93 octane vs. 87?

[Bobd1001]

What is everyones thoughts on which to use? My 2000 3.8 Camaro seems to respond and run a bit better off 93 octane.... is it worth the extra $, and can the 93 hurt anyting running it for long periods? I have been using 93 for the past 3 or so months, and it seems to increase throttle response and acceleration quite well...

[thedetailman]

Re: 93 octane vs. 87?

no. It does not hurt it.
Ive actually heard that 3800s love 89 so midgrade.
im sure 93or 91 does the job sure... but its not realllly gonna give you that much more hp over 89 so there really is no need for 93or 91 cars that are TUNED for 91 or 93 cannot go lower in octane being that the timing is not SET for that and thus you get what is called a knock ping. which is the spark and the piston being at top dead center is not aligned correctly.

you can run a higher octane in a car all day long. but too high, you run into temp issues and or burning of the valves.
no worries though. you will probably never accidently put 116 or 110 in your tank lol

[96RS Alex]

Re: 93 octane vs. 87?

I used to use the higher octane 89 and on occasion the 93 on paydays. However, when I found and installed the pricey Diamondfire E3 Spark Plugs, my Camaro runs better on Sunoco, Shell or Mobil 87 and none of that Citgo, Valero or Hess discounted fuel blends here in the Northeast. Californias highest has 91 instead of 93. Just worth mentioning that higher altitudes also require a different octane rating for engines to perform well. More importantly, a motor that's tuned and tweaked via software or hardware upgrades will allow you to enjoy the fuel octane you feel is best for you. My '02 LS1 SS V8 loves Shell V-Power :tup:

Just a pic of what these E3 DiamondFire spark plugs are. Up to you if you want to run 93 if it makes you happier in the long run. I just save more in the longer run with this kind of investment in my 3.8L motor. I recorded 417 miles to the tank on these awesome plugs on 87 octane.


I still wonder what is behind Shell's Nitrogen Enriched Fuel Blend which is advertised to be a superior grade of fuel over those lower discount fuel brands. They also say you get the maximum benefits of nitrogen cleaning molecules if you stay with Shell's V-Power Super Unleaded. Good question for discussion if it hasn't already been hashed out already.

[whitdog54]

Re: 93 octane vs. 87?

no problem running 93. But if your stock, or just bolts on and not tuned for 93 octane. Save yourself a couple bucks and just use 87

[Jtels2593]

Re: 93 octane vs. 87?

My 2000 3.8 is for the most part stock, except for NGK plugs, MSD 8.5 mm wires and a K&N filter. I run the car constantly on 89 octane and it performs very well. I noticed it was a bit sluggish running on 87 at first. For .10 cents more per gallon, it won't eat your wallet.

I fill up at a variety of fuel stations depending on where I'm at. I use Mobil/Exxon, Marathon, BP and Sunoco. I can't tell a difference between the brands so.. use your own judgement.

[cam98aro]

Re: 93 octane vs. 87?

i usually use mid, which is 89.

87 makes it run a bit rough, but i think high octane is a waste of money, because the engine doesnt need it.

some people claim that using high octane (which is either 91, or 93 depending on where you live) will give you better gas mileage and save you money over using 87, but it seems to help the wallet a bit more when going with the lower grade IMO

[LETZRIDE]

Re: 93 octane vs. 87?

basically it's like this...if you're not getting any knock what so ever, you should not feel a difference...higher octane doesnt give you more power, it just makes the gas harder to combust, therefore it takes longer to burn (if it burns too quick then you get knock, premature detonation)

so if you have knock, higher octane will get rid of that, and you car will stop pulling timing, that is where you will feel the difference. It will be because you will have your full timing back, rather then having some pulled timing. But if you are not getting any knock, you should have full timing anyways.

The only other way you will notice a power difference is if you have a tuner, and you manually raise you spark timing up some...

[Mogobs30th]

Re: 93 octane vs. 87?

93 isn't going to have a bit of difference on a stock 3.8l over 87 grade. None. If you're thinking that your acceleration is better, and you're getting better performance, its probably in your head, because you want to justify using a more expensive octane gas.

[cam98aro]

Re: 93 octane vs. 87?

i remember reading somewhere where with the stock tune, there is still some spark retard when using high octane, i dont know if that is true or not, but if you are using higher octane, and the computer advances the timing a tiny bit, you're going to see a slight increase in power

[timthescarred]

Re: 93 octane vs. 87?

I run 89 and while I'm probably crazy, it does seem a little smoother that 87. Mine is stock but for NGK plugs

[LETZRIDE]

Re: 93 octane vs. 87?

93 isn't going to have a bit of difference on a stock 3.8l over 87 grade. None. If you're thinking that your acceleration is better, and you're getting better performance, its probably in your head, because you want to justify using a more expensive octane gas.

oh you will...but if, and only if, you are getting knock already and the pcm is pulling timing...the higher grade will allow that timing to be added back as you will get rid of some/all of the knock.

[Mogobs30th]

Re: 93 octane vs. 87?

oh you will...but if, and only if, you are getting knock already and the pcm is pulling timing...the higher grade will allow that timing to be added back as you will get rid of some/all of the knock.

Why would you be getting knock on a stock 3.8l? If you are, it has nothing to do with the gas, but you have some kind of problem with the engine of some kind. Should be no reason to get knock if the stock motor is operating properly, hence no reason to use 93 octane gas. Simple as that.

[LETZRIDE]

Re: 93 octane vs. 87?

Why would you be getting knock on a stock 3.8l? If you are, it has nothing to do with the gas, but you have some kind of problem with the engine of some kind. Should be no reason to get knock if the stock motor is operating properly, hence no reason to use 93 octane gas. Simple as that.

not necessarily true...I believe extreme altitudes will require a possible change in octane to prevent knock. (I think)

But I do agree, there isn't really a reason why you should have knock in a stock 3800, and if you do, you most likely have other issues you're right...

[ssms5411]

Re: 93 octane vs. 87?

The stock timing tables on our 3800's are really low compared to 05+ 3800's , there about 6-7 degree difference. But I think GM got there KR sensor problem fixed in the 03' 3800. 3.8's are common for false KR, but looking at a 05 Buick Lasabre running 27-28 degrees timing stock is pretty sad for our 20-21 stock timing tables. But yes running the higher octane will put your cars timing tables to the high timing so you'll get less mileage but more performance. Using low grade will keep you in the low timing tables for better gas mileage.

[ThaDyce17]

Re: 93 octane vs. 87?

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