Muscle Mustangs & Fast FordsHow To Engine
Want some juice for your 4.6 Mustang, but you've got a returnless fuel system? Fear not--Nitrous Express now has a system for '99-up Stangs.
Once upon a time, drag racing was a sport for men only. That is, until the great Shirley Muldowney and Shirley "The Drag-On Lady" Shahan burst on the scene. Muldowney eventually won the Top Fuel world championship and Shahan had a successful string of factory-backed doorslammers.
Today, more and more women are building race cars and competing week in and week out at race tracks all across the country. Many of them are pretty darn good and the Ford ranks are filled with such competitors. One such person is Emergency Medical Technician Susan Bodnar of New Jersey and she owns the pristine yellow '99 Mustang GT you see here.
Having been around race tracks for as long as she can remember (and even working at Raceway Park in New Jersey for a few years), Susan had always wanted to try her hand on the straight and narrow to determine if racing might be something that would interest her.
From the first day that she laid eyes on a Mustang she knew that, one way or another, she would some day own (and race) one of her own. "My dad got my older sister started racing junior dragsters and it looked like a ton of fun," explained Sue. "As soon as I turned 17, I started racing myself."
Her first car was a '93 Mustang LX that utilized a 4-cylinder for power. "I always loved my '93 and it was the first Mustang that I had ever raced," she continued. "But it was a little slow (19 seconds) and so it wasn't all that much fun."
Soon thereafter, she purchased her '99 automatic GT and began modifying it. Susan is a hands-on girl who isn't afraid to get a little dirty as she installed her own ram-air kit and underdrive pulleys. As if that's not impressive enough Susan constructed her very own Mustang web site (eastcoaststangs.com) and with over 160 members it is quite the place to visit if your into Mustangs as much as we are.
After hovering around the high 13-second barrier for a year or so (with a 13.87 at 98 mph being the best), Susan decided that she wanted to take her racing operation to the next level. That next level would be achieved by way of a nitrous oxide set up. The problem, in case you didn't know it, is that virtually no one makes a kit for '99-up Mustangs because of their returnless fuel systems.
But we said virtually no one. Nitrous Express in Wichita Falls, Texas, does have such a system available and it's a custom one that is designed for engines that don't utilize a fuel return line. We were quite anxious to see how it worked so we ordered it for Susan's car.
Hurdling The Obstacles
In 1999, Ford redesigned the fuel system on the Mustang by eliminating the return line from the car. They did this mainly because the new computer system no longer needed the excess fuel to be returned to the tank (for emissions reasons). Of course, now that we don't have a return line to use to help boost fuel pressure when the nitrous is armed, it will make for installing nitrous on our Mustang slightly tougher.
"Our nitrous system is designed to be used on vehicles that don't have a return line on the fuel system," explained Brian Havins of Nitrous Express. "The kit taps into the valve on the stock fuel rail (for extra fuel pressure) and is adjustable from 35 to 150 horsepower, which in turn can decrease the car's quarter-mile times by over one full second."
With the kit in hand, we began the installation process by first popping the hood and evaluating the situation. We performed the installation at my house to make things easier and Sue brought her good friend Jay Sabo along to help with the install. Jay is very familiar with the ins and outs of nitrous installations (he and his friend campaign a Super Street Outlaw nitrous car in the NMRA) so he was brought along to ease the process.
He began by marking where the nozzle would be going on the air inlet tube before removing it to drill the necessary hole. Using a 1/2-inch drill bit, Jay drilled the hole in the tube and then fed the nitrous nozzle through it. After reinstalling the tube Jay and Susan placed the 75-hp jets into position on the nozzle (for a safe starting point) and tightened the two braided lines down.
After that Jay positioned the first of two solenoids on the engine. We decided to bolt the bracket for the fuel solenoid onto the idle speed motor (bolt) located in front of the engine. The braided line from the solenoid then connects to the fuel rail in the stock diagnostic valve position.
With the fuel solenoid installed, Jay and Susan began to tackle the nitrous side of the kit. The nitrous solenoid is a little more involved because a purge valve will have to be connected to it. The valve taps into the solenoid and tightens down onto the side of the assembly.
Jay chose to bolt the second solenoid at the rear of the engine compartment (on the firewall) because this was the position that had the most room. Using a 3/8-inch bolt he connected the small bracket to a metal tab located on the firewall. He then bolted on the purge valve tube that will direct the (purged) nitrous straight up past the hood and out of harm's way.
"I have been dying to install nitrous on my car for a very long time now," explained Susan. "I really don't even care about going a bunch faster. I just want to be able to purge my nitrous on the starting line." We hadn't even run the car on the nitrous yet and it seemed like Susan was hooked on her newfound power already.
The two solenoids were now on and ready for action but we still had to get the electrical power to them and this is where the wiring will come into play. The first step Jay performed was to mount the full-throttle switch to the throttle body.
