Nitrous Installation Notes

[Dave]

Nitrous Oxide? Ah, yes, the subject that breeds controversy on virtually every automotive newsgroup. Yes, it’s true; I’ve installed it on my Elise. I hesitated posting these notes, as it surely will invoke a magnitude of flaming - not the first (or last) time for me I’m sure. But before you gather to light your torches and circle the wagons, at least hear me out…

I’m hardly a nitrous guru (or car expert for that matter), but can say I’ve been installing systems since the early 80s; five of my own personal vehicles, and several for friends. I’ve had my head under hoods for over 30 years now…always loved cars. I don’t hold a candle to many of you in this forum – there are some incredible minds here. I’m a conservative installer with safety being paramount - I don’t push any vehicle to its mechanical limits, or even close. I’m not out to impress anybody with track times or horsepower numbers, but rather enhance my own driving experience. I’ve always been picky about functionality, with aesthetics coming secondary. Conservative also implies that I’m not a nitrous junkie, and always have my finger on the trigger switch – not a good idea. In fact, in the 3 months I've had this system installed, I've refilled the bottle only once. No, I’ve never destroyed an engine, or even caused any damage whatsoever (via nitrous). I can say that with complete conviction.

The reputation of nitrous has been clouded in the past, and I feel it’s primarily due to the lack of experience of the installer, coupled with that ‘need to be the fastest’ mentality. The nitrous manufactures further complicate matters with attractive advertising and promises to awaken the beast under the hood, provoking amateurs to do-it-yourself, with some probably over beers. There are plenty of horror stories out there, and I’ve witnessed a few myself. I pity those who slap on a kit, jet it to the highest HP setting, and go out looking to take over the street racing world. The best-case scenario is that they’ll only blow their engine into dust. Nitrous can be damaging and even dangerous when used improperly, just like anything else. We all know that. I am, however, a firm believer that if it’s used properly and conservatively, it’s an effective (and safe) way to increase vehicle horsepower, at a fraction of the cost of forced induction. I didn’t come here to sell you on nitrous, or even recommend it for that matter – it’s clearly not for everyone. Most consider it too ‘radical’ or ‘taboo’ - it’s obviously a personal choice and commitment. Also, I’m not endorsing NX, NOS, ND, or any other company that makes these systems.

Before installing on the Elise, I wrestled with some of the variables: warranty, longevity, expense, etc. I must admit it probably took a couple of weeks for me to decide, and some sleep was lost along the way. I researched the Toyota/Celica tuners websites and groups until I couldn’t stand to look at them anymore. So, why didn’t I just go out and buy a Z06 or Viper? No thanks; I’m crazy about this car (and Lotus for that matter – this is my 3rd). Anyway, I’m very happy with my decision. The 2ZZ is very receptive IMHO, and the results are MUCH better than I had anticipated. Zero fuel pump delivery or timing issues with the wet system. The stock Elise is without a doubt a quick car. With the nitrous engaged, it becomes a fast car. The ‘boost’ is phenomenal; similar to the kick-in-the-pants you get from the second cam. If any owners are passing near Dayton, send me a pm & stop by for a look/drive to experience this acceleration…you won’t believe it. I’ve also shot some in-car video which I need to convert to mpeg…I’ll post a link when I do if anyone is interested.

I’m off my soapbox and here's some brief install notes. I didn’t post a complete step-by-step set of procedures, as I’m sure few others will elect to do the install.

Kit: Nitrous Express Stage I EFI Import Kit (wet).
Jet: 50 shot, Shark nozzle (35, 50, 75 100 jet options are included).
Installation Time: ~6 hours.
Cost: $575, bottle fills ~$40.

The 10lb bottle fits perfectly in the left side of the trunk. The bracket was secured to the floor using some short lag bolts. I painted it SY to match the car (www.towerpaint.com). Having installed a PC645 dry cell battery, I found the excess space in the battery box a perfect place for the solenoids & relay. I secured them in place with cable/wire ties to facilitate an easy removal of the system. I also like the fact they are segregated from the hot engine compartment.

