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2004 to 2008 F-150 and Mark-LT 4.2L, 4.6L and 5.4L equipped F-150s and Mark-LTs. |
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#1
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The Gryphon and speedo will always read the same (actually, the speedo will be about 2 mph higher due to a quirk in the way Ford does things, according to Bill). They BOTH get their input from the PCM, which has been programmed by the Gryphon to interpret axle revolutions to determine speed and distance. The fact that they agree with a GPS, though, says the overall effect of the gear and tire circumference settings is producing correct speed and odometer values.
But, and this is a big but: Both gear and tire size COULD be wrong. I'm positive the default values in the Gryphon have nothing to do with what's in your truck. On the f150 forum, someone had 3.55 gears and the Gryphon said he had 3.73 gears (and he had "funny" shifts). I think 3.73 might be the default gear ratio. The tire size on mine always defaults to 2356, but my actual tire circumference, accounting for "squish" is about 2481. Since my gears ARE 3.73, if I don't set the tire size manually, my speed and distance values are about 5% lower than actual. And, I don't recall the MAX RPM default in the canned tunes but I know it was lower than 5400. The MAX speed is set to 99 MPH, by the way. All these things are adjustable in the custom options menus. You select something, such as Tire Size and hit Enter. You'll be shown what the Gryphon is going to insert into your PCM when it "tunes" it. If you don't like what you see, just use the up or down arrows to change the value, then hit Enter to set that new value. I doubt you can hurt anything unless you do something stupid like advancing the spark on low octane gas, or, possibly setting the Rev Limit to a very high value and then standing on the gas pedal. You can actually go through all the settings without changing anything just by hitting Enter at each and then hitting Enter again to accept the value once you've seen it. When you're through looking or customizing, hit Enter on the "Done" option and you'll be told to turn the key off and then back on. If you've gone through the custom options and looked at any of them (or changed them) the programming process will take quite a bit longer than if you just skip the Custom Options step. Don't worry, just make sure your battery is healthy and that your headlights, AC blower and radio are off to minimize battery load. Don't do it in really cold weather either. Hope all this information helps. I'd be more afraid of damaging the truck through hard acceleration and high speed, rather than through playing with the Gryphon. And, I hope Bill chimes in here sometime to say I haven't been leading you astray. - Jack |
#2
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The F-150 PCM is broken down into 3 sections: RTOS, Strategy, and Calibration. There is also a small (256 bytes) section called the VID block that stores the vehicle specific parameters like tire size, gear ratio, and VIN number. It looks a little like this... 0x1:0000 - RTOS |[VID] | | | | | | 0x50:0000 - Strategy | | | | 0x58:0000 - Calibration | | | | 0x60:0000 - Memory End When our programmer modifies the memory, we only read and write the Calibration section of the memory. Ford, in its infinite wisdom, saw fit to not only put the TS/GR in the VID block but also have values that are located in the Calibration portion of memory. In normal situations, the PCM uses the VID block for TS/GR information. If you have stock tires or gears we don't bother that setting. When it is necessary to make changes to TS/GR, we have to make those changes to the Calibration because we do not access the VID block which is stored in the RTOS. The confusion comes when we grab the default values located in the Calibration. These values have no relationship at all to what TS/GR is actually in the truck and are simply place holders for arbitrary data values. Some trucks are 3.55, some are 3.73, and we've even seen 3.31. When we change TS/GR, we write the values into these spaces and then set a switch that tells the PCM to ignore the VID block and use our new values instead. Since we assume that neither value in the Calibration is accurate, this is the reason we always say to set BOTH TS/GR values. Don't change one or the other and expect it to all be correct. One other note about custom tuning... Viewing the custom options sets a flag that tells the programmer to write those values to the PCM even if you didn't change it. We recommend that if you don't plan to change it, do not go into it. You may take a 20 second reprogramming session and easily turn it into 2 or 3 minutes. Shifts are especially slow to process so use those sparingly. Does any of this make sense? I hope so. ![]() Take care.
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Bill Cohron - The Mad Doctor ![]() ![]() ![]() Power Hungry Performance - The ORIGINAL in Ford performance tuning... Since 1997! (678) 890-1110 www.gopowerhungry.com - Home of the Hydra Chip, Minotaur Tuning Software, and the new Orion Reflash System for Navistar! Bring back ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Much to my surprise, I'm actually quite enjoying Linux! ![]() Last edited by Power Hungry; Tue, December 23rd, 2008 at 11:00 PM. |
#3
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Bill, I think you meant to say "don't" here, where I've highlighted "do", but I don't feel comfortable editing your post.
