91 since i bought it.. no reason why, just have in all my vehicles. best tank was 14mpg, for a total distance of 380miles a tank.

 

I ordinarily run 87.... never had an issue with any knock yet. I do put in 89 when I'm towing the trailer, though, just to be on the safe side. Never tried towing using 87, and don't plan to.

 

If you want to try something different try this. Put your truck into the towing mode and run it. When I did that when I towed my boat that weighs 6,000 lbs my mileage went up to 13.4 from around 10 to 11. locally. I guess all that shifting and trying to run on four cylinders puts too much of a load on the motor. so if your doing a lot of stop and go under 45 mph try the towing mode. It worked for me.

 

4 cylinders? what option did you get to do that?

 

Also interested in the 4 cylinder thing. First I've heard of it.

Anyway, once I get back to LA, I will put the stock air intake back on, drive it around, and see what I like better. The weird thing is, days it makes me grin from ear to ear because it sounds meaner than hell, other days I feel so nervous about the noise being a loose or broken valve spring that it makes me nauseaus to want to drive it the 300 miles to LA. I'm wondering what it would sound like if I opened up the exhaust, but don't have the 900 bucks, for the Borla kit I want, to spare.

About the octane rating, we in Cali and Nevada have uber crappy gas. I mean, my old Thunderbird with the blown 6 had detonation with 91 octane in it. I sent PM's to some of the other California members on here but I guess I smell bad or something because they wont reply [:'(]

Should have just kept it stock

 

The 2006 Dodge Ram will have huge changes. Lets start with the powertrain changes. The 5.7L HEMI "MAGNUM" V-8 will return throughout the Ram pickup lineup, however you will see a huge change in the performance of this engine. First off, the engine will recieve the same treatment that the car version of the 5.7L HEMI V-8 (2005 Dodge Magnum and 2005 Chrysler 300) with the introduction of MDS or Multiple Displacement System, which will turn the V-8 into a gas saving V-4 in 40 milliseconds at crusing speed, improving gas mileage by almost 5 mpg in the city. A big rumor is that the 5.7L HEMI "MAGNUM" V-8 will recieve additional horsepower from the factory making it have an additional 5 horsepower (350) and another 10 ft-lbs of torque (385) by tweaking the computer. This is so Dodge can brag about having the best torque in class over the 5.6L "ENDURANCE" V-8 by Nissan.


got that from here, in the concept forum.

 

I guess I have a surprise for some of you. The hemi engine works llike the old caddy engine that came out in the ninety's. As you take off your engine is running on eight cylinders. after you get up to speed say around fifty mph if your not putting a load it drops down to a six cylinder engine When you get on the open road and your doing say seventy or faster it's a four cylinder engine. It's all done by a computer, the spark jumps around so that all the cylinders are lubercated. Haven't you noticed the difference in engine sounds. Why do you suppose they have a towing button. It's to keep the engine in the power mode.. This is in the Chrysler Hemi 300c as well. That's why they get 25 mpg on the road.

 

That also explains the "weird noises" I have been hearing and complaining about. Seems the CAI just accentuates them. Oh well, after Saturday night's light to light battle with a Hemi Sport, I know the kit is doing its job on the HP department

 

To date none of the truck 5.7l Hemi's have the MDS system.
There has been talk of this being added to the truck engine, but in my conversations with the DCX engineers they say it will have a hard time finding it's way into the trucks any time soon.
We'll just have to wait and see. Personally I believe them. Trucks aren't about MPG.

 

Correctly worded direct from Chrysler:

"Your vehicle is equipped with a 5.7 HEMI engine which has been designed to work with 87 Octane gas. 89 Octane gas may be used for Optimum performance. 91 Octane can actually decrease performance."