93 vs. 87 Octane fuel

[chevy04]

Has anyone programmed their vehicle for 93 octane only to use 87 and find any pinging or just normal running. I have logged some test data on my Carchip and would like to compare the results with other AV's before I post the results of just my own. I can tell you the difference is really nothing to brag about, but the engine data I will post when I hear back from some of the other fellow AV'rs. If you know of any guage differences like you were running cooler or hotter (190 vs. 210), please post. I do have the flow rates and internal temps for the intakes and heads as well as the coolant just to name a few. Horsepower was nill. The rest after we can compare data if you feel like sharing.

Any of the mechanics want to comment on the knock sensor stopping the pinging or causing pinging. I would be curious about the PVC valve having input on this matter. I have set mine up both ways and have run 87 with the 93 program installed and have notice no external differences, but there are internal differences. Input would be appreciated.

Thanks..

 

[kwinsor]

As you guessed, there are a lot of computer functions that will over-ride the 93 octane tune.

There are two timing tables in the PCM, high octane and low octane. If the sensors pick up knock for an extended period the computer will switch to the low octane table. This is in addition to the knock retard funtion that comes into play for intermittent knock.

When I run EFILive it detects and records knock events. There are many times when the data logger picks up knock that I didn't hear.

kw

 

[chevy04]

Hey KW,

It makes no difference in numbers or performance on 87 over 93 with my setup, so I went ahead and left the prgramming at 87. I never did get any indications of pinging running on 87 with 93 and no responses, so after looking at your truck and a couple of others with the same changes it was decided that 87 was good enough and the added expense had no benifit.