Hello everyone,

I just first wanna say happy thanksgiving. This may be something stupid but felt the need to post this. I've been running 93 octane the last few tankfulls and for those who run 87 it makes a world of difference. Just wanted to pass along that these engines love the higher octane. Smooth quick acceleration and my mpg has been unaffected. I'm currently running AC Delco irridium plugs which I know isn't recommended but I'm having very nice results.

 

From conversations with multiple Saturn Techs over the years, S car engines are "tuned" for best "performance" with 87 octane in the tank. When you run higher octane, it detunes itself to get back to what it thinks is are more overall favorable operating parameters.

What you're likely experiencing is the fuel injector cleaning benefits that come along with most 93 octane gas. Combine that with max fuel flow and pressure due to your fill up, and you've created a idealized fuel flow rate-->> (volume per unit time) that wasn't there before (once the injectors are clean).

So the engine will feel as though you can wind it up easier and therefore it "seems" smoother b/c the injectors are cleaned out.

Your mpg remains unchanged because although your higher octane fuel should give you more "bang for the buck" each time a charged cyl is fired, the PCM has detuned the operating parameters sufficiently such that that "bang" is not fully realized.

You could rebut that with the fact that you're leadfooting it with 93 in there.
My response to that would be to have someone else fill your tank the next six or seven times at the same pump at the same station, but NOT tell you what they put in. For this to work well you'll need to get the tank pretty low before refilling or you'll end up w a bunch of 90 and that doesn't help

To make it even more fun, have them add Techron (fuel sys treatment) to ALL tanks of gas.

Calc mgs and come back n post em. I am very interested to see them (no sarcasm)

 

I was thinking about recording how well the engine performed after dumping a fuel treatment in the tank vs. performance without it but I never got around to do it. I have an oil change coming up soon. I think I'll start up a little log.

 

Will Do. Just filled up this morning with the 93. I'll run it til the fuel light comes on and top off with 87 the next two tankfulls. I'll post MPG of the second tankful and then I'll try 87 with Techtron and post my results.

 

I will keep my driving technique the same for each rating, simply for the science of this test.

 

alrighty then

 

Place your bets!!! I have a feeling deff is gonna be right...Has been in all the threads I've read thus far. Got lucky with the techron...On sale at AutoZone...2 for $9!!!

 

Okay so keep in mind I would say about 80% of my driving is city 20% highway. Finished off the tank of 93 octane and averaged a whopping 22.65 mpg. Now on to regular 87. With the 93 the car idles smoothly and is peppy getting up to speed. I'll update with my 87 octane findings.

 

Plain 87 octane...24.88mpg. Not much difference performance wise either. On to the final test...87 with techron!!! Plain 87 seems to idle more rough compared with the 93octane.

 

23.125mpg with 87octane. Ran like it was on the 93 octane. Engine running sooo...smooth and peppy on acceleration. I think it actually runs way better with the additive. With it posting an mpg between 93 and plain 87, I think I'll be picking up a few more bottles while it's on sale at AutoZone 2 for $9. Derf... You were right again. Best mpg on plain 87 but a noticable difference with the techron. After winter I'll go back to the copper core plugs, just don't want to waste thes irridiums. Gotta hand it to ya Derf, I'll be seeking out your recommendations in the future. Hope all is well!