7* of Knock from 2-3 shift at WOT.

[hunterbabich]

Just put an 91 Unleashed 3 bar on the 2010 Sho. Datalogged it a few times and found high knock values. I can hear the knock on the shift from 2-3 and even 1-2 sometimes. I attached the log file with the  7* of knock. Hopefully someone would be able to give me some insight into the cause of this problem. I emailed Torrie and he suggested poor fuel quality. I'm about to add some oct booster and run that until i fill it up again from a different gas station.

 

[SHOdded]

New, properly gapped plugs installed prior to the tune?  How many miles on your SHO?

 

[ajpturbo]

I will look at the log later....but i too have seen fuel quality variation and also you are probably getting a huge boost spike on the 2-3 shift...its hard to avoid but i have a decent method

The boost spike causes a fast load spike which creates the favorable condition for knock and knock retard...its why the stock tune uses the throttle blade to control boost and some tuners are hell bent on keeping the throttle open

 

[hunterbabich]

Plugs gapped to 0.027 (motorcraft sp534). Miles: 131xxx

 

[FoMoCoSHO]

If you have audible knock at WOT and the knock sensor is pulling its max I would suggest extreme caution until you sort it out.

Curious, what kind of fuel is in the car now?

 

[hunterbabich]

I'm running an 87 octane tune right now. I have shell v-power 91-octane no ethanol in the tank right now.

 

[ajpturbo]

I would think 91 octane with 10% ethanol is better than pure 91 gas

 

[FoMoCoSHO]

I would think 91 octane with 10% ethanol is better than pure 91 gas

You would think but all the research I've read shows it actually performs worse than pure 91.

The benefit starts at 15-20% and moves up as volume increases.

 

[hunterbabich]

I do remember now that the gas station i filled up at has been know to have water in their storage tanks before, so that might have affected quality.

 

[sholxgt]

Everyone has their opinions on fuel stations, but I have not had good luck with Shell in general.

Not sure what your options are, but I have good luck with Chevron, BP, Amoco, Texaco and Mobil.

FWIW, you're not the first person on here to have trouble with 91 octane fuel and an Unleashed tune.  I don't think he quite accounts for how poor the 91 octane fuel is.

 

[hunterbabich]

First time tuning a car so I guess I really never had to worry about fuel quality quite as much as I would now. There is absolutely no 93 where I live. All 91 and below. Even worse all the gas stations are mostly shells, athough I do have a few mobile BP and krist stations by me. Guess I'm just gonna have to keep testing the different fuels until I find one the car likes.

 

[FoMoCoSHO]

The Shell 93 around these parts is no joke.

Hunter, are you in Cali by any chance?

 

[hunterbabich]

Northern Wisconsin

 

[FoMoCoSHO]

E85 available?

 

[hunterbabich]

Not where I live in the summer. I go to school in platteville, Wi though and there is a station that has e85 down there.

 

[sholxgt]

The Shell 93 around these parts is no joke.

Hunter, are you in Cali by any chance?

I think that different areas of the country pull from different refineries or get different mixes.  My neighbor, originally from IL, talks about how good Shell 93 was up there and how cruddy it is here.  He has a Silverado SS and SSR.

Growing up in South FL, no tuners used Shell.  It was strictly Amoco or Mobil for any shop I asked if running 93.

I'm just grateful to not have to deal with 91.  I feel for you guys!

 

[Korn2012]

How far north in Wisconsin are you? Most kwick trips have e85 now.

 

[hunterbabich]

How far north in Wisconsin are you? Most kwick trips have e85 now.

The closest kwiktrip is a half hour away. I actually made a run there tonight and put a half tank of 91 premium and 1.5 gal of e85. (ending with something around 93 octane e12 or e13.) Poof, knock is gone at WOT.

 

[ajpturbo]

Did you re log?

 

[hunterbabich]

Did you re log?

Yes sir. With this new log i noticed a little richer conditions under WOT. 0.76. Before it was around 0.80. And fuel pressure kinda drops off after the desired afr is achieved. ~2200 down to ~1400. Im guessing this is caused by the higher octane.