I have a 4.6 09 with an automatic. I have a cold air intake and a SCT with a 93,91 and 87 tune.

I am currently running the 93 tune and I am loving it. How ever, finding 93 octane is alot harder then I thought.

I have only found 1 station in 30 miles that has it. I can just make sure I fill up there, but I could easily for see a day when I run into trouble because I can find any thing but 91 octane.

I am concidering just going with the 91 tune. Does any one know how much of a power loss I could expect going to 91 from a 93 tune??????


I figured some one might have an estimate.

 

Want be much, if any of a difference. I have a 93 tune on my car but occaissionaly because of the lack of Gas staions that provide 93 Octane fuel, have to go with 91 octane. 91 is as low as I will go though. Also I like to put some kind of fuel additive in my car (every two weeks). Just my 2 cents..

 

According to Doug from Bamachips, the difference between octanes is about 3-5RWHP.

 

Thanks GMAN


Thats exactly what I wanted to know.


I will probably switch it over to the 91 tune over christmas.

" I think the neighbors are concerned about my mental health. I just keep sitting in my car for 6-8 minutes at a time in below freezing temps. "

 

Last year or so I dynoed my car back to back with Bama tunes. I did have 91 octane in the tank at the time. With the 87 tune, I dynoed 293 RWHP/305 RWTQ. With 91 tunes (race and tq) my avg was 298 RWHP/308 RWTQ.

 

Every octane point is equal to ROUGHLY 1 degree of timing. So 91 octane will have 2 less degrees than 93 octane. This is very basic and not in all cases, but it's a good rule of thumb.

And on a 2005-2010 3V 4.6, 1 degree of timing is worth about 2RWHP or so. That being said, 91 octane should lose about 4RWHP. 87 Octane should lose about 12RWHP.

It works out pretty closely.

 

Thanks.


I went back to 91. There just arent that many 93's left.