UltraPower GM / Workhorse 8.1L Custom Tuning

UltraPower GM / Workhorse 8.1L Custom Tuning


Order Shipment Notice: 

Most orders are shipped within 24 hours from the order date. Orders placed on the weekend or after cutoff on Friday, and orders placed on select holidays are processed on the next business day. Please see our shipping terms for more information.

Part # UPGM

If you will be sending us your ECM for reprogram you do not need to select core charge but if you are wanting us to program and send you a computer you must choose the core charge.

For your convenience, we include a prepaid return label to send your core(s) back.

If you are sending your ECM and/or TCM in ship to this address:

Ultra RV Products

3912 Harrison Ave.

Centralia, WA 98531


UltraPower Custom Programming for the GM 8.1L 496cu has long been the ultimate performance modification you can make to your Workhorse/Chevrolet RV or truck with the highest power gains on the market, at the best price. Thousands of satisfied customers have reported fuel economy increases along with the addition of the extra pulling power when tackling steep grades. Also, less downshifting will occur as a result of the increased power. UltraPower Custom Tuning works very well on both stock engines or ones that have been upgraded with Banks Power Systems. Banks even admits their handheld AutoMind only changes one parameter within the computer, whereas UltraPower changes approximately 400 parameters. That is the difference between cookie-cutter and custom.

We are now offering 5-speed Allison Transmission tuning on model years 2001-2005 W-Series. The main change you will notice is the transmission will shift into overdrive below 50 MPH when under light throttle. We also demand more load before it will downshift when pulling hills which means less downshifting. Increased line pressures also helps prolong the life of the transmission and optimizes the shift points. If you select this option with core exchange you will pay an additional $500, however, if you return your original TCM we will credit you $400 back.


  • GM/Workhorse 8.1L Engine
  • GM Trucks/SUV’s with 8.1L Engine (May require Passkey and Crankshaft Position Relearn Procedures)
  • Workhorse Motor Home Chassis from 2001-2011
  • Kodiak C4500/C5500 Chassis with 8.1L


  • Gains of 50-60 HP and 70-80 lb-ft TQ
  • Gains of 1/2 - 1.5 MPG
  • Downshifts less approaching hills
  • Improved throttle response
  • Improved acceleration for merging onto freeway and passing vehicles


ECM Removal Video: 

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 The state of California requires that this warning be posted for people purchasing products that reside in California.

WARNING: Products may contain one or more chemicals known in the State of California to cause cancer and/or birth defects or other reproductive harm. For more information, visit www.P65Warnings.ca.gov

Not Legal for California Use

This product is not legal for use in California on pollution controlled motor vehicles.

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  • Product Code: UPWH
  • Availability: In Stock
  • $803.25
  • $595.00

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