Dry Nitrous Kit

[300ex07]

Has anyone ever put a dry nitrous kit on a 250r. What are your thoughts between wet and dry for an atv?

[GPracer2500]

I also want to learn about nitrous for 250rs.

[wilkin250r]

Originally posted by GPracer2500
I also want to learn about nitrous for 250rs.

Well, I never thought I'd see GPracer asking for information.


First and foremost, let's clarify the definition of "dry". I would never reccomend any system that injected only nitrous. You NEED extra fuel. Injecting only nitrous will lean out your mixture really quick and cause serious problems.

However, some kits are often called "dry" kits because they come only with nitrous, and rely on the existing fuel system to supply extra fuel. On a carbureted engine like an ATV, a dry system will pressurize the float bowl to shoot extra fuel through the jet. They are safe, because they do supply extra fuel, but they are called "dry" because the extra fuel isn't injected by the nitrous kit itself, it's added through the existing fuel supply.

I've never done official dyno testing, but logic says to me that nitrous is slightly less effective on 2-strokes. Because it goes through the crankcase, it has time to expand from liquid to gaseous form. On a 4-stroke, you can inject it directly into the cylinder in liquid form, so it doesn't displace any existing air/fuel mixture, and the liquid will help keep the piston cool and reduce the dangers of a lean mixture. Not quite so with a 4-stroke.

I've never put it on my 250r, but if I did, I would inject it far back, probably right after the filter. If it's close to the carb, it can freeze the slide and cause your throttle to stick wide open. If it's AFTER the carb, it will be spraying directly on your reeds and freeze them, and I don't think that would be good either. I would put it as far back as possible to give it time to expand.

[300ex07]

http://store.summitracing.com/partde...t=nos-05029nos I was thinking about this kit.

[blasterandy]

I dunno, i would like to know more also. I would think about the boss noss kit. Its more expensive but there made for quads. Boss Noss website

[wilkin250r]

Originally posted by 300ex07
http://store.summitracing.com/partde...t=nos-05029nos I was thinking about this kit.

I wouldn't suggest that kit. It only injects nitrous, it doesn't inject additional fuel at all. It requires you to run your jetting rich, which means you're rich all the time and probably fouling plugs.

Also, if you're only relying on rich jetting, you're only going to get a few horsepower on the nitrous. You can't run rich enough to get major horsepower, or you'll be so rich when you're off the nitrous that your quad won't even run.

If you want a nitrous system, I would suggest something a bit more expensive, but it injects fuel along with the nitrous. This makes it both more powerful, AND safer. I know it doesn't sound possible, but believe me, it is. More powerful, and safer. Like this kit http://store.summitracing.com/partde...5&autoview=sku

[wilkin250r]

Originally posted by blasterandy
I dunno, i would like to know more also. I would think about the boss noss kit. Its more expensive but there made for quads. Boss Noss website

I can't find anything specific for "quads" on their website. I saw systems for 2-cylinder motorcycles, but I can't see any specs on exactly how they are installed, and what type of fuel delivery they use.

However, I DO see an advantage from reading their website. It appears their bottles are regulated to 300PSI, which is an advantage over other brands like NOS and NItrous Express.

Ordinarily, nitrous bottles sit somewhere between 900 and 1200psi depending on outside temperature (or bottle heaters). However, when you press the button, bottle pressures will drop quickly. Less pressure means less nitrous. So the longer you hold the button, your power gains will drop.

I've never done any dyno testing to determine the actual drop, it might be a small drop, or it might be a large drop. Let's say you start with a 20HP boost. After five seconds, it will drop to anywhere from 15HP to 5HP.

If your bottle is regulated down to 300PSI, you'll need larger jets, but it will be much more consistent, because it's REGULATED. So the pressure doesn't drop (or more precisely, it doesn't drop much). So instead of your 20HP boost dropping down to 10HP after five seconds, it only drops to 18HP after five seconds. You've still got a significant boost, something that you can realistically hold for 30 seconds (as long as your motor lasts that long). OR, you can make repeated back-to-back runs without waiting for your bottle pressure to rise and stabilize.

[blasterandy]

They do offer them i have seen two or three banshees running them. You will probably have to call them. They are in a bunch of atv mags dirtwheels quad atvaction. just to name some i have seen them in.

[imprezkid]

I've never put it on my 250r

You say you've never added nos, but i can understand that with the power that 340pv is pushin out, why would you need it?

[imprezkid]

You say you've never added nos, but i can understand that with the power that 340pv is pushin out, why would you need it?