So, I'm still confused (have pity on an old man). As I understand you now, the VID is used whenever we are in Level 0 (stock) and the PCM sees the stock values for GR and TS. But, if we move to any other level (1, 2, or 3) the PCM is going to use values found in the Calibration section? Or, is it that the Calibration section values are only used if and only if we open the Custom Options menu? My truck's GR and TS are both stock and match what's on the sticker, which I also have. I put these values on the custom tune form when I sent it to you. When I choose one of the custom tunes you wrote, and check the GR and TS, I always see 3.73 for GR (correct) but 2356 for TS (way small). My tires are 275/65R18s and I've found that I get correct speed and distance using a 7% squish value (using the Gear Calculator) of 2480 at the recommended pressure of 40 psi. Or finally: ![]() ![]() ![]() And I know this is an extremely confusing post and I'm just glad I can feel free to express my ignorance. - Jack |
#4
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I was thinking the exact same thing Bill said
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#5
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I see where there is confusion about Custom Tuning versus Custom Options. It's a difficult concept to get your head around, especially if I don't explain it correctly.
In regards to the VID and TS/GR, here's the deal:
As you mentioned Jack, you should always complete the first programming session before doing any custom tuning. This helps to ensure that the custom files are built from valid data from the PCM. The Load Previous Settings menu option in the Custom Options is used only when you've made prior changes to the Custom Options and you want to reload those settings the next time through. It may not be clear yet, but hopefully were at least going from mud to brackish. ![]()
__________________
Bill Cohron - The Mad Doctor ![]() ![]() ![]() Power Hungry Performance - The ORIGINAL in Ford performance tuning... Since 1997! (678) 890-1110 www.gopowerhungry.com - Home of the Hydra Chip, Minotaur Tuning Software, and the new Orion Reflash System for Navistar! Bring back ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Much to my surprise, I'm actually quite enjoying Linux! ![]() |
#6
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OK, so let me see if I understand the "load previous settings" option. I am going to eventually get slightly bigger tires when these stock 31's wear out. May go with 33's at the most. If I change the TS/GR correctly to the custom tunes you are doing for me now, then I can just load previous settings when I switch back and forth from perf to tow and vice versa? Or, do I have to enter in the TS/GR each time I change back and forth? I hope not since I do tow a boat about 3-4x per month during the Spring-Fall months. Thanks for clearing it up a bit.
Mark |
#7
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Bill! Thank you, thank you, thank you!!!
![]() ![]() ![]() Everything's totally clear now (I hope). I've been going into the Custom Options menu every time I've loaded a new tune (switching from Tow to Economy to Stock, depending on need) and now I see my confusion. In the Custom Options menu, the GR and TS information is obtained from the Calibration section and it may be bogus (unless a valid set of numbers had been written there before, and you Load Previous Settings?). So, whenever changing tunes, Mark. Simply enter the level you want and skip the Custom Options part. Let the PCM accept the new tune. Then, if you need to verify or change anything, go back, reload the same level, enter the Custom Options menu and in it, first thing, Load Previous Settings. Then, change or verify anything you would like to customize your tune, recognizing that for each value you even look at, programming is going to take longer. Did I get it right, finally, Bill? The problem is not in your explanation sir, the problem is in the explanation or lack of same in the Edge manual (but I know it's a tricky concept). - Jack |
#8
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Okay.....I'm gonna try and make this as simple as possible for myself because now I am slightly second guessing what I should be doing!
Bill: My custom tunes were built without me specifying any change from the stock TS/GR! My truck has 3:73's and stock 275/65 18's.........do you recommend I touch the TS/GR settings or not? Currently I have my snow tires on and they are 265/70 18's.......again, should I just leave the settings alone? I have tried playing around with many custom settings but I always keep coming back to your custom tune because it feels like it works the absolute best in every area........the only thing I tweek is the standard driving 1-2 shift and 2-1 shift. I drop it 1 because I want it to be slightly less aggressive when gently taking off from a dead stop!
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08 FX4 CREW K&N 63 series Intake Magnaflow SI/DO exhaust Custom tunes |
#9
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Someone may have to help me a little here...so when I went to 87 tow (truck currently in 87 tow) and selected yes on custom tunes, I then went down to load previous settings. When I scroll through to check the settings, all of the shift point speeds are at 0??? Also, the tire size reads 2356 which is way off for 275/55-20 tires. Oddly enough, my speed is accurate with the GPS. If I put in the circumference of tires with 5% squish, my speed is about 2mph faster than GPS at 55mph.
Is there a way to see current settings loaded on the unit with 87 tow mode? I can't seem to get the "load previous settings" to load anything for me to view. As I'm typing this, I'm thinking to myself "My truck runs great; I can't wait for my custom tunes; Why am I tinkering with this?" Oh well, guess it's part of my figure-it-out nature. Don't anyone lose any sleep or family time over this. I guess we're just tinkering around. Merry Christmas |
#10
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265/70-18 = 2543mm Difference = 1.5% or about 1 MPH at 60 MPH. It's up to you, but if you want the speedo to be dead accurate then you should change it. When running the stock tires, leave the TS/GR alone. ![]()
__________________
Bill Cohron - The Mad Doctor ![]() ![]() ![]() Power Hungry Performance - The ORIGINAL in Ford performance tuning... Since 1997! (678) 890-1110 www.gopowerhungry.com - Home of the Hydra Chip, Minotaur Tuning Software, and the new Orion Reflash System for Navistar! Bring back ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() Much to my surprise, I'm actually quite enjoying Linux! ![]() |
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