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

[FoMoCoSHO]

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.

It should only be dropping if its commanded to drop.

At WOT you ideally want to see over 2K PSI.

As pressure falls so does droplet atomization (drops get bigger)which is not ideal.

The pressure should be basically static (tiny peaks and valleys) at WOT and the amount of fuel is determined by how long the injectors stay open.

Adding E85 requires additional fuel....that combined with richer commanded AFR..... probably the cause for the dip.

 

[hunterbabich]

So is the pressure drop anything to really worry about?

 

[FoMoCoSHO]

So is the pressure drop anything to really worry about?

Worry?

IDK it is something I experienced and fought for a long time with E.

While it is not ideal I'd rather have no KR and less pressure than seeing the knock sensor pull 7 degrees, that makes me nervous.

Ideally though you want that corn being sprayed over 2K PSI.

The more it is atomized the more effective it is in absorbing heat in the cylinder which is why corn is just so damn awesome at suppressing knock in DI applications.

 

[Korn2012]

I'd worry at the fuel pressure drop considering you only put 2 gallons of corn in.
What did Torrie say when you sent him the log?

 

[hunterbabich]

He said that is that is going to happen when you add e content and the air get better.

 

[ajpturbo]

He said that is that is going to happen when you add e content and the air get better.

You should never have your knock sensor maxxed out...and if only 2 gallons of E85 cause your fuel pressure to dip that much the you are running too much boost or boost isnt being controlled that well

 

[ajpturbo]

Your new log is kinda short. You only did a 1-2 gear WOT pull.....I'd be willing to bet if you stayed WOT for a 2-3 gear change your boost spike would be worse and your fuel pressure would've fallen more...2-3 is always the worst.

So you are about 1400 psi...If the 2-3 brought it down to 1200 psi and it's summer now then maybe you are close to 1000 in the cold....And you aren't getting tq reductions during shifts, I can tell by the spark curve during downshifts

Speculating a little here but when you see those big dips early in a pull with the knock sensor and then it goes flat that usually means your spark is set that you won't get any spark added from the knock sensor...But it is good on this pull that you didn't get knock retard

 

[16MagSport]

This is sounding like my wife's Explorer.  I was thinking about trying Unleashed, but this is exactly what I am afraid of.  OP, did you ever log your stock tune on 91 octane?  If so, what KR did you see?  I can only get crappy 91 Cali fuel.


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[StealBlueSHO]

So is the pressure drop anything to really worry about?

Worry?

IDK it is something I experienced and fought for a long time with E.

While it is not ideal I'd rather have no KR and less pressure than seeing the knock sensor pull 7 degrees, that makes me nervous.

Ideally though you want that corn being sprayed over 2K PSI.

The more it is atomized the more effective it is in absorbing heat in the cylinder which is why corn is just so damn awesome at suppressing knock in DI applications.

I hate to say it...show me an Unleashed log where they sit at 2K through the whole run... I have not seen it... But then again... He uses nothing to control boost spikes... Those kill your fuel rail... He is 100% balls to the wall all the time... No tq control and no throttle control... Not that there is anything wrong with that... It's just his style... Part of the race car feel I believe is riding out those boost spikes with no reductions...

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[BOT_ROCKET]

I hate to say it...show me an Unleashed log where they sit at 2K through the whole run... I have not seen it... But then again... He uses nothing to control boost spikes... Those kill your fuel rail... He is 100% balls to the wall all the time... No tq control and no throttle control... Not that there is anything wrong with that... It's just his style... Part of the race car feel I believe is riding out those boost spikes with no reductions...

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Is that uncommon among the various tuners?

 

[StealBlueSHO]

I hate to say it...show me an Unleashed log where they sit at 2K through the whole run... I have not seen it... But then again... He uses nothing to control boost spikes... Those kill your fuel rail... He is 100% balls to the wall all the time... No tq control and no throttle control... Not that there is anything wrong with that... It's just his style... Part of the race car feel I believe is riding out those boost spikes with no reductions...

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Is that uncommon among the various tuners?

Not at all, it's very common in general. Because our cars tend to have massive boost spikes at shift other tuners have taken to using some kind of method to try to control boost spikes.

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[metroplex]

Are you seeing boost spikes at the MAP or the TIP? It would be normal at the TIP, but shouldn't be that high for the MAP.

As for knock retard, I was seeing the max using a stock factory tune with 87 octane (7.5*)

Can you confirm the amount of boost you are seeing with the Unleashed tune? With 91 octane, it may be pushing it too much, I probably wouldn't go over 15.2-15.5 psi (which is where a 3-bar MAP is needed).