Yes, Darren, setting the idle in the Custom Options menu back to zero will put it at the stock tune setting that Bill created for you.

There may be an easier way though to get totally back to the "virgin" custom tune - just program it in and completely bypass the Custom Options step. Or, if you want to have a "Previous Settings" file that is mostly "virgin", open the Custom Options menu but DO NOT "Load Previous Settings". If I've got this right, you are now in the process of creating a NEW "Previous Settings" file, but most of the settings are what Bill wrote for you. There are two exceptions though - Tire Size (TS) and Gear Ratio (GR). One or both of those values will now likely be wrong and you'll have to manually set them. Check both and adjust as necessary. Then, scroll to "Done" and let it program. The new Previous Settings file will hold Bill's values and your TS and GR.

As I said though, I don't know if the RPM drop during braking is normal or not, since I don't recall ever looking at it. I don't think I get that big a drop, but I cannot be sure.

And, I'd give Bill's settings a try before trying to "customize" them. After all, it's what you paid him for. Also, if you don't like something in them, it's probably best to discuss that with Bill, so he can fix the root cause, which is different than you putting a "band aid" on it with "Custom Options".

- Jack

That interesting to know. I looked at my settings earlier while I was out, I see Bill has it set 1-2 shift = 5100, 2-3 shift is also 5100, 3-4 shift is 4600, and rev limiter is 5600. I noticed that my avg econ was hanging in the 17 - 22 area, so i calculated some miles and compared my rpm and speed and realized that my tire circumfrence was wrong. It was 2340 something i think, and with the canned tune it was 2550, I did the math in the manual and came up with,, 255 x 70 x 0.02 ( 357 ) 17 x 25.4 ( 431.8 ) both together 788.8, and x that by the 3.1415 and got 2478.0, going to re-program that in the morning.

I'll definitely be testing out his settings. I was just wondering if there was any improvements I should make prior, but since its my truck and I have my driving style, I suppose I am the only one who can answer than question lol.

Darren, please look at my Q & A on the Custom Options menu. Any number you see in TS or GR in the Custom Options menu is likely to be "bogus". Does the 2478 you calculated account for "squish"? If not, subtract about 3% or about 74 mm from it and use that as a starting point.

You ARE NOT going to see the values for GR and TS that Bill put into your program if you open the Custom Options menu! I know this doesn't make sense, but, it's the way the software in the Gryphon functions. If you bypass the Custom Options menu though, you'll load correct TS and GR values (unless you've put in new gears or wheels since your tunes were written).

And, Bill tried to write tunes for you based on his understanding of your needs. I'd give them a chance. Oh, and I think the WOT shift points and max RPM Bill used was fine too.They're only about 100 above my settings and I asked for tunes that would save gas and give me good passing performance, not peal rubber off the tires from a standing start performance.

- Jack

My gear ratio is correct ( 3.73 ) and I thought the 3.1415 was th squish factor. I do not have ( or have access ) to a GPS to verify my speed but I would think I did do the math correctly. I did record a mileage mis count though, from my house to my buds is exactly 3.0miles, I re-set the mileage counter and it told me 3.3 miles so I think the size is a little off and 1200rpm at 47mph cruising in 4th gear and overdrive, I dont believe thats possible, or is it? I'm checking out the Q&A right now.

I've had my truck dynoed........and with my setup, I was still building power at 5000 rpm's.

My power actually topped out around the 5200 mark.......

Hi Chris - The 08's have a somewhat different power curve than earlier models. I think they DO drop off later. I know your engine can develop more power and torque than mine.

Regardless, I really think Bill will set the WOT shifts at the correct points to get you what you want. And, thinking about it a bit more, it makes sense to set the shift point somewhat past the peak HP and torque point because then the shift will bring in the next gear at a higher RPM setting, overall, giving you better acceleration (if WOT acceleration is your bag). This of course means the max RPM has to be set higher too, so that the shift can complete properly.

I DO want the acceleration, but I'm also interested in protecting the transmission, which I feel is a weak link in this truck. (Wish it was a manual).

- Jack

Darren, 3.1415 is pi (It's really closer to 3.1416). When you do this calculation: 17 x 25.4 = 431.8, you get the rim diameter in millimeters. Adding in 255 x 70 x 0.02 = 357 gives the additional diameter of the wheel contributed by the tire, so the overall diameter of the wheel is 788.8 mm. Now multiply by pi to get the unloaded circumference, which is about 2478.1 mm. OK, this is how far a wheel will roll in one turn if you take it off the truck and roll it across your garage by hand.

But, the truck's weight "flattens" the tire, effectively reducing the diameter under load. On the truck, one revolution will cover less distance than it did when off the truck. I've found for my tires that about a 3% reduction in circumference is about right. I suspect this will be close for your tires too, so subtract 3% or 74.3 mm from the unloaded circumference of 2478.1 which gives 2403.7 (round that to 2404).

You can avoid all the math, of course, by just entering your tire size in the "Gear Ratio Calculator" that is one of the tools in Pegasus. The "Old Tire Size" you should enter is 255/70-17. The calculator has a default "rubber squish" of 5% which gives a circumference of 2421 mm. The calculator uses higher "squish" values because the rim doesn't deform, only the tire does, so the percentage change is being applied only to the tire's contribution to the diameter. I've found my calculator "squish" needs to be about 7%, and if I use that on your tires, I get 2399. A 6% squish gives 2410. So, you can see that the 3% total reduction I used earlier is between 6 and 7% rubber squish.

Anyway, try 2404 (or maybe 2410, since you inflate your tires higher than mine) as a starting point. I think it will be close. (And I hope I haven't confused you too much)!

By the way, 3.3 recorded miles in 3.0 actual miles is a huge error! (About 10%). And, showing more distance on the odometer than actually traveled says your tire size is too large.

- Jack

Thanks yet again Jack for the information. I will try this again. Hopefully this will be resolved soon. I'll put in the 2410mm size and go back down that 3.0 mile route and see how it goes. I keep my tires at 40psi so that should be a good starting point.

Darren, since the max pressure on your tires is 65, I would not hesitate to inflate them to 45 or 50.

- Jack

The max is actually 44psi. I have General Ameritrac's