Aside from the waste of money - is there a problem running 93 octane fuel with the 87 octane tune is installed? Does the computer even know the difference? My concern is - if it does - would it conflict with the parameters of the lower octane tune.

Thanks,

 

The computer MAY sense a slight difference since I think the stoich A/F mixture for 93 octane is somewhat different than what it is for 87. If that is the case, the O2 sensors will make some adjustments in closed loop to keep the Lambda at 1.0.

But, IF you use 93 octane gas in an 87 octane tune, you should advance the spark. The Edge manual says 0.5 degrees for each octane number difference. So, you should be able to advance the timing by +3.0 degrees. I'd probably do it in steps though, starting with 2.0 degrees, and then if all seemed well, change it to 2.5 and then finally 3.0 degrees.

- Jack

 

Thanks for the feedback. I am pretty disapointed with the Superchips Flashpaq I purchased for my 01 screw, 5.4, CIA, Catback, 2WD, transmission rebuilt 2K ago. The only time I felt good about how my truck ran was when I 1st loaded the 87 octane tune.

Then I adjusted it for a change in tire size stock (28") to the to 31". I understand the tire size change - changes everything. But, it was drastic. I ran it all but out gas, and filled up with 93 octane, thinking it would be better - no such luck. It actually runs better w/the 87 octane tune - hence my question.

By running bad I mean - sluggish shifts, poor throttle response - it's in OD before I am going 40 MPH. The guys at SC indicated that running it less than WOT, it wouldn't seem much different than stock. I told them I don't do WOT. They did a "one shot tune" that changed it to shift 2 MPH sooner.

I downloaded the "one shot tune" with the 93 octane program - and something is wrong. At highway speed I noticed the Tranny temp was up 10 degrees higher than usual. When I let off the throttle - it lugs - like it is locking or unlocking - it's not normal - it is shifting into OD - maybe it's doing what it's suppost too?

The whole experience has been a drag. I guess my expecations could be out of line? I wish the initial tune wasn't as nice as it was. I guess I shouldn't have messed with the tire size. Basically, I wanted firmer shifts (assuming firmer/quicker would create less heat and be better on the tranny)- now, I am concerned that it is doing more harm then good.

Thanks again - and sorry for the rant.

 

I don't see it as a rant, I think you are giving an honest, pretty well thought out opinion of a product that does not live up to your expectations.

I will say, though, that the effects I feel with my programmer are most noticeable at WOT or reasonably heavy acceleration. I think the tune did more for the way the truck shifts than some of the other things. I know that PHP adjusts line pressure, torque reduction and slip time in the transmission.

Of course there were changes made in the way fueling is done (and possibly spark advance) too, but these changes mostly effect the truck when it's in open loop.

I imagine Troyer and VMP do similar things, and, I suspect SC does also, but it's kind of a "canned" tune, I think.

I know I get better fuel economy now with my custom tunes than I did at stock or with the canned tunes.

Back to your post, I would have thought SC would have modified your tune so that upshifts were delayed, not made sooner. You'd probably want downshifts to occur at higher speed too. I don't think you're going to feel anything with a 2 mph difference though.

And, the way you describe the TFT and the fact that it "lugs" when you let off on the throttle is just wrong.

I'd talk to them again. I think they can make the device work the way you want it to, but you may have to be persistent.

- Jack

 

Update - I uninstalled the tune (returned it to stock) and it still does the new lugging thing. It feels like the little lug/bump the tranny does when the TC locks up. The odd part is it doesn't change the RPM, and when getting on the freeway - it shifts fine and appears to go into OD with the proper lock-up of the TC.

I posted the issue on the transmission side to see if it sounds like a know issue. Leaving the door open for the possibility that it is normal.