Hyper Blog

# From 1,200 Miles to 901 RWHP: Josh's Whipple-Charged 2025 Mustang GT

Some builds start with a plan. This one started with an itch.

When Josh rolled into Hypermotive, his 2025 Mustang GT was about as fresh as they come — completely stock, Performance Pack, and barely 1,200 miles on the odometer. Still breaking in. Still smelling new.

His goals were simple on paper: *make more power, and look good doing it.*

For a lot of owners, a Performance Pack GT is already plenty of car. Plenty of noise, plenty of grip, plenty of grin. But Josh isn't a lot of owners. What most people would call a finish line, he treated as a starting point.

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## Round One: Go Big or Go Home

There was no easing into this one. No intake-and-tune warm-up lap. Josh's very first modification was a Whipple Stage 2 supercharger — and even with Whipple's own potent calibration out of the box, he wanted more out of it. So we put the car on the dyno and gave it a custom Hypermotive tune.

He stayed on 93 octane to start, which meant keeping it sensible: a boost-a-pump to shore up fuel delivery and a 3.75 pulley to keep boost in a safe window for pump gas.

With the blower handling the power, the rest of the car got the supporting cast it deserved:

- Kooks 1-7/8" x 3" long tube headers — opening up the exhaust side so the Whipple isn't fighting to breathe
- Corsa Performance valved cat-back — quiet when it needs to be, absolutely not when it doesn't
- MGW short throw shifter** — because a car making this kind of power deserves shifts you can feel land
- Steeda Sport lowering springs — dropping the stance and tightening up body roll
- Steeda Stop the Hop kit — settling down the rear end so the power goes to the pavement instead of into wheel hop
- Gulf Coast carbon fiber driveshaft — serious rotational mass savings and a stronger part than what it replaced

Then came the part everyone sees first. Josh finished the look with Velgen V5 Classics in gloss black, completing a full blackout treatment that leaves people genuinely unsure whether this thing is a show car or something they really don't want to line up next to.

**Round one result: 750 RWHP.**

For most people, that's the build. That's the car you enjoy for the next five years.

Josh made it about two weeks.

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## Round Two: Chasing 900

The phone rang. Josh wanted *significantly* more power — and we knew exactly what that takes.

At this level, the conversation stops being about boost and starts being about fuel. To make big numbers on these Mustangs reliably, you're running E85 or race fuel. There's no third option. That meant the entire fuel system had to be rebuilt to support it:

- Injector Dynamics ID1050x injectors — the flow capacity E85 demands
- Fore Innovations dual pump fuel system — enough supply to keep up at wide-open throttle, all the way to redline
- Innovate ethanol content reader — so Josh can verify exactly what's in the tank before he leans on it

That last one matters more than it sounds. When you're boosting these cars, E70 is the target. Ethanol content isn't a set-it-and-forget-it number — it varies pump to pump and season to season. Being able to confirm content in real time is the difference between a safe pass and an expensive lesson.

Josh also stepped up to a 3.5 Whipple pulley for more boost — while staying respectful of the fact that he's still running a stock short block and stock transmission.

After a few tweaks and another round of tuning, the number on the Dyno Graph screen read 901 RWHP.

On a stock bottom end. Two weeks after leaving at 750.

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## Round Three: Making It Stick

But wait — there's more.

Two weeks later (yes, we're seeing a pattern too), Josh came back. This time not for power, but for protection and traction. Because 901 RWHP is only useful if the drivetrain survives it and the tires can actually use it.

- Mantic twin disc clutch — holding torque a stock clutch was never engineered to see
- GForce Engineering half shafts — reinforcing one of the most common failure points on a high-horsepower S650
- Weld Ventura beadlocks wrapped in Mickey Thompson ET Street R 305/45/18 — real drag radials on a wheel built to hold them

That combination turns 901 RWHP on paper into 901 RWHP that actually goes somewhere.

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## The Full Build Sheet

**Power**
- Whipple Stage 2 supercharger (3.5 pulley)
- Custom Hypermotive dyno tune
- Kooks 1-7/8" x 3" long tube headers
- Corsa Performance valved cat-back exhaust

**Fuel**
- Injector Dynamics ID1050x injectors
- Fore Innovations dual pump fuel system
- Innovate ethanol content reader
- E85 (E70 target)

**Drivetrain**
- Mantic twin disc clutch
- GForce Engineering half shafts
- Gulf Coast carbon fiber driveshaft
- MGW short throw shifter

**Chassis & Traction**
- Steeda Sport lowering springs
- Steeda Stop the Hop kit
- Weld Ventura beadlock wheels
- Mickey Thompson ET Street R 305/45/18

**Wheels & Appearance**
- Velgen V5 Classic, gloss black

**Result: 901 RWHP — stock short block, stock transmission.**

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## Where It Sits Today

This is where Josh's Mustang stands right now. Fully blacked out, fully fueled, and putting down numbers that most people wouldn't believe from a car that had 1,200 miles on it a few months ago.

Emphasis on right now. If history is any indication, we've got about two weeks.

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### Thinking About Your Own Build?

Whether you're chasing 750, 900, or just want your Mustang to hit harder than it did off the showroom floor, the path matters as much as the parts. Every build we do is planned around your goals, your fuel, and what your drivetrain can actually live with — then backed up with in-house dyno tuning.

Ready to talk about your build? Get in touch with Hypermotive and let's put a plan together.