93, but because I have high compression and advanced timing. A stock or lightly tuned Duratec should only need 87.

 

87, and I've never heard it ping and it idles nearly as smoothly as an electric motor.

 

I use 87, I should try 89 or 91 sometime though.

 

i use 93,i have basic mods a tune from FS for 93.

 

87 octane, no REAL engine mods that require the higher stuff

 

these cars are made for 87 ONLY!!! only time you run a high test gas is with a tune. if you dont the ECU will not allow the spark plugs to get hot enough and you WILL blow your catilictic coverter out and i hear there about 1k-1500.

 

ive used 93 on my 06 since i drove it off the showroom floor and 19,000 miles later still no problem and all i have a cai, roush exh, and a 75 shot it says only use 87 in the manual but who really listens? or reads it

 

87, nothing done to it to want the premium stuff.

Stupid question - can you Get <85 octane?? I suppose E85 would be 15, but otherwise do they make lower?

 

Stupid question - can you Get <85 octane??

I've seen 85 out in NM or AZ. But nothing less.

 

87 in my wifes 05 zx3

 

86 or 87

 

87 is for beasts lol. if u are cool u use 87 k?

 

you guys rock! thanks for the quick responses!

 

87 woot

 

06roushzx3 ehh its not a good idea cuz your car isnt made for 93 you have to get a SCT fash to run it. PLUS you should get a tune for your exhaust and NOS cuz your car is running stock #'s for air fuel and stuff like that. the flasher will give you alot more power and be way safer to run also everyone here will agree with me. but problem is the ECU knows it needs to run spark hot enough for 87 octane. well 93 needs a hotter spark or it wont all ignite which means the gas that doesnt burn goes into your valves and exhaust and could cause o2 sensor to go or a CAT. and are cats are in the exhaust manifold so you may want to re think what your doing before you hurt your car but hey just my advice

 

manual recommends 87 so I'll run 87. don't know if i would improve if i went to 89, but don';t really care

 

yeah i do need a tune but for the 379 for the sct and then another 275 for a tune and dyno

 

i thought by running 91 i was doing a good thing for the car

 

91 because it's the best we have here in AZ []

 

People, people! Please read this carefully:

93 octane is not "better" than 91 is not "better" than 89 is not "better" than 87!!!

With higher octane, a hotter spark is required to ignite the mixture. Period. It doesn't burn faster or better or more explosively. It DOES allow engines with more ignition advance to have a higher safety margin against detonation. It does NOTHING, NADA, NICHTS for an engine that is not tuned for it. Of course, the corner gas station is more than happy to sell you whatever you ask for...

 

Well said but it don't think they get the picture.

 

My stepdad's Taurus gets some pinging on 87 (what it asks for) which promptly goes away 100% on 87, so he uses that. I don't know if that's a proper use, but it does seem to work. We have 87, 89, 93 I think, occasionally a station has 91 instead.

As for new cars that don't ping or urn perfectly fine on 87, I would just do 87. Like others said, at best it's a waste of $, but do what makes ya happy I guess.

 

My stepdad's Taurus gets some pinging on 87 (what it asks for) which promptly goes away 100% on 89, so he uses that. I don't know if that's a proper use, but it does seem to work...

Then there's something causing the car to be prone to detonation, and using a higher octane is just putting a band-aid over the problem. Maybe clogged injectors or something causing the car to run lean? Could be lots of things.

 

I've used 89 in my old 92 Dynasty. As things collect 100s of thousands miles, detonation is unavoidable sometimes. Running a high octane to avoid pinging is a valid application, short of an engine overhaul.

 

i use 91 because i have the sct flasher tuned for 91

 

johnzim, it's been looked over a hundred times, I think it's just like Egz said, a little old and tired (so it's ok as a Band-aid, it's on its last leg anyway). But it runs surprisingly well for its age/mileage otherwise & was gotten for a steal.

 

Whatever gets you through the night, it's all right, it's all right. (Wasn't that a John Lennon lyric?) [] You may end up with clogged cats eventually. Anyway, I'm done pontificating on the subject. Peace out.

 

06roushzx3, i sent ya a PM.

 

http://www.jimhightower.com/node/1777

87 tuned with dealer software and getting 37MPG on the summer blend, and 35 on the winter blend.

92 octane (and tuning) didn't net any more MPG (in my case), but lots of "grunt".