Effects of different fuel - Timing Logs

[Avned]

I finally had a chance to review my logs and compare the different fuels I have been using. This is not a scientific test. The conditions these logs were taken were very similar, ie temps, route. All are on APR Stage 1 tune.

[91map] This first one was taken a couple days ago using 91 octane Shell. Lots of red throughout the log anytime I am WOT. Sometimes, even at light acceleration.


[91map] Next, is Rebel Oil 91oct + 5gal Rockett brand 100oct = ~93.5oct. A lot less red. Still a bit pulling at WOT, but not as bad.


[91 map] Next, Rebel Oil 91 oct + 4gal E85 = ~93.8oct (E25). Little to no red. Very clean log.


[93 map] Finally, Rebel 91 + 4gal E85 = ~93.8oct (E25). A little bit of red. Not bad, still very clean log.


Observations:
1) My local Shell sucks or APR is very aggressive in their timing even for 91 map or it's hot as hell out (105F ambient/156F IAT) and timing is pulled. Maybe all of the above.
2) Higher octane leads to better results even on the 91 map.
3) E85 blend is awesome (cooling effects?), though long term effects of increased alcohol content has its risks.
4) Roc Euro intake probably did not cause the gain seen by my previous dyno. More likely the effects of E85.
5) Going back to the 91 map from 93, sucks!

I will eventually try out different 91 stations in my area in addition to logging when the ACES IV fuel catalyst comes in. Happy driving!

[Chris Morales]

Did you have about 16 gallons of 91 octane in the tank for the E85 log?

[Avned]

Did you have about 16 gallons of 91 octane in the tank for the E85 log?

Yes. Our tanks (S6) are 19.8gal. I put in 4gal E85 then filled up with 91. So should be about 15.8 gal or so.

[Clipse3GT]

Seems to be inline with a high octane can do. Is prevent pre-detonation / pre-ignition. Makes perfect sense the car run much better on higher octane fuel especially with a tune.

[kouzman]

Very nice test! I am really surprised, espacially with the e85 mix.

I have a bunch of people that swear by the e85 mix approach even when running a 93 octane map, simply because of the cooling effect of the mix.

I told a friend of mine that I noticed that the car feels better with the shell vpower and he said that they actually run 10 ethanol and not up to 10%, like it other brands...

I should do some logs of my own and test it.

Thanks for sharing again!

[Chris Morales]

So here a 20% E85 blend worked. I think Vol once posted that he was running a 50% E85 blend in his S6. My question is what is the largest proportion of E85 you can get away with using the stock fuel system? From what I understand the issue is volume of flow (E85 requires more flow than normal fuel). A 20% blend almost eliminated knock on 93...but more cooling is better...probably can't go far enough to use the 100 octane map, but that would be great...

[bhvrdr]

Yeah I think we spoke on another thread. I had a feeling the e85 would make a significant difference even on the 91,program. They definitely put some headroom in there.

Mike

[Avned]

So here a 20% E85 blend worked. I think Vol once posted that he was running a 50% E85 blend in his S6. My question is what is the largest proportion of E85 you can get away with using the stock fuel system? From what I understand the issue is volume of flow (E85 requires more flow than normal fuel). A 20% blend almost eliminated knock on 93...but more cooling is better...probably can't go far enough to use the 100 octane map, but that would be great...

According to my research, non-flex fuel vehicles seem to max out at 40-50+% before CELs and fueling issues happen. I was definitely surprised to see how well E85 did to the timing maps. It's incredible the measured difference it made. I wonder if 91 shell would perform better in more ideal Temps (50F).

[Avned]

Yeah I think we spoke on another thread. I had a feeling the e85 would make a significant difference even on the 91,program. They definitely put some headroom in there.

Mike

We did in my dyno thread ha! In fact, you inspired me to pursue this analysis further. Thanks!