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 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 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


ECM Removal Video: 

Hi I had the ecm and tcm done also added banks torque tubes added, would I be able to run the overdrive while towing a 5k trailer now? Thanks in advance. ( jeffrey wyllie, 05/28/2019 )
Yes you should be fine running in overdrive. ( Support )
We purchased a Fleetwood Fiesta LX 32K brand new in 2007 we have 20K miles we pull motor cycle trailer. We have Ram Air Intake the GM 8.1L has good power will your UltraPower Tunner help and would we need on for the Allison 6 Speed Transmission. ( David Herman, 04/10/2019 )
Yes our UltraPower Custom Tuning will work very well in conjunction with the Banks Ram Air intake. You won't need anything else for the 6 speed transmission. ( Support )
2008 GMC Topkick C4500 8.1L When replacing the PCM for the tuned one will the passlock and crank position relearn be necessary. If it helps the key for ignition is common key. I bought a blank online and had the key cut locally as they didnt have blanks. No relarn then. Based on pictures it looks like Passlock. ( mike, 03/30/2019 )
The only vehicles we usually have to do a passkey and crankshaft relearn procedure on are light duty vehicles. The medium duty Kodiaks and Workhorse chassis don't need it. ( Support )
Do you need to have the Allison for this?
I have a 04' (03 built) P-32 with the GM4 trans.
( Kevin J Parker, 02/18/2019 )
Yes we do, we custom tune the ECM on Workhorse chassis with both the Allison transmission as well as the 4L80/4L85E transmission. ( Support )
Hello, I'm doing an 8.1 vortec swap that will be mated to a TH400. Donor truck is an 2001 K2500 Suburban. I want to lose the VATS and keep the emissions.

Is it possible to program for manual transmission and still keep the original Cal ID?
( Dan Green, 02/13/2019 )
Yes, this is possible. ( Support )
How much change (if any) do you make to torque management with this eco tune?
( Kevin, 02/11/2019 )
On trucks and SUV's we generally remove torque management in normal (not tow/haul) mode unless otherwise requested. ( Support )
What is the turn around time on doing ecm and tcm. ( Charles McKnight, 01/18/2019 )
Typically 1-2 business days. ( Support )
I have a 2005 Yukon with 8.1. I do live in Carnation WA so not to far. In the above questions concerning another yukon you mention that may require passkey relearn and crankshaft postion Procrdures. being not to far is this something you can do at your shop in centraila. 2, does the tune change at what peak torque is obtained. stock is 3200 RPMs. getting another 70 Lbs of Torque and HP. would i need to beef up the L485E transmission? its reted at 460LBs of torque but not sure if that means on the ground or not.
( gary armstrong, 09/04/2018 )
You can call or text and schedule an appointment with Barbara to have this done at our facility. 360-736-9494 You would not need to change the transmission in any way after the tune :-) ( Support )
I just want to make sure I'm look at this correctly assuming all these numbers are RWHP and RWTQ.

Your stock numbers: 268 rwhp / 419 rwtq
normal gm truck stock 281 rwhp / 341 rwtq (from what I can find behind a 4L80E)
ultrapower tuned 305 rwhp / 475 rwtq

If these numbers are correct, with everything else stock and just your ECM I could possibly gain in my 2005 yukon xl 8.1 24 rwhp and 134 RWTQ?

Am I missing something? If not this is a great deal and I would be very interested.

Thank you for your help.
( whitney thornbrough, 06/05/2018 )
The problem of comparing horsepower and torque numbers at the rear wheel is that all dyno's will measure differently. Type of dyno, elevation, temperature, calibration of dyno, etc. all come into play when you are comparing numbers from different dynos. The gains that we get on the RV's is just about the same as the Kodiaks, Pickups and SUV's with the 8.1L. ( Support )
1. Have you ever done a dyno for the 8.1 4L80e trans combo?

