91 octane tune

[Freno679]

Can you run 87 octane on the 91 tune without any problems? Also would there be any benefit of using srt fuel injectors? My plugs seem that they are running lean.

[06MonteSS]

Uh, no... the timing/spark advance is set higher in the 91 octane tune, for the higher 91+ octane gas... you will get knock using lower octane...

If you're only going to run 87/89 octane gas, then you need to install the 87 octane tune...

[Freno679]

I have only been running 91 or 93 octane. I was just wondering, but I figured it was a bad idea. I have been getting knock retard only at very low rpms while cruising. Almost right before it wants to shift down. The highest number I have seen is 6. My air/fuel command ratio is 14.63. Just wondering if all that's normal.

[mikel]

14.6:1 is perfectly normal at cruise. I highly doubt its running lean. No need for larger injectors.

[Freno679]

Thank you

[Freno679]

Is a good reputable octane boost additive sufficient for boosting octane and running the 91 tune? Say from 89 octane. Thanks

[mikel]

tough to say without monitoring knock.
Also, lots of different interpretations of what a reputable octane booster is

[06MonteSS]

The only ones that actually work and raise the octane full points, are Torco and Boostane...

I use Boostane myself in my Camaro....

They actually raise full octane points, so you can get up to 98+ octane if you want, depending on how much you mix in with your gas, and what octane gas you start with..

the cheap crap you find at gas stations or auto parts stores, that say they raise octane by 4 points, means it would make your 89 octane into 89.4 octane... useless...

so you want to get Torco or Boostane...