Installing a Nitrous System in an Elise

By Dave Kushner

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 10 lb 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.

Follow-up Questions from Ground Loop, Answers from GoLotus and Comments from OneFastLotus

Q:(Ground Loop) Where did you put the actual trigger? Purge switch/outlet? How hard was it to tap the wet nozzle into our fuel rail?
A: (GoLotus) With this system, the 'trigger' is simply a SPST toggle switch, which is the one I mounted on the lower seatbelt housing. 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.

Comments: (OneFastLotus) It's 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.

Q: (Ground Loop) What safeguards are there aside from the WOT switch.. is there anything to ensure revs are sufficiently up?
A: (GoLotus) 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.

Comments: (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.