I disagree to rich is your friend and lean makes you go boom this is only correct to a point lean is not good but to rich is not good either you need the right fuel mixture.

PS>plugs didnt look to bad.

 

Obvioulsy you need a good "mix", but we all know that in an effort to create a dyno queen, the last thing done is to "lean" the car out. We both also know that the next thing done after the dyno sheet is printed out, is that the car is then riched back out. We also know why this is done.


LEAN goes BOOM!.........

With my current tune, I have right at 525 fly HP, prior to riching back out I was 560. Not worth the extra ponies to go "boom".

 

Actually you’re both right. To rich is not good especially at idle and normal driving conditions as it burns(wastes) too much gas and it could kill your CAT sooner, if you’re running one. Too lean, and it will make your combustion chamber run hotter than it should(although not necessarily go boom) and emit higher than normal NOx, possibly even creating hot spots. However, at Wide Open Throttle(WOT) rich is better(about 12:1 AFR) but lean will make you go boom. At WOT even the stoichiometric value of 14.7:1 (desired mixture for idle and normal closed loop operation) would be considered too lean and will make your engine go boom. So it is all relative to what condition you are talking about and what you would consider lean and rich.

 

better gas should only be considered when changing your compression ratio or adding force induction. the Octane rating is used to determine how much you could compress gas without it self combusting. By adding an intake or headers or any other bolt on that doesn't affect compression it shouldn't be neccissary to run a higher octane rating.

Now when it comes to the newer engines that have knock sensors, the ecu will always try to run the engine as advanced as it can without knocking so better gas “might” make a difference since now you have dynamic timing control using the knock sensor as the determining factor and running higher octane “might” allow for more advance. However it is not necessary as I previously stated.

 

wow i learned something today.

btw the right mixture is 14:1 right?

 

14.7:1 makes the least amount of polutants and best fuel mileage at sea level.

 

you want lambda to equal 1 and for pump gasoline it is 14.7

 

I wanna know why you don't have a cat and how you plan to pass emissions. I do recommend you install your cat because it doesn't look like you have enough mods to merit running an exhaust with no cat. Also, your car has to be throwing a code b/c you have no cat, unless you did something to the O2 sensor 2.

 

You're right on the pollutants, but the best fuel mileage is achieved at a slightly leaner mixture of about 15.7:1. the problem with that is what I stated, hotter combustion chamber and higher NOx emissions which is bad for the environment. The CATs are more efficient at 14.7 as well so they further complete the combustion of the unburned fuel and free up the Hydrogen so it can combine with the oxygen in the NOx to form harmless water(vapor) and nitrogen(gas). The added fuel economy doesn’t warrant for the added harmful emissions. That is why automakers set the closed loop AFR to 14.7:1.

 

I would also recommend you install at least a high flow cat for the reason I stated above. The added 1-2 HP, if that, is not worth the added harmful emissions. Just my 2 cents