Does anybody have any factual information about the spark curves for the Magnum that would suggest if adding premium gas is beneficial at all? I know what the owners manual said, but I wanted to know if there was any more information.
The reason I am asking this is if the car is tuned for 89 octane lets say, then adding the premium stuff not only is a waste of money, but COULD cause damage to the spark plugs over a long period of time (the slower burning premium gas will leave a "film" over the pistons, valves and plugs, eventually fouling them out prematurely). I know there are some that will call "horsehocky" on this, but I have seen it first hand, and wouldn't have believed it either unless I had...
Another example, on the 1996 Impala SS, it was rated at 89 Octane fuel. Well, it was more than okay to run premium in that engine if you wanted as the spark curve and fuel tables were actually designed for premium gas. The way that they got around this was to make the knock sensors much more sensative on the Impala as compared to the Camaro or Corvette of the time. It basically let the knock sensor pull the spark back if there was knock.
Okay, I have blithered on enough now... if anybody has any information on this, I would like to hear about it. I tried premium gas in the Magnum for the first time to see what it would do, and of course I have not noticed any difference (duh)... but was hoping that I wasn't doing any harm to anything but my wallet!
Thanks!
MagnumFreak
11-22-2004, 10:20 AM
Chances are that running premium will not hurt the car. With the dual plug set up on each cylinder you should get complete burn without any problems. I did some testing on gas in the magnum and could not measure any difference in performance between 89 and 91. 0-60 times were within 0.03. Same temperature and humidity on both tests.
So, if you just want to spend the money... put 89 octane in it and send me the difference. LOL!!! :crazy: Seriously, I would just stick with 89 and enjoy the savings.
senglehart
11-22-2004, 10:27 AM
Have you compared 87 to 89 octane? I just wonder if the knock sensors would compensate for that. I always run 89.
ramification1
11-22-2004, 10:32 AM
Switching to premium would be a waist of money unless you have some kind of pinging. If you do have pinging, switching to super is a nice way to hide a potential problem. I ran my Magnum RT on the dyno yesturdayand found that the air/ fuel mixture is on the rich side. I feel Dodge does this on purpose untill the motor is completely broken in. I have heard that the motor has a "wake up" after 150hours of driveing over 30mph. Looking at anouther Magnum numbers that dynoed yesterday, he is makeing about 25 more horses and about 30ftlbs more torque. Both our RTs are bome stock. His RT has 225 hours on the clock. Also his air/ fuel mixture is dead even and he claimes he felt the car become quicker and more resposive in the past month. We questioned about the cooler days of October and November but he said there has to be something more to it then temp for the diffrence he feels. :gr_patrio
MagnumFreak
11-22-2004, 12:01 PM
Have you compared 87 to 89 octane? I just wonder if the knock sensors would compensate for that. I always run 89.
Haven't tested 87. I might in the future but I haven't as of yet.
Oh, the 150 hour legend is real in my book. See my post on "something interesting happened on my trip this weekend". Almost a 2 mpg jump right at 150 hours.
Blackcomb
11-22-2004, 12:37 PM
Damn.....is there any way to tell on a SXT what your hours are?
MagnumFreak
11-22-2004, 01:17 PM
Not sure if it will work on a sxt or not but try this:
1. get in and close the door.
2. turn the key to the accessory position.
3. wait for all the bells and whistles to finish their chatter.
4. make sure your odometer is showing in the display (anything else in the odometer slot and this won't work).
5. push and hold the trip reset for about 10 seconds.
6. display should change to hours if the sxt will do it.
I am curious as to if it will work on a sxt myself.
sikpuppy
11-22-2004, 02:14 PM
Doesn't work on an SXT, unless it has the computer readout that comes with the upgraded system in the RT, you know, BA stereo, controls on the steering wheel etc. It's what they call the EVIC (Electronic Vehicle Information Center).
Josh Brown
11-22-2004, 02:22 PM
what were the Dyno #'s
McClane
11-22-2004, 03:08 PM
Switching to premium would be a waist of money unless you have some kind of pinging. If you do have pinging, switching to super is a nice way to hide a potential problem.
I agree, unless your vehicle has high compression and requires premium (ie. Viper, or Mopar Perf ECM for the trucks) then running premium will only lighten your wallet.