2. "GM Trucks with 8.1L Engine (May require Passkey and Crankshaft Position Relearn Procedures)" Are these hard procedures? Would it be necessary on a 2005 yukon xl 2500 8.1?

3. You stated your tune requires a higher octane, 89? 91? If i run on 87 will it damage anything or just lose a little performance? Would it ping and knock?

Thanks in advance.
( Whitney Thornbrough, 06/01/2018 )

Yes we have dyno'd several 8.1L/4L80E combo's but mostly in the P32 Workhorse configuration. Results are very similar to what we see with the 8.1L/Allison. We do not state that a higher octane fuel is required, we tune for 87 octane but CAN tune for a higher octane if desired. No pinging or knocking as long as your engine and sensors are healthy :)

The crankshaft relearn will require a scan tool but only takes a minute or two to complete. The Passkey relearn is a fairly lengthy process (~30 minutes) but is very easy, we can send instructions on this if needed.

( Support )
I pull a Ford Edge and sometimes a trailer which weighs loaded 6000 lbs. Will I have pinging on long uphills in hot weather and need to run higher octane? Can I keep my stock ECM in case smog laws in California become tighter and peace of mind.

( Steven Thomas, 05/21/2018 )
We do not push the spark advance to the point that you need to run higher octane, under any conditions. You can keep your stock ECM, you would just not get your core refund back ($150). ( Support )
I'm building a truck with a 8.1l engine, the engine is coming out of a donor C3500HD 2002 YEAR MODEL. what POWER GAINS CAN I SEE WITHA TUNE. ( Avery, 04/07/2018 )
Not answered yet.
I am considering using U P 8.1 engine tune on my 32 foot 2006 Fleetwood Terra lx motorhome. My research states that it should have an Allison 6 speed, Im sure it has a 5 speed transmission. Ques. 1. Will my vin tell which trans I have. Is there a better way to id my trans? Ques. 2 My 8.1 has 19,000 miles on it, being a 2006 does the Allison trans need a computer upgrade, or is that upgrade for earlier transmissions. Ques. 3. I am going to upgrade the suspension i.e. sway bars f + r and your rear track bar. I am going to upgrade in stages. I think I should start with your rear track bar for my w22. Your advice please Ques. $ Can you recommend a Workhorse chassis shop in the Phoenix area?. Thanking you in advance, Robert Myers, Mesa, AZ. ph.605-415-6518 ( robert myers, 03/14/2018 )
Not answered yet.
I f I have you program my ECM, do you know if it will effect my emissions test here in Denver CO, or will I have to have a stock
ecm for the testing?
( Kevin, 03/01/2018 )
We have no issues passing emissions with the custom programming in place. You can keep the stock ECM for a backup or peace of mind but it really is not necessary. ( Support )
Hello I have 2003 Workhorse w22 8.1 . I have been running strange problem . When the motor home starts and we drive it down the road it runs fine. But when I stop for 10-15 minutes it start up very rough and will not take the gas. It will only drive at 10-15 miles an hour. I stop and wait about 10 minutes and it starts up and runs fine. The codes it pulls are P1516 and P0151 . Does this sound like a computer problem and need reprogramming ? If that is the case I would like to get it in to you as soon we get back in town. I did the wire pull and checked the connections at the throttle Body and the tac and found nothing. The unit has 18530 miles on it. I did install the rear sway bar that I ordered from you and it works great. ( Gary Croson , 02/28/2018 )
Not answered yet.
you show allison tune for 01-04 do you have one for my 2006 2500HD with 8.1 If you
do how much for both ecm and tcm if I send both to you and how long does it usually take thanks
( Dave Dvorak, 02/06/2018 )
Our tuning on the Allison transmission computer is only for the 5 speed controller up to model year 2004. The 6 speed controller in your pickup is not supported. We can tune your engine computer for $595 and if you send yours in instead of buying a core it is a 1-2 day turn around. ( Support )
with the upgrade of the ecm power boost will the engine noise be louder??? ( c.r. kent, 12/17/2017 )
There will be no difference in the noise of the engine. ( Support )
Will tbis work with a chevy 3500 . I tow a dunp trailer [8400lbs empty] with up to 20000lbs of material. 29000 loaded ( Sean Reed, 12/06/2017 )
Yes this will work with a Chevrolet pickup. ( Support )
Once you receive the TCM, how long will it take to re-program and be returned? Thank you. Mike ( Michael W. Caldwell, 11/09/2017 )
Not answered yet.
Hi I'm interested in ordering this ecm and was wondering if the coach will still be smog legal with the programming. I live in southern California.
( Shad Warner, 07/24/2017 )
Yes our ECM programming will pass California emissions testing with better than stock results. It does not show up on their scanners as having been modified. ( Support )
I have a 2007 Winnebago Itasca Suncruiser RV with the Chevy Vortec 8100 gas motor. I am interested in towing a vehicle and was told that a custom tune would help with more horsepower/towing power, etc without shortening the life of the motor? Is this one I want? Or do you have another better solution? ( todd stanley, 07/10/2017 )
Yes, this our best upgrade for both power and fuel economy. There are no reliability issues and we even include an engine data recorder so we can do a "health check" on your engine.  ( Support )
Hi, I was wondering if you tune it to the mods that are installed on the motorhome currently. In my case, I have a Banks Ram air intake and I have Magnaflow performance exhaust but I do not have headers. Can you tune it to those mods? And would the performance gain be different? Thanks
( Jerry McManus, 06/19/2017 )

