TwEECer guys quick! Which tune?

this is just a guess here...but I'm pretty freakin' sure it wouldn't make a whole lot of difference either way. The programs are similar and since both are for Ford EEC programs, fuel efficiency is already priortized for maximum amount. You'd be lucky probably to see half a MPH difference.

Your driving style, how often you get on it, and what RPM you are crusiing at in 5th will make more of a differnce. Higher octane will also get you a slightly better MPG.

94DreamGT said:

Higher octane will also get you a slightly better MPG.

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How do you figure? Last I checked, higher octane only prevented detonation. It doesn't add power, it doesn't add mileage, it doesn't do anything except ward of pre-ignition.

baglock1 said:

How do you figure? Last I checked, higher octane only prevented detonation. It doesn't add power, it doesn't add mileage, it doesn't do anything except ward of pre-ignition.

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Yep.

It may help if the tune is made with 93 octane and you're running with a bunch of base timing.

With stock timing and 93 octane, the fuel is going to be much more difficult to burn, which is actually going to reduce the produced "horsepower" of the motor.

Joe

I know what is said...but I'm telling you, everytime I run 93 or 94 octane as opposed to 87 or 89, I seem to get better MPG.

Maybe its just my particular case, but I would suggest trying it and calculating fuel mileage before you debunk my claim. I've had my car for almost 5 years and have checked this many times.

94DreamGT said:

I know what is said...but I'm telling you, everytime I run 93 or 94 octane as opposed to 87 or 89, I seem to get better MPG.

Maybe its just my particular case, but I would suggest trying it and calculating fuel mileage before you debunk my claim. I've had my car for almost 5 years and have checked this many times.

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Your car probably runs that way because the tune favors 93 or 94.

I've had my car since 1998, and it seems that even when I have the car set up to run 93 octane, I consistently get better MPG while using 87 (I do have to back timing out of it though).

I just offered my bit of "technical" information, as to why, theoretically, you do not get better gas mileage with high octane gasoline. I wasn't try to take a shot at you. If it appeared that way, I do apologize.

Let's put it this way: "Results may vary."

Joe

Is your MPG gain enough to make up for the extra cost of the higher octane?

Rick

I was thinking about getting a TwEECer. Are they worth the money? What all can you do with it?

Thanks

Joe...no offense taken. I would agree results would vary by car. I don't really have a "tune" for my car as its all stock EEC with no chip, tuner, etc... All I know is that it does what it does.

Rick: I run 93 or 94 because I used to have an issue with detonation and it went away with the higher octane. With my aluminum AFR's, I run 18 degrees of timing and haven't put lower octane in it mainly because I don't drive it that much and don't mind spending a little more on gas. I might try lower octane though just to see if it still detonates.

i want to let you all know that everyone that says higher octane isnt always better. you want to run your car with the lowest possible octane with out detonation. whenever you run a higher octane (you gotta test a lower octane first) that is for your car, it loses horsepower. you want your car to almost cause early detonation without actually causing detionation.

that is why this new shell vpower stuff is complete ****. they are basically running fuel injector cleaner in their gas which makes you lose a good bit of power because it is a strong alcohol. more alcohol requires more compression (as the menthenol guys) and thats not what a mostly stock car has.

if you want to clean your injecectors then get to near empty on a tankl, put 4 12oz of the cheapy injector cleaner crap (i get mine in the gray stuff from kmart) and put $5 of gas in there. ur car will feel like crap but it will clean the crap outta the injectors. just put in normal gas after that............higher octane isnt better. dunno if this relates to anything but put the lowest octane in ur car and use the "worst" (usually means the most conservative) tune possible. a w4m0 isnt better than a j4j1 cause the cobra is different from the start. its all about how your car responds to everything and everything.......no one's tune is good for anyone else

T4MO should give you better mileage. Looking at your set up I assume you have the stock injectors. The J4JI is for the Cobra calibrated for the larger injectors causing a stock engine to run richer, more fuel. As for octane rating... I agree with using the minimum rating that performs, It is not the higher octane that will cause problems but what is added to the fule to increase the octane rating, there are many ways to increase and every gas manufacturer has a different formula. Most have a winter summer mix.