engine knocking when accelerating

[WRBlue]

Originally Posted by hans_fh

I JUST CALLED THE SALESPERSON TONIGHT, HE TOLD ME UTAH IS ON HIGHER SEA LEVEL SO THAT 85 IS FINE FOR MOST OF CARS. HE IS BS!!! ANYWAY I WILL SWITCH TO 91 AT CHEVRON TOMORROW.

He's right. At higher elevations, an engine needs less octane fuel to prevent knock. It has to do with the lower density. Thats also why you can't compare quartermile times at different elevations.

You're probally getting knock because of the summer heat. Hot air explodes easier than cooler air. Thats why You run richer in the winter and leaner in the summer - but the computer corrects for it. Also thats why carbs need to be retuned every season to run the best.

[Pars]

Originally Posted by WRBlue

He's right. At higher elevations, an engine needs less octane fuel to prevent knock. It has to do with the lower density. Thats also why you can't compare quartermile times at different elevations.

You're probally getting knock because of the summer heat. Hot air explodes easier than cooler air. Thats why You run richer in the winter and leaner in the summer - but the computer corrects for it. Also thats why carbs need to be retuned every season to run the best.

True, I usually run with regulars gas (which is 87 Octane), but if a heat wave is coming, I'll switch to Premium to help the engine run as cool as possible (engine knocking does generate extra heat).

I haven't notice any real advantages with performance (premium vs regular), however on occasion, the engine will feel a little more sluggish then usual, but those isolate occurrence only happen when I'm running on regular gas (probably caused by a bad batch gas, with octane level lower then the required 87).

[churp]

Originally Posted by WRBlue

He's right. At higher elevations, an engine needs less octane fuel to prevent knock. ........

Haven't heard that one before????? Who told you that?????