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Discussion Starter #1
Tonight i was distracted and accidentally put 93 octane in my car (i do not have the KDOII yet) Noticing a little increase in oomph it reminded me that our cars can "learn" different changes and adapt the system to those changes. Driving hard will cause it to adapt and allow more power at the expense of fuel and vice versa. When you have the computer reflashed by Kenne Bell...does it retain this feature? I know you're supposed to run 92+ but if you dont' won't it just detune a little? I didn't know if the reflash just permanently set it to be tuned for 92 and anything less would just ping or how it worked.
 

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Not sure. :dunno: I suspect that when they created the program, they found that high octane yeilded the best results and wrote the program based on that. I would think that using a lower octane would negate any benefits gained from the program (excluding shift points). She would probably run rough and knock and ping. I personally would NOT run regular or plus. If you are trying to save on gas then it might help to know that my gas milage has seemed to have increased.
 

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The optimizer runs high octane because of the timing advance. If you run anything below you will knock or ping. Running anything above 92 octane will make the car run better. So I wouldn't sweat it.
 

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Something tells me if you have the KB opt computer then you aren't too concerned with saving on gas prices...LOL. :)

--Gorm
 

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Well, now I have a question. Does 91 oct work with the upgrade? It is a tough to find anything abouve 91 in Colorado. I have heard that because of the altitude 91 here is the smae as 93 at lower altitudes, but that seems odd to me. But all of the oct is wierd here. We have 87, 89, and 91. I have found 93 oct around, but it is way too far of a drive to be worth it.
 

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If all you have is 91 around you, the best thing to do before getting the optimizer upgrade done is telling KENNE BELL that you'd only like to be upgraded to use 91 octane since that is all thats around you. I dont know how much performance you would loose, but its better than Knocking and pinging.

Although i've heard from one user that has it on his R/T....its done for 92 octane, but runs 91 because thats all thats left in CA. He's never had an issue.
 

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qp_20 said:
Well, now I have a question. Does 91 oct work with the upgrade? It is a tough to find anything abouve 91 in Colorado. I have heard that because of the altitude 91 here is the smae as 93 at lower altitudes, but that seems odd to me. But all of the oct is wierd here. We have 87, 89, and 91. I have found 93 oct around, but it is way too far of a drive to be worth it.
That's all we have, too, unless you're willing to go out to the 1/4-mile track every so often.
Of course, you can buy octane boost at the parts store ...
 

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guys... his 91 octane should be running at atleast 93 octane at sea level, i believe its every 3k feet from sea level it goes up half a octane or something like that... but it should be atleast 92 octane for him if not 93.

plus you can just buy octane boosters... throw them in with each fill up.
 

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Just a quick question:

Does it benefit performance/gas milage to run say 93 instead of 87 in the 2.7L? Or does it in fact hurt performance/gas milage because the car isn't required/built to run higher octane?

Thanks.
 

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The computer for our engines will adapt to whatever gas you're using when the computer is in "closed-loop" mode. So if you put premium in, you'll notice a performance increase during all driving conditions except for WOT. WOT is an "open-loop" mode, and when in that mode, the computer doesn't pay attention to the sensors and just reads the calibration data set at the factory... so you won't see the performance increase. What KB does is set the calibration data for premium, so even during WOT you'll notice the performance increase. If you use a lower octane, the computer will react to the knock sensor by retarding the timing so it should still work fine if you end up having to use a lower octane with the KB.
 

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Treppin99 said:
Just a quick question:

Does it benefit performance/gas milage to run say 93 instead of 87 in the 2.7L? Or does it in fact hurt performance/gas milage because the car isn't required/built to run higher octane?

Thanks.

the fuel itself really wont do anything. well... unless your supposed to run 93 and put in 87 instead, cause that could definatly destroy your engine. but if you put it in the 2.7L the octane itself only keeps the gasoline from combusting too early. in a engine that puts out more power from its engine the compression would set off the fuel in a lower octane too suddenly before the plug can fire to ignite the mixture. thats why higher octanes are used when you increase the compression or add extra boost to the mixture. but if there is more octane then needed it wont do anything, it'll just be over kill cause your plug will still ignite it.
 
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From the 2002 FSM (0-4) ...

DESCRIPTION - FUEL REQUIREMENTS
Your engine is designed to meet all emissions regulations and provide excellent fuel economy and performance when using high quality unleaded gasoline having an octane rating of 87. The uses of midgrade, octane rating of 89, gasoline is recommended for the 3.5L H.O. engine. The use of premium gasoline is not recommended. The use of premium gasoline will provide no benefit over high quality regular gasoline, and in some circumstances may result in poorer performance.

This is probably just a reprint from the 2001 manual since it doesn't mention the 300M Special, which can get some added benefit from premium gas, though there has been some discussion that maybe any HO can get some benefit from it.
Antibody said:
WOT is an "open-loop" mode, and when in that mode, the computer doesn't pay attention to the sensors and just reads the calibration data set at the factory... so you won't see the performance increase.
The PCM uses those preset tables, the MAP sensor and the TPS. It also uses the long-term memory correction factor (though that isn't mentioned here).

WIDE-OPEN-THROTTLE MODE
This is an OPEN LOOP mode. During wide-open throttle operation, the following inputs are used by the PCM:
- Inlet/Intake air temperature
- Engine coolant temperature
- Engine speed
- Knock sensor
- Manifold absolute pressure
- Throttle position
When the PCM senses a wide-open-throttle condition through the Throttle Position Sensor (TPS) it deenergizes the A/C compressor clutch relay. This disables the air conditioning system and disables EGR (if equipped).
The PCM adjusts injector pulse width to supply a predetermined amount of additional fuel, based on MAP and RPM.
 

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Discussion Starter #16
...which i knew and brings me back full circle to my original question: would a KB optimized computer still use a long term memory adaptive behavior if one were to "HAVE" to use a lower octane rated fuel? Or would it simply ping away until the fuel situation was remedied?
 

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Archael said:
...which i knew and brings me back full circle to my original question: would a KB optimized computer still use a long term memory adaptive behavior if one were to "HAVE" to use a lower octane rated fuel? Or would it simply ping away until the fuel situation was remedied?
I'm pretty sure long-term memory only effects the amount of fuel - not the timing. But the anti-knock sensor should catch any "pinging" and adjust the timing accordingly so you won't ruin the engine. Still, if it's got the recommended octane on it I wouldn't ignore that ...
 

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Discussion Starter #18
right thanks :) just wondering if the adaptive behavior was built into the PCM or if it was on a part of the car that would remain MOPAR lol Thanks again :)
 

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Discussion Starter #20
I noticed Lafrad's thread in the buy/sell/trade forum and wondered if it would interfere with the KB programming. Wouldn't the KB override this part or would they compliment each other. I'd like the autoshift removal in autostick and he says it shifts considerably firmer an sooner (hope that doesn't mean at a lower rpm) but anyhow.. i just thought i'd post my query.
 
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