2003 400ex and Nitrous??

[Nutster_98]

Howdy guys,
I managed to work my way into a 2003 yellow 400ex and it ran great until I purchased a White Bro's E-series s bend pipe.......and now it runs awesome. Anyway, to the point. A fella that I work with is a very knowledgeable drag racer and comes from a family of racers (****, his brother even works for Mark Martin) and we have been talking lately about mods for my quad. He has totally convinced me that we can run nitrous without any risk of damage to the quad. It will not be a "dry" shot (meaning just nitrous introduced into the carb) but instead a "wet" shot with fuel and nitrous being sprayed together. We have estimated by the size of the jets to add about 15-17 horsepower on the bottle. We are almost done with the gathering of materials and about to set it all up. The best thing about it is that it will be all hidden :) So bring on the 250r's, the Raptor's, and the Banshee's. What do you guys think about my project and does anyone wanna see pictures as we are hooking it up? Lemme know as I like a good discussion,

Nut

[wyndzer]

you talkn' about NAWS?

[matchstick]

What are you going to do for a fuel supply? NX makes a kit that will kinda take a little of the guesswork out for you. What size jets do you figure you'll need?

Sounds kinda retarded ta me,,,,I bet it will ride like a champ in the woods...:blah

[300exryder]

lets see the pics!!!

[ChadEXer]

It will last,,,,,,,,Id say 3 months at the most!! Any of you guys want to make a bet how long it will last??? Put it this way,,I wouldnt do it!!!

[Nutster_98]

Matchstick,
We are gonna use a small electric fuel pump to keep the fuel pessurized at about 4psi and it is looking like a 45mm jet on the nitrous side and a 50 mm on the fuel side. May have to alter those sizes to get it tuned right, but that's not a big deal.

Rico,
It will still ride perfect in the woods. I will have to have a switch to arm the setup and even armed it will only open at WOT. So as long as the switch is off I can ride it just like normal.

Will post some pics of the setup once we start to bolt it together. Should really make it fly :)

[Nutster_98]

Chad,
It should not hurt it that much at all. The only thing that really kills you with nitrous is that people want to try to cram too much in the engine and they don't know when to let off. At least that's how I understand it. But isn't that what the 4 year warranty at Honda is for? :)



Nut

Originally posted by Nutster_98
But isn't that what the 4 year warranty at Honda is for? :)



Nut


If it blows and honda finds out it had Naws on it..they gonna laugh at you and tell ya ta stick what's left of your motor in your butt...:eek: ;) Not tryin ta be a butthole about it,,but some dealers won't even warranty a quad with aftermarket exhuast on it..:(

[Nutster_98]

Rico,
I know what you mean. Actually I have talked to my dealer and he said that exhaust, jets, and air filter would not void it. Talking about nitrous, yes it would :) Nothing's gonna happen to it, trust me on this one. And if it does, I will eat my words,

Nut

[Pappy]

NOS is a go fast goody.....and you can get the fuel/air just right so it doesnt lunch a piston......but NOS is extremely hard on cranks. have fun with it:D

[sleestack71]

I could talk from experience, I had a kit on an 82' ATC185s for 2 years and currently have one on my car ever though I haven't used it in about 2 years.

As for your 400ex, if done and used correctly the engine will last.

Things to condider:

Unless you gear it really high all you are going to do is hit the rev-limiter faster. Gearing it this high will render your quad weak and feeble on lowend power when it is being ridden normally (off the NAWS). As you may know or not know this (hitting the rev-limiter while on the juice) could leathal to the engine. Automotive NOS systems have a fuel pressure switch that shuts the NOS off if a dip in fuel pressure is observed. I don't know if it is avaliable for ATVs, but the fact is that if you hit the rev-limiter while squeezing the juice and the ignition is momentaly turned off due to the rev-limiter, upon resumption of the ignition firing you will have an abnormal accumilation of fuel and NOS in you intake, enough to sometimes cause backfire strong enough to damage the engine.

