(I'm talking bone stock cars here folks.)

Anyone have experience on a dyno, or a lot of miles checking fuel economy, to see what the difference might be here?

Does the PCM dial back the boost on 87, only cut timing, or ?

Chris

 

*knock, knock* whose there?
more knock!

 

More knock so it will pull timing. I wouldn't recommend it.

 

It will knock and pull loads of timing on 87 octane and considering the stock timing advance is only 5-10* at WOT. Having the ECM pulling as much as 8* or more timing advance will make for major power loss. I doubt a stock tune LNF on 87 octane would make more than 190 whp.

 

I just got the car this week, and it's only making 14 psi. Could it be the dealer gave me a tank of regular? Isn't is supposed to be like 22?

Chris

 

15psi +/- a couple of psi due to a few atmospheric and elevation variables.. 14psi is plenty within reason

 

21 psi would be a GMPP upgrade or aftermarket tune.

 

Quit being cheap and put in 93

 

Nope stock tune is 13-15psi normally.

 

This.

Its $2 a tank. Spend a little extra on your car.

 

A buddy I know runs 89 in his usually & has ran 87 a few times lol car ran like complete **** & even went into limp mode. I warned him not to do this & just put good gas in it only, maybe next time he'll listen to me. I have never used anything lowe then 91 usually its 93 depending on what gas station I go to.

 

When I first bought mine, I tried 89 octane in it. The power dropped drastically and the gas mileage dropped by about 3 miles per gallon. I usually average around 32 mpg with my dialy driving and have averaged 36 mpg on a longer trip, all of this on 93 octane.

In the manual, it even says that with lower octane you will lose power. They do not tell you that you will also lose gas mileage with it.

 

Think I had this problem recently.


HOUSTON—The Texas Department of Agriculture is investigating 16 Houston-area gas stations for allegedly mixing lower-octane gasoline with higher-octane, higher-priced gas.



Records show gas stations pump out low-octane gas from premium pumps | khou.com | Khou.com - News, Houston news, Texas News, Headlines

 

It's not a drastic loss in power but it isn't a good idea. Just put premium in it and call it a day. The gained mpg at regular driving conditions will make up the differece. You will probably see 3mpg better.

Sure wish we had 93octain here....

 

So what your saying is it would still be faster than a new Civic Si and Golf GTi

 

according to GM...

stock 87 will work fine, 91 will work optimal

gms1 91 will work fine, 93 will work optimal

 

Thank you to those of you who answered my question. I don't mind spending the extra $$$ on 93 but still would like to know if anyone has dynoed to see the difference.

 

I do think it says in your owners manual to use preamium fuel for the SS/SC & SS/TC

 

I ran 87 for the first 30k miles and ran a 14.1 all stock I didn't notice any problems and when I was tuned we did a short data log on the stock tune with 87 and it was almost perfect.

Now that im tuned though I run 93

 

I was curious about this myself. I've run 91 Octane in the vehicle since I bought it (pretty much the highest grade fuel I can get where I live). With winter rolling around I was considering putting 87 Octane in it, I just do city driving and don't imagine the turbo will be spooling up anytime soon.

After poking around the forum though I think I'll stick with my 91 octane.

 

I'm not even going to bother reading through all the posts, because there is only one real answer. Use premium fuel in your car!!!! /thread.

 

There is no way it did not knock on 87 octane with the stock tune.

 

even with 93 octane the turbo balts like to knock on stock tune. this is like the most idiotic thread i've seen on this forum for a while.

 

For sure. Im getting ready to make the move to E85 myself

 

Mine runs best on 93 and I have Meth also. I even tried addind a gallon of 110 to the tank and it didnt run any better. Ill stick with 93 until Im ready to go to E85