gaylemarlowe Report post Posted March 26, 2014 We have a 2005 Newmar Dutch Star 4320 with Cat C9, 400hp. Our previous coach was a 38 footer with a 450 Cummins. This one, with the tag and almost 44 ft is quite a bit heavier and as such, I miss the performance that we had before. Has anyone pumped up the horsepower on the Cat C9 with reliable results? A friend of mine that is a heavy machinery mechanic says they use the same engine on a lot of the big loaders and they are rated at 450 & 475 hp and he thinks that we could bump it up to one of those ratings. Going east from our home in Colorado onto the flats it works just fine, but pulling a toad up into the mountains out here is slow going up the higher passes. Comments from you guys are appreciated. And yes, I do know that a little lighter right foot works well too. Share this post Link to post Share on other sites
wildebill308 Report post Posted March 27, 2014 While I haven't had a Cat to play with there are several people selling chips and or tuners for Cat. I think the Bully Dog works similar to the Banks diesel tuner. https://www.bullydog.com/product.php?ID=95 The "Cat" guys will be along to probably give you more advise. One thing is to check your transmission to see if it will handle more torque and horsepower. I would add a boost and EGT gage to keep track of whats going on. Bill Share this post Link to post Share on other sites
gaylemarlowe Report post Posted March 27, 2014 Thanks for the info Bill. I was hoping to hear from some other Cat guys to see what if anything they have done. I do have a request in to Caterpillar to request the same info as I figured if they pulled more hp out of this engine, they would tell me. Hopefully, that will be the case. But, haven't heard from them yet. I do know there are aftermarket upgrades available, but always like to hear what can be done using the original manufactures info. Share this post Link to post Share on other sites
mpierce Report post Posted March 27, 2014 Seems to me like you would be pushing it awful hard to go above 400hp. A C15, which is more that 60% larger, only goes to 550 in a normal rating! CAN you get more? Yes. SHOULD you? Not if you want reliability. And, this is assuming the tranny will take it. I do not know if yours will. Share this post Link to post Share on other sites
gaylemarlowe Report post Posted March 27, 2014 Just got an email back from Cat. No, they will not boost hp of this engine, even though other applications go to much higher ratings. Marine applications have tremendously high horsepower ratings, but are run at higher speeds and constant speeds. Cat says to live with what I have and I probably will. Oh well, maybe the next coach will have one of those BIG motors that some of you guys have!!! Share this post Link to post Share on other sites
wolfe10 Report post Posted March 27, 2014 Yes, marine application have one other thing we in motorhomes do not-- unlimited COOLING! Share this post Link to post Share on other sites
kaypsmith Report post Posted March 28, 2014 Right again Brett, my 335 hp 6V92 Detroit can be turned up to 500 hp for marine use only! Share this post Link to post Share on other sites
