Tippmann Low Pressure Mods

[Toestr]

Hope to make this thread as a definitive list as to the mods required to make a Tippmann run LP.

The mods Tippmann included with their stock LPKs are:
- Front grip Asa/volumizer/low pressure valve assembly (valve has larger channels for better flow, lighter spring, valve stem has a larger OD going into the blowback hole, and valve seat ID is increased)
- Lightened hammer(w/lightened drive spring?) And rear cocking assembly with slot cover

In my experience with home brew low pressure mods, you'll need at least a foregrip sized volumizer (and obviously a regulator) off the valve in order to work at lower pressures (sub 600psi). The other mods will also likely need to be done (but maybe not, depending on the order they are done). Personally, I've had bad luck doing these mods homebrew in the order I did.

If anyone else has any more insight into what the factory low pressure kit included/did to function, please post up so I can add them to the list.

Also, if anyone has any other mods, parts combinations or ways they set up to make their Tippmann run low pressure, please post up.

Thanks!

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[Magmoormaster]

So Apamburn has been doing LP mods on his 98 for the last few years, with minor consultation from me. I sent him an LP valve pin and we found it actually made things worse. With the stock pin, he was able to get his to chrono in sub 400 PSI ranges. I'll let him come in and say more, I'm kinda fried right now (he is on vacation right now though).

[Toestr]

So Apamburn has been doing LP mods on his 98 for the last few years, with minor consultation from me. I sent him an LP valve pin and we found it actually made things worse. With the stock pin, he was able to get his to chrono in sub 400 PSI ranges. I'll let him come in and say more, I'm kinda fried right now (he is on vacation right now though).

No way! I'll have to give that a try. This is BLINDMAN btw.

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[Magmoormaster]

Ah, I was wondering if that was the case.

I know the most recent mods he did was to widen the valve flutes, lighten his hammer further, and redo his volumizer. He said he was chrono'ing at 250 FPS at 300 PSI with the heaviest hammer spring in his kit.

[Toestr]

Ok, so I added the stock valve pin again, and now it won't recock at any spring input pressure, spring tension or hammer weight. I don't think I have enough volume.

I know apamburn and I were both using gutted wgp lprs as volume chambers. Do you know what he is now using?

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[Magmoormaster]

From what I understand he used another Sledgehammer, just actually gutted it this time and drilled it out.

[DavidBoren]

I widened the channels, and put in a lighter valve spring, using the stock valve stem for my homebrew LP valve. I seem to remember using a mechanical pencil spring, although it was half my life ago, and I could be mistaken.

I also significantly lightened the striker, polished the internals, and used a full-size gas-thru grip as a low pressure chamber.

These modifications got me below 500psi, and I was shooting noticeably above the whistle... back in my high school outlaw-ball days, velocity was king. If you weren't shooting straight through t-shirts and clipping pine bows out of trees, you weren't to velocity yet. The only thing that was too fast was a barrel break. My "LP" Tippmann had no problems shooting velocity. As a note, this was all back with CO2 through a PPS Stabilizer.

[Toestr]

Thanks guys.

I'm going for try and add the middle part of another sledgehammer and see how that goes. I think volume was my problem.

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[Toestr]

Ok guys, opinions on macro vs steel braided for this application? It's a 4-5" length that I will be needing.

I like steel braided for the durability, but it seems like macroline would flow better. I have some pretty large ID macro (shown below), but I'm not too sure how the ID of steel braided stacks up in comparison (I know the ends at the fitting seem smaller).

Does it really matter? Durability is really what I'm looking for over ease of use/the possibility of better performance, but if it will significantly impede function then macro it might just be.

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[DavidBoren]

Significantly impede performance? It won't.

If stainless braided is what you want to use, use it.

The ID of your hose is not going to be what makes or breaks your low-ish pressure Tippmann.

[Magmoormaster]

Yeah I wouldn't worry about it.