98 Octance Fuel Burning Difference Tuned/untuned

[Pattygtst]

Searched but couldnt find anything relevant to my questions

My car is currently tuned with bp ultimate 98

Previous to pfc on stock ecu i used ultimate 98 and sometimes caltex 98 depending on what was available at the time. Now prior experiences with both i much prefered the caltex. I definetly got more economy out of the caltex but i could not tell the difference in power. Maybe inclined to say the caltex was better for power.

Now that my work has relocated there is a caltex with vortex 98 real close. So i thought i would try it see what its like on the new tune. Now the thought did go through my head "hold on this is different and the tune may not be setup for this". Then i thought "nah its the same octance level and the tuner didn;t say anything so it should be fine".

I was wrong the knock levels went through the roof, After going to about 6000 the warning lights came on and the readin was 68. Now i cant really understand why. I spoke to the tuner about it and he said its cause the fuels burn at different rates. But its not really an explaination.

The readings on ultimate never went about 25 no matter how hard i flogged it.

I guess i am an idot for trying but there is no problem as long as i dont go into the 5000+ rpm. So basically i cant flog it until the fuel runs out which sux.

Note since putting it the caltex the economy has been a dream.

Cheers

Pat

[DECIM8]

Yeap .. Caltex fuel runs hot I think I've know it for awhile.

it also produces higher power.. 1 RWKW which is prob why.

You wont run into any issues if you go buy yourself some octane booster and poor it in the hole.. 12 bux saves ur ass.

I find BP is best economy shell is mild caltex is useless. this was when the car was stock. When it got tuned BP best, caltex second shell last.

Note Caltex and mobil/ampol same fuels.

[Pattygtst]

so your saying if i put octane booster in there the car will reduce knocking?

I dont think fuel can run hot.