HI all, my sister just purchased a brand new VE SV6 and i thought i would do a bit of research on the 3.6L Just wondering what others think about the Compression Ratio on these engines being 11.5:1 and the recommended fuel being still only 91RON. They have dual knock sensors and all but thats rather high to only use 91 Octane. My falcon has a compression ratio of 10.4:1 and when using crappy fuel on hot days it pings a bit. What do others think?

It is what it is. Much smarter men than us design these things. Lots more goes into pinging than just octane of the fuel.

I always put in 98 no matter what car im driving, it's not too much more expensive

Quote: Just wondering what others think about the Compression Ratio on these engines being 11.5:1 and the recommended fuel being still only 91RON. I use E10 Caltex fuel in my VY SS Commodore and the LS1 has a compression ratio of 10:1 , my car actually performs better on that fuel than the Vortex 98 octane fuel. That's because Ethanol contains oxygen and has a higher octane rating than the old 91 octane fuel, it's octane rating is actually 94, since the fuel is oxygenated, it actually makes the engine perform a bit better on top of that octane rating, the downside being that o2 sensor controlled vehicles will sense a leaner mixture therefore the computer will tell the injectors to inject more fuel into the engine, this is because the calorific value (ability for a certain amount if energy to be produced from that amount of fuel) has changed. I've had pinging once with that fuel on a hot day, but I was also getting an incorrect fuel level reading that morning, ethanol is a bit like that "damp rid" stuff, it tends to suck moisture out of the atmosphere, some of that water may have been getting stuck in the fuel filter too. Refilling the tank fixed the pinging and fuel level problem, usually the fuel level problem goes away after driving the car around for a bit (e.g. when I leave a car that has 1/4 of a tank of fuel in it sit overnight and the next day it's reading at 1/3rd on the fuel gauge.)

Quote: Originally Posted by Duke57TT [View Post] It is what it is. Much smarter men than us design these things. Lots more goes into pinging than just octane of the fuel. No way, smarter guys than us? Pfft I doubt it, what would combustion chamber design and ignition timing have to do with anything??

Quote: Originally Posted by 88 Chaser [View Post] No way, smarter guys than us? Pfft I doubt it, what would combustion chamber design and ignition timing have to do with anything?? I have a holesaw and a boost tee.

Quote: Originally Posted by Duke57TT [View Post] I have a holesaw and a boost tee. Whats the boost tee for? Just crimp it off and run full boost bro