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Discussion Starter #1
Hi all
Can you help me please, I have a 2014 Challenger 392 6.4L and we are going to fit Drop in pistons and Rods ( Forged by Arrington)
all is stock at present and the only thing we have done is put in the 93 Octane Pre tune in by SCT, we have 98 octane in the UK otherwise nothing else done !, Question is would it be best to return the Pre tune Octane back to its stock original PCM factory set up ? I cant see what it will do if we leave the Pre Tune in just disconnect the battery and carry on we are only replacing pistons and rods to forged (no machining is being done hopefully!) change for new oil, filter and gaskets etc
I would appreciate your comments
Thank you
 

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Hi,
We are in a similar position in New-Zealand with fuel octane ratings as you. The 93 oct tune you have installed is measured AKI. Our and your UK fuel is measured in RON . Our 98 oct BP fuel here works out 93-94 oct on the US method so any US tuner with a 93 oct tune preloaded to your car requires you to run minimum 98 oct. US tuners 91 oct tune needs our 94-95 rated fuel minimum.
There should be no reason to change the 93 oct preloaded tune in your car as long as you use UK 98 oct fuel or higher.
Hope that answers your question....
Hi all
Can you help me please, I have a 2014 Challenger 392 6.4L and we are going to fit Drop in pistons and Rods ( Forged by Arrington)
all is stock at present and the only thing we have done is put in the 93 Octane Pre tune in by SCT, we have 98 octane in the UK otherwise nothing else done !, Question is would it be best to return the Pre tune Octane back to its stock original PCM factory set up ? I cant see what it will do if we leave the Pre Tune in just disconnect the battery and carry on we are only replacing pistons and rods to forged (no machining is being done hopefully!) change for new oil, filter and gaskets etc
I would appreciate your comments
Thank you
 
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Discussion Starter #3
Thanks Phil for that, nice to here from the other side of the World!.... yes you are right we use 98 Octane I put in Shell V-Power cos its local to me., looking forward to the tear down this weekend hope all goes well very nervous! its glad to know that I don`t have to put it back to stock factory setting when we are only just changing pistons and rods
really appreciate the input
 

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Just wanna ask a question too about my challenger 6.4 392 a/t. On my driver’s manual it says 98 RON or higher. But upon researching some manuals only say 91 or higher. I’m just a little confuse. I dont know if i have to put 98, 91 or 95 just to be safe. Please help thanks.
 

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2020 Dodge Challenger Hellraisin Scat Pack
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The reference to "98" octane I believe comes from say the UK or Europe or Australia/NZ which go by a RON rating (Research Octane Number).

"91" is for the USA (and a few other countries) which uses an AKI (Average Knock Index) number which is (RON+MON)/2. (MON is Motor Octane Number).

Here's a Wiki link that might be of some interest to you:

https://en.wikipedia.org/wiki/Octane_rating
 

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I have access to 108 octane racing fuel. I ran 2 consecutive tank fulls in my 2015 R/T A8 5.7l but noticed nothing. My car is basically stock with a Scat Pack 1 PCM. Is there a tune to take advantage of this? Would it be worth the tuner pcm and 7 bucks a gallon?
 

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Short answer is "no".

Longer answer: I believe your car's engine is designed to work just fine with a lower octane grade of gasoline from the factory. Running a higher grade of octane wastes money most of the time. The exception is if you are racing then arranging to put lead free racing gasoline in the fuel tank -- ideally with as little street gasoline in the tank as it is "safe" to have to minimize dilution of the racing gasoline -- is highly advised. The racing fuel gives the engine a bit more protection against detonation but racing gasoline has other attributes that are beneficial in a racing situation.

Any "tune" that required 108 octane would almost certainly require changes to other areas of the engine other the just the engine controller. Often a tune that requires high octane gasoline involves major internal engine modifications: high compression pistons, or lower compression pistons if a super-charger is being added; special heads; special cam; reworked valve train; better intake; better exhaust. The engine delivers much more power but can be a real b*tch to drive on the street.

While the HP gains may be impressive -- there is a video (Engine Masters?) of the guys taking a "stock" 5.7l engine and adding a centrifugal supercharger and eventually getting the engine to produce around (I think a bit over) 750hp and around 650ftlbs of torque -- essentially Hellcat power and torque territory -- the engine had considerable help: 118 octane gasoline and some dialed back timing and the engine only ran on a dyno. In the real world on the street or the track one of the guys said eventually the motor would let go and one would drive over the crankshaft.

For the street just stick with the recommended grade of gasoline. However, to ensure getting the freshest gasoline be sure to buy from a busy station. Also, experiment with different brands of fuel but I would recommend you stay away from discount/supermarket gasoline. Stick with the name brand, top tier stuff.

With my Hellcat I have found the engine feels like it prefers Shell V-Power vs. say Chevron Supreme. Others have told me they too notice Shell V-Power better for performance and none are running a Hellcat. Might add that some have told me they occasionally run a tank or two of Chevron Supreme to obtain some benefit from the fuel system and engine deposit detergent effects of Techron in the Chevron fuel. (With one of my previous cars, a 2002 Boxster, I noticed an improvement after less than a tank of Chevron Supreme this after a couple of years of running mostly Shell V-Power.)
 
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