Thor Forums

[gmtech16450yz]

Hey guys hang in there on the 5 Star thing. I had an idea that I'm working on.

On the MPG question, here's one thing that in my 4 decades of "tuning" engines in just about every vehicle made has always seemed to be true...

Power is easy to increase. Mileage is much harder to effect.

On every engine I've ever worked on, my goal is primarily increasing or optimizing efficiency. Better efficiency IN THEORY results in better gas mileage. In actual real life though, it doesn't always work that way. The biggest reason I can say is as simple as "the more you have, the more you use". lol.

RV's are a little different though. They spend a large portion of their life going freeway speeds at a set throttle/load level. In those situations, increased efficiency usually DOES make a difference. It's the stop and go, pulling grades and WOT situations where the "more you have, the more you use" part comes in.

I can give your engine more hp and torque. On a climb up a grade that increase will result in your RV going 45mph stock vs., say, 60mph tuned. Will your gas use in that situation be lower? Probably not, and could actually be higher. Now IF you still went 45 up that same grade while tuned, you MIGHT get better mileage. But who's gonna do that? Nobody. lol.

But freeway cruise or steady state throttle is different. If stock your RV takes 32% throttle to maintain 65mph, and tuned it only takes 27%, that means you're using less fuel. That WILL make a difference. And in these Ford V10 tunes in particular, there's a LOT of steady state/freeway cruise efficiency that can be gained.

My Vegas is tuned by me. I log every mile I drive it and have every mile of our 6300 mile trip across the country and back logged. Our average for the entire trip was almost 10mpg. Our average speed was probably 70mph, which is hella fast for an average. I spent 3 hours straight on the way back with the cruise control set at 90mph and went 95 for probably a half an hour. (and have the logs to prove it.) I doubt seriously if my mileage would have been almost 10 if it wasn't for two things, my tuning and the wheel/tire swap I did.

So bottom line on the MPG question... It might increase your mileage. lol. It WILL ABSOLUTELY increase your power and engine efficiency. Your hill climbing or towing speeds will be higher at the same throttle/load levels. Will the gas saved pay for the tune? Debatable. But will the way your engine and transmission operates make driving more enjoyable? Absolutely without a doubt.