i installed Superchip tuner 1714.

I set everything superchips "87", 3.73, tire height 31.50" and i finally used my GPS and it read that my truck MPH gauge is 4-5MPH faster...

GPS reads 65mph and gauge read 69-70mph.

WTF ? My 18" tires is 31.5" so i reduced to 31.25" thru superchip tuner set and it now down to 1-2MPH off and call it nite cuz i m a bit tired from work all day..

Could i reduce to 31.00" thru superchip tuner or leave it 31.25" ? I will test 31" and compare w/ my GPS.

i checked my tires and they all are at 35-36psi.

Any feedback ? If 1-2mph off is common then i ll okay with it


Thanks!
YOMAN!
2004 screw FX4 3.73

 

Unless you have made modifications (change rear gear, change tire size, etc, etc.) you need to run the Superchip setting. It notices the size of all your equipment (rear gear, tires, etc) through the VIN number of your stock tune. Let me add that this is just my guess. I’ve read posts on this forum about similar problems…

 

Got my Scangauge installed about a week before I had my customer tune removed by the dealrer. At that time the speedo in the scangauge indicated about 3 mph slower than the truck speedo. ie: 40 indicated on the truck and 37 indicated on the scangauge.

Now after going back to stock tuning its just the same??? Maybe the scangauge is a bit off I am not sure. The tachometer in the scangauge and my Autometer tach indicate the same.

I am anxious to see what happens as soon as I get my Xcalibrator this week.

And jpdadeo, how are you enjoyiing your new Xcalibrator?

Larry (Hamradio)

 

Loving it Larry, it brought the truck to life, it jumps when I hit the gas now instead of lagging. I’ve been using 93-octane Sunoco. Hey, is that Air Raid intake you got noisy & does it drone at cruising speed (45 to 55 mph)? I’m thinking about getting one instead of waiting for the Air Force One.

 

If I lug the engine down to around 1900 rpm under load it droans a bit. I just pop it outa overdrive and go about my business. It really howels like a BIG 4 bbl when you get on it. I put on about 7K miles towing my TT up and down mountains and on flat running 55 mph to 75 mph and it never bothered me except on a long high angle grade like on hwy 395 up the Sherwin Grade out of Bishop Cal going north. Then it is fairly loud.

I'll put $$$ down that if and when airforce gets one on the market its gona be about the same on the noise. Ford even made up that monster of an intake with the tuned sections to deaden the intake noise.

I know when I get on the throttle, heads turn in my direction. Don't know if you want that or not.

Larry (Hamradio)

 

I adjusted back to "stock" gear and "stock" tire height..its still 1-2 mph off.

I also tried adjusted back to 3.73 gear set and 31.00" tire height and its the same...I m a bit puzzled..

I guess i am fine with 1-2 mph off..

Thanks!
YOMAN!

 

YOMAN,

I played this game too!

Also what I found was that getting the speed correct then sends the milage off! (Drive a measured 10 miles and the odometer will read only 9.8 miles etc.)
My gut feeling is that to correct for tire or gear size only changes the tires rev's per mile calibration. I'm sure the computer only is looking at the rev counter on the rear axle and adusting itself according and if the time base in the computer is off, then the miles/per/HOUR is off. And we can't adjust the time base (I don't think)

And then again maybe there is no time base! And the sweep movment of the dial is just a prebuilt thing that can't be calibratied.

I was told the sweep part of the guage is a variable current device that recieves it's input from the computer, so calibration should be able to to be changed by electronic's.
This has been driving me nuts like you, I too have a gps unit and also use the stopwatch and speed trap marks on the interstate to check my speed and was able to get those two to match my indicated speed within 1 mph, but then the odometer is off(like 1.5 miles per 50 miles traveled)

Maybe were just to picky?

Gene

 

LOL yeah i think we were too picky LOL!

I actually just talked to Troyer product thru e mail and over the phone today this morning.

Heres they said ( i copied&pasted from email).

