800+ HP 17-Liter CAT C15: Inside a True Competition-Grade Diesel Engine
E Edwin Matias

800+ HP 17-Liter CAT C15: Inside a True Competition-Grade Diesel Engine

Jul 1, 2025

Brought to you by Texas Truck Market – The Authority on High-Performance CAT Builds

If you’ve ever dreamed about pushing your CAT C15 beyond stock limits and into full-blown competition territory, buckle up. This is the breakdown of a real-deal 800+ horsepower build, featuring a 17-liter big bore conversion, cryo-treated bolts, custom calibration, and more.

Let’s dig into the full spec—from bare block to ready-for-the-track.


⚙️ Core Engine: Starting Point

  • Original engine: CAT C15 6NZ core

  • End use: Competition-only 2020 Pete Glider

  • Goal: 800+ HP, non-highway, show/track use

  • Issue: Original 6NZ block cracked at the pan rail — replaced with an ACERT block

⚙️ Machining Work

  • Block received:

    • Six upper inserts and six lowers installed

    • Water passages machined

  • Crankshaft:

    • ACERT crank (magged, polished, balanced)

    • Flywheel dowel had to be burned out and replaced due to prior damage


🔧 Engine Kit: IPD Big Bore 17L

  • IPD C15 Big Bore Kit:

    • Uses C18-style 5.71-inch bore pistons

    • 6.75-inch stroke from ACERT crank

    • Total displacement: ~17.1 liters

    • Only for off-road/competition use

  • Rods: C15 ACERT rods

  • Compression ratio: 16:1

🪜 Liners & Protrusion

  • Liner flanges measured in 4 places per liner

  • Final protrusion: 0.005" average, with all 24 measurements within 0.001" — perfect setup

⚡ Piston Cooling

  • Upgraded C18 piston cooling jets (Part #: 274-8359)

  • Replaces standard 6NZ jets


⚖️ Head & Fastening

  • Cylinder head installed with:

    • Cryogenically frozen IPD head bolts

    • Final torque: 340 ft-lbs

  • Spacer plate and all seals replaced

  • Front gear plate and timing gears reinstalled

  • Camshaft used: 332-7308 / 0R7652 (pushes 55 injectors)

  • Injectors: CAT 55s


⚖️ Top-End Upgrades

  • New cat reman rocker arms

  • New CAT rocker shafts

  • Rocker shaft bolts upgraded to heavier shank style (Part #: 257-2122)

    • Used 9 total (one thin bolt still required for oil supply)

    • Torque: 50 ft-lbs + 90 degrees (final ~120 ft-lbs)


📅 Oil & Cooling

  • ACERT water pump for higher flow and better cooling

  • Oil filter base rebuilt:

    • New springs and plungers

    • New O-rings on plugs

  • New CAT oil pan installed:

    • Bolts: 0L-2070 (x24)

    • Washers: 9L-9132 (x24)

    • Sleeves: 240-1614 (x24)


✨ Final Assembly

  • New ViperTech crank damper installed

  • Full Tilt exhaust manifold installed (recommended: get hardware kit w/ studs & spacers)

  • Flywheel tip: use trimmed guide bolts to help hang it cleanly

  • Cam gear backlash set

  • Fuel transfer pump installed

  • Rear coolant bonnet cleaned (removed rag blocking flow — cause of past overheating)

  • Thermostat ("regulator") housing rebuilt w/ new CAT thermostats

  • ECM: Brand new, flashed with modified 7CZ file


🏋️ Jake Brakes

  • Rebuilt with Jake Brake brand tune-up kits

  • Includes:

    • Valve seals

    • Springs & control valves

    • Retainer screws

  • Tool tip: Use C-clamp + socket to reseat washers & snap rings if you don’t have the factory tool


✅ Final Thoughts From the Shop Floor

This isn’t your average inframe. This is 17 liters of precision-built, high-compression, competition-grade CAT muscle.

A build like this takes countless hours of attention to detail. It’s not about cutting corners—it’s about making sure every bolt, bore, and spec is exactly where it needs to be.

And while most CAT drivers don’t need 800 HP for daily freight, what this build shows is what’s possible when you start with a rock-solid foundation.


🚗 Want to Build Power Like This?

Start with a Texas Truck Market inframe kit—the same quality foundation used on real horsepower builds:

  • C15 & 3406E kits from IPD, PAI, Interstate-McBee

  • Optional big bore kits (off-road only)

  • Cryo-treated head bolts, 16:1 pistons, updated jake bolts & more

📞 Call 832-867-3345 and talk to us about your CAT engine build. We'll help you spec the right kit, parts, and supporting hardware so you can build it right the first time.


Texas Truck Market – Real Parts. Real People.

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