412 HP w/ 91 octane, what about 93?
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why I guess you would...but the #'s are still a significant increase....I am done...I posted info that this person has shared in a couple of locations based on his feedback and exposure take for what you like as I do other posts by other members.
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#25
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Ain't me that's for sure. Otherwise i'd have 94 in there right away. That's the top octane fuel we can get here at Petro -Canada. Can't wait to do the first fill up.
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Look - its not magic - its old fashioned ignition timing. The ignition timing can be advanced more aggressively with 91 octane without detonation. I believe Ford writes the factory tune for 91 but with the Adaptive Spark Ignition System, it senses octane and retards timing for less than 91 to avoid damaging the hypereutectic pistons from detonation.
As for the new 5.0, its still an engine. It may breathe better and be a little bigger than the 4.6, but it is still bound by the laws of the internal combustion engine. If anything, I bet the 5.0 has less advance for 91 because of its higher compression ratio.
Buying a tune is an entirely different matter - and its the tune advancing timing for 93 (and A/F tweaks) that brings the HP bump (assuming the tune is written for 93). However, none of the tuners have figured out Ford's Adaptive Spark Ignition System so that is overwritten and you better make sure you're getting good 93.
Detonation is influenced by chamber design (shape, size, geometry, plug location), compression ratio, engine timing, mixture temperature, cylinder pressure and fuel octane rating. Too much spark advance ignites the burn too soon so that it increases the pressure too greatly and the end gas spontaneously combusts. Backing off the spark timing will stop the detonation. The octane rating of the fuel is really nothing magic. Octane is the ability to resist detonation. It is determined empirically in a special running test engine where you run the fuel, determine the compression ratio that it detonates at and compare that to a standard fuel, That's the octane rating of the fuel. A fuel can have a variety of additives or have higher octane quality.
Last edited by cdynaco; 3/12/10 at 11:13 PM.
#28
MOTM Committee Member
#29
The key is what maps are included with the stock tune. I can tell you right now that on my 997 going from 93 to 91 (93 octane is recommended)it cost 8-10rwhp and this has been dyno proven countless times. If you can get a good aggressive tune geared towards 93octane it could be worth something...what it is is purley conjecture at this point.
Dave
Dave
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Well, from all the information I have gleaned about the 5.0 engine, and all things being equal. I estimate the output of a 93 octane tune (not a performance remap) to be:-
416 HP / 395 TQ
If I had to guess, a better tune, better CAI and freer flowing exhausts would see the largely stock 5.0 develop around 430 HP.
416 HP / 395 TQ
If I had to guess, a better tune, better CAI and freer flowing exhausts would see the largely stock 5.0 develop around 430 HP.
#37
I Have No Life
...or is there a limit to the stock tune with respect to what the cealing on what it will try to run.
It's not as if you could put 100 in there and expect it to just keep adjusting.
I think the maps will have limits. So it may be that 93/94 octane is just doing nothing for you without a tune.
It's not as if you could put 100 in there and expect it to just keep adjusting.
I think the maps will have limits. So it may be that 93/94 octane is just doing nothing for you without a tune.
#38
Even the old 4.6 3V had maps for 94 octane. I read an article, similar to the one in 5.0 Magazine for the Coyote, regarding the 3V when it came out. Obvious it was a long time ago but I thought the 3V had maps for 95 or 98 octane. With the much improved Copperhead, I'm think the 5.0 will have maps for at least 94 or higher octane. The 5.0 software is much better than the 4.6 at taking advantage of higher octane fuel.
#40
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Come on, man, it's a bunch of Mustang enthusiasts talking about the first real V8 to give the competition fits in a long time -- the first new one in, what, twelve years? What do you expect? Give us all a break...