hi everyone i ve searched around but couldnt find an answer i dynoed my 09 gts yesterday to get a baseline for future reference and the car was running pig rich i mean the guage couldnt even pick up the actual reading it was uder 10 is that normal? is it just the stock tune being ridiculusly bad?

 

Well, how did they get the reading, did they use a wideband O2 sensor?

It is true that these cars run rich from the factory but that number doesn't seem right.

 

they put a wideband sensor in the muffler the lowest the gauge can read is 10 and it was at 10 but it could ve been lower since the gauge doesnt read any lower than that i mean my gas mileage isnt too bad but if the air fuel ratio was where its supposed to be the car could pick up like 5mpg and maybe some hp since it only dynoed at 139whp 137wtq

 

that seems way too rich from the factory. No tune previously on the car? Get them to lean it out a little and fix that up, enjoy the new gas mileage, and increase in power.

 

Is it just me, or does anyone else not trust the 02 sensor in the muffler deal.....

When i had my wideband in my turbo outlet i could immediately tell a minute exhaust leak because i'd start to lean out on my wideband. So i'd get under there and tighten it up and it was fine again. If that small of a leak can change my AFRs, whats to say the same cant happen with an open o2 sensor stuck in your tailpipe. I dunno, maybe i'm just paranoid haha

 

everyone elses afrs were dead on so that makes me think that that sensor works just fine but yeah i need to bring the car to the stealership for a routine service anyways so i ll talk to them about it and see what they have to say

 

Was it 10 or less across the board?

 

That is not an uncommen situation, seing the car int he 10's on the dyno on a power run. We saw the same thing with our R&D work on the lancers in australia, although interestingly, it was the auto models running way richer than the manuels. We found the auto 4B12's were running in the 10's whilst the manuel 4B11 were running in the 12's on stock trim.

That is why you can create so much power with these cars, simple tuning and some leaning / flattening out makes large gains

 

i just think for an N/A car to be in the 10s or even lower is just wrong so idk i ll have to figure it out

 

well if you have a cat, putting the sensor on the muffler to get readings will provide inaccuracies

 

The stock 4B12 should run around 11-12 AFR.

The best is 14.7 in theory and yes, I took my thermodynamics classes.Pr1/Pr2.

Did you test the car when it was running cold? I know for a fact that cars run rich when it's cold.

 

yea it was actually pretty cold that day that might ve been the problem idk im getting a catback and a cai and im gonna throw it on the dyno again and see what happens