Ultimate Control

Everybody likes to be in control. You tell the nitrous to jump, and with a little electronic help, it should ask, "At what rpm?" While those simple button-pushing deals are OK, there are more sophisticated ways to control your nitrous system and make it work more consistently. It's even better when you design a system that is completely automatic. That way, all you have to do is concentrate on driving. Let's take a look at some interesting ideas on nitrous management systems and how they work.

Let's start with a single-stage, 200hp plate system that you're hitting with a button mounted on the shifter handle. Our first mod would be to move the trigger from a button to a throttle-activated nitrous switch. This way, all you have to do is keep your right foot planted to engage the nitrous.

If you really did read "Nitrous Basics," you probably know what's coming next. Engage a 200hp nitrous system at 3,000 rpm and that's worth 350 lb-ft of additional torque. If you're already making 350 lb-ft at 3,000 rpm (which is a conservative number), torque at the flywheel now jumps to 700 lb-ft at 3,000 rpm! That's instant tire smoke, which doesn't help the e.t. So now we either delay nitrous onset, which is counter-productive, or introduce the nitrous in stages.

Stage Fright

Staged nitrous systems are not new, but the control that you can exercise over these systems is now much more precise. The simplest is a two-stage system. Many plate systems now incorporate two sets of spray bars that allow you to launch the car on the 100hp stage, for example, and then bring in the second stage of perhaps another 100 hp at a later point down the track. A variation of this idea is to launch with that same 100hp first stage, then turn off >> stage one and turn on a 200hp stage-two system. Then for stage three, you turn stage one back on to add an additional 100 hp for a total of 300 thundering ponies. Of course, all of this must be timed perfectly, which sets you up for electronic controls. For example, a simple window switch from MSD, Mallory, or NOS can be connected into the ignition system to track engine rpm. Then at the pre-set rpm, the module completes a circuit to a relay that triggers the nitrous solenoids. These switches also turn off the nitrous at a predetermined rpm. Let's say you have a separate electronic rev control set at 6,500 rpm. If you don't remember anything else from this story remember to never trigger a rev limiter while on nitrous. This is a great way to destroy your engine when the rev limiter starts dropping cylinders.

Think Slow

There's much more to nitrous than just toggling it on and off. All nitrous systems require an ignition retard based on the amount of nitrous injected into the engine.

For single-stage systems, you can just retard the initial timing before you make a run.

However, add a second stage and the greater amount of nitrous requires more retard. The best way to compensate is to employ a multistage retard box that retards the ignition timing the proper amount for each stage. MSD's three-stage retard will handle up to three stages of nitrous with a separate additive retard for each stage. For a three-stage system, this means you might want to retard the first stage 2 degrees, the second stage 4 degrees, and the third stage another 2 degrees for a total of 8 degrees of retard. Each retard is triggered when that stage is activated. Other systems that offer this kind of control are the Crane Mini-DEC digital Engine controller and the Mallory multistage ignition retards.

The Works

Up until now, we've talked about add-on electronic boxes that do one specific job. But the nitrous control market is far more sophisticated than that. The Jacobs Nitrous Mastermind offers multiple layers of nitrous control in one integrated component. The Jacobs unit offers a single-stage nitrous retard, an adjustable nitrous start rpm, a dial that establishes when the nitrous flow is at 100 percent, and a rev limiter that is designed to switch off the nitrous flow 50 rpm before the rev limiter engages. At the initial rpm trigger point, the Jacobs Mastermind pulses the nitrous and fuel solenoids, gradually increasing nitrous and fuel flow until it reaches the 100 percent flow rpm point set on the dial. The lower the 100 percent rpm point is set, the faster the nitrous system attains 100 percent. The beauty of the Jacobs Nitrous Mastermind is that it incorporates all these nitrous control features in one box. The Mastermind also comes with a fuel pressure sensor that will close both solenoids in the event of low fuel pressure while also triggering a warning light. This is a slick system that offers all the control you need all in one easy-to-use module.

If you are looking for even more integration, Holley has created an extremely powerful Pro Strip Annihilator CD ignition system that incorporates a fully programmable timing computer with four rev limiters and four rpm-activated nitrous switches. The system can be modified with a simple handheld Quickshot programmer.

We've hit just the highlights of a few simple techniques and components that can be used to manage the nitrous monster. The more control you have over any nitrous system, the less chance there is that you will have a problem. So put your foot down and exercise some authority over your next nitrous adventure. We guarantee it'll be fun.