A 400ex being an aircooled quad is prone to damage due to the additional heat the NAWS will create. In other words you must let it cool between runs and you have to be careful to not squeeze it for too long.

Frequent oil changes are imperitive due to the load being placed on the crankshaft and the heat build up.

Also, as a rule of thumb you shouldn't add more than 50% of the engines overall hp. A 400ex has about 28 hp so a 14 hp kit should be that max. I would actually make it 10 hp to compensate for airfilter and pipe mods that you may already have. Remember what you are trying to do is keep from over-stressing the crank, the crank doesn't care where the HP came from.

Other than that it's a lot of fun while it lasts which isn't very long if you plan to conceal the bottle (due to the small size of the hidden or "cheater" bottles).

[wilkin250r]

A nitrous kit will actually be MORE reliable than going with engine mods like a big bore and stroker crank. The engine mods will stress the engine ALL the time, while nitrous will only stress the engine when the button is pressed. And stress is stress, it doesn't matter where the power comes from.

Most nitrous problems occur because people think there is no limit to the horsepower increase, and try to cram too much in there. Just because you can add 100hp with nitrous, it doesn't mean the engine and transmission can handle it.

17hp sounds pretty safe. Anything more and you may want to upgrade to a heavy duty rod, and think about rebuilding the crank often

[sleestack71]

That is true, used properly it is the most reliable form of power increase because when you have it turned off it is 100% stock.

[Syrus]

Pictures, i wanna see many pictures .. heh

[northeast400]

I have run it in cars, stuff rocks!!!!!!! I say let it rip!!!!:macho

[wilkin250r]

One issue I have seen with nitrous is the bottles and nitrous pressure.

Obviously, when you hit the button and the nitrous flows, you lose bottle pressure. This is caused not only by decreasing the amount of nitrous in the bottle, but also because the tempurature of the bottle drops (Boyle's Law)

In cars, you can either: A) get a larger bottle, or B) get a bottle warmer.

You can't really do either of these on a quad. Since the amount of nitrous you are injecting depends on the jet size and the bottle pressure, you can't hold the button very long before you start decreasing the amount of nitrous you are injecting. Pretty soon you will actually LOSE power because your mixture is way too rich.

Yes, I speak from experience, I have nitrous on a 250.

[stevengates45]

NOS wont hurt your quad..... right.....:D

[wilkin250r]

I saw one of those little motorized scooters with NOS on it, it was selling on ebay a while ago....:huh

[matchstick]

Those jets sound a little big to me. So long as you keep your head with it though it will be fine. I've installed over 30 nitrous kits personally, and never had any trouble with any of them until someone got ignorant. My favorite saying is that you have to be smarter than the nitrous to use it!

[0240099r1]

nitrous is only as safe as its user if its installed right tuned,and you don't get greedy like most people do i even did about 5yrs ago on my 98 cobra i tried to put more into it than the intake would flow the fuel puddled in the intake and kabamm instant removel of intake but i learned and have had no problems on any of the cars,trucks,bikes and 4 wheelers i have put it on or have it on but i do think you need to check your jet sizes asap i don't know what system you are putting together but i always use around 20 thousandths jet in the nitrous and 24's for the fuel that equals to about 15 hp you can go up from there 17hp 22/26 and remember jet sizes are in thousandths..........hope this helps

[13RAZOR13]

youll snap a rod but i love it

[DGR Designs]

NITROUS!!! A-1 BROTHA! YOU SAID NITROUS! lol i hat people that go around throwin the term "NOS" around like they know something lol its gonna be sweet lol giv'er
~Dave

[Nutster_98]

0240099r1,
A 45mm jet works out to about .018, so that is close to your figures. I am a machinist and work in MM, so it is easier to say it like that.

To the dude that was giving me props on saying "nitrous", I know what ya mean about people says "naws or nos" :)


At any rate, when we start bolting it on, many pics will follow.


Nut

[0240099r1]

ok nut ijust wanted to make sure i am used to thousandths never delt with mm in jet making sure it sounded alittle big to me didn't want you to blow it up before you got to enjoy it well sounds like you got it under control.........later