So if I am reading this right, "if" the dealer put in Regular gas, it won't damage anything, but I got confused on one thing? Will the ECU permanently reset the timing or just while that gas is being used to compensate for knock?

Not permanent. It will quickly recover when premium gas is put back in.

:wtf: the cylinder volume does not change when you rev past 4k, the compression is the same at 1k or at 8k. it may not be as detrimental since it's not exploding 8k times per min, but it's still exploding prior to the piston reaching TDC which damages the piston, piston rings, cylinder walls, valves, spark plugs, injectors, if it's in there, it's damaged.

don't put regular in your car unless u have some kind of piggy back or stand alone ecu which will redo the timing.

^^ what does your manual say about regular gas? It's ok :)

Your volume statement is correct, but your conclusion about pre-detonation is incorrect. If the ECU detects pre-detonation, it will retard the timing to alleviate the knock. It's very unlikely to suffer any damage from low octane gas, your performance will just suffer.

All higher octane gas lets you do is advance the timing which can increase the torque generated by starting the combustion process earlier on the compression stroke without detonation.

Essentially, there's no additional energy available in the air/fuel mixture, it's simply how it's being used that results in the generation of more power.

Well, I filled my blue one up today with Premium....93 Octane.....17.5 gallons.....$47.....ouch!

when i had my 350 i 80% of all the fillups i used with unleaded... didnt feel any diverence. my dad who grew up with datsuns and had a 300Z for a long time always used the 'cheap' gas... idk the only gas u should b worried about NOT putting in ur ar is from "THRIFTY"..

Didn't feel any "diverence" between the unleaded and leaded? :confused:

$2.69/gallon?? You get no sympathy from this quarter. 91 octane in Santa Barbara county is well north of $3/gallon.

True
 

Point seen....Money gone on that one my friend.

are you high? if i'm reading this right, u're saying to ignite the fuel before TDC so that force will be applied to the piston head in the opposite direction of travel :ugh:

if that's what u mean then just use low quality gas so the fuel mixture detonates prior to TDC. u want to ignite the fuel right after TDC as the piston moves back down to get the maximum amount of force applied, the high octane fuel allows you to achieve that high compression ratio at TDC without self detonation.

now idk how this new system works, but i'm figuring that if it does adjust then all it's doing is igniting the fuel mixture prior to detonation, since a control ignition is safer than a uncontroled explosion. since it ignites prior to TDC, the force is pushing against the piston, which would naturally decrease the output.

are u familiar with PV=nRT? V, n, and R are constants so as pressure increases in the cylinder, temp increases also. Low octane ignites at lower pressure/compression and high octane ignites at a higher pressure/compresion. actually V is a variable, but if we take it at TDC, it's a constant.

if i remember correctly, regular is used for compression < 8.5psi, 8.5 < plus < 10, 10 < premium < 12 or something like that.

agreed

Yes, you ignite the fuel before TDC. It takes time for the spark to ignite the fuel and complete the burn, so with a piston traveling at 150mph you must account for this delay and fire early. Obviously the goal is as you described, to have maximum gas expansion right after TDC, but to get there you have to start before.

Why would the dealer put regular gas in it?

Wait, did I just ask that question? ;)

:iagree: Which is why Premium fuel has a slower burn rate. Allows for more timing advance..