Take a car like this 1991 Mustang LX with its 5.0-liter pushrod V8, and effectively double the horsepower with forced induction. What do you get? Well, without upgrading any of the engine’s internal components or the fuel system, if we were to guess, we’d venture to say an unhappy Fox. Fortunately, the fellas at Sweitzer Performance in Temecula, California, know better than to just bolt-on a power adder and let that Fox ride.
We tend to estimate on the safer side when it comes to sizing fuel components. — Mark Hutchison, DeatschWerks
Since Lee Sweitzer daily drives his ’91 LX, we would need an array of fuel components which could not only support more horsepower later by way of forced induction, but could reliably get Lee back and forth from his humble abode to his performance shop for work. After all, if you want his shop to install your own go-fast parts, he needs to ensure he can get there, first. In this segment, we follow along the installation process of the new fuel system, detailing the basics to get you started for that initial boost in power.
Give Me Fuel
DeatschWerks Fox Parts
• DeatschWerks 60 lb/hr fuel injectors, PN 18U-01-0060-8
• DeatschWerks DW300 Fuel Pump, PN 9-201-1014
• DeatschWerks fuel pump installation kit, PN 9-1014
• DeatschWerks In-Line Fuel Filter, PN 8-03-160-010K
• DeatschWerks DWR1000 fuel pressure regulator, PN 6-1000-FRB
As our friends at DW pointed out, the factory return line is rather small – about 1/4-inch in diameter. This means that we won’t be able to support big power yet, but there is hope.
“Most of the factory Mustangs will use a 5/16-inch fuel line for the supply,” Mark Hutchison, Marketing Coordinator for DeatschWerks, explained. “On many of the applications we deal with, 5/16-inch, or -5AN for an inside diameter size reference, will support around 750 horsepower. Beyond the 1,000 horsepower mark, a 1/2-inch or -8AN equivalent would be necessary. However, with the small return line, upgrading the fuel supply line to 1/2-inch/-8AN and converting the 5/16-inch supply to the new return line would be an economical solution for most Fox Mustang enthusiasts chasing more power.”
Pump It Up
According to Mark, our DW300 fuel pump flows 315 liters per hour of fuel at 55 psi, and will support more than 800 horsepower on gasoline (or 650 horsepower with the use of E85 fuel) on a forced induction application. Since we aren’t making any serious power right now, we opted for the single pump for the time being.
A side note for all of you folks planning to run a fuel pump voltage booster with your DW pump: Mark says that the company warranties all of its pumps for three years, and that many of its customers utilize a FPVB to get more out of the pumps. Beware, however, that DW’s warranty only covers the pumps with the use of a FPVB at 18 volts or less. It goes without saying that running any component harder diminishes the part’s life, but DW’s testing shows that its pumps are able to maintain flow while being used with voltage boosters within reason (around that 18 volts mark) while under warranty.
Injector Detector
It’s well documented in our previous articles with DW that the company has multiple calculators available at its disposal. In this instance, we used the company’s fuel calculator choosing the correct injector size. Mark tells us that our 60 lb/hr fuel injectors will happily support up to 800 horsepower on gasoline, and around 625 on E85, in a boosted application.
“We tend to estimate on the safer side when it comes to sizing fuel components,” he said. “If pushed, those numbers could be higher, but there is a risk of running out of fuel and the engine going lean.”
Regulators! Mount Up
According to Mark, there are several ways to plumb a fuel pressure regulator in the system. “Depending on how many lines are used, the location of the FPR and what other systems the FPR needs to access [vacuum or electronic reference] will determine how to set up the supply components of the fuel system.”
Once everything buttoned up, Lee and his crew were able to use the tuning data that DeatschWerks provides on its website, which enables tuning professionals to set the parameters from the beginning, and gives them a perfect foundation to work off of to make adjustments.
That wraps up this segment, folks. Next, we plan to catch up with Lee after he’s installed his newfound boost at Sweitzer Performance. Keep an eye out for that article in the future…