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Discussion Starter #1 (Edited)
I read that you can use the 91 octane tune, but retard timing at WOT in order to use 89 octane gas. I am fairly new to the Predator, and i initially installed the 91 octane (no cai) in the r/t only to realize that the stations around here use 89 and not 91 octane for the mid grade gasoline. Regular is 87 octane, mid grade is 89, and premium is 93. I really do not want to use 93 for daily driving duties, i can use 89, and while the tune is in the car currently i'm not going wide open with it yet, it feels responsive enough at mid to low throttle in traffic. But i'd like to adjust the tune appropriately so I can use it safely.

What do i need to do to adjust the timing or fuel a couple degrees at WOT? can someone point me to the steps necessary to adjust the tune? I still haven't installed the 180 thermostat yet, i figured i'd wait till spring before changing it out, and then i'd need to adjust the fans.

Thanks,
Lord Warlock
 

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I cant imagine wanting to run 89 octane in this car.
It has high compression and is designed as a performance motor. Pulling spark to run 89 octane would be detuning it, and thats not what we do ;)
 

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Discussion Starter #4
Its been running just fine on 87 octane, before the tune, I only put 89 in because of the canned tune, but don't want to risk wot and engine damage, i'd remove the tune and go back to stock, and only switch tunes on a track day or a time when needed instead of risking it with sub par gas. I'd heard the six speeds needed 91 octane, but the autos were fine with 87 regular, and it runs well on regular. It runs better with the canned 91 perf tune. But not enough to pay for premium daily. Too much traffic to actually enjoy it driving daily with premium.
 

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go to this web site, pretty good article on predator tuning
Diablosport Predator
That is an excellent article. For info relating to the OP's question, check the last entry:

"17) Running 89 or 100 Octane Fuel
Since the introduction of this tool, many have asked if they can run 89 octane fuel with a Predator tune. The answer is Yes and No! If you are going to install a Canned Tune shipped with the Predator, you Must run at least 91 octane and NO you cannot run 89 octane fuel. Diablosport has authorized using Modify Tune on the Perf 91 or Perf 91 CAI tune, by retarding timing 2 degrees in all six WOT Spark settings to run 89 octane fuels, so in this case, YES you can once timing is retarded 2 degrees as listed. Make sure you log some WOT passes and play them back to insure no LT Retard appeared. Similarly, if you are at the race track and can purchase 100 Octane Low Lead, you can Advance the timing of the 91 octane tune by 4 degrees, maybe 5 with data logging to check for knock."
 

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Just keep in mind, you are detuning the car to run low grade fuel, seems kinda backwards to me, but to each their own ;)

I can assure anyone who thinks that their HEMI powered car 'runs great on 87 octane' that they are mistaken. Log it, and you'll see what I mean.
 

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Discussion Starter #7 (Edited)
That was actually the article i mentioned in the first post, where i'd read you could back off timing at wot. I was just asking how to do it with the predator, not whether detuning was a good idea or not. I'm sure it will run better with premium, which is 93 octane here, we do not have 91 octane here, so unless i want to half tank it with 89/93 in order to get 91, i'm stuck with one or the other. As for it running great on low octane fuel-i said it ran just fine, not great, we're talking about 9.5:1 compression, that is hardly hi compression, at least not compared to the 10.25:1 that was stock on the 440 magnum i have in my 69 Charger R/T SE i've had for 30 years. It used to be ok to run regular in a 9.5 car, the original documentation with the car said 87 octane was fine with an automatic, so thats what i use. If i wanted to run premium all the time, i would have bought an srt8. If i supercharged it, then yes i'd run premium. If i was hotrodding it all over town, i'd run 93 as well, but the car is driven in traffic daily, and rarely gets over 80 on the 10 mile trips to work and back every day and traffic pretty much keeps your foot off the floor most of the time. by the way, i am not disabling MDS. I prefer to have the MDS active.

I'm disappointed that i can't get 91 octane mid grade fuel here, if i'd paid a little closer attention beforehand, i'd have skipped the predator purchase until i needed it. I was under the impression that the 91 tune was for midgrade gas. So far, i have not "heard" any detonation under wot with the stock tune and at wot and using 87 regular. If i did, i would move up to a higher grade fuel. Evidently the challenger doesn't make the same noises as the 440 does when the fuel isn't up to the task. I'm familiar to listening to the motor, rather than logging to check fuel and timing. I'll have to spend a lot of time with the predator before i know what i'm doing regarding logging with it. My previous two daily drivers were supercharged, or dual turbocharged-both put out over 450hp to the wheels, and they survived 10 years without ever seeing a logger. But they also stated premium was required, and thats what they got. Since i put the canned 91 tune in, i've used 89 and its run fine, but i've intentionally stayed off WOT situations. Since it isn't raced, that is fairly easy to do.

Can the tune be set so that timing is reduced at wot over 4500 rpm? or will it detune it All of the time whenever its under wot in the lower gears? I wouldn't want to detune the car under all conditions, i'd only want to retard the timing if I floor it and have the lower octane in the tank. The fuel controller i have in the stealth turbo allows me to run richer at high rpm levels and leaner at low rpm levels. I can adjust fuel maps at any rpm i want, and each cylinder or injector if i want to. The SCT tuner i had with the cobra also let me custom tune it, course i had it professionally done on a dyno. Which is likely what i'll eventually have done with the R/T when i'm ready to take that step.
 

