Yes the higher octane yields more power. Higher octanes are less prone to ignition by hots spots so it is easier controlled by the your trucks ignition system. Now I don't know if you can re program your speedo. I would email sean and see. When I emailed him with a question he responded with in 30min.

 

I will have to agree. I don't run 93 in my D, because the 20c difference per gallon is too much. If I could afford the difference, I'd upgrade from the 89 octane to the 93. Even if you don't tune it, it will still run better on higher octane gas!

 

Actually higher octane doesn't mean the engine will run better... It has to be tuned for it first.

Anyway, my concern is not speedometer. I wonder if it's worth that money, or not? Will I definitely notice the performance difference when I use it?

 

1) FI engines will run more efficiently with higher octanes. These trucks it is not very noticeable or beneficial because we don't have knock sensors. It would have to be tuned to yield the benefits of higher octane. Stay away from ethanol these trucks don't like it at all.

2) Do a search in the 2nd gen ram section those guys love what sean does with the tune. Sean again messes with torque management a lot, superchips and hypertech don't do that, at least to my knowledge.

 

I have a 2000 R/T with the 5.9. I have a thrush welded series muffler, the custom DIY intake with k&n filter and the superchips 3715. I run the performance tune all the time on 93 octane gas and it really made a difference in mine. Lots more power all over the board. All my other buddies with 5.9s can't keep up with my D at all

 

I did notice a difference between 89 oct with eth and 89 without. Just better all around performance IMO. But the only place that you can get it within 100 miles of where I live you have to have a cfm card...I wish they offered it in more places...
Question for all you though. How hard would it be to make a D run on E85?
I know you need a tune and different injectors if I remember right...
Also mikeismadness: did you notice any mpg gain with the superchips? I am torn right now between the superchips and sct...

 

Also they have a "new" superchip programmer out. 3865.
With the 5.9L it provides: 91 PERFORMANCE37.0 HP @ 2200 RPM80.0 TQ @ 2000 RPM
https://www.superchips.com/Store/tab...9/Default.aspx
Just thought I would throw this out there...Wheew! And I heard if you have an older programmer you can trade it in for $150 towards another programmer.

 

RollerRed you are correct. I'm gonna be tradin mine in here soon.
After changing my o2 sensors and the chip I get an average of 12.5-12.7. I drive a good mix of town and highway. I'm not exactly the easiest on my D either lol. This past weekend I was moving and hauling my 22 foot trailer loaded down and was managing 11.8

 

higher octane fuel will give you exactly 0 benefit (well maybe a little bit of weight savings since your wallet will be smaller) over what is called out in the manual for it, dont waste your money on it unles syou have an aftermarket tune which requires it. this is true of any vehicle on the road, whoever told you otherwise is nuts.

note: there is the possibility of gaining a little bit under very heavy load situations in poor weather conditions (high heat or humidity, as mentioned in the FSM and owners manual, but for the average person if it doesnt knock with regular gas the higher octanes are a waste of money)

 

I still couldn't get the answer I want... Is it worth to buy it for a 120K mile truck, and can I use it with regular gas? Don't wanna spend much on premium.