The tuning can be altered to modifications made on the vehicle. The mufflers do not require it but if we know you have headers or air intake we can tweak some settings to get just a little more out of it.

( Support )
I wish to convert my motor to run E85. I do not wish to use an add-on device (Have one now that is malfunctioning)
I'd like to have the ECU programmed to allow ethanol and ethanol blends. Can you do that?

( Frank Caridi, 05/02/2017 )


We do not have any previous experience with tuning to run E85. Workhorse sent out a TSB that was very adamant that E85 NOT be used in the 8.1L. 

( Support )
In reading about the custom tuning ECM talked about 60 -70 gains in horsepower and in torque same as the $2600 banks kit why would anyone buy the banks kit. Thanks Jim ( james dean, 03/03/2017 )

Hi James,

There are other benefits to the Banks system other than just performance. The reliability of their TorqueTube headers make them a good upgrade if you have exhaust manifold leaks. Letting the engine breathe better does also help but on these electronically controlled engines, the ECM tuning is always going get you the most performance for the money.

( Support )
i have a 2003 w32 with the 8.1 in it. will the Allison tune fit it with no issues. It seems every thing I look at says except 2003. Thank you Barney Chappell ( barney chappell, 02/22/2017 )


Yes, our tuning works with no issues on the 2003 model year.

( Support )
The 8.1 has hypereutectic pistons that are very sensitive to detonation and would limit the amount of timing used with 87 octane without causing engine damage (holes in pistons). Gains of 60hp/70tq without changing hard parts seems hard to believe, or is the factory programming extremely conservative? ( Tom, 07/18/2016 )

Hi Tom,

As long as the mass air flow sensor is clean and there are no other issues present we have no problem getting those gains on 87 octane with pre-detonation. What a lot of people don't know was that the 8.1L was offered in a variety of applications ie; marine, auto, medium duty and RV without much difference in programming other than calibration changes for the speedometer and fuel tank size. We are able to find a lot of "hidden" power without hurting reliability, I have several customers with over 100K miles running our programming.

( Support )
I am a new customer to this web site and going though the workhorse 8.1 section I notice this ultra power GM custom tuning and was wondering if it should help the performance of my rv and fuel mileage. How does it work? Thanks joe ( Joe Alcantar, 07/09/2016 )

Hi Joe,

The UltraPower Custom Tuning is one of our most popular performance products for the 8.1L. It is a new engine computer that is programmed with your vehicle info and settings that optimize the power and mileage. We see gains of about 60 horsepower and 70 ft-lbs torque as well as fuel mileage gains between .5-1 MPG.

