91 vs. 93 octane [by (r + m)/2 method]
 

I've noticed that many SVXers on the boards are using 93 rated octane (where available). Here in Cali, the highest rating available is 91. This is also the minimum specified rating required by the SVX.

I've heard different opinions from different people, but does it really matter, in terms of better performance, if you use a higher-than-minimum rated octane?

Some people say the increases in performance are negligible. Some people say it definitely makes a difference. I, personally, can see both sides of this argument. I could understand why using 93 instead of 91 wouldn't make a difference, since your ECU creates the timing advance of the spark in presumption that you are utilizing 91. Then again, I could see the 93 taking advantage of this advance since it combusts more efficiently than 91. I'm no performance pro, but by simple logic, these are two possible sides that I see.

Would the knock sensors notice the difference between 91 and 93? I don't know exactly how the knock sensors function, but I understood that they only look for detonation.

I'm just sort of thinking aloud, but it is something to consider with the price of gas rising at such a ridiculous rate.

Gas prices are raising quickly, but they aren't actually all that crazy. Gas has been $4-$5/gallon in many countries for years. I'm sure motorists in those countries would kill for $2.50/ gallon. And when you take inflation into consideration, gas prices are lower today then in 1980! But I digress...



I don't think the ECU would notice any difference. The knock sensors only "listen" for knocking or pinging, so I can't see how it would affect them either, as neither one of those octanes should cause pinging. I think it really comes down to prefference and availability.



Dave

My sister lives in north hollywood said there is a gas station there sells 106...must be for ferarri's and ****??

93 would be better than 91 if the ECU detects knocking at 91. If no detect, then no advantage.

That's what I thought, too.

You could maybe reset your ECU to take advatage of the 93 octane, but if the ECu doesent sence knoking with 91 you wont gain performance by using 93, if anything you would lose horse power becasue the higher the octane the slower it burns.