royal flush

if 91 keeps the motor in high octane table there is NO advantage to 93 octane correct? I have 2001 z06

aaronc7

assuming you're not going to tune the car and ADD timing to the high octane table then yeah I would say no real advantage. 93 would give you a little more 'headroom' in high heat or track conditions...but that's about all i can think of. it's my understanding the cars were tuned for 91 stock so I wouldn't expect much going to 93.

royal flush

thx for the reply--i live in vegas so we have 100 plus 100 deg heat--thats when ill mix 100 with 91 to get 93--i always want to stay in high octane table--never can tell when a dodge demon pulls up--haha

nickalltogether

If a Dodge Demon pulls up you'll need more than a little 100 octane in the tank to compete.

tblu92

Even a 2001 Z06 has a compression ratio of maybe 9.75-1 or 10.0-1 The comp ratio dictacts how high your octane level should be with normal stockish timing---On a finely tuned engine that a tuner has added lots of WOT timing would need better fuel--Most tuners will tune a car for the type of gas the user is going to use Pump gas 91 in Calif pump gas 93 in some states where availiable or a dedicated race car using only race fuel at 100+ octane Unless your tuner tuned your car for using 93+ oct fuel there would be no benefit to using higher oct fuel
How the high/low octane system works
Your ECM counts "occuanaces of knock" when it reaches some magic number of knock occurances the ECM will slip into the low oct table to protect your engine--Knock can occur from poor fuel or low octane or a lean WOT fuel mixture---
Your ECM can re set itself back into the high octane table by----Emptying your fuel tank--then re filling it to past 3/4 full---This will automatically re set it back into the High Oct table
PS: Many tuners will copy and paste the high table into the low table so the ECM will never have timing less than the High table or even have a low oct table--This is only reccomended on non daily driver type usages--