93 octane vs. 87?

[cam98aro]

Re: 93 octane vs. 87?

What combonations do you guys suggest for a 3.4L engine.... Should I run 89 or 87 octance?

i would run 87, but thats a personal preference

[ThaDyce17]

Re: 93 octane vs. 87?

Which spark plugs should I run in my 3.4 to get the best gas mileage

[cam98aro]

Re: 93 octane vs. 87?

Which spark plugs should I run in my 3.4 to get the best gas mileage

spark plugs wont change your MPG like that, unlike what the companies say.

just buy some ac delcos, or ngks and be done with it (and yes, i know ngk makes delco plugs)

[ssms5411]

Re: 93 octane vs. 87?

NGK TR55's $2.00 a plug for N/A engine, and if 87 runs fine without any issues then go for it. I run a 9.8:1 compression right now with a cam , so I like to run the highest I can get at the pump which is 91 OCT. My next build going in this FRI. I hope will be like a 9.9:1 compression.

[Rob Bell]

Re: 93 octane vs. 87?

I would just run the lowest octane that provides knock-free performance. Back in the day when I had my other car, I ran 92 in it for years until I read that it made no difference. So I tried 87 and got an immediate good increase in mlieage. Which showed me that the engine liked 87 because it was tuned for it. So I think it's best to use what is recommended for your engine, unless you have mods that require higher octane.

Others on here are correct in that higher octane only means it burns slower, which reduces knock. But if you are running it in a car that is tuned for 87, the piston is already on the way down while the mixture is igniting. So, you are wasting that combustion. Hence lower mileage. If your performance is improving, I agree, there are other issues that the higher octance gas is addressing. Which is probably carbon buildup.

[Cammy98]

Re: 93 octane vs. 87?

I noticed when I run 87 here in CA it runs a bit rough and the acceleration isn't to smooth. I usually use 89 and sometimes 91 when I get her washed. But I do feel the difference at 89.

[Mighty Thor]

Re: 93 octane vs. 87?

I noticed when I run 87 here in CA it runs a bit rough and the acceleration isn't to smooth. I usually use 89 and sometimes 91 when I get her washed. But I do feel the difference at 89.

They add O2 to the fuel here in Calif. That's why our rating only goes up to 91. It was 92 5 years ago, but the EPA brought it down.

Rule of thumb. You look at your compression ratio of the vechicle. Ours are almost on the low side 9:1, so an 87 oct. would do just fine. There really is no performance difference if you go to 91. Unless, you live up in the mountains or high elevation where O2 is low.