We decided it was time for...
We decided it was time for the Fridge to get healthy, so we cruised down to JDM Engineering with our Nitrous Express nitrous kit in hand.
If you're like us here at MM&FF headquarters, when you were a kid your parents told you to eat your vegetables and drink healthy things like milk and orange juice, as these foods were supposed to make you grow big and strong. While most of the MM&FF staff aren't all that big (except for around the middle), we like having strong things, like our resident project Lightning, the Fridge.
When done the right way, adding a nitrous-oxide kit to your romping Ford adds a measured amount of horsepower with just the flick of a wide-open-throttle switch. The question remains as to just how much the sauce can help a car-or, in this case, a truck-with as many bolt-ons that the Fridge has on it already. Is the juice really worth the squeeze? We set out to see by installing a Nitrous Express Ford EFI nitrous kit and accompanying GenX-2 accessory kit on the in-house SVT special.
Before we started drilling...
Before we started drilling and cutting, we looked around the truck to see where the best possible spot was to mount the bottle. Nitrous Express shipped us its Ford EFI kit with a 15-pound bottle, so we needed a decent-sized area to fit it. Putting it in the cab is not recommended, so the back left area of the bed was the spot of choice for the bottle.
Before we get into the meat of the dyno runs, let's review a bit. The Fridge features a Whipple blower, a JDM engine, a JDM exhaust system, and a custom tune that allows the SVT special to crank out 670 rwhp in race trim. Instead of going for the super-extreme horsepower number, we decided to go down a different road with this install. We wanted to showcase what the Fridge would do with the street tune. Rather than jacking up the boost and timing and loading the tank with C116 race gas, we ran the truck the way we would run it on a normal test-and-tune night at the local track. We came in with 93-octane high-test gasoline in the tank, drained it, added 100-octane race gas, hooked up the nitrous kit, and let her rip on the dyno. To say we were astounded with the results would be an understatement. The truck was run with 9 degrees of timing at the start, and the Whipple blower was pushing in 14 pounds of boost. The combination of no nitrous and 93-octane gas was good for a 565-rwhp baseline pull. More importantly, the air/fuel ratio was perfect throughout the run, so we knew that running the nitrous would not be a problem.
Take a look at the dash of...
Take a look at the dash of the Fridge. By the time we got done installing the kit, the needed switches for the kit would be cleanly mounted. The goal with this installation was to keep the truck as clean and as factory looking as possible.
We started off with a 50 shot of the juice and were rewarded with a rear-wheel-horsepower figure of 643. The air/fuel ratio measured 11.3:1 throughout the pull. According to Jim D'Amore of JDM Engineering, however, the 11.3 was a bit richer than he normally runs with a nitrous system. He usually likes to see the air/fuel ratio between 11.7 and 12.0. He also noted that upon tip-in, the engine was running quite rich. In an effort to lean it out while not changing anything within the tune itself, we switched to a leaner fuel jet when we stepped up to the 75 shot.
The 75hp dyno run netted a peak power number of 675 rwhp, but in looking at the curves for both horsepower and torque, D'Amore noticed that the truck was begging for more timing. Any change in adding timing to the engine would undoubtedly add power, but we also added in timing to increase reliability when we would spray the truck with the 100 shot. It's common knowledge that you can have too much timing and hurt the engine, but by the same token, not having enough timing can do damage to the powerplant as well. With that in mind, D'Amore added 1 degree of timing, and we stepped on it again. This time with the 75 shot, the truck turned the dyno rollers to 683 rwhp. The added degree of timing allowed the truck to pick up 8 hp.
"The truck wanted more timing, but with the street tune we kept the timing on the conservative side to accommodate for the varying quality of pump gas," D'Amore says. "With pump gas, 12 degrees of timing is on the ragged edge of detonation and reliability, and above 12 degrees is problematic. We could have run 11 degrees, but I didn't want to push things. Ten degrees as opposed to the 9 degrees will still be streetable with pump gas, but as you can see, it made a difference in the peak power numbers. Overall, though, with this combination, an everyday truck will make between 550 and 575 rwhp without the nitrous."