Lund Flex Tune - E85 looks odd, Thoughts?

[venumous]

My buddy just got his 14 GT Flex Tune from Lund, mods are headers, Boss IM, 47# injectors and JLT. I installed everything but the headers on this car which were done by a reputable Mustang shop. He got the go ahead from Matt H when he was on 93 that he was good to go and the logs looked ok with reference to the 2nd image though the log did not look as mine did when I was NA on Lund Flex with GT350 IM.

1st image is the latest log after filling up with E85 (near E) and driving for 25 mins before logging. Notice the positive knock coming in abruptly at 6k and hanging to the end.

2nd image is his car on 93 prior to filling up with E85. Looks like it pulled some at 5k and more at 6k but never went positive. Both of his prior logs show some pull at similar RPMs.

3rd image is a log of MY car when NA on Flex Tune running 93 for comparison, I don't have a log while on E85 handy.

Any ideas as to what is going on here? False knock seems possible but I'm not sure. He has looked at the typical exhaust explanations and found nothing so far.

Top curve is Timing, rising curve is RPM (left axis) and bottom is knock.

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[Sasuketr]

Had similar problem on mine with Lund Flex tune, the third revision solved the issue. They had to pull little timing off and commend more fuel on top. It is totally normal. All you need is a revision.

 

[Jay-rod427]

I'd say thats real knock, and the tune just needs dialed back a small amount. My first revision looked similar on 91. What was the air/fuel in that same span?

 

[DarkestHour]

I'd wager it's false knock (if your fuel is good) or something else is wrong. Please post the log on Datazap.me as putting pictures on a forum doesn't tell us much of anything.

Timing should be ramping up too as RPM increases.

With Lund FF I too have timing being pulled on 93. Curious if their non-FF calibration is a little less aggressive on the timing.

 

[Sasuketr]

I'd wager it's false knock (if your fuel is good) or something else is wrong. Please post the log on Datazap.me as putting pictures on a forum doesn't tell us much of anything.

Timing should be ramping up too as RPM increases.

With Lund FF I too have timing being pulled on 93. Curious if their non-FF calibration is a little less aggressive on the timing.

Thats what i was thinking too. If they add too much timing on 93 it messes up when you put higher octane in the tank. In our case E 85. That is why they want you to log on 93 and then E 85 to find the sweet spot. I might ask for a separate 93 octane tune but the problem is, if I can't find 93 octane on a road trip and get stuck with 91, i might be in trouble!

I tried reloading my rev2 version of the tune which was dialed in for 93 octane during winter to see what was going on. With winter blend fuel and higher ethanol rating it was giving me positive knock above 6000 rpm. I may try it again when the weather gets warmer and winter blend fuel is gone!

 

[dubster99]

Send it to Lund and see what they say. Could be false, could be poor quality E85, could be the tune.

 

[venumous]

Lund told him that it likely false knock and not the tune because it is so abrupt. Actually before he specifically asked about the knock he was told "it looks good, have fun" which is slightly disconcerting. I highly doubt its fuel as the same knock was there on 93 and now worse on what is probably at least E70, though I plan to give him my tester to see what it is. I'm going to check the purge valve assembly to make sure its not bumping anything as we mounted it on the front of the block. He mentioned his axle-backs may chatter when going uphill after talking to him some more so this very well could be it as well.

 

[dubster99]

From your post, it was still adding timing on 93 all the way up. The E85 log looks like it goes from -4 to +2 instantly. Whatever that event was, wasn't present in the 93 log. The 93 log was at 28ish degrees up top, which is normal. On E85 he should see 30ish. Based on what the ks was pulling, it's not like the tune is commanding crazy timing. It's pulling 5-6 degrees, and he's ending up at 25 after it pulls. His timing before that event looks good. It jumps slightly in a couple spots, but nothing crazy.

 

[Sasuketr]

My 93 octane with lund flex fuel can go up to 30 degrees of timing and maybe half a degree knock pull above 6300 rpm. The timing around 4000 to 5000 rpm is around 23 degrees of timing and then it starts going up. My previous revision tune, the car was seeing 29 degree max but 25 degree timing around 4000 to 5000 rpm. It was seeing the high spark timing way too early. With the new revision I thought i lost power, but on the dyno the car put down more hp and torque every where! Pulling some timing early on and commending more fuel on top solved my issue.

On E85 i can see the more advance timing early on and it goes around 30's without positive knock. I also thought i had false knock back with the early revisions, and checked my engine bay and exhaust setup under the car. What also helped was switching to full synthetic mobil 1 oil vs ford blend. Car runs smooth even when its cold! Totally recommend it!!

 

[venumous]

Here is the datazap file for those asking.

http://datazap.me/u/shuck13/log-1488891427?log=0&data=4-14-17&trim=14&tmin=2424.25&tmax=7208.00

 

[dubster99]

It should have way more than 23.5* of timing on E85 at 6300, and more than 25* up top. Something is going on here. His AFR's look fine.

 

[3beeps]

Actually before he specifically asked about the knock he was told "it looks good, have fun" which is slightly disconcerting.

This is the part that concerns me. The log had positive knock and they said that to him? :shrug:

 

[venumous]

This is the part that concerns me. The log had positive knock and they said that to him? :shrug:

Yes, I saw the email myself.

The fact that the same person is working on my 100octane blower tune is also concerning now.

 

[dubster99]

None of my lund tunes have ever seen positive knock at WOT. I did get some when I had a BAMA tune, but that was from false knock. Header was contacting the ac bracket bolt. Once I fixed that, no issues again. Like I said, the fact that it's knocking on E85 at 30ish and pulling that much timing leads me to believe that it's fuel quality, or false knock.

 

[GTBOB]

Matt H. has been working on my Lund FF tune for the GT350 MANI/TB/INTAKE, 47lb injectors. Been pretty smooth so far and I've been paying attention to my logs. Final logs submitted tonight on E85. We will see what he says tomorrow then I should be done. Midrange power and power after 6500 is the cat's ass. Very pleased.

OP, is your friend's '14 lowered at all? Check all along the passenger side exhaust from the tailpipe up. This is the side that moves the most during WOT. Any contact with the bumper, axle tube, floor board will cause false knock.




Under the hood, make sure intake tube isn't able to "buzz" against anything when the engine is torqued. The bottom of that JLT intake tube is going to press down on the heat shield at WOT ;). I would actually go as far as jacking the motor up with the passenger motor mount loosened a bit to simulate WOT motor movement and check for clearance issues.

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