ok well what kind of fuel do you recommend or does it not mater?. and should i just get a tune on the 100oct and still be able to bring the boost up??

i never new the info you just said. cool stuff

 

Tune to what ever you have available, then stick with it.

 

Sounds like maybe a combination of things may have caused your change. Air temp, barometer maybe, and fuel's oxygen content. Good place to start looking, anyway.

 

two thoughts: try removing the the wideband O2 sensor and resetting it in ambient conditions, 2nd, could you have a leak around the bung in which your wideband is screwed into?

 

i understand. well it is cold as hell out so that might play a role.

now what gas is better? as with more or less oxygen?

and i will get a 100oct map made up. can i still turn the boost up a few psi as i origanaly planed to do so like everyone else?

 

well, it seems to me that you wouldnt want to have a map on that particular 100 octane... Maybe try somewhere else to see if another fuel has the same effect. Im betting it wont...

 

what other gas stations can i got 100+oct gas then???

 

hold on a minute.

if you are looking at a gauge while driving and seeing different numbers from one wot to another...

I believe you need to do a log so you can see what psi, what afr, what timing you are at and what the numbers look like at the same relative position.

(maybe you did, its to early for me)

anyway that is what I would do before I raised my psi.

 

You shouldn't be getting a tune, then varying your boost without using a different tune. Changing the boost adds more air, provided your not going out of the turbos efficency range. With more air, you need more fuel. Octane rating for anti-knock characteristics isn't the same as AFR. They relate to each other, but shouldn't be confused as the same thing. By adding 100 octane to the tank COULD reduce knock and therefore allow you to increase boost, but you ALSO have to add more fuel for the air to achieve the correct AFR, such as 11.2 or 11.4. If you simply turn the boost up, you haven't done anything to add the additional fuel necessary to maintain the correct AFR.

 

well, in general I agree mr 9sec9 but the increased air that goes in is maf-ed so the afr should not go wrong because of more psi.
your point about afr and octane and their relationship to anti knock is an important one for the thread starter.

I guess, since he does not know what his motor is doing his best step would be to get his tuners advice. AND the tuner could log his supposed afr anomaly and see what is really going on

 

it sounds to me that it has to be bad gas... there is no way on 100oct and the same boost it will get leaner... unless your wideband needs a new o2 sensor and it`s not reading correctly

 

maybe you have a smart car and it adjusted your fuel table for you ? lol

i have no idea why your a/f's would of changed, they shouldnt of

 

That is what I was thinking. The LC-1 can re-calibrate the sensor. That is what you need to do. Pull the sensor from the downpipe and re-calibrate in free air. This way you will re-set the sensor to new conditions.

 

The LC-1 will give you an error code if the sensor is going bad rather than give wrong AFR values.

 

so bottom line is you need to get tuned for race gas!!!!!!!!!!!!!!!!!!!