I had already installed a FF cold air induction kit (love it, BTW). The coupling made a perfect injection point for the Shark nozzle. The preferred point is approximately 3-5 inches before the throttle body. I elected to use a 50 shot with the Elise. From my non-scientific research, most of the 2ZZ tuners consider 50 to be ‘safe’, 75 acceptable (and most common), and 100 marginal/take what you get.

The WOT (wide open throttle switch) mounted to an existing bolt on the back of the throttle body, using the supplied universal bracket. You just need to bend the bracket about 45 degrees toward the linkage.

The system power switch was mounted to the lower seat belt housing…plenty of room there, out of the way, and hardly noticeable. Routing the wiring was somewhat of a pain. I finally removed the left rear speaker and drilled a hole through the firewall. The exit point was just a few inches from the WOT. It ended up being a very clean install.

EDIT: One follow-up note. I have finished up with the gauge bracket/nitrous monitor. I added a meter to monitor the voltage while the bottle warmer is operating. Also, I installed a yellow LED (Radio Shack) to the bottom of the bracket which indicates when the heater/warmer in on. It's a nice peace-of-mind feature to have in the event the warmer pressure sensor were to fail. Zero voltage issues thus far with the heater and PC625 battery. A bottle warmer in cooler climates is mandatory. The second gauge is nitrous bottle pressue, with electric sender. It works fantastic (about $260 on the internet). I've also updated a few photos.

[Dave]

Originally Posted by Ground Loop

Holy Moley!

No need to make excuses around here.. I'm drooling over the pictures, yellow bottle and all. Very clean installation.

Where did you put the actual trigger? Purge switch/outlet? How hard was it to tap the wet nozzle into our fuel rail?

What safeguards are there aside from the WOT switch.. is there anything to ensure revs are sufficiently up? I've never run NOS, but haven't ruled it out if it can be done with minimal risk and wear.

I think you have the first NOS Elise on record, and I, for one, look forward to your video and long-term experience with it. Awesome work!

With this system, the 'trigger' is simply a SPST toggle switch, which is the one I mounted on the lower seatbelt housing (hard to see on that lousy picture above). When on, the WOT is hot and full gas pedal deflection will activate the system. Nitrous requires you pay attention to the tach, but we should all be doing that anyway. You need to avoid activating the WOT below 3K RPM, and of course hitting the rev limiter. That's where that red light really comes in handy I've been looking at adding a second light, or somehow enlarging the stock one.

The purge is not included with the kit. It's next on my list now that I'm satisfied with the core install. The only item I installed aside from the kit was an inline fuse holder...can't believe they don't supply one. It's connected to a fused accessory outlet, but I like the added redundancy. I used a 10A, which correlates to the relay wire gauge.

BTW, thanks for the other kind remarks...

[OneFastLotus]

Originally Posted by Ground Loop

Holy Moley!

No need to make excuses around here.. I'm drooling over the pictures, yellow bottle and all. Very clean installation.

Where did you put the actual trigger? Purge switch/outlet? How hard was it to tap the wet nozzle into our fuel rail?

Its not a direct port set up.

The trigger is his little switch he showed a picture of. You flip that on and it arms the system. Then when he goes wide open throttle it trips a switch on the throttle body which completes the circuit and hits the fuel and juice. The fuel and gasoline both come out of his "fogger" which you see going into the blue silicone line there. It's a Y type fitting with two nozzles. Red lines are fuel, blue lines are nitrous. You choose what size nozzle for fuel, and what size nozzle for nitrous. When he goes WOT the juices flow and atomize somewhat...this mixture sucks into the intake.

Without a purge what happens is this. He flips the switch, see's a Porsche Carrera GT ( ) so he floors it and goes WOT. There is a little air in the line so the first thing to come out of the fitting is fuel. The extra fuel BOGS the car down pretty bad, then POW the nitrous finally fills the line and starts entering the intake too...then DOUBLE POW, he goes from BOG to FOG and takes off.

The crappy part about nitrous in my opinion is that unless you pay the scrilla for a remote bottle opener you sometimes find yourself without the juice. Also you'll need a bottle warmer for the cooler months.