"The full-throttle switch will ensure that the nitrous will come on when the car is at wide open throttle," said Havins. "If you are cruising around on the street (with the bottle on) at part throttle, you won't have to worry about the nitrous arming because the switch only works in the wide-open position."
Jay positioned the switch so that it would come in contact with the throttle bracket when the loud pedal is depressed about 7/8s of the way to the floor. After that, he mounted the relay onto the stock fuse box (under the hood) and ran the necessary wires to the full-throttle switch and solenoids. With that said and done, Jay positioned the on/off toggle switch to arm the system under the dashboard by the radio.
First he ran the solenoid wires through a factory grommet that was located on the firewall. He connected the hot wires to the switch so that when it is in the "on" position the system will arm. If turned off, the system will not operate because the solenoids won't have any power.
"An on/off switch is a very important safety feature to have," said Havins. "You don't want the nitrous to come on accidentally when the engine is not running or severe engine damage may result due to the lack of extra fuel when the engine is first cranked."
The next step is to route the nitrous line from the solenoid (under the hood) to the bottle that will reside in the trunk of the car. To do this, Jay recommended that the line be routed inside of the car (out of harms way) and began by feeding it through a small hole in the firewall by the computer harness. The line was fed through the car to the passenger side floor where Jay and Susan tucked it under the carpet for a neat and clean look.
After feeding the line into the trunk (around the rear folding seat), it was positioned to the location where the bottle would be. The next and final step will be to mount the nitrous bottle onto the floor so that it will be secure and safely mounted.
With the nitrous system pretty much installed and ready to go, the only step left to perform was to mount the actual bottle and bottle warmer. We began by marking where the brackets would be sitting (on the floor of the trunk) and then drilled the four holes for the bolts.
Making sure not to come in contact with the gas tank (what do you get when you mix heat from a drill bit with a flammable liquid such as gasoline?) we secured the two bottle brackets and then positioned the bottle inside of them.
After hooking up the burst valve fitting, Jay placed the bottle into position and tightened the wing nuts on the two straps. "The burst panel fitting is a very important item to have," explained Havins. "If the bottle is exposed to too much pressure (or heat) the valve will burst and allow for the extra pressure to safely escape."
With the bottle securely mounted in the brackets, Jay positioned the bottle warmer onto it and connected the two wires to the arming switch on the dash. "The bottle warmer keeps the bottle at a consistent temperature," said Brian. "Nitrous needs to be between 900 and 1000 psi in order for optimum horsepower to be achieved and the bottle warmer (by circulating electrical current through it) keeps the nitrous pressure stable."
Now that the bottle is installed and ready to go (we had it filled up beforehand at our local speed shop) the only thing left to do was to check for leaks and test the system out. One flick of the switch told the story. The bottle warmer was indeed doing its job and the (inline) pressure gauge gladly displayed 900 lbs. of nitrous pressure.
A small hit of the momentary purge button put an instant smile on Susan's face as a cloud of nitrous filled the sunny sky. The next stop on our to-do list was to track test this baby and see what we could expect from a 75 hp shot of the laughing gas.
As we mentioned earlier, Susan has run a best time of 13.87 at 98 mph in the GT. That number was achieved on an average day (80* and 50 percent humidity) by staging the car as shallow as possible, leaving the line at 1500 rpm (remember, this is an automatic), and cooling the intake slightly with ice.
On her first nitrous pass, Susan (with the 75 hp jets installed) ran a surprising 13.07 at 106 mph with a 2.04 60 ft. That run was very respectable considering that we had started off with the "small" jetting and knew that there would be a lot more in store with the larger (150 hp) jets. A backup run revealed a hair slower 13.08 at 106--no doubt due to the slightly hotter engine.
Next up were the 100 hp nitrous jets and they were just dying for some seat time. We popped them in and watched the scoreboard and got giddy as it flashed a 12.34 at 108 mph with a 1.70 60 ft. That's 7 full tenths and two miles per hour over the 75 hp jets.
Returning from the .012 blast, Susan mentioned that the car would probably run in the 11s with the 150-hp jets onboard. We were all hesitant to try them because there was no way of retarding the timing without an aftermarket timing adjuster (the engine has a fixed crank trigger system and the timing can't be adjusted).
Steeda Autosports in Pompano Beach, Fla., offers a 4.6 timing adjuster for '99 and up Mustangs and she will be installing one in an attempt to have some better timing control when using the nitrous. Susan was more than happy with her 1.5 second reduction in elapsed time and decided to wait on the 11-second trip until she could purchase a timing adjuster.
All in all, for under $600 we were able to take a high 13-second Mustang and damn near turn it into a high 11-second player in just one short day. There were no complicated engine modifications to perform such as heads and intake manifolds and no blower belts to worry about. The nitrous bottle lasted for well over six runs and would probably have been able to deliver another trouble-free pass but we decided to simply call it a day.
With the timing adjuster onboard and the 150-hp jets in place, we're sure that this stylish EMT will be getting to her next destination in a big hurry--11 quick seconds at a time.