To tune or not to tune?

Discussion in 'TFI Settings' started by Dan.1977P, Jun 12, 2015.

  1. Dan.1977P

    Dan.1977P Active Member

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    During my trip last weekend I noticed my gas mileage had taken a nose dive. I was averaging 37ish but I ended up getting 33 - 35 the whole trip. I figured it was the crosswinds and multitude of canyon passes but I also expected it to get better since I had hours of straight level interstate so I was a bit bummed.

    I decided to zero out the power commander today and go for a normal ride for me that would give me 36-37 mpg. When I fueled up, it was 45 mpg. I expected that, but what I didn't expect was the minimal difference in performance I could feel. At the lower RPM's I noticed it was lugging more so I was having to downshift on a couple climbs I would usually stay in 5th gear on and maintain 60 mph. I also noticed the gas smell when I stopped was gone, though I expected that too. Oil temp hung around 190 - 210 like it usually does until it gets hot outside or I'm running 80 mph for long stretches. I didn't notice any pinging either. I checked the plugs before the ride and they were slightly fouled (dark grey) but I put them back in as is just to make sure it wasn't them causing the fuel to not burn.

    I;ve been holding out on getting it dyno'd until I had the cash and found a good deal on some 2:1 pipes. If it's not getting to 250 deg+ and not pinging, do I need to concern myself with running on a stock ECM? If I play the numbers, it would be about 30k miles before I would reclaim the money spent on a tune if it cost $350 and increased my average from 37 to 42. If I ever break down and get new cams, I'll absolutely get it tuned but until then, will I be good?
     
  2. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

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    If you don't want to get it tuned. I would error on the rich side just to be safe. You could get it tuned and not ever worry about it......
     
  3. Breeze3at

    Breeze3at Well-Known Member

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    Why don't you try small increments from "zero" in the Power vision settings? You can get a little extra fuel in, and still get acceptable mpg.
     
  4. chief08

    chief08 Member

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    u should be fine with stock ecm. ran mine for years with header and big sucker its fine. friend has 08 super guild thunder header se in take runs fine. I just put in ss cams in it no problem on stock ecm. every body thinks stock afr is going to make your bike melt specially with header and intake.
     
  5. Dan.1977P

    Dan.1977P Active Member

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    I was thinking the same thing, chief, until after a 50 mile ride back from the range and I was showing 240+ oil temp in 75 deg weather for the first time ever. Decel pop is all but gone now so I'm certain somewhere in the canned map it was dumping too much fuel. Guess I can take all the values and drop them to about 10% of their originals and increase from there until temps come back down and stop when gas mileage plummets and I get raw fuel again.
    [​IMG]
     
  6. Stevecracker

    Stevecracker Member

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    Dan,

    I would get it tuned. Your bike and wallet though!

    Steve
     
  7. chief08

    chief08 Member

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    normal operating temp of oil is 230. I never messed with pcIII why don't u set cruse rpm range afr to 13.75 see if mileage gets better. I set mine 13.85 it gets any were from 40to 45 doing 80+. for what every its worth I use thunder max.:small3d008: