Pulley, Fuel, & Tuning Upgrades Boost 2018 Mustang Over 941 RWHP

When we last checked in on Lethal Performance’s Goldmember project, the Whipple-supercharged 2018 Mustang GT ran a 9.79-second quarter mile thanks to more boost, E85 fuel, and a custom calibration. Breaking into the nines checked a goal off the list, but Team Lethal wasn’t ready to rest on its laurels, so more upgrades were in order and they produced big power.

To keep belt-slip at bay, Goldmember headed to Power by the Hour in West Palm Beach, Florida, for an upgrade to Whipple Superchargers’ 10-rib supercharger belt drive system and Lethal’s new return-style fuel system for the dual-fuel Gen 3 Coyote.

Every time we do something to this car the results keep getting better and better and exceeding our expectations. — Jared Rosen, Lethal Performance

“We know from past experience that the six-rib setup can only take you so far,” Jared Rosen, CEO of Lethal Performance, explained. “Even though the car makes great power and runs well at the track, the plan to go deeper into the nines really requires us to upgrade to the 10-rib setup. More belt-to-pulley-surface ratio prevents belt slip and power loss.”

Lethal Performance continues to push the performance envelope of its Whipple-supercharged 2018 Mustang GT, which runs under the Goldmember moniker. Its latest updates pushed the Gen 3 Coyote’s output well into the 900-horsepower range. (Photo Credit: Lethal Performance)

“The 10-rib system allows better supercharger pulley traction for higher boost levels, this results in less belt stretch, more tensile strength and less slip,” Dustin Whipple, Vice President at Whipple Superchargers, explained. “The result is higher power when boost levels are high and better strength for two-steps and rev-limit abuse.”

That extra grip definitely paid off as the new combo was able to easily support six more pounds of boost, and would support even more if the engine was up to the task.

“We went from running the six-rib setup with the stock balancer and the 3.625-inch upper pulley that made around 12 psi to the 10-rib setup using an ATI Performance 20-percent overdrive balancer and a 3.75-inch upper pulley,” Jared said. “The new combo yielded us 17-18 psi. We’ve got a 3.50-inch upper pulley but we were a little hesitant to run it as that would put us around 20-21 psi, which is a little suspect for the stock motor.”

Feed The Boost

Even keeping the boost at reasonable level might have been dangerous had Team Lethal not opted to feed Goldmember with an ample supply of E85. That meant making further updates to the fuel system, which led the company to develop its own return-style upgrade.

It is absolutely astonishing that Ford has given us such a powerful package. — Dustin Whipple, Whipple Superchargers

“The return-style fuel system was definitely in order for taking this car to the next level. We did great with the 415-lph DeatschWerks pump and JMS FuelMax fuel pump voltage booster. However, to safely support the power we planned on making with the 10-rib setup on E85, a return-style fuel system was needed,” Jared said. “There’s no reason to ever skimp on a fuel setup. That’s the backbone of the car. If you cut corners or do the just the minimal you end up paying for it in the long run.”

To support more horsepower and lower e.t.’s, Team Lethal upgraded its project Goldmember with a new return-style fuel system (see sidebar) featuring two regulators and a 10-rib belt drive upgrade from Whipple superchargers.

Of course, Lethal has fuel systems for earlier Coyote applications, but it was quite as easy as just installing one of those on the latest Mustang. The dual-fuel arrangement on the Gen 3 Coyote makes it even more essential that the system delivers a stable volume of fuel.

“This system is slightly different then the fuel systems we’ve done in the past. The reason is that the ’18+ Mustang is both port and direct injected, where the previous year Mustangs were just port injected,” Jared explained. “So, we wanted to make a setup that provided the high-pressure fuel pump on the direct-injection side with solid static pressure so there is no pressure drop at all. In addition to that, it provides more volume on the port side. This required us to use two fuel pressure regulators and slightly different plumbing.”

divisionX Fuel System

• divisionX fuel hat

• Fragola pre-assembled PTFE fuel hose

• Two Aeromotive fuel-pressure regulators

• Three Walbro 465-lph fuel pumps

Return-Style Tuning

Having this system in place allowed Lund Racing to create a new custom calibration (see sidebar below) to make the most of the increased boost with the confidence that there would not be a lean situation that could be catastrophic.

“The fuel system is a definite requirement for this power level because the factory direct-injection pump cannot keep up with the fuel demand from the power level and the E85 fuel…” Jon Lund Jr., of Lund Racing, said. “The lift pump feeds both the DI pump and the port injectors. Pressure drop can result in a bad day in some scenarios. Having a full return fuel system with enough fuel pump delivery allows the pressure to maintain a constant feed to the DI pump, as well as a constant feed to the port injectors, so nothing goes hungry.”

The cornerstone of the 10-rib belt drive upgrade is one of ATI Performance Products’ Super Dampers. Not only does it provide a wider 10-rib sheave, but it also carries an SFI certification that ensures its legal at the racetrack. Moreover, Lethal opted for an overdriven unit, which helped pump up Goldmember’s boost to 18 psi.

With the out-of-the box kit installed, this combo produced over 755 horsepower and 560 lb-ft of torque. After the latest round of upgrades, this boosted 2018 Mustang put down 941.42 horsepower and 742.36 lb-ft of torque at the wheels on the Dynojet chassis dyno at Power by the Hour.

“I’m extremely happy with 940 rear-wheel horsepower on a stock long-block Coyote,” Jon said. “These Gen 3 Coyote engines never cease to amaze me.”

Calibrating The Changes

As is tradition for Lethal Performance, the company turned to Lund Racing to create a custom calibration for its project’s latest combination. The biggest change to account for was obviously the return-style fuel system.

“I had to make a few small changes to accommodate the return fuel system. Fortunately, because these cars have an OEM lift-pump rail pressure sensor, we’re able to tune it similar to how we tune ’07-’14 GT500 fuel systems and retain the FRP sensor for safety!” Jon Lund Jr, of Lund Racing, explained. “After that, it was just a matter of reviewing logs to make sure fueling was good. We left the timing the same as we had it before and the added boost picked up the power!”

Even remote-tuning the car, it wasn’t that big a deal to put such a traditional fuel system in the modern Mustang, thanks to his experience with previous high-performance Mustangs calibrations.

“It’s not challenging at all to tune the return system in the 2018 platform,”he said. “I had reviewed the calibration closely when we got access to it and realized a lot of similarities to GT500 fuel system logic on the port injection side, so it wasn’t difficult to carry any of that tuning strategy over.”

The resulting calibration obviously delivered in a big way on the dyno.

The Gen 5 Whipple blower is pretty impressive as well, especially when bolted to the latest 5.0-liter engine.

“The Gen 5 has been incredibly successful. This supercharger has exceeded our expectations and has really made some of these cars run some blistering times,” Dustin said. “Not to mention that Ford chose it over all others for the all new Cobra Jet, which is an incredible honor.”

Ridiculous Results

“This car is ridiculous!” Jared added. “Every time we do something to this car the results keep getting better and better and exceeding our expectations. We are making 941 rear-wheel horsepower on a stock-motor car with just a blower, fuel system, and some bolt-ons. To think we went 9.79 at 144.6 MPH with over 150 rear-wheel horsepower less than the car is making now. We’re really excited to see what it’s going to do with the new power. If that’s not enough, Jon Lund Jr. grilled and baked some changes into the tune that should work well for us at the track.”

With its newfound power, the Lethal 2018 Mustang now awaits the gradual march toward fall and more performance-friendly air temps.

As compared with the out-of-the-box Whipple system, the tuned-up kit with a mega fuel system, a 10-rib belt drive, and a custom calibration added another 185.88 horsepower and 181.85 lb-ft of torque to Goldmember’s rear-wheel output. Its new 941.42 horsepower and 742.36 lb-ft credentials should deliver much quicker elapsed times at the drag strip.

“We’re looking to take Goldmember deeper into the nines and then decide what’s needed to get that 8-second pass,” Jared added. “It’s almost that time of the year where it starts to cool off down here. Racing in the Florida summer heat isn’t that fun and never gives us the results other people see in cooler parts of the country, so we’re here with open arms awaiting our fall/winter racing weather.”

So the chase for eights will have to wait until South Florida cools off, but when it does, it will be fun to see just how quickly this car can run.

“Making 941 rear-wheel horsepower is just amazing for a stock engine with a supercharger, exhaust and E85,” Dustin added. “What’s even more amazing is that it can maintain this power and live. The supercharger and engine have more to go as well. This is just the start of it! I see some eights in Jared’s future. It is absolutely astonishing that Ford has given us such a powerful package.”

Goldmember 2018 Mustang Mods

• 3.0-liter Gen 5 Whipple supercharger

• 3.75-inch blower pulley (18 psi)

• E85 fuel

• 132mm Whipple throttle body

• ATI Performance Products overdriven Super Damper

BMR Suspension Bread & Butter upgrades

• BMR Suspension MagneRide springs

• Boundary Oil pump and crank sprocket gears

• Driveshaft Shop carbon fiber driveshaft

• Hoosier rear slicks

• Injector Dynamics ID1300X fuel injectors

• Kooks long-tube headers and midpipe

• Lethal Performance resonator delete

• Lethal Performance axle-back exhaust

• Lethal Performance return-style fuel system

• Lund Racing nGauge tuner and custom calibration

• M&H front tires

• Race Star 95 Recluse wheels

• Reische 170-degree thermostat

• Whipple Superchargers 10-rib belt drive upgrade

Article Sources

About the author

Steve Turner

Steve Turner brings decades of passion and knowledge in the world of Ford performance, having covered it for over 20 years. From the swan song of the Fox Mustang to the birth of the Coyote, Steve had a front-row seat.
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