zebra]

Hey Guys upgrading my kraken ak what type of spring should i get to bring fps to around 375 FPS thanks

[Styrak]

Perhaps look at the chart at the beginning of this thread?
That's what it's for.

[Thenooblord]

A kraken should shoot around 375 out of the box anyways....

[Rugger_can]

Originally Posted by glankel zebra

Hey upgrading my Kraken Ak what spring should i get to increase FPS to 375 FPS

A pdi 130% or pdi 140% would probably do the trick of bringing you very close, But Im not entirely sure that the Kraken would be your best choice of platform. As other factors play into the Final FPS of an AEG, such as airseal, piston and piston head quality ect.

Cheers

[ScooterVauto]

Hi Guys.
I found this little chart pertaining to the Element spring For VSR availalbe at Ehobbyasia
Speeds are from Stock Mauri
M105 : 350~380 F.P.S.
M115 : 370~400 F.P.S.
M125 : 390~430 F.P.S.
M135 : 420~460 F.P.S.
M145 : 450~500 F.P.S.
M175 : 450~600 F.P.S

[fabiomarqs]

and what about 0.12g bb's?
how many is the fps difference between 0.12g and 0.20g bb's ?


thank you

[ScooterVauto]

My VSR jumps from 494 on .2s to 553 on .12s
although i dont use anything under .25s when playing

[ILLusion]

Originally Posted by fabiomarqs

and what about 0.12g bb's?
how many is the fps difference between 0.12g and 0.20g bb's ?


thank you

Use an airsoft FPS calculator to figure this out. There are tons on the internet. Just Google it. As long as you are using a spring gun or AEG, then your work output will be constant. Use that as the constant and change the BB weight.

[fabiomarqs]

Originally Posted by ILLusion

Use an airsoft FPS calculator to figure this out. There are tons on the internet. Just Google it. As long as you are using a spring gun or AEG, then your work output will be constant. Use that as the constant and change the BB weight.

thank you,

but I have a question, if I cut a spring in half, will the fps decrease half too?

[ILLusion]

Originally Posted by fabiomarqs

but I have a question, if I cut a spring in half, will the fps decrease half too?

That would depend on the brand/model of the spring. More importantly, it would depend on the material used, the hardening used to temper the material, and whether the coiling is linear or non-linear.

I can not answer that question for you, as there is no definitive answer. You will just have to try it out and let us know what your experience is.

[m102404]

Originally Posted by fabiomarqs

thank you,

but I have a question, if I cut a spring in half, will the fps decrease half too?

LOL...maybe I'm taking your question to litterally...but cutting a spring in half won't work at all. It won't push the piston far enough forward and you'll end up stripping your gearbox.

If you're referring to the power curve for the expansion of a spring...each spring/make/type is different, so it's near impossible to answer definitively. In general though...the answer to your question is no.

If you want to alter the end resulting power/fps of a given spring...you can clip some coils off the end of it. How many is very much guesswork and trial and error (IMHO, it's far easier to simply buy a couple of extra springs). Measure...clip...bend/regrind the end...reassemble...measure....repeat as necessary.

*edit*
nevermind...Illusion responded already

[fabiomarqs]

hmm, sure
it will be a Guarder spring.

Let me explain: I have a crappy aeg, and I think that the piston is smaller than a normal piston. The stock spring has 90mm, and the Guarder spring has 180mm. So I'll have to cut the spring.
I've just bought a new motor and I'm going to buy metal gears.
I want it to shoot around 290-300fps with 0.20g bb's. So what spring do you think I should get?

I'm thinking about the Guarder SP120
my reasoning (rule of three):
18cm -> 428fps
x cm -> 300fps

428x = 5400
x = 12,62 cm

So I would cut off 5,38cm of the spring.

What do you think? I really need help, haha

[ILLusion]

The spring is non-linear. I can not answer this question for you, nor can most users here unless they have a degree in mechanical engineering or some form of metallurgical physics and have accurate distance measurements of the different coils as they change through the length of the spring so that they can calculate the varying tension through its stroke. You are asking a very difficult question with no easy answer.

If you want to do some hardcore research on your own, Guarder uses oil tempered Si-Cr steel for their springs. The tempering is different per spring. The main difficulty is the varying coil tightnesses through the length, and thus, it is non-linear. Your equation is not accurate for this case.

It would probably be easiest to just attempt trial and error: clip off one coil at a time and try the gun after each clipping. This is how most do-it-yourselfers do this. However, realize that by doing so, you must also look at WHERE you are clipping coils on the spring. If you cut the loosely spaced coils at the front of the spring, FPS reduction would be lowest, and will likely present high initial resistance for spring wind up.
Likewise, if you cut the tightly spaced coils at the rear of the spring, FPS reduction would be highest, but a reduced compression strength at the end of the stroke may "throw" your sector gear in to overdrive. You will be affecting the intended power curve by attempting such modifications without education.

This is not something I would attempt.

[fabiomarqs]

Since it's non-linear I can let it a little bit longer than 12,62cm (ie. 14 cm, just guessing). But it would be better to go for the SP130. So it's really trial and error.


Thank you again.

[LongStone]

basic question here but I'm a bit overwhelmed by all the spring info :-/
I'd like to upgrade my spring, nothing crazy just an extra 10-20% over my existing spring, problem is I don't know where my spring fits in the chart.
(I'm also assuming I can do this with out an overhaul of the gear box)
the gun is a stock ICS M4. I believe its shooting roughly 330 fps out of the box (roughly King Arms M90 ?)
I looks like a Systema M100 might do the trick.

Not expecting anything "definitive" but a rough idea would be helpful.

thanks