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Discussion Starter #1
Just ordered a C&L CAI + Predator package from Maryland Speed - anxiously awaiting their arrival on my doorstep! Now I'm starting to pay closer attention to the octane ratings on my local gas stations' pumps. I always run super (premium) unleaded in my R/T 6 speed, but I'm noticing that my stations here in the small town where I live all have that rated at 92 octane. To be honest, I haven't surveyed the stations in the (larger) city nearest me, so I don't know if they've got 93 octane premium, but if I'm stuck with 92 oct premium in my region, what would be the suggested canned tune to run with from the Predator to start out? Would I be better sticking with the 91 CAI tune, or can I go with the 93 CAI tune? Will the results vary from engine to engine, and will I just have to try out each tune to see which works best with 92 octane gas?

Ideally I'd like to gather some data and get a custom tune eventually, but I'm all tapped out for now, so it'll be the canned tunes for awhile. Also, just FYI, no other mods on the car at this point, though I do have my eye on the Blastin' Bobs glasspacks........ :browsmiley:
 

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a couple ideas

Would I be better sticking with the 91 CAI tune, or can I go with the 93 CAI tune? Will the results vary from engine to engine, and will I just have to try out each tune to see which works best with 92 octane gas?

Ideally I'd like to gather some data and get a custom tune eventually, but I'm all tapped out for now, so it'll be the canned tunes for awhile. Also, just FYI, no other mods on the car at this point, though I do have my eye on the Blastin' Bobs glasspacks........ :browsmiley:[/QUOTE]

I would drop in a K&K filter into your stock box AFTER buying a 3" to 4" silicone transition with a 45 deg. bend (find them on Ebay or turbo shops). You will know where the silicone piece goes once you pull out the stock filter and you can see the hole in the body just below the air cleaner housing (2 min tops... including lifting the hood). Poke down with something long and sharp so you can mark or tap to know where to cut a little half moon into the aero skin which covers the underbelly of your engine area. Then cram the silicone transition 45 so pull the air from just above the plastic aero skin. Then spin it so the top exits just inches from where your new K&N and button it all up. Then lift the front of the car and find the little hole or mark you made in the plastic underbelly cover. Cut a 3" half circle or "V" in a way that when you are done you can bend it downward to "scoop" some cool air just 3" from the 3" silicone transition piece you just installed. This "fresh air" coupled with the K&N flow will set you back 1/3 of a typical CAI and be within 1-2 HP.
Then replace the the thermostat with a 180 deg unit. With the loss of coolant from doing the job, replace with Redline's Water Wetter or similar product (Royal Purple and many others).
Bye doing this you will provide yourself the opportunity to run the 93 octane tune on days when you have "good air" as your intake charge and water temps will both be down which aids in preventing detonation. On days when you have "bad air" (overly hot and or humid), you can simply splash a gallon or two of 100 octane unleaded in with your 92 octane. Or just swap to the 91 tune as it will only take you five minutes to do so.
Good luck......
 

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Discussion Starter #3
Thanks for the info on all of that, but the C&L and Predator are already paid for and on the way. Also, I don't have access to the higher-octane (racing) gas in my local area, so that's not really an option in my case. What I'm gathering is that with the C&L CAI setup and 92 octane, I'd be better off running the 91 CAI canned tune; if I ever find a station in my area that I can regularly get 93 octane at, flash the 93 CAI tune and see if I have detonation issues. Beyond that, installing a 180 degree TS and running a true CAI (i.e. underbody) will guarantee better results in any case, correct?
 

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Load the 91 CAI tune and data log for knock you might also want to add a catch can. there is a lot of good info on the Diablo forum ;)
 

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I agree on the catch can.... 100%

While there is debate on any HP claim know this.... any oil mist being burned in the combustion process INCREASES the octane requirement. Thus, not burning oil mist through the EGR lowers the octane requirement. This is the same "gain" that the 180 thermostat and lower water temp (from a water wetter type product), are helping with. Cooler combustion lowers octane requirement, and the removal of the oil mist helps in this regard AND promotes a better flame travel to boot. The three of them by themselves are a negligible gain, together they are said to be worth one octane point and with good (cool), air, that might be all you need to try the 93. And as one guy stated the N-Sensor will remove timing if they "hear" a knock.

BTW our Mobil 1 0w40 has a not so great flash point and as such goes to vapor easier than other tested 0w40 oils. I pull about a pint of oil out of my catch can every 5,000 miles (not a ton but Id rather not burn it.... and the inside of my intake is clean too, it doesn't remove all the oil but it catches 80-90%). I'm not knocking the Mobil 1, the 0/w40 factory fill does very well on the dyno. I run 5/40 Royal P only because I don't see temps lower than 65 and as high as 115

Enjoy!
 
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