BLOWN IN NC

I remember racetronix chiming in and recommending that all FI cars stay over half tank because it created more reserve? A full tank helps weigh my tail end down so I can get a little traction! :smash:

A Z06 In CA

very very interesting, some people are laughing about it, while others are not as skeptical about this.

but to clear things up, i did not misunderstand. He specifically told me that adding MORE than 1/2 tank helps.

JBBlownC5: i tried to send you an email

Can anyone elaborate what he said in regards to "adding 5 more gallons"?????? Is this with a 1/2 tank????

cmacleod

To answer this question I need to know is the tank half full or half empty. :lolg:

:skep:

6SPD98

I'll have to agree with Z06 Quinn, and SAXN8R that if the PCM picks up a bad octane reading, it will retard the timing.By adding at least 5 gallons of fuel it will reset the timing table for a more advanced timing :flag :steering: :flag

aaaa

My car always feels faster after I wash it.

L76

My old man once told me "chase the money trail and you'll fnd the answer." His wisdom surely applies here... if we want to know if GM DID establish a computer setting that would retime the curves when the tank is less than half full we need to ask why they would do it. What economic advantage is there for GM? Is there money to gain/save? E.g. - would the car get better gas mileage and/or avoid a gas guzzler tax? Would there be lower maintence/warranty repairs due to a leaner running car on bad gas? Where could GM make/save money by adding additional capabiltities to the car?

I am not sure what I believe at this stage... except that it isn't yet clear to me WHY GM would do this. Until this question can be answered I don't believe it. :skep: I could speculate :rolleyes: , but there's a forum already set up for the speculator crowd... the C6 forum. :D

Cheers,
L76


[Modified by L76, 6:21 PM 2/11/2003]

John Shiels

:bs

66ImpalaLT1

Usually I just set my low octane table to equal my high octane timing table before going to the track. :D

Eric

Godspeed

Or you could just drive conservatively until all the bad gas is gone.


As others have said there are (2) Spark Advance tables in the LSx PCM's - High Octane and Low Octane, with about a 4-6 degree difference in timing. After excessice knock retard is detected the PCM switches from the normal High Octane table to the Low Octane table. Once the car is filled up the PCM will assume you have better gas and switch back to High Octane. On the cars I tune I usually leave the Low Octane table untouched and adjust timing in the High Octane table unless otherwise requested by the customer. On a Supercharged car both tables need to be adjusted accordingly, because even the stock Low Octane Spark Advance can be too much for boost.


:chevy

wstory1

:lol: :lol:

Z06 Quin

Not the reputable tuner I was refering too, but a very reputable tuner none-the-less.....thanks GODSPEED for clearing that up! :cheers:

jbsblownc5

I know he takes a beating on the forum for his slowness, But Steve Cole has told me that the timing table is reset by the addition of gas. The computer recognizes the movement of the gage with the addition of aprox 5 gallons. The car may not feel quite as strong as you get down to the end of the tank due to any knocking causing the comp to go to the low point of the timing curve.
As far as SCed cars, My experience is that I do hit the knock senser sometimes after gasing up and then getting on it as I get back on the freeway. My car is tuned pretty close to the line and seems to need to find its spot once I gas up. With SCed car that have high flow fuel pumps and boost-a-pumps, like mine, I find it very important to keep it over 1/4 tank of gas. If I don't and get on it, I seem to suck air.