Dodge Challenger Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
For a 2010 Dodge Challenger r/t classic 5.7L with a 6 sp. Manual transmission do I need to run 91 Octane fuel? Dealership is saying I only need 87 but i found online and in an owners manual to use 91 since its the 6 sp manual. The source I found online said the same thing but it also had a disclaimer that said it excluded the rt classic model. Any suggestions?
 

·
What's Old is New Again!
Joined
·
33,960 Posts
At least 91 octane for the 6 speed R/T. Runs better with a 93 custom tune!
 

·
Registered
Joined
·
8 Posts
Discussion Starter #5
That's what I figured. I have been running 87 oct for the last 6 months (because thats what the dealership told me to do), to switch to premium should I just use up the 87 gas I have in the tank, then switch to 91 then on? I know mixing gas is bad, but also I've heard the car will run rough while the computer adjusts to the change in octane.
 

·
Mopartial to Challengers
Joined
·
8,977 Posts
also, having run 87 oct for a while, could that have cause ping damage to the motor?
Pinging is caused by off-timing detonation. Insufficient octane is the most likely cause. If you notice your engine pinging, you may need to run a fuel system cleaning additive through a couple of tanks.
 

·
Dazed & Confused
Joined
·
34,913 Posts
The way I understand it there are two types of spark knock, short term and long term. A little bit of short term is not bad and happens quite a bit around shift points. Long term is bad like you would get from running too low an octane for an extended time. What happens is the PCM picks up on the fact that it's constantly pulling timing due to the knock and effectively builds it into profile. If I were you I would run it on down and fill it with the proper octane and then pull the #2 fuse (car off) under the hood for about 30 seconds to reset the pcm.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #9
Thanks for the help guys, I think I will run it down to empty and refuel with premium and use an injector cleaner, then reset the #2 fuse.
 

·
Registered
Joined
·
12,969 Posts
If you can run 93 do that, otherwise at least 91 octane. The stock tune is designed to run on 91 octane on the 6 speeds. The autos can run on 89 octane. I would only run 87 octane in some old beater car that I didn't care much about.

Pulling the #2 fuse should help reset the adaptives and fuel trims so it should start running better and take advantage of the better fuel right away.

I've found my car runs the best on BP 93 or Shell 93. (I datalogged and got the least amount of knock retard with these fuels). I get the best mpgs out of Shell 93.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #11
Got her running 91 now. pulled the #2 fuse and used an injector cleaner. Immediately noticed a significant improvement in gas mileage. Thanks for the advice everyone.
 
1 - 11 of 11 Posts
Top