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i had a tank of 87 in mine and i was running the 91cai tune and there was no knock. i drive in elevations from 3500 to 2500 ft. i modded the 91cai tune and adv spark beetween 2-5 deg and watched the live data from the st knk and lt tknk. i wen back and fourth with spark adv. till i had very little st knk. i feel that i picked up throttle response and power.i just filled tank with 91 so i will plug and play again and see if i can tune further. you can back or adv spark in 3 rpm ranges on my 2010 rt. when i got st knk i could not here it.even if you get some knk the car should pull timing back. or you can watch or record the the sensor data. i heard the knk sensor are very sensitive. hope this helps u out. i have been having fun tuning with live stream data.
 

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Discussion Starter #9
I'm currently running the performance 91 tune, while i have a drop in K&N it isn't cai equipped so didn't think i should start off with that tune. When i put the tune in, the car had a tank of 87 octane in it. Initially the first perception was that i got improved throttle response and slightly better mileage with the new tune, after i ran the tank out i put 89 in it, then half a tank later put 93 in it, and haven't noticed any improvement in power using the better gas...yet.

I'll have to check out the tuner this weekend, and maybe at the local gathering over the weekend i can talk it over with some of the other locals, i'm sure at least a couple have a predator and can give some tips. Its good to hear you can adjust the timing in different rpm ranges, it makes sense to me to retard the timing at upper rpms in case i'm running 89, and when i fill up with 93, maybe i'll change it to the other tune or put the timing back.

I'm sure diablomike is speaking the truth and knows his stuff regarding tuning the 5.7, if i was looking at getting the highest performance out of the car or prepping for a track day, I'd be shooting for the optimum solution instead of the safe way to set it up for just daily driving. I'd just like to enjoy the peppier performance and be able to leave the canned tune in it during daily use without swapping tunes based on what fuels in it on a day to day basis. I'm more of a set it and forget it type.
 

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Furious Fuchsia 2010 Challenger R/T Classic A5
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I was going to get a Predator to tune my 5.7 Auto but I'm not so sure anymore since DiabloSport doesn't seem to support "detuning" Challengers with mid-grade 89 octane fuel. (I too use my R/T as a 70-mile daily driver with MDS and have no ambition to use premium 93 octane.)

So much for all the Predator-tuning hooplah for me... I just wanted a better-than-factory tune, not a high-perfomance track tune.
 

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you can mod the factory tune.you can run 89 in the 91 tune and enjoy better throttle response and some more hp.it may pull some st knock. i like the way mine shifts with the firmness raised.it seems like you need to try out the predator. look at my previous reply.i had no knock running 87 fuel,but then again i live at 3500 to 2500 ft. run a 180 tstat that will let u run more timing with 89 fuel. hawaii cool ocean air can run more timing.i drive 85 miles back and forth 2 work and still enjoy my predator,the tranny shifts so much better and the car feels much more responsive. predator tunes are way better than stock tunes.:thumbsup:
 

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Discussion Starter #13
I'm at sea level, or maybe 20 feet above sea level so a little less altitude. I've got a 180 degree thermostat in the box waiting for the install, will probably go in the car in a few weeks. With the 91 tune, i'm not noticing any knock or detonation using 89 octane fuel yet, and i've had some increased throttle response, which is a good thing, and more torque off the line initially but i think the adaptives are choking back on that as it adjusts. I plan on firming up the shift points and raising the speed limiter, as well as adjusting the fans for the thermostat when i do install it. I can tell the tune is better with the 91 tune, but also don't want to risk damage to the new motor by using too low an octane. At this stage i'm not sure what the 2010 5.7 compression is, initial search said 9.5 but other posts are indicating 10.5 which would normally tell me it would need betterr fuel than regular. I'd prefer to use regular for normal driving, then on weekends fill it up with premium or 89 to add a little kick to it. I doubt even running 87 in low rpm daily driving is going to hurt it much as long as i didn't get into it too often. Which normally doesn't happen often. I'm just not finding myself heavy footed with this car as much as i did with the older cars i have.
Looks like i'll have to get the old turbo car out of mothballs, have to teach another driver in the household how to use the clutch, and its the only car left with a clutch in it. Have a month before she gets a learners permit, time for parking lot hijinx.
 

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I cant imagine wanting to run 89 octane in this car.
It has high compression and is designed as a performance motor. Pulling spark to run 89 octane would be detuning it, and thats not what we do ;)


So what would be the answer to someone who lives where 89 is the highest octane available ??
 

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The stock 5.7 is set up from the factory to run on 89 octane, read the manual, at least for the 09 R/T auto.
 

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So what would be the answer to someone who lives where 89 is the highest octane available ??
Seriously nothing over 89? wow... sad..

Octane boost or buy fuel by the drum would be my guess... you could blend if you need...

Still not feeling the detuning as the way togo. Not likely to get much in the way of MPG... and if your going to drive it aggressively at all you'll need to detune it quite a bit to be safe....

Just not sure... BUT it could be done...
 
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