Uploaded May 2026 | Updated September 2026, 3 days ago
We’re at the PDI facility in St. George, Utah, with racing legend Mark Martin to push the boundaries of luxury performance. His BRAND NEW 2027 Newell P50 motorcoach is barely a week old, but the stock 605HP Cummins X15 won't cut it towing his stacker trailer up mountains with his iconic number 6 NASCAR Ford Thunderbird inside it.
We’re performing a complete PDI "Add-a-Turbo" compound turbo conversion to transform this 45-foot luxury rig into the most powerful motorcoach on the road. This deep-dive documents the entire 4-day process working with Mark—from the initial engine bay teardown and plumbing fabrication to the final chassis dyno test that revealed some truly shocking numbers.
Chapters
00:00 - Building Mark Martin's 800HP Custom Newell Coach
01:30 - Cummins X15 Performance Parts & PDI Turbo Unboxing
08:40 - Engine Disassembly & Unexpected Mechanical Issues
13:50 - How to Install a Compound Turbo on a Cummins X15
27:00 - Custom Fabrication for High-Horsepower Diesel Engines
43:50 - First Start & Final Engine Assembly Checklist
51:10 - Cummins X15 Dyno Test: Measuring Horsepower & Torque
01:02:45 - Final Dyno Results & Mark Martin Street Test
01:05:40 - Technical Breakdown: Diesel Performance Upgrades
In this video:
The Setup: Understanding the limits of the stock Cummins X15 platform in a high-weight luxury application.
The Build: Breakdown of the PDI compound turbo install, including pipe fitment and turbocharger specifics. Design choices and custom Chrome with PDI owner Jerad Wittwer.
The Results: Chassis dyno testing to verify the real-world horsepower and torque gains on a semi truck water brake dyno.
Build Specs: 2027 Newell P50 Motorcoach (45 foot)
Engine: Cummins X15 (605HP Stock)
Performance Upgrades: PDI Add-a-Turbo Compound Kit, PDI Manifolds, Custom ECM Tuning
Facility: Performance Diesel Inc. (PDI) - St. George, UT
Employee Of The Month: Karson
#MarkMartin #CumminsX15 #PDI #NewellCoach #DieselPerformance #CompoundTurbos #DynoTest #Stapleton42
Channel T-Shirts Hats and Decals! stapletonautoworks.com
My Facebook Page: facebook.com/Stapleton42
Follow me on X! twitter.com/stapleton42_
We are on Instagram too!
Mitchell: @stapleton42_
Logan: @Logann42_
Our Favorite energy drinks and supplements! 1stphorm.com/stapleton42
Become a Stapleton42 channel member to gain special perks. Sign up Here!
youtube.com/channel/UCAfcdqiPUDqIr3Pv_AGIjZQ/join
📩 Business Inquiries: mdstapleton42@gmail.com
We’re at the PDI facility in St. George, Utah, with racing legend Mark Martin to push the boundaries of luxury performance. His BRAND NEW 2027 Newell P50 motorcoach is barely a week old, but the stock 605HP Cummins X15 won't cut it towing his stacker trailer up mountains with his iconic number 6 NASCAR Ford Thunderbird inside it.
We’re performing a complete PDI "Add-a-Turbo" compound turbo conversion to transform this 45-foot luxury rig into the most powerful motorcoach on the road. This deep-dive documents the entire 4-day process working with Mark—from the initial engine bay teardown and plumbing fabrication to the final chassis dyno test that revealed some truly shocking numbers.
Chapters
00:00 - Building Mark Martin's 800HP Custom Newell Coach
01:30 - Cummins X15 Performance Parts & PDI Turbo Unboxing
08:40 - Engine Disassembly & Unexpected Mechanical Issues
13:50 - How to Install a Compound Turbo on a Cummins X15
27:00 - Custom Fabrication for High-Horsepower Diesel Engines
43:50 - First Start & Final Engine Assembly Checklist
51:10 - Cummins X15 Dyno Test: Measuring Horsepower & Torque
01:02:45 - Final Dyno Results & Mark Martin Street Test
01:05:40 - Technical Breakdown: Diesel Performance Upgrades
In this video:
The Setup: Understanding the limits of the stock Cummins X15 platform in a high-weight luxury application.
The Build: Breakdown of the PDI compound turbo install, including pipe fitment and turbocharger specifics. Design choices and custom Chrome with PDI owner Jerad Wittwer.
The Results: Chassis dyno testing to verify the real-world horsepower and torque gains on a semi truck water brake dyno.
Build Specs: 2027 Newell P50 Motorcoach (45 foot)
Engine: Cummins X15 (605HP Stock)
Performance Upgrades: PDI Add-a-Turbo Compound Kit, PDI Manifolds, Custom ECM Tuning
Facility: Performance Diesel Inc. (PDI) - St. George, UT
Employee Of The Month: Karson
#MarkMartin #CumminsX15 #PDI #NewellCoach #DieselPerformance #CompoundTurbos #DynoTest #Stapleton42
Channel T-Shirts Hats and Decals! stapletonautoworks.com
My Facebook Page: facebook.com/Stapleton42
Follow me on X! twitter.com/stapleton42_
We are on Instagram too!
Mitchell: @stapleton42_
Logan: @Logann42_
Our Favorite energy drinks and supplements! 1stphorm.com/stapleton42
Become a Stapleton42 channel member to gain special perks. Sign up Here!
youtube.com/channel/UCAfcdqiPUDqIr3Pv_AGIjZQ/join
📩 Business Inquiries: mdstapleton42@gmail.com
