ok i just ordered a full exhaust, and ive been reading about o2 sensor CEL's
and I thought why cant a resistor be used?\

ok what I think is before i install the exhaust, find the 02 sensor Signal wire the one that sends signal to Ecu, and with the car at normal temps and idle check the voltage.

After Doing the Full exhaust (test pipe included) check the o2 sensors voltage at idle and normal temps again.
Then running to radioshack and putting a resistor inline between the o2 and ecu.

All this To keep the CEL from coming on.

Has anyone done this? seems like it should work due to the second o2 sensor is for mainly emissions, not as much for drivability as the First o2 sensor.

 

Won't work

The PCM alters the AFR and expects certain responses from the 02 sensor when it does....

 

please search, read and learn, it has been discussed ad nauseam already

 

Give this a shot, a simple circuit using a 555 timer. Shouldn't cost you more than 10 bucks to build ordering parts from digikey.com

http://www.bobblick.com/techref/proj...sim/o2sim.html

 

You feeling ok Team? I saw the thread and expected some lawls to be had

 

The best thing to do is not just put a test pipe there. A high-flow cat works much better and allows the minimal backpressure that is required, which on any car is 1 to 3 lbs minimum. IF you have the extra cash to spend, a Cobb accessport will take care of that problem.

 

1 to 3 lbs minimum

You think your car needs 1 to 3 psi of backpressure?!

Wowsers.

 

Please explain how backpressure is beneficial in any way or form.
Don't help spread false notions just because your buddies maybe once said that yo, backpressure is cool!

 

Dude stuff a wad of tissue up you nose, its gonna help you breath better for sure.

 

since this guy did not search I am going to go ahead and assume he did not read the FAQ on that site either. Probably not his best option.

 

actually i did search and yea that option is useless because its needing of constant adjusting

I just dont see why the ecu would need to make adustments from the second/downstream sensor.

the upstream sensor is what the ecu uses for feedback on just about any car,

the downstream is mostly to monitor the efficiency of the cat, just like when the COBB masks it, it pretty much ignores it because it isnt really usefull for the engine to run, That's what the upstream is for.


So i dont see why dropping the signal to a range that is " normal" for a functioning cat

I.E,,,,random numbers used..... stock car might have 2 volts or .8 ohms depending which one it goes by for a warmed-up idle .... with a test pipe if it reads 3 volts , i know id need a 1 volt resistor... or if it read 1.5 ohms with test pipe id need to have a .7 ohm resistor....
All this is theoretically, of course it would drop signal on a linear scale which may be the issue.

 

Mid-pipe and a cobb ap should go hand in hand.
For many reasons

 

Yea in that example the guy is actually using the circuit on the upstream, surely it would need to be modified a bit to work on a downstream but it is a start for anyone who wants to take up the challenge :D

 

My buddies did not tell me that. I am not some idiot who knows nothing about cars and I am not spreading false notions. I happen to be a professionally train auto tech. with about 10 years experience. How someone took out of what I said that you need lots of backpressure is beyond me, but people have to have a reason to say something, just how it is. Exhaust balance is important, just a fact.

 

Exhaust balance is, backpressure isn't. The trade off is between total exhaust flow and exhaust velocity.
Backpressure means very little if not directly nothing.

 

^ bse50 is correct

Back pressure is pretty pointless and a moot discussion point. The leading myths about back pressure are that it creates more torque, and or prevents your valves from burning up.

I'll start with the valves, it's not true as valves burn up due to the engine burning lean. Secondly, we have no valves, so who cares.

As for the torque, if an engine produces power by moving air through the engine at a peek velocity, then how can a restriction in an exhaust system ever relate to "more power". Again, power is determined by the AFR and overall velocity of the air flow through the engine and out the tail pipe.

Back pressure acts as nothing more than a restriction to flow.

 

the problem is some guy gets a little experience and suddenly he is an expert on everything, even though the circumstances behind the situation are entirely different, which in turn leads to a different end result. Your earlier post is wrong on several levels whether you want to be open minded to the idea or not.

you still have much to learn, grasshopper ....

 

Search around there was a post that said the voltages it uses I think, I do not know where the post is but I believe it was by MazdaManiac. Like others said its been covered A LOT so just check around. Any idea you have has probably already been tested and shot down, but if it has not then please make what you want and let us know the results.

Just use google to search this site, if you are not then thats why you have had trouble.

site:www.rx8club.com o2 voltage

^ Google that exactly and it will find things talking about o2 voltage, change o2 voltage to any other words and you can search the site for that.

https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/adjustable-o2-sensor-simulator-187761/ - recent thread talking about this. Also scroll to the bottom of the page there should be several others.

 

OT, regarding being an experienced tech.

My ex brother in law is ASE certified and has been a tech for 20 years or so and has told me on more than one occasion that torque wrenches are not needed if you are experienced Hence why only I work on my car. Just because you have been doing something for a long time doesn't make you good at it.

OP,

read, read, and read some more.

 

Ok i have just been using this sites search function. the google Idea is already showing me better results,,, maybe that should be a sticky to search google instead

 

Actually, I am very good at what I do. I never said backpressure created torque or that it was great for the engine. You want as little backpressure as possible, I am very aware of that. I was trying to help him find an easy alternative to messing with the O2 sensor, by just doing what has been proven to work, which is a test pipe or high flow cat, and a Cobb accessport. It was not a question of openmindedness, because a lot of people who turbo use a straight pipe since the turbo creates any restriction on the exhaust that is needed, as I have done installs on other cars like that which worked great with a tune. I am openminded to any proper installs that have been proven to work. I mentioned my experience since the reply about just believing what my buddies told me was pretty much saying I was a dumbass who knew little about cars, and I never said anything that shot down another's recommendation.

 

Also, if you feel that someone has posted something that you may know a better solution to, then post what it is and why it is better so the person seeking help can try and apply that solution, which is the purpose of the thread. It works a lot better than insults, and I am sure the person starting the thread appreciates it a lot more.

 

if you don't want to have something commented on out in the open then you would best start by not putting it out there in the first place. You are not the only person who has been around and seen a few things. We have discussed this ad nauseum in the past. Nobody is inclined to keep bringing up past information, especially to someone who makes authoritative yet incorrect statements.

 

It doesn't matter if I want someone to comment or not, but there was a misperception of what was said, I was trying to be nice and help him, but I know, it is not the person who makes a nasty comment, but the one who reacts to it. I guess the only statement you thought was incorrect was the backpressure comment, but the one about the accessport and exhaust was true, not because I said so, and how is it authoritative. If you don't want a reaction, then dont make a stab at them without knowing them.

 

Now I know why not many people on here don't like to help.