Rule of thumb : use the lowest octane fuel possible that does not cause pinging.
ramification1
11-22-2004, 05:56 PM
My Dyno nubers are 273 rwhp and 317rwftlbs of torque
Blackcomb
11-22-2004, 06:46 PM
So if I fill it up with 87....is that a no go?
Wicked96SS
11-22-2004, 07:53 PM
Fill it with whatever the owners manual suggests to do... I believe it is 89, but check...
The only reason I was asking was the experience I had with the LT1 in the1996 Impala SS... with the sensative knock sensor... it DID benefit from premium gas (not much but some).
Shawn57
01-19-2005, 11:29 AM
I have a 2005 RT and I have run 87 octane since day one and it gets 25.8 MPG on a trip with cruise set at 70MPH. No pings or knocks and feels plenty strong. It has 2200 miles on it. I also had a problem with the ESP and had to have a new gadget put in the steering column. Shawn
CraigInCT
03-23-2005, 12:51 AM
When I picked up my RT in December, the salesguy had filled the tank with 87 octane. I had a check engine light appear with in one day. By the time I got in for a system check, I had refueled with 89 octane, the light had turned off and the code was a generic code. I've run 89 and 91 since them and had never had the light return.
desquirrel
03-23-2005, 02:50 AM
When I picked up my RT in December, the salesguy had filled the tank with 87 octane. I had a check engine light appear with in one day.
More than likely, the fuel cap was not tightened the first time.
flhthemi
03-23-2005, 08:45 AM
Not sure if it will work on a sxt or not but try this:
1. get in and close the door.
2. turn the key to the accessory position.
3. wait for all the bells and whistles to finish their chatter.
4. make sure your odometer is showing in the display (anything else in the odometer slot and this won't work).
5. push and hold the trip reset for about 10 seconds.
6. display should change to hours if the sxt will do it.
I am curious as to if it will work on a sxt myself.
FIRST make sure your CCN software revision date is 7/27/04 or newer!
To see this date you need to press the compass button and the radio mode button on the steering wheel at the SAME TIME and hold them down for about 8-10 seconds before it will display in your speedo. Mine had a date of 2/24/04 (until yesterday) and I could NEVER get the hours to display until yesterday.
MagnumSXT
03-23-2005, 11:56 AM
With the dual plug set up on each cylinder you should get complete burn without any problems.
Just wondering if it annoys any of my SXT brethern that all Magnum discussions seem to assume RT unless specifically stated otherwise. Do the RT owners not realize that there are other models and engines?
flhthemi
03-23-2005, 02:01 PM
Just wondering if it annoys any of my SXT brethern that all Magnum discussions seem to assume RT unless specifically stated otherwise. Do the RT owners not realize that there are other models and engines?
Oh...yes we know you're there. All you gotta do is speak up. :) What you see happening is not R/T owners being rude or forgetting about you guys with the SXTs. It's just that it's human nature, for most of us (people) to assume what we have is what everyone wants to know about our experiance with.
But we still love you....:)
MagnumSXT
03-23-2005, 02:25 PM
Thanks, I feel the love now.
It just seemed odd to me that the first reply automatically assumed RT. Maybe he knew the guy had an RT or something
Anyway, maybe I'll buy some RT and HEMI badges so I can join the club. :D heh
Blackcomb
03-23-2005, 06:32 PM
Heh.....well....
:P
magnuman
03-23-2005, 09:54 PM
I've been running 87 for the last couple months now. I actually get about a mile per gal. better with regular. I noticed it the first tank I tried. Then went back to 89 and mileage went back down. Now I use only 87, but may return to 89 in the summer months when it warms up. I have noticed no difference in performance. The last two 85 mile trips (same route) in rolling hills, 2500-3000 ft. elevation, 45-60 degrees, 60-70 mph I got 28.2 and 28.3 mpg respectively. Only mods. are my home made insulated CAI with K and N filter (intake air runs right at ambient) and I run 40 PSI in the tires. I've never tried 91 and see no need to. Both these runs were made after 150 hours. I am around 190 hours now. Previous best in mileage before 150 hours (with 89) was 26 mpg on a 200 mile trip in similar conditions. Maybe there is a wake up???
gsjoe
03-24-2005, 03:03 PM
I have the jetchip stage2 installed in my Magnum RT and I notice NO difference between 89 or 93 octane BP/Amoco. Seems that 89 does the job just as well even though the chip says it requires 91 or better.