( Support )
Is the core charge a full refund once I send my ecm back to you? Can't afford to lose the truck to long if I send the one currently in the truck for reprogramming.

2007 Chevy C4500 Kodiak
- Bucket truck
Thanks Mike
( Mike konke, 05/21/2016 )


Yes the core charge is fully refunded upon the return of your ECM. 

( Support )

Is there reprograming required, or is it just a plug and play add on device

( Mel, 01/28/2016 )


It is a programming of the engine computer so either you would remove your computer and send it in for the reprogram or you pay for the core and we send you a computer and you just swap out the computers, essentially making it plug & play.

( Support )

I have a Workhorse R-26 Chassis, rear pusher with an Allison transmission. Is the Ultra Power compatible with this setup, and where might the computer be located. Also does this device plug into the computer, or is the computer replaced. Is there any programing required?

( Mel, 01/27/2016 )

Hi Mel,

Yes, the UltraPower is compatible with the R26 UFO chassis. The ECM will be located at the rear of the coach on the drivers side in a compartment right behind the rear wheel behind a removable panel.

( Support )

I'm considering the Ultra Power upgrade on my my 2006 Southwind W22 which is a California vehicle. Would the programing have any impact on California DMV smog checks? Thanks, Chris

( Chris, 12/10/2015 )


We are 100% confident that you will have no problems with passing your smog testing with the UltraPower programming. We have a ton of customers in California that run the programming and we've never once had a report of smog failure due to the programming. In fact, in most cases the emissions are actually reduced and they pass with better than normal readings.

( Support )

I have a 09 class a safari, just purchased. How can I tell if a tune has already been done because it runs pretty decent?Would your name be on the ecm? Thanks. Garry.

( Garry Shaw, 09/29/2015 )


If you have the name of the last owner we may be able to look through our database to see if we have done it. The only other way to tell is if there is a sticker on the ECM or you can mail us the ECM and we can check the program.

( Support )

I would like to have more power when going up hills. I don't like my tranny to downshift to 3rd. gear at highway speed because then my motor is running 4000 RPM. Will this product help with my 2005 Gulfstream (2004 W-24 Workhorse) pull grade without downshifting from 5-4-3 and instead just drop from 5-4 gear? Also is this product just plug it in and it learns and adapts to my motorhome? Would I also need a TCM to reduce downshifts? I like to drive highway speed 70-75 MPH but do drive slower at times for my wife, get my point! Will it perform well in the 65-75 MPH range?

( David Andersen, 09/26/2015 )


Yes the UltraPower Performance Programming would work well for what you are trying to accomplish. It will help it hold the higher gears going up hills and also get you up to speed easier. The computer will be programmed with your VIN and will be 100% compatible with your vehicle. The TCM reprogram allows the transmission to shift into overdrive at a lower speed under light throttle and it does help a little bit with holding 5th and 4th gears longer.

( Support )

Just wondering if it will hurt the engine at all not familiar with this upgrade? I have a 2005 Georgie boy Landau with the Allison trans . Also where would the computer be for me to take it out? Thanks a lot ,Jim

( jim, 07/01/2015 )

We have been doing the UltraPower programming for over 10 years now with no ill effects on engines in anyway. In fact, we have had initial customers that have been running the UltraPower since 2005 that have been sending in oil samples to Blackstone Labs for analysis on a regular basis with no signs of increased wear compared to stock engines.

The engine computer is mounted right above the radiator and can be accessed from either the front access hatch or from behind through the engine doghouse cover. 

( Support )

Ask a question

Note: HTML is not translated!

Write a review

Please login or register to review

 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

Shipping Insurance Notice

NOTICE: For orders outside of United States

If you are placing an order to ship outside the United States, Shipping Insurance will be required and added automatically at checkout.


  • $803.25
  • $595.00

Available Options