fuel octane

[supra887mgte]

i was wondering what a 7mgte should use for fuel and what will get me better gas milage what octane is better for the turbo and the motor i was jw cause ive been mixing the octanes together ... get bak to me
thanks

[ddmcse]

i use 93 octane and have for years
i get 17 mpg around town which i think is pretty good for 300 ponies

[Poodles]

highest I can get from the pump...detonation is baaaaaaad.

[monkihead]

93 only. come to think of it, when i was broke @ss in college it was the only time i used regular. i use 93 even on my non-turbo cars.


oh, but if you get a chance, try some 103 or 112 octane fuel....fun as hell!!

[rnoswal]

The octane depends on the compression ratio and the boost. The owners manual should be a good guide. If you have done any modifications to the waste gate for more pressure, then a higher octane and timing should really be spot on. The lower octane will give you better bang as it does explode faster, but under higher pressures, a hot spot will probably occur in the combustion chamber, probably a sharp edge on the piston and that will cause the fuel to ignite early or the same time as the spark plug goes and the two flame fronts colliding causes that pinging sound.

You try to use the lowest octane you can for the best power before detonation. Anything higher and the fuel burns slower and not completely all the time. It is a pain sort of but after I finish the car and want to get it as close as possible, I take a twelve mm wrench with me. make a few hard runs somewhere and if it pings, I retard it some, just small movements and if it doesn't ping the I advance it a little bit. You can do this at any drag strip, but you have to wait for openings, so I use any un-used street. I don't need to go crazy with speed, but a stong pull in 2nd and 3rd should give some idea.

Good luck

Russ

[supra887mgte]

ill try the 93 sometime when i can afford it lol .... but i dunno about going too high couldnt it be bad for the motor to use too high of an octane maybe blow a sencor out somewhere i just want it to run good right now i got a problem with it kindof like bucking when the boost starts kicking in... i really need to find out what it is and dont know when i get on it and the boost kicks in the car bucks kind of and i dunno if that could be from running bad fuel too much or is it something like my transmission well if anyone knows anything or ur supra does it get back at me

Originally posted by ddmcse@Aug 22 2005, 12:55 AM
i use 93 octane and have for years
i get 17 mpg around town which i think is pretty good for 300 ponies

i run highest i can get at the pump and i get 26mpg (My Best) on the highway and 21-23mpg boosting in town at 12 psi and im at 340 hp

sleeve your cats or install "test pipe" i mean so your turbo can spool your gas milage will improve5+

[rnoswal]

I think if you could spray a little water injection it would help out cooling, give more boost and help it say just a bit cooler. I son't see how any stock car withstand much more performance without getting hot. Put in a 26x19x3 in chevy racing radiator, 2 core and your problems go away. Then put more boost in it and not worry about overheating, which means BHG.

The higher octane will not help you get any better fuel milage. Timing and good airfilter and higher tire pressures. Bump the timing for several degrees with higher octane and your milage will improve.

Good luck

Russ

[supra887mgte]

how do u do this , "sleeving cat" ??????

[joel w]

Originally posted by supra887mgte@Aug 23 2005, 03:42 PM
how do u do this , "sleeving cat" ??????

well the second cat is easy, just unbolt it and knock out the stuff inside while Holding your breath.!!!bad stuff.. slide a 2.5 inch pipe inside. cut it to length. and weld it inside the cat and bolt it back up, the first cat is a bit harder, need to cut the cat close to the flange and mark it so it can be welded back in the same spot, then do the same to the inside as the first cat and weld it back up. its not legal and if you live in a area where they check your emmissions you will not pass the test. If so then i would recomend the test pipe install so you can reinstall your cat before testing. h34r: