1993 Cobra Registry

Hey everybody what brand and level octane gas do you run in your cars. I've heard that Shell refines most of the gas in the U.S., and other companies buy from them. After they get it from Shell they mix their own company's additives and detergents to it. But i've only read that a few times on the internet so that might not be necessarily true. I've also seen that some of the small franchise stations use the purest form of gas due to not mixing in all of those detergents & additives. Another thing that was illustrated was how some gasoline that contains methanol or ethanol is bad for fuel injectors. So I wonder if any body knows about that?

Next, some guys I know that work in an automotive plant, that make and test actual motors, said that the high octane level gas is not really needed. To test the motors they run it on low grade gasoline, somewhere around 85 or 86, check emmissions and they pass there performance levels. The higher level we buy at the pump is simply used to help cut down on "Engine Knock". As you know our manuals require us to use a minimum of 87. In the past I have always pumped 93, but I may move down to 89. Actually it was said that some motors are not to be run off of Premium or Supreme gas. I've heard that if your exhaust smells a little like sulfur or rotten eggs, you are using too high a grade of gas.

So what do you guys think. I'm looking for anybody with some comments or experiences with these matters. I know we have some mechanics out there. Where you at BADBOYSPACK I know you got something for me!

This is a related comment but not an answer to your question. All 5.0's only needed 87 from the factory, but many people bumped the ignition timing up to 14-15 degrees and that necessitates 93 octane. I believe (correct me if I'm wrong) that 93 Cobras require 91 from the factory. Does this mean we can't mess with the timing? What is the reason for the premium octane requirement?

I too have heard that Cobras require 91. I don't know where it came from though. I guess they just decided to print the same manuals for all mustangs which states 87 being the minimum. I'm not that advanced to even start talking about retarding or advancing timing on motors so I'll leave that alone.

93 Cobra's only required 87 octane. If your car was bone stock and you bumped up your timing, then 91 or 93 was a good idea. Mine never pinged using 87 and 14 degrees of timing. I'd only run 87 if I couldn't get the higher octane fuel.

Both of these articles state that the Cobra REQUIRES premium.

Motor Trend

Road & Track

What about the brand of gas? Which do you guys use?

svt2205 wrote:93 Cobra's only required 87 octane. If your car was bone stock and you bumped up your timing, then 91 or 93 was a good idea. Mine never pinged using 87 and 14 degrees of timing. I'd only run 87 if I couldn't get the higher octane fuel.

This B/S, if your timing was at 14 degrees (priving you did it correct) it would be a must to run 93 octane.

I run Mobile 93 octane.

They require 93, the good stuff!

I think its very possible for him to have run 14 degrees on 87 octane. Don't forget that each car is different when it comes to timing. Most were set at 10 from the factory but I've seen several that had never been messed with that were set at 11 including my 89 GT. Some people get away with 17-18 degrees with 93 octane. Again I personally wouldn't run 14 degrees on 87 or 17 on 93, but I'm sure its possible so I wouldn't be calling BS on the guy.

phorty wrote:I think its very possible for him to have run 14 degrees on 87 octane. Don't forget that each car is different when it comes to timing. Most were set at 10 from the factory but I've seen several that had never been messed with that were set at 11 including my 89 GT. Some people get away with 17-18 degrees with 93 octane. Again I personally wouldn't run 14 degrees on 87 or 17 on 93, but I'm sure its possible so I wouldn't be calling BS on the guy.

I say B/S on the 14 with 87 and 17-18 with 93 on field experience.

Being a Ford tech and having a 5.0, it is not realistic.

I agree. with badboy. Based off my experience you could not set base timing to 14 degrees and not use 93 octane. Bitch would ping like no tomorrow under WOT. If you NEVER went WOT then no it probably wouldn't ping

QWKSNKE wrote:I agree. with badboy. Based off my experience you could not set base timing to 14 degrees and not use 93 octane. Bitch would ping like no tomorrow under WOT. If you NEVER went WOT then no it probably wouldn't ping

At the standard ignition 10 BTDC timing, a stock '93 Cobra should do just fine with 87 octane. I bumped mine to 13 BTDC, and used 93 'just to be safe'. However, I was unable to detect any noticable preignition with 87 octane during numerous WOT runs on a 90+ degree day back in 1995. (As we all know, high intake air temps = more tendancy for spark knock.)

In 196,000 miles I've used just about every major brand of gas here on the east coast and never had any pinging problems. (Except for Motorsport stainless/ceramic shorty headers, my car's bone stock.)

I too was quite curious about the Road & Track report that the '93 Cobra required premium. So back in the mid 90's, I called Doug Kott, who had written the story.....he had nothing to back that up and could not recall where that info came from. And of course, the owners manual calls for 87.

Best Regards,
Bob S.

rufus wrote:At the standard ignition 10 BTDC timing, a stock '93 Cobra should do just fine with 87 octane. I bumped mine to 13 BTDC, and used 93 'just to be safe'. However, I was unable to detect any noticable preignition with 87 octane during numerous WOT runs on a 90+ degree day back in 1995. (As we all know, high intake air temps = more tendancy for spark knock.)

In 196,000 miles I've used just about every major brand of gas here on the east coast and never had any pinging problems. (Except for Motorsport stainless/ceramic shorty headers, my car's bone stock.)

I too was quite curious about the Road & Track report that the '93 Cobra required premium. So back in the mid 90's, I called Doug Kott, who had written the story.....he had nothing to back that up and could not recall where that info came from. And of course, the owners manual calls for 87.

Best Regards,
Bob S.

I have an 04 F 150 Super Crew and 05 Ford 500. I would never run 87 in either of them.

Do what you want, but if it was mt car I wouldnt even concider it an option.