There are plenty of threads on how nitrous works, but I am coming up short on safety details. When you piece together a nitrous kit, I feel like the chance for things to go wrong increases. What are the big things to look out for when shopping and installing old used components, and what to do about them? Let's compile a good list of tips.
Here's where I'm struggling currently:
- What exactly does NHRA look for when inspecting nitrous cars?
- Bench testing solenoids. Is air compressor enough? Or should you hook up to an actual tank when bench testing to see the full 1000 psi? Is that safe to do on your own?
- Bottle safety. How old is too old? Can old bottles be inspected and re-certified? Is there a cut-off age or other red flags to look for when shopping?
- Valve safety. These changed over the years, but there is little documentation. What's the difference in bottle valves over the years and is there anything to look out for here?
- Lines, fittings, gauges. Will any old AN fittings and braided hose hold the high pressure? Or do they have to be nitrous specific?
- Emergency shut-off valve. Can you simply rely on the solenoid to close or should there be a shut off valve accessible by the driver?
In for this discussion!
I've read a lot about nitrous systems on this page - http://www.nitrous.info/ - I think it is pretty good for DIY stuff vs just going to buy the name brand $$ stuff.
Another: Should nitrous lines run inside or under the car?
Know this when shopping. You can buy a brand new nitrous kit with everything necessary for $400, Nitrous Express MainLine kit. Picking up a second on the drags is worth the $400 in the budget, nothing is easier or cheaper except tires when it comes to cutting time at the challenge.
Run the line under the car, if the bottle is mounted in the passenger compartment of the vehicle you will need a blow down tube. I believe you are supposed to have an SFI jacket on at minimum if running an aftermarket power adder running under 13.99.
In reply to Andy Neuman :
Is that a wet kit or dry kit? Dry kit to me sounds cheap but way more complicated making your stock fuel system pick up the slack.
In reply to Robbie :
Wet.
This recommendation came from Pat on my $2015 challenge car. Went from a 15.0 to a 13.9 on a 100 shot.
Can be had cheaper through other retailers.
Nitrous lines between bottle and solenoid are recommended to be rated at 2000psi or more. You can use stainless brake lines as well, but I’ve found nitrous specific lines cheaper.
You can go through cabin, I have passed tech at ihra events with it inside or outside the cabin.
Blowdown tube will be required in datsanity so look that up. Make sure you get a valve that can take the necessary fitting, then making the line is a simple flare/nut/sleeve on 1/2” aluminum tubing.
Nitrous express shows in their mainline kit directions the fitting part number necessary, be warmed those bottles sometimes have valves incompatible with that fitting. I was told directly by a rep that because those are the cheap kit they use whatever valves are around, and the medical bottle valves don’t accept the automotive sized blow off cap. I shipped my bottle to NX and they shipped it back on their dime with a brand new lightning 500 valve in it to accept the fitting the instructions call for. Also, the ZEX fitting is the same but costs half as much.
bottles have to be recertified at I believe 5 years, then every 2 after that to keep being filled by someone else(i get mine done at Summit Racing currently). I’m going to get around this by making a filling station and buying mother bottles at Airgas.
You can use a microswitch somewhere on the throttle linkage to only allow it to be run at WOT, so if you lift it stops spraying. If you’re like me squeezing the last penny from the budget and rely on brain, foot, and finger on button all to communicate in perfect harmony when you get loose mid track, it can bite you in the rear(personal experience speaking).
Buy an sfi rated jacket, it will be inspected along with the car and your helmet.
Solenoids either work or they don’t so testing with compressed air is fine.
There are charts for jetting. You will need to know your fuel pressure to properly jet. If your engine has a fuel pressure test port on the rail, you can generally remove the schrader valve core and screw on a -4an line and feel your fuel solenoid that way. See below for that
Thanks a ton Patrick. This is one of those fields I don't fully understand yet so I want to play it safe as I go. Glad to have such a good group to learn from.
Maybe two microswitces in series, one on the pedal and one on the wheel, is a good idea. I've also read to put both solenoids on the same relay, so if one turns off they both do. And a kill switch on the dash for power to the relay.
What about nitrous filters? Do they really do anything?
I have never used one. I trust that Summit is using one when filling my bottle and I plan to get one when I start filling at home. Definitely do everything in your power to keep lines clean, tape over the ends when running them too so no junks get inside. I’m 20 years deep on nitrous use, and generally treat lines and solenoids and fittings like I was assembling a fresh engine - very clean and deliberate.
forgot as well, when I shipped my bottle to NX for the new valve, which they provided and installed free of charge, they sent me a prepaid UPS label. So I try to exclusively use their products because they take care of me unless I get a stupid deal on stuff for challenge use. So because the fitting wouldn’t work, they paid shipping both ways AND supplied and installed a $95 valve for me on a $395 kit. If buying new I’ll never recommend anyone besides them.
also just because the jet chart says something doesn’t mean that is what you’ll get, every combo is a little different. Start low and work up. I made a calculated 168hp more on 150hp jets on my challenge 5.3.
You’re overthinking this. Just make the bottle look like a fire extinguisher. Challenge tech isn’t that hard.
Just don't have a beef with Johnny Tran at the Challenge.
