By on September 24, 2014

TTAC commentator Raph writes:

Hey Sajeev I’ve got a a bit of a conundrum with 09 GT500. I recently purchased a blue-tooth OBDII dongle and the Torque Pro app for my phone which provides a variety of useful functions including monitoring various PIDs (On Board Diagnostic Parameter IDs).

While checking over the various PIDs I noticed the throttle body was limited to 75% of WOT and I’m not sure if that was just a limitation of the app or perhaps the tune was limiting the range of movement on the throttle body?

Also I noticed that the boost inferred by the car’s factory boost gauge does not correlate to the boost reading in Torque Pro? The Torque Pro app has an adjustment feature to scale the boost reading by either setting it to zero, a positive value or 14.7 psi or a negative value of 14.7 psi.

I’m unsure how Ford references boost with the MAP sensor since fiddling with the scale adjustment in Torque Pro hasn’t produced any worthwhile results (a best 4 PSI but the blower on the car is pullied to produce in the neighborhood or 18 psi.

Long story short: Am I leaving some power on the table and what about that damn boost reading?

 

Sajeev answers:

Whoa duuude, you mean that the fancy smarty-phone app says you are only at 75% throttle when you floor it?

We’ve been down this road before, as these apps often read parameters sans the accuracy of tools available to powertrain engineers or even shade-tree tuners with EFI hacks. While it’s been proven many times over that the GT500’s stock tune is pretty conservative, it surely ain’t 75% throttle conservative.  As much as I love new tech, while my career revolves around Web 2.0, we need a reality check: sometimes apps aren’t that awesome, they can kinda suck.

To wit, I sent your queries to a real tuner, Mr. Torrie McPhail, who is both a trusted friend and a well-regarded dude in the tuning world.  This isn’t an endorsement (even if it is) because I can’t possibly know the stuff in Torrie’s brain. So let’s do it, to it:

“First point: what calibration is in use? If you are using something non-stock, I would request calibration information from that source as to vehicle output.

I doubt anyone would be limiting throttle angle on a car like this, most likely that is how the phone app construes the PID output while at WOT which would put it squarely in the shadow of the shaft anyways.

And the factory boost gauge isn’t actual and just calculates inferred manifold pressure from sensor output. I would stick a good Autometer boost gauge in the car to solve that.”

So there you have it: if you have a stock tune, you are leaving PLENTY of power on the table, even a conservative tune will unlock plenty more power. And don’t take the engine app too seriously. Off to you, Best and Brightest!

Send your queries to [email protected]com. Spare no details and ask for a speedy resolution if you’re in a hurry…but be realistic, and use your make/model specific forums instead of TTAC for more timely advice. 

 

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20 Comments on “Piston Slap: Factory Tune, Power On The Table?...”


  • avatar
    danio3834

    Pretty well nailed it. You’ll notice on some automatic transmissioned cars that the factory torque management calibration reduces throttle angle between shifts, but since this is a GT500, that’s not what’s at play here. That’s an area where some acceleration is left on the table at the expense of comfort and mechanical stress that can be taken via an aftermarket tune should someone want to.

  • avatar
    LeadHead

    Assuming your dongle is ELM based, and you have a windows laptop/tablet, download the program FORScan. It’s a free piece of software designed for Fords, and you can data damn near everything – even fuel level.

  • avatar
    Sky_Render

    Power left on the table?

    Sort of.

    Factory tunes have to operate well for a variety of conditions and for a variety of drivers. As an example, consider the ’11-14 Ford Mustang 5.0.

    From the factory, and below about 50% throttle, there is very little difference in acceleration between the V8 and the V6 models. Why? Because that frumpy 40-something secretary named “Babs” who just bought a shiny, new 2014 Mustang GT can’t handle the fact that her car makes more power than a first-generation Viper. So, Ford engineers added something called “torque management” below about 4,000 RPM or so. It helps fuel economy, and it helps Miss-Frumps-A-Lot to not wrap her pony car around the nearest tree.

