UltraPower GM / Workhorse 8.1L Custom Tuning

UltraPower GM / Workhorse 8.1L Custom Tuning

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 UPS 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 Allison Transmission tuning on model years 2001-2004 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 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 with 8.1L Engine (May require Passkey and Crankshaft Position Relearn Procedures)
  • Workhorse Motor Home Chassis from 2001-2010
  • Kodiak Chassis with 8.1L


  • Gains of 60 HP and 70 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


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  • Product Code: UPWH
  • Availability: In Stock
  • $714.00
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