esanmiguel

I get much better performance using super,.. The car feels faster, more responsive, and idles better. Porsche only recommeds 87 octane for the NA right? I dont mind paying the extra cents for Super if it gives me benefits. I even buy a can of Octane booster to add to the tank (too much octane is bad??) Am I just imagining the extra performance I get with super or can anyone attest to this?

iloveporsches

It's all in your head, honestly.

Since the gas door sticker only listed RON rating, I didn't know exactly what I was supposed to use so I've always put in 89 rated fuel. But putting higher octane fuel than required doesn't give you any benefits, except maybe a weight reduction in a lighter wallet

Dave

What he said! And "cans" or "bottles" of octane booster don't do anything either so DO NOT waste any $$ on them! It would take gallons of the stuff to do what they claim, search for "rocket fuel" (might be in the "old" archive) but an hour of reading will give you a heck of an education about octane.

Jessa

Yep, I'll second that. Its in your head. Higher octane fuels are more resistant to combustion. So, a higher compression engine needs a higher octane to prevent detonation. If your older NA was designed for 87, give it 87. If anything, 89+ won't burn as cleanly in that car, and lead to some build-up.

Ditch the octane booster, fill up on 87, and run some injector cleaner through that puppy.

iloveporsches

Further question: Is gas from places like Mobil or Chevron actually better than places that are .05-.10 cheaper per gallon?

Luis de Prat

I'll third (or fourth) that. I blew money on premium for years in the 83 before following Rennlist advice that I was simply throwing my money away. Car drives exactly the same with 87 as with 93.

esanmiguel

I use Redline Fuel System and Techron on a regular basis.
I always thought a higher octane fuel burns cleanlier..I guess this is wrong?
I swear, it can't be in my head that I feel this. Anyone else?

Antonio951

i run highest octane(93) and the only reason i do is to run clean stuff through the motor. I dont do it for it to run any faster because it wount, just to keep it clean. Money isnt really a factor because 1 tank last me about 2 weeks(drive it 1-2 times a week.)

esanmiguel

There is a difference. Fuel contains additives that clean your engine. Chevron's famous techron (which is a proven formula that will actually clean your fuel system) is added to their gas. You go to that Mom and Pop gas station and you won't get those additives. And some of those cheap gas contain methanol.

Jessa

I put 89 in my big old Mercury for a while, simply because I hadn't a clue what it was supposed to have. One day, a gas station was only selling 88.5 in stead of 89 for some reason. I filled up, and swore that the car ran worse with it.

Well, it, too, was supposed to run on 87. I switched, the gas milage went up a smidge and I doubt it got any slower. Sometimes our assometers don't measure accerleration very reliably

Luis de Prat

As I understand it, the likelihood of methanol IIRC is greater in the lesser brands, but I may be mistaken. I stick with major brands just in case, but no more premium for the 83.

Peckster

They all buy their gas from a few suppliers, and the additives are all marketing IMO. The only reason I'd stay away from a no-name gas station is that their equipment might not be as well maintained, possibly allowing water into the gas.

If you really believe your car runs better on premium, than maybe it is worthwhile!

esanmiguel

Well, after searching the net re: octane, seems like the added octane does not benefit anything unless your car knocks on 87 octane. Same with octane boosters being no advantage. The only benefit a high octane gas would give you is if your car has knock sensors which I dont think my 944 has. I guess the peformance gain is in my head.

So why does our Volvo 2.4 Turbo require premium gas then? Cause its Turbo?

Dave

Maybe my source is wrong (He does fuel testing for Exxon), but I was told that most of the lesser brands sell the same stuff as everyone else and get it from the same trucks. For example, A truck full of Exxon fuel may also deliver to non-Exxon stations, the smaller companies don't own refineries and need to either have someone else's refinery make their fuel for them or just buy from that refinery the same fuel that the refinery already makes. In most cases it's cheaper for a "mom and pop" to sell Exxon than it is for them to get poorer quality fuel "custom" made for them. They pay no franchise fees so they are cheaper and the Exxon station up the street will tell you his fuel is better to get you to pay extra for it. It is also not unheard of for a station to be supplied by another brand, an Exxon station could be so far off the beaten path that they are supplied by Hess and vice versa.

He works in a big Exxon refinery and swears it's true...

Carl Nall

I'll agree with esanmiguel that there's a subjective feel of improved performance with the higher octane. I usually run the lowest octane that eliminates pinging under load but in the 944 with a modified DME, exhaust and intake, I prefer to use premium to reduce the risk of detonation! It's only money, right?

Note that FR Wilk's site recommends running super for a while after chip installation... so presumably after a certain period the DME/AFM adjusts to optimize combustion with the lower octane.