    So, enter the Ford Racing Performance Parts (FRPP) Professional Calibration, or Pro-Cal for short. The Pro-Cal does a few things. First of all, it gives you about 8-10 peak horsepower, because it assumes you will now always use 91 octane or better. But the real advantage is the fact that it now removes the torque management, resulting in–wait for it–

    An additional 65 lb-ft of torque at 1,500 RPM.

    • 0 avatar
      heavy handle

      Why the sexism? Besides, everybody knows that Mustangs are only purchased by post-retirement baby boomers and rental car companies. And secretaries don’t exist anymore (nor do typing pools, BTW).

      • 0 avatar
        Sky_Render

        Sexism? Seriously? That’s all you took from my post? Stop looking for things to get offended at.

      • 0 avatar

        Actually one of my friends, a 35 year old female and car nut, recently purchased a Mustang.

        Somehow I’m not bothered by the Babs story. But then my grandmother was the first woman in Colorado to earn a PhD, in 1915, and my maternal aunt was president of Hunter College for a while, and one of my best friends is a woman who changed our understanding of how the immune system works. I’m sure there are male equivalents of “Babs” but I don’t know any, but I don’t know any Babses, either. (None of the women I know who are in their 40s–or even 50s–are frumpy, either.) The story made it’s point, although I suppose Sky-Render could simply said they added torque management so people who can’t handle a lot of power wouldn’t wrap themselves around trees.

    • 0 avatar
      danio3834

      The difference in this tune is incredbile on those cars. It’s kinda like going between track-key and non-track key on the Boss.

    • 0 avatar
      mnm4ever

      Wow… 65 lb-ft extra from a tune. Just another reason why my next car is likely to be a Mustang.

    • 0 avatar

      One Million Percent Correct!

      Torque management is the biggest “reason” to get a tune. Not surprised to hear that the 5.0 got an extra 65lb-ft close to idle. My far stupider EEC-IV Mark VIII with a traditional throttle cable got +25lb-ft at 2500rpm after a tune.

      Hell, even my tuned Duratec Ranger can now go up modest hills in 2nd with no problems. Peak power didn’t change, but it was still $$$ well spent.

      • 0 avatar
        NoGoYo

        Well sh*t, wonder if computer tuning can get anything out of my SOHC 4.6.

        Though I’ve got plenty of acceleration, just not all that much power. Think I’m gonna need actual hardware for that.

        • 0 avatar
          patman

          Maybe. The 4.6L 2V’s timing curve is known to be pretty conservative.

          I bumped up the ignition timing a few degrees with a timing adjuster on my Mustang and the difference at the top end wasn’t a huge deal but the difference at lower RPM was dramatic – much snappier throttle response and noticeably more torque down there. With a proper tune with air/fuel adjustments and more precise timing mapping it would probably be better.

          The 4.6L (and the last of the old 5.0s too) ECU’s are also known to pull timing between shifts to make shifting smoother and lessen the shock on the transmission, both manual and automatic.

        • 0 avatar

          Pretty sure it would, and you’d also get a smarter transmission with the change. But honestly, since your Tbird doesn’t have the PI heads you should do a head swap and a tune.

          Which of course, is another slippery slope. Be happy with what you got.

  • avatar
    bachewy

    Raph, the Torque app on your phone is crap. On my 2009 Tacoma it said I had 350HP.

    Cruise over to http://www.fortgt500.com which has a lot of folks eager to answer your questions (on there myself). It’s also one of the more mature sites for discussing cars (unlike http://www.svtperformance.com). Also, there are several tuners who can help you understand what you’re seeing and provide new tunes if you want. One I prefer is http://www.vmptuning.com

    Ken

  • avatar
    Eiriksmal

    *grumbles* The domestics get such a sweet community of tuning. Nissan’s largely left in the lurch.

    Er, I mean, “Nissan pushes their engines closer to the limits, so there’s not as much to be gained from a simple tune.”

  • avatar
    cbrworm

    UPRev has decent tunes for some Nissans. Mostly 3.5+ liter ones.

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