I had nitrous on my 5.0 miata. I sitting at a light to get on the interstate one day when a mustang SVT pulled in behind me and revved on me. I guess he saw the rollcage and also heard my car loping. His car sounded MEAN too, and he had a giant tach, and a large VORTECH sticker across the windshield. So I though, oh **** he's gonna try and jump on me when we get on the interstate.
Pathetic me, pops the trunk, gets out of the car at the light, turns my bottle on, then run back into the car. I gave the guy a wink and a smile. The guy in the stang behind knew EXACTLY what I was doing and was laughing his ass off and gave me thumbs up.
I vowed to get a remote bottle opener after that, but some arsehole decided he wanted my nitrous system more than I did, it got stolen about a month later.

[Dave]

Originally Posted by OneFastLotus

Without a purge what happens is this. He flips the switch, see's a Porsche Carrera GT ( ) so he floors it and goes WOT. There is a little air in the line so the first thing to come out of the fitting is fuel. The extra fuel BOGS the car down pretty bad, then POW the nitrous finally fills the line and starts entering the intake too...then DOUBLE POW, he goes from BOG to FOG and takes off.

The crappy part about nitrous in my opinion is that unless you pay the scrilla for a remote bottle opener you sometimes find yourself without the juice. Also you'll need a bottle warmer for the cooler months.

Good points Jen,
Yes, a purge is a must for this system. Nitrous Express claims 'A purge valve is usually worth about one tenth decrease in E.T.' Maybe, but it's value to reduce the chance of detonation from a fog filp-flop is more important to me. It's also imperative to check the jets regularly for clogs. Again, I wanted to test the core install prior to throwing any more cash at it. I ordered the purge last week ($120) and pressure gauge ($55). The bottle warmer is sitting on my bench and I'll install that come fall.

A remote opener would probably be a good investment for off-track use. BTW, I would love to have seen you jump out and spin the top of your bottle! Guessing the Mustang stayed in your mirror?

[Dave]

Originally Posted by hpman

No consideration to retard timing???

Looks clean I like it.

Some consideration was given, but the NX Stage 1 wet kit works with the factory fuel system/computer and does not require any timing retard. I've run it through all the gear cycles (except 6th), and the performance has been great...not one single backfire/detonation or bog. Regarding octane, 92-94 octane is generally recommended for up to 50 shot. One nice thing - I have a Sunoco nearby with 94.

[Dave]

Originally Posted by NMRJock

I'm not Nitrous savy. I've always assumed a '50 shot' means 50 horsepower. True? How long does a bottle last? I know it depends on how much you use it, but some idea would be cool.
I'd like to try Nitrous on something.

Yes, the shot/horsepower are synonymous.

Usage (quoted from the NX website for 100 shot, so just interpolate): The formula for calculating your nitrous usage is .8 lbs N2O X 10 seconds = 100 horsepower. I.E. If your system is jetted for 100 horsepower it will use .8 lbs of nitrous for every 10 seconds of usage.

[Dave]

Originally Posted by hpman

91 Octane is the max at the pump here in CA. That could be a problem???

Where did you tap into for the fuel input/mix with the nitros??

The 91 could be an issue with a wet system. You can buy octane boosters at the local auto store to supplement...usually runs about $6/bottle/tank. The booster from NOS seems to be the most popular. I tapped the fuel line where it runs just below the coolant overflow tank. The supplied T adapter/tap is the correct fuel line diameter. NOTE: The fuel line is hardened PVC. I split the line on my first attempt to insert the tap. I then used a blow dryer to warm then ends and soften them a bit...worked perfect.

[OneFastLotus]

Originally Posted by mrluky

quick question:

can you go WOT without Nitro if the switch is off? even if the bottle is open?

Yes.

If you're wanting to go out and "ready" you can simply turn the bottle on and drive around. You can go WOT all day long and not use the NOS.

Unless you throw the switch nothing will happen, even with the bottle on.

[Dave]

As promised, here is an update on the NX nitrous install. Hopefully this won't kindle up the fire like my Ragnorak wing install After ~5 1/2 months, the system and car are still running perfectly. I've been testing the 75 shot, and the motor has been very receptive. I find this is the most common shot used by various Celica tuners. I've refilled the bottle 6 times, averaging about 8lbs per fill.

