We've been developing custom programming for 99+ LS1 PCMs to support nitrous systems and we wanted to let you know about the project.

Nitrous system makers typically recommend that nitrous shots only be activated at wide open throttle, and above 3000 RPM. Many stand-alone nitrous kits come with microswitches attached to the throttle linkage to activate the system.

Furthermore, in cases where large nitrous shots are run, it is usually necessary to add additional fuel to maintain proper air to fuel ratio and adjust the timing to reduce the chances of experiencing spark knock. Many nitrous kits will use a mechanism that adds fuel to the intake manifold separately.

Our custom PCM mod eliminates both the need for a throttle microswitch and plumbing additional fuel into the intake manifold. By wiring an "arming switch" to an unused input at the PCM, and the nitrous solenoid to the EGR control output, the PCM can decide when to activate the nitrous by checking whether the throttle position sensor is reporting a >90% throttle position and the RPM is between 3000 and 5500 RPM. All of these parameters can be adjusted.

Additionally, this PCM mod can optionally use an alternate timing and PE mode table so fueling and timing for the nitrous system can be adjusted separately.

We are currently testing this on our stock 1999 Z28, with a single nozzle, an .039" jet, and on the dyno this produced about 100HP at the crankshaft. This is interesting, but it's not at the power level where additional fuel is generally required. We're going to test an .055" jet on it soon, which should produce closer to 200HP, which, without a PCM mod, would require additional fuel (a wet shot). We're going to prove that this PCM mod can support a large shot without additional fuel injected into the manifold (because we can make the PCM add it for us with the alternate PE mode table).

We plan to make this feature both available in the form of a stock calibration file, for people that do their own tuning, and as an option with our full custom programming.

If this is something that you might be interested in, feel free to send us mail at info@trifectaperformance.com

 

whats a price range on one of those? would there be some sort of screen so you could view what is being done?

 

We were planning on selling the stock calibration files with the this mod at the introductory price of $74.99 but I'd be willing to work with anybody on the price that wants to help test it on vehicles other then 1999-2000 Z28s, since they use different operating systems and would require modified code.

The test vehicle we have (1999 Z28) uses a two switch/two LED control panel to indicates the status. The first switch arms the system, and the second switch is a safety kill for the nitrous solenoid (fortunately we've never had to use that!). The first LED indicates the system is armed, and the second LED indicates the nitrous solenoid is active.

If you use a data logger, you can log the state of the nitrous solenoid by logging the commanded EGR position. You can see the modified PE table and timing table come into play by logging the commanded air to fuel ratio and spark advance.

 

Very interesting. What tuner program is this based upon, or is it going to be for all packages? The one thing I noticed in your intro, was the greater than 90% activation point. Could this be tailored to be actual 100%. The reason being, on the 6-speed cars, some of us run the off rpm real close to the shift rpm, and lifting just a tad insures that the mega torque subsides during shift. Because sometimes shifting is not as accurate as we like. also, on a slippery track we may decided to short shift, and again lifting a tad is a way to get the N2O to stop flowing. If it was still flowing during shift, we would likely miss the shift as RPMs would continue to climb at a very fast rate, been there done that. Sent you a pm on some behind the scenes endeavors.
Robert

 

For LS1 (Gen III), the file containing the mod will be available in .BIN format, which can be imported into all of the major tuning packages (as far as I am aware). Yes, the TPS threshold can be set to anything from 0% to 100%.

Just noticed you are in the Seattle area. I should bring the car by and do a demo for you. (I'm in Duvall) ;-)

I'll look for your PM.

 

Im confused. Who can set this up? Just tuners?

Pics?

 

Great, sounds good. I will be around next weekend.
Robert

 

Too bad it doesn't include 98's

Strict tracks still require a WOT switch though.

 

I'll take some pictures and post. It requires a PCM flash to enable this feature. If you're a tuner, we can provide the calibration file by itself and you can do your own thing. If you're not a tuner, but would like this feature, we can send you a custom tune using our GT Tuner handheld programmer (see our website for more details) and instructions for hooking everything up. You'd just have to tell us the parameters under which you'd like the nitrous to come on (TPS, RPM, and fuel/timing changes required per the nitrous kit maker).

I can look into this for 98s also, chances are it can be done with this PCM as well. Good to know about the WOT switch - our system could be used in conjunction with a WOT switch for tracks that require this - you'd just wire the WOT switch inline with the 'arming switch'.

 

Hook up a fake one.

 

That was my initial thought, but by the time you get done faking one, you might as well wire it in.