[SpookyStang]

Originally Posted by travelers

You could drive it but I would do it very carefully. No hitting the gas. And No the PCM will not be able to compensate for that much difference. You do need the front O2s and will need to turn the rears off. You can't turn off the O2s with the X3, It has to be done in the tune.

I have no idea where you got the 'you can't turn off the O2's with the X3'. Reason being is because with my X3, I have the option to turn off my rear O2's. I just walked outside and checked right before I typed this message, just to be sure.

[bigwilly43729]

Originally Posted by Ricesmoker

I just installed Kooks 1.75" long tubes and besides the P0155 (O2 sensor heater circuit) I havent any issues.

Guess I can quit paying for tunes then.

[rltrahan]

Originally Posted by SpookyStang

I have no idea where you got the 'you can't turn off the O2's with the X3'. Reason being is because with my X3, I have the option to turn off my rear O2's. I just walked outside and checked right before I typed this message, just to be sure.

Yes it does have the option in the X3 to turn them off but unfortunately my X3 is locked to the Black mustang I recently sold. Didn't really have a choice other wise he wouldn't have driven off in the car with out the tune. I have to fork out 150 to just unlock the darn thing. 250 more and I can own a dyno computer that hooks to my laptop. Any body want an X3 for 100 bucks 150 to unlock it, thats 250 for a barely used X3. Maybe I'll toss it in the classifieds

[sqidd]

There is just no way that putting LT’s with no tune on is going to be dangerous. What do stock GT’s make at the rear wheels? 275hp? And I know there have been claims of 25hp with long tubes but I don’t buy it, especially with what is, for all intents ad purposes a “stock” motor. I’m thinking 18hp MAX. That’s about a 7%hp increase. But just for fun, and to shout up some of the whiners lets call it a 10%hp increase. Now lets say that Ford has their stock tune dialed right in perfect (for making max hp/tq) for a NA motor which is about 13:1. But I have never seen an OEM car make anywhere near that. They are usually down in the 12.5:1 range (a bit fat for bad choices in fuel, etc). So now you take that 12.5:1 motor, throw some headers at it that gain at MAX 18hp (a 7% increase) and what do you theoretically get? You get a motor that will be 7% leaner. That’s only .875:1 leaner than stock for a A/F ratio of 13.375:1, which is still safe by MILES (actually it’s just about ideal for a high performance motor with aluminum heads ad block).

Of course all the above calculations are rough and don’t take into account the billions of variables that make up a true ruing A/F ratio. But they are going to be close. And an A/F ratio of 13.375:1 is nowhere near dangerous. You could add a whole point more and it would still be under schizometric (14.7:1) which is not ideal for maximum power, but certainly safe. And in addition to that it’s not like you get to 15.7:1 and the motor melts down. It would just be lean, run hotter than it should be and not put out much power. But permanent engine damage, no way.

Yes, it would be ideal to tune for the headers. But we are talking about a super lazy, mass production V8 that was designed for the lowest common denominator and all the stupid crap that it could be subjected too. Compared to a “built to the max” 3v the stock motors are incredibly safe. How safe? Well I just rammed enough air into mine to increase the HP 72% without removing a valve cover. I think it’s fair to say that the stock motors are pretty stout.

[travelers]

Originally Posted by SpookyStang

I have no idea where you got the 'you can't turn off the O2's with the X3'. Reason being is because with my X3, I have the option to turn off my rear O2's. I just walked outside and checked right before I typed this message, just to be sure.

This is where I got that info from the X3 instructions from SCT. I guess there have updated your abilities, which is a good thing.

USER ADJUSTMENT OPTIONS
‘05-06 Mustang GT
87 Octane, 91 Octane, 93 Octane, Economy, Speed Limiter, Idle Drive, Idle
Neutral, Shift Point 1-2, Shift Point 2-3, Shift Point 3-4, Shift Firmness 1-2, Shift
Firmness 2-3, Shift Firmness 3-4, Rev Limiter, Cooling Fans, Spark 0 - 2000,
Spark 2000 - 4000, Spark 4000 - 8000, WOT FUEL, Axle Ratio, 30lb injector, 42lb

injector, 90mm Lightning MAF, C&L CAI, JLT CAI, PHP CAI, Steeda CAI

[ski]

Originally Posted by sqidd

Now lets say that Ford has their stock tune dialed right in perfect (for making max hp/tq) for a NA motor which is about 13:1. But I have never seen an OEM car make anywhere near that. They are usually down in the 12.5:1 range (a bit fat for bad choices in fuel, etc).

It's my understanding that Ford has designed things so that a stock S197 GT's combustion chambers remain super cool during extended WOT runs in order to minimize the chance of any damage. This is played out on numerous dyno charts that I've seen with WOT A/F's in the 11's, and a few dipping as low as the 10's.