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LongWeekends's avatar
LongWeekends
Explorer
Feb 05, 2016

HP question on a Cummins 8.3

So our DP sold and we are shopping for our "upgrade". Engine size is one of the things we want to improve. I see the following in an ad:

"THE 8.3 LITER CUMMINS 360 HP ENGINE HAS BEEN RE-RATED TO 425 HP AND GETS 2 MPG BETTER FUEL ECONOMY. "

Can anyone shed some light on this? What is done to magically change the HP other than some creative typing?

As always, thanks in advance.
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  • Executive45's avatar
    Executive45
    Explorer III
    Feb 05, 2016
    I'm sure they added a "chip" to increase HP. On my ISM, which is rated at 500HP the chip increased the HP to just a tad over 525HP. Did it change anything..? Well it lightened my wallet a bit but no noticeable change in power or mileage....Dennis
  • Tom_Barb's avatar
    Tom_Barb
    Explorer
    Feb 05, 2016
    LongWeekends wrote:
    So our DP sold and we are shopping for our "upgrade". Engine size is one of the things we want to improve. I see the following in an ad:

    "THE 8.3 LITER CUMMINS 360 HP ENGINE HAS BEEN RE-RATED TO 425 HP AND GETS 2 MPG BETTER FUEL ECONOMY. "

    Can anyone shed some light on this? What is done to magically change the HP other than some creative typing?

    As always, thanks in advance.

    More than likely, a "BANKS" programer, that changed the fuel schedule to allow lower fuel flow at low power settings, and more fuel flow at max power.
  • Passin_Thru's avatar
    Passin_Thru
    Explorer
    Feb 05, 2016
    I have an Edge on a Duramax, increased by 40 hp and fuel mileage went from 13.5 ety to 17-19 ety and 10.8 loaded at 67 MPH and GVW 20000 lb.
  • Ivylog's avatar
    Ivylog
    Explorer III
    Feb 05, 2016
    If you want 425 HP, look for the 8.9L ISL. Without changing the injectors and the turbo a 8.3 is already pushing it's max at 360. In PU's much of the mileage increase by a chip is done by increasing the tire size in the computer... making it LOOK like you've gone more miles than actual.
  • sch911's avatar
    sch911
    Explorer
    Feb 05, 2016
    Ivylog wrote:
    If you want 425 HP, look for the 8.9L ISL.


    Another vote for the ISL. Ours is rated per factory specs at 400HP, but can be chipped easily to 450HP.
  • tinkerer's avatar
    tinkerer
    Explorer
    Feb 05, 2016
    One thing to remember when you do anything to increase the hp of your motorhome you will increase the heat the engine produces and if the radiator remains the same size you could overheat your engine which can be detrimental.
  • barmcd's avatar
    barmcd
    Explorer
    Feb 05, 2016
    I don't think an 8.3 can reliably put out 425 hp. That doesn't mean this particular engine might be unreliable. It might not be putting out 425 hp.
  • prstlk's avatar
    prstlk
    Explorer
    Feb 05, 2016
    Chipped rigs can also be worth less on trade in or outright sale. Some of us have concerns about reliability. I'd take a box of donuts to your local cummins dealer and ask some questions 360 to 425....thats sounds to good be true.
  • Tom_Barb's avatar
    Tom_Barb
    Explorer
    Feb 06, 2016
    prstlk wrote:
    Chipped rigs can also be worth less on trade in or outright sale. Some of us have concerns about reliability. I'd take a box of donuts to your local cummins dealer and ask some questions 360 to 425....thats sounds to good be true.


    When you have any engine that is well known to go way past 1 million miles, you can turn the horse power up, and it will still last 500K. ever see a coach go past 500K?
  • Ivylog's avatar
    Ivylog
    Explorer III
    Feb 06, 2016
    Sorry, but the 8.3 is not known as a million mile engine at 360 HP... Closer to 600K. If you could get 450 with just a chip it would still last long enough for most.

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