Considering adding NOS to my 03 F7, EFI of course. What is the best system out there or most durable or consistant and most safe? I'm looking for people who have first hand experiance with it. It also is going on my trail sled. Just want it if I need it in a pinch or if I do some lake drags or some grass drags in the off season.

I have used NOS on some race sleds and currently on racing karts, unfortunately no expieriance with EFI. I also have used it extensively on cars. the answer is a solid understanding of Nitrous and good back up systems. NOS will be safe with your engine if you understand how it needs to work. In both karts and sleds, I use a standard 'Car" fogger nozzle mounted in the intake manifold. It is important to keep the Nitrous/fuel ratio correct. this is done by staggering the jets in the nozzle and most important, keeping a constant bottle pressure. The pressure in the bottle will change drasticly with changes in the temp of the bottle, easily by several hundred PSI. Regaurdless of the Nitrous jet size, it is being forced through by the pressure in the bottle, that means when its either very cold ambient there will be considerably less pressure then when the bottle is hot, remember that under hood temps can be much greater then ambient temp, or mounting the bottle near the pipe can drive the temp up quickly throwing off your A/F ratio quickly. If your jetted for 600 # of bottle and heat drives that up to 800#, you will burn it down. Always have a bottle pressure gauge on the sled and look at it before you push the button. Another thing to think about, Filling the cyl. is RPM/time related, at 6000 rpm you physicly have more time to fill the cyl. then at 9000 rpm. I interfaced a MSD, RPM chip off the automotive line into the system. This stops the system from being activated at anything below what ever RPM chip you choose, For racing I used 9000 RPM. This also serves the convienent purpose of not accidently hitting the button when your not ready, then having to chase the sled down after you pick yourself up off the ground
I also ALWAYS use a full throtle switch, which only allows activation at WOT. Another must have for me is a elec. fuel pressure switch, these are ajustable to what ever fuel pressure you use and if for any reason the pressure drops, will shut down the system before it becomes to lean and detonates. The best advise is to start very small on jets and build up to the level you want, use EGT gagues to moniter you jetting. Most engine failures are a result of not controling the system. Good Luck
Bob Vehring
www.4cyclecentral.com

Go with the boondocker with adjustable pressure regulater.Don`t have to worry about bottle pressure or heating the bottle as it is designed to operate at around 420 psi or less.No need to change jets ,just turn up the pressure regulater for more power.The boondocker box moniters bottle pressure and adjusts fuel accordingly.Pretty easy to use system for the trail guy .Base kit goes up too 70 hp

From what I know, NOS only has one system available for snowmobiles.

http://www.holley.com/03403NOS.asp

NOS is a brand name ...plenty of N2O systems available for sleds

Excellent replies guys, I know there is alot of stuff available for carbed stuff, not too much for efi on sleds. I know Boondocker and what about Boss Noss? I guess I'm looking for somebody who has used it on a EFI F7 and their thoughts on it, if thats possible.

Boondocker seems logical but others may work just as good or better?

I guess you don't know much then.

BoonDocker For Sure!! Great system.. 35 40hp shot 91octang 50hp shot or higher Recommend Some race gas mix 65 hp or higher Race Gas.. I highly Recommend You talk to someone to get a baseline Setings For the boondocker box!! I run the the system on My 06 Efi Firecat And its awesome Longest I have held the Botton Is 12seconds But dont recommend that. 8 seconds max Nitrous is like playing with FIRE Never no whats going to happen! Good luck bud!

Cool, thanks for the info man!

I ran a boondocker set up on an efi f7 mod on asphalt.simple to use. I have to admit its awful nice changing jetting with the push of a button.

The Big Thunder systems work good.....

boss noss is great uses own power/batteries we use the carb system without a controller for fuel!!! on the efi!just tune your efi the same as you would with out n20 with in line or pressure reg than slap on boss noss tune according to instructions run premium for the 30 shot and haul ass all day! we run the crap out of this thing holding button all the way acrossed the lake 1/2 mile to 3/4 completly stock 03 f7 efi non welded crank only clutching! ready for this? jumped to 60hp shot nozzles from boss noss 120mph 1000 ft ice wanna see heads twisting off when this stock improved f7 runs ,big bores, pipes porting expensive burndowns? dont bother if you burn a jug just replace with stock piston/cyl and go and i mean go.this sled is trail ridden all day every day every way. dont recommend 60hp with out reliable premium

I second the Boss system. Very impressive

Holtzman system works good and is easy to install, ran it on one of my asphalt sleds last summer, stock motor 9.08 @ 140

works great

I tuned a boondocker system for a lad in Quebec this past winter, he was running a F-7 based Cutler with a synergy regulater.

Base engine dynoed at 208 hp and we ran a 50 hp shot into it, to make over 250 hp.

Sled ran bullet proof once it was setup.and was really easy to tune.

Sled ran 165mph in 2000'

Cliff yeatman
Advanced DYno

Boondocker works better