I was told to unplug my O2 sensor in order to gain some performance. I am not concerned with Check Engine lights or any of that since I am racing on a half mile oval. Will this help/hurt me? How so?

Thanks a ton for all of your advice as I am not only trying to win races, but becoming a "mechanic" at the same time.

Um, whom ever told you that is an idiot. If you unplug your o2 sensor, your computer cant adjust your a/f correctly, and will throw your car into limp mode. In another words, if you were able to get above 5 mph in Limp mode, that in its self would be amazing.

Check engine lights are important too, because it means something is wrong.

ok your right and wrong, why would you not be able to get over 5mph. i had a problem with my car, and it ran with no o2 sensor hooked, and i could have maxed my car out if i wanted. you are right in the fact that the car won't be able to adjust the a/f ratio correctly and it will cause your gas mileage to be crap, which can cause your cat to clog up (atleast mine did) which caused even more problems.




Goal is to make my N/A Auto faster then a manual without doing engine internals

Well when my bank 1 sensor went, the car just died, i could have a brick on the gas pedal, and get out of the car and out run it. Maybe its just the differance in engines?

You mention Cat and it makes me ask another question. Please also keep in mind that I am not a mechanic, nor do I understand a lot of this. I do understand carborated engines, but this computer crap wears me out.

Our rules require that we remove out catalatic converter. Does this help/hurt performance?

removing the cat does both depending on the car. Usually you are reducing back pressure, but our cars need a certain amount of backpressure to run its best.

I have no cat with a 2.5 pipe back to a thrush turbo muffler. Is this ok?

I have power, but not what these two others have. I would like to find more power coming out of the turns, and would like a little more going in. So basically, accelleration and top end... I want it all.....

Thanks for the input.

For starters what engine does your car have? You can't expect a 2.2 to go out and run with an older q4 grand am or anything. Not on the dirt track atleast.

Even if you unplug the O2 sensor, you won't gain power.

No your ecm won't go in limp mode. It will use the preset data. Same thing when the engine is cold.


Gilles
2.3 Ho

if you had a problem with the o2 and it was stuck showing full lean then you might have a driveability issue

but full rich , or unplugged you will still be able to drive it



and do not disconnect your o2 , it run on a preset mapping table , and is not the best for full power

if you want to get the most out of the motor , and stay n/a do all the bolt on mods you can , and get HP tuners so you can tune the pcm

El Fuego ( the grounded one ) wrote:removing the cat does both depending on the car. Usually you are reducing back pressure, but our cars need a certain amount of backpressure to run its best.

That is incorrect, You don't need any backpressure. That is a one of the biggest myths about cars. Once again read this, from the FAQs.

Todays monolithic Catalytic converters are very efficiant and cause very little loss of horsepower, compared to the early pellet style converters. Over time they will develop a build-up of carbon deposites that will block them up , but that takes years for a typical well maintained car. Yes leaving a stock cat in a performance exhaust system will reduce the power of that system, because its designed (and sized) for the stock system.

Round Racer wrote:I have no cat with a 2.5 pipe back to a thrush turbo muffler. Is this ok?

2.5" is too big for the class and rules restrictions you must run. That is way beyond the powerband you would be able to reach in your class. 2 1/4" would be just right, with a straight through muffler, such as the Dynomax Race Magnum Bullet Mufflers

kflo wrote: You can't expect a 2.2 to go out and run with an older q4 grand am or anything. Not on the dirt track atleast.

Most all stock 4 cylinder racing classes limit the number of valves to just two valves per cylinder.

Leave your bank one O2 sensor in. You'll have better part throttle torque, horspower and response. At full throttle the car reverts back to a fixed fuel/spark map that will only adjust by you knock, IAT and MAP sensors. If you wanted, you can tune the motor a little better with the HP Tuners ('97+ only), but I doubt you would want to spend that kind of money.