OCTANE QUESTION

BLKVERT · May 31, 2004

Alright guys and gals....quick tech question for ya....me and my boss are in a slight dissagreement over this. On a '00 GT he states that it only needs 87 and would run fine.(Cus I bitched over gas prices? Whiel i disagree and only run 93, which i have heard stops the car from knocking and pinging?
Please someone help settle this so I can rub it in his face.

Aaron 4.6 · May 31, 2004

You lose. You only need 87. Ford cars requiring higher octanes will say "Premium Fuel Required' instead of 'Unleaded Fuel Only' on the dash.

Higher octane will help stop pinging, but your car should be OK on 87.

BLKVERT · May 31, 2004

Well dammit...SOB...oh well...guess I am fired. Is there any negative impact that I am doing to the motor..as I have always used 93???

FallenPhoenix · May 31, 2004

You'll see lower power the higher octane you use, assuming you don't need the higher octane fuel. I don't think you've done anything damaging really, higher octane fuel is harder to ignite though.

Jesus · May 31, 2004

I will second the lower power thing. I have been running 91 and 93 in my car on and off since I installed a timing adjuster, but since I only set the timing to 13* I have found that the car runs a lot better on 89 octane than on the higher stuff. It all depends on ignition timing (and of course boost in non N/A cars) It seems like people running 15-16* of timing need the 91-93 octane. Stock the cars ignition timing is set at 10* so 87 should be enough. That is not to say the car wont ping every once in a while (a little pinging is normal under certain circumstances) But, I have had several mechanics drive my car with the 13* and 89 and they say it runs and sounds fine. And, I can definately feel a power difference when I run the lower octane in the car. If the car doesnt need the higher octane you are better off not using it in my opinion. I will add though that under certain circumstances I will run Premium in my car to be on the safe side (because of the timing adjuster) like if the weather is really hot for a long period of time and I actually hear some pinging.

twogts4us · May 31, 2004

Good thread guys - exactly right. Octane is to prevent pre-ignition. The more octane you have the less volatile the fuel is and less power is the result. So it's a balance of how much timing advance, compression, etc you have as to what gas you need to run.

LocoStrange · May 31, 2004

Unless you got like a BIG supercharge or twin+ turbo.. there is no need to use 91 or even 93

twogts4us · May 31, 2004

LocoStrange said:
Unless you got like a BIG supercharge or twin+ turbo.. there is no need to use 91 or even 93

Ummm, no, that's not correct. Increased timing advance (or increased compression) requires additional octane to prevent pre-ignition (detonation). I have to run 91+ because of increased timing advance via my SCT chip tune.

BLKVERT · May 31, 2004

So then stock timing is 10*...and because of this there is no need to run 91 or 93..and I will be fine to run 87. And what about the old theory that the higher octane the gas the more it cleans out the injectors so there will be no need later on to have injector cleaner dropped into the tank????

Jesus · May 31, 2004

BLKVERT said:
So then stock timing is 10*...and because of this there is no need to run 91 or 93..and I will be fine to run 87. And what about the old theory that the higher octane the gas the more it cleans out the injectors so there will be no need later on to have injector cleaner dropped into the tank????

As far as I know all fuel grades have detergents in them that are designed to keep injectors and valves clean. I could be wrong though.

Go HoTO! · May 31, 2004

twogt and Jesus nailed it! Dam, how can a guy be wrong named Jesus? Years ago, the lower grades had less detergants in them, hence the reason why you thought that. Now, they are all about the same.

One more thing, higher octane fuel burns slower. This is why you advance the timing.

Also, blowers run at higher intake temperatures due to the air being compressed. This is another reason why they need high octane, right? I do know that higher ambient temps will tend to cause pre-ignition (pinging) too.

Jesus · May 31, 2004

Tis true, the thing about higher ambient tempperatures causing detonation. This is one of the reasons a modern car can run 10:1 compression ration on 87 octane gas. Back in the sixties all the cars had comp ratios of at least 10:1, but they needed 102-104 octane fuel; the reason: almost all of those cars had iron heads instead of the more modern aluminum heads. Iron heads retained more heat, hence causing preignition. Other reasons modern cars can run higher comp. ratios are: electronic Fuel injection, and modern roller or overhead valvetrains.

Joel's98GT · May 31, 2004

Good accurate information here, don't waste your money on better gas if it is not needed.

GoBabyVroommm · May 31, 2004

In a 4v you should put nothing less then 91. Your good with 87 in your car. Damn your lucky.

GregGTStang · May 31, 2004

So, if your car is 100% stock, run 87 or the 89????

FallenPhoenix · May 31, 2004

run the 87 unless you ping then run 89. If you still ping with 89 I'd take it to the dealer and raise some hell.

Mr GT 02 · Jun 1, 2004

I run diesel in my car..is that safe?

BLKVERT · Jun 1, 2004

Mr GT 02 said:
I run diesel in my car..is that safe?

Of course it is.

Thanks guys for the informative info. Guess I will start saving some $$ and start using 87 or 89.

GoldnGT · Jun 1, 2004

Hmm.. running nitrous i think i'll stick with the 93 octane

Mike

Joel's98GT · Jun 1, 2004

GoldnGT said:
Hmm.. running nitrous i think i'll stick with the 93 octane

Mike

good choice.

OCTANE QUESTION

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