Project: Maulin' Magnum

Turning up the late model Hemi (giggle) gas

In our May 2011 issue, we showed you how to install a basic nitrous oxide kit on a late model Hemi, our own Project Maulin’ Magnum. Using just a basic Nitrous Express EFI Hemi kit and out-of-the-box 50 horsepower jets, we picked up an astounding 1.1 seconds at the track in the quarter mile—proving that these cars can really take advantage of the big torque boost even a small shot of nitrous provides at wide open throttle.

We wanted to turn the nitrous dial up to 11, but were held back by the stock axles and hubs. By now, most of the late model community is aware that the LX/LC cars are hamstrung by rather weak half-shaft axles. You could probably build a bridge across Lake Erie using all the busted late
model Charger, Magnum, 300C, and Challenger axles littering drag strips from sea to shining sea. If you lucky enough to have a 2009
or later Challenger SRT8, then you have a factory enhanced rear end, the rest of you are in our boat.

Well, thanks to great products from The Driveshaft Shop, Richmond Gears, and Wavetrac, we’ve surgically removed the LX/LC Achilles heel and replaced it with robust and more capable rear end components. Stayed tuned to these pages for a full article on that upgrade soon.

For this month though, we’re going to upgrade our basic Nitrous Express kit to an advanced big dawg system and go for it with a 150 horsepower shot. Now we should note that the Maulin’ Magnum is a 2007 SRT8 with the 6.1L engine and most experts agree that a properly installed and configured nitrous shot of up to 150 horsepower is the upper limit for these SRT8 vehicles with stock engine internals. If you have an R/T
with the 5.7L engine, these same experts recommend you cap the joy juice fun at 125 horsepower shot.

There are a few more ingredients you should put into the nitrous stew when you step up the power. These include a fuel pressure safety switch, a purge valve, a bottle heater and either a window switch or progressive controller to give you some command over the entrance of the
bottle boost power.

Let’s talk about these components from bottle to spray nozzle--first up, the bottle heater. Why do you need a bottle heater? Well, two reasons. First, the flow of nitrous oxide entering your engine through the system’s nozzle is dependant on pressure—high pressure, high flow; low pressure, low flow--and low flow means lower power. The optimal pressure of the nitrous bottle should be around 900-1000 psi, and you’re just
not going to achieve this pressure without a heater.

Secondly, physics tells us that as a pressurized gas experiences pressure drop (i.e., your bottle is discharging) it loses heat along with pressure. This means your bottle gets colder as it discharges, dropping pressure and resulting power output even more. This is especially
undesirable for us—bracket and index racing requires consistent power output.