Additions since the original post:
1)Bottle warmer w/ pressure temperature regulator (opposed to thermostatic). You can set the sensor to heat the bottle to exactly 1000psi...it's much more accurate than thermostatically controlled types. The warmer is absolutely necessary in cooler climates to maintain nitrous pressure, which being low could result in rich fuel mixtures. I also added an LED to the gauge bracket (at the bottom, 3rd photo) to indicate the warmer status. This was just an additional safety feature for visual monitoring of the heater from the cabin.
2)Remote electric tank pressure gauge. I like now being able to monitor the tank pressure while driving the car. I removed the mechanical one on the bottle. A sender is mounted on the tank, along with the warmer sender with a dual-manifold adapter.
3)Voltage gauge. Having a smaller PC625 battery, I was concerned I may have to return to stock for the bottle warmer. This ended up not being a problem...the drycell handles it well. Even without the heater, I think a voltage gauge is not a bad idea to monitor overall electrical health.
4)Bottle blanket. Helps to insulate the bottle and provides some cosmetic improvement. My wife stitched on a Lotus patch. The blue color (NOS brand) isn't really ringing my bell, so I'm looking for a black one.

For the gauge/sender wiring, I ran shielded cat 5 cable from the gauges to the boot. It routes fairly easy by removing the center console and feeding through the spine, around the driver's seat, then through the firewall. The hardest thing I ran into was finding an accessory 12V source under the dash. I ended up using the wire that feeds the indicator light on the emergency flasher button...worked perfect. Everything installed very clean, with no exposed wiring.

I ended up *not* installing a purge system (purges nitrous line). Normally with a front mounted engine and trunk mounted bottle, you have a nitrous line which is ~15' long. Since the Elise bottle is near the engine/intake, I bought a custom 3' line which IMO leaves relatively negligible amounts of air and vapor in the line. I've also switched to cooler plugs to help return the spark plug tip to a safer operating temperature more quickly - in between or after nitrous use. EDIT: Here is a good site with some nitrous FAQs: http://www.go-fast.org/z28/new_to_nitrous.html

[Dave]

Originally Posted by vidoprof

So here is a quick question. I understand that 50 shot gets you 50hp and so on, but how long does that last? Meaning if I am doing 50mph and hit it, how long do i get the extra ponies?
Thanks
Ryan

Technically, you can run it as long as you maintain the recommended N2O pressure. That doesn't mean run the bottle dry; with the NX, that's 1000psi. However you're asking for trouble if you hit the track and burn it continuously. It should only be used in moderation, not to mention bottle fills run about $40 bucks. Regarding bottle duration (from earlier in the thread, typical bottle is 10lbs): The formula for calculating your nitrous usage is .8 lbs N2O X 10 seconds = 100 horsepower. I.E. If your system is jetted for 100 horsepower it will use .8 lbs of nitrous for every 10 seconds of usage.

Originally Posted by evomind

can i ask why u went with a wet system vs dry?

The wet system is an easier install. No need to retard timing, and it utilizes the existing ECU fuel pump directives. If I was going to drag race this car, and get really serious about squeezing 1/10th off, yes I'd probably do a dry instead...

[Dave]

Originally Posted by JnC

In regards to detriments, aside from avoiding situations where knock could occur, I guess the only thing you have to be concerned about is a bottle explosion. To my understanding that would only happen if the temp regulator failed on the bottle heater, and the heater kept on heating, correct?

The bottle is actually rated at a much higher psi. According to the manufacturer of the warmer, even if the thermostat were to fail, it would never attain a pressure anywhere near explosive. On my gauge bracket, I did install an LED which is wired directly to the heater leads - just for peace of mind I guess. Having the nitrous pressure guage in the cabin is also a plus.

Originally Posted by crudson

How about some 0-60 times?

With a G-Tech Pro (subjective, but my only resource) I average 4.0 - 4.2. A better driver than me might be able to break the 4 mark.