on www.t4r.org plenty of threads on octane, almost all the guys V6 or V8 are using 87 or regular, I've tried 93 but it just burns more and I don't notice a performance gain.

What did you sell the Legend for, my friend had 2 similar cars a Legend and a Vigor, both mint totalled in a flood, how many miles did it have

 

well, i sell the legend for many reasons...its a 91 car but only had 92k mileage on it. even w/ the low mileage the car still has problems. And Legends are not a cheap car to fix..Legend coupes still have some kind of value so i sold it.

 

Good move

 

If the motor isn't timed for 93 then dont use 93. With higher octane gas the timing has to be advanced. higher octane gas is lit more by compression rather than spark, for example diesel gas can be 130 octane or so and diesels ignite by compression not spark. My wrx runs on 110 leaded now. I can run 93 in it but 28psi out of a 56 trim turbo with 9:1 pistons would blow it all to pieces. I have a knock sensor with a display and with 93 i get a knock at 15psi but with 110 I dont unitl 28.

 

hold the phone. I was taught that if your motor pings to run a higher octane, seeing as the ping is a detonation, and keep running higher until it stops. Then back off for one tank to make sure you don't have to pay the extra .10 a gal. Like with HO motors 'Ex. vette' the manual says to run 91(in Dallas). otherwise detonation is likely. All of ya'll are saying the opposite. Am I backwards in my thinking? It says here http://www.prime-mover.org/Engines/G...es/octane.html that diesel is around 15 to 25 octane.

oh yeah, and I don't notice the power gains of 91 but I do see better MPG

 

I recently changed my fuel pump and filter and ran a tank of premium with fuel treatment. I seemed to be getting better milage but oddly enough I got the same 13.5 as the previous tank with regular. As far as build up in the chambers, just redline it and burn it out... maybe the reason for 13mpg.