"HI Greg,

Did you change your gears or are the 373's stock? If they are stock - do not enter them in. Many make this error. Only enter in parameters that have been changed. This should take care of the problem. Also, if you have another way to measure the speed for accuracy - try that as GPS is not always dead on.

Please give a call if you need further assistance.

Thanks and Happy Holidays,

Anita Troyer
Troyer Performance Products
(540) 862-9515"


Try that set it to stock gear and stock tire.

I did to set it back to "stock" gear and tire and leave it alone.


YOMAN!

 

My scangauge reads about 2-3 mph different than the speedo also...Kevin

 

kevhunt.

Scangauge...is it worth it ??

Dont you think it will cause problem w/ Superchip tuner??

Thanks!
YOMAN!

 

My speedometer seems to be in-sink with the local police radar. The cops have those portable radar billboards setup somewhere (A1A) beachside all the time.

 

When you do a calibration for tire size change, whether it's in a 1715 or 1714, you enter the tire height (which needs to be physically measured at the right rear tire, and then subtract 1/2" for best accuracy in most cases) - yes, ultimately it's the revs-per-mile spec that is being altered, of course, that's how all electronic speedometers work with regard to tire size. But it starts with an accurate measurement of tire height.

Most people don't bother to actually measure their tire height when using the standard Micro Tuners (like the 1714 & 1715), and what those tuners do is take the tire height you enter and divide that into 20,800 - that's how it's done to convert to revs per mile, you see. Say you have a 31.5" tall tire, you divide that into 20,800 and you get 660 revs per mile (the number of revolutions that tire has to make to travel exactly 1 mile). You enter in 31.5", and the 1714 or 1715 causes the revs per mile to be altered accordingly, so it's doing a conversion internally. So the actual tire height that is entered is critical, and even at that, there can still be a percent or 2 of error.

Speedo errors are not of a nature that will give a result like being 1-2 MPH off at all speeds, for example - it doesn't work like that. Speedo errors are constant percentage-based errors, so if it's 2 mph off at 50, it will be 4 mph off at 100 mph, and so on. Also, when someone changes gear ratios & tire sizes and enters that info into a Micro Tuner, that *does* alter the odometer as well - as you'll quickly find out by asking anyone who has swapped in a set of 4.10's, 4.56's, or 35" tires, etc.

The kicker here is that some of the newer consumer GPS gear is more accurate than your vehicle is - so don't be surprised if you see small differences there. I'm not a fan of using GPS for checked speedo or odo accuracy, simply because there is far too much GPS gear out there that isn't accurate enough to do this - but some of the newer stuff certainly is, and can be *more* accurate than what's in your vehicle.

Car & Driver did a speedo accuracy comparison a couple of years ago, and found that many vehicles tend to have some slight speedo error, 1 or 2% or so from the factory, just to give you a rough idea. And that transfers right over when you recalibrate, there can sometimes still be some slight error there - not enough to matter, but for those who try to get it "perfect," we generally advise not to bother, as you may not get that result. Once it's within a percent or two, it's fine.

Last - tires do *not* always adhere to the P-metric sizing dimensions as they are supposed to, unfortunately. Meaning for example, all 265-70-17 tires are supposed to be the exact same height and deliver the exact same revs-per mile spec, but they don't always - some can be a bit off from their advertised height, and that will throw the speedo calibration off. So we do on occasion find that we cannot use standard P-metric size data to determine the revs per mile spec, but instead must contact the tire manufacturer directly to get that data. So when using a 1714 or 1715, measure your actual tire height at the right rear wheel, with the vehicle on level pavement (not grass, rock, etc.), and physically measure the tire height from the pavement to the top of the tire - then subtract 1/2" from that measurement for the squish of the contact patch, and enter that number for tire height into your 1714 or 1715 - and remember that those Micro Tuners have an effective "resolution" of 1/4" - meaning the height increments in 1/4" intervals.

Hope that helps!

 

YOMAN,
I like the scangauge very much. I wish they would have had oil pressure as one of the functions though. Since all its doing is reading what the PCM is recieving from the various sensors, I don't think will interfere with the functionality of anything. It hasn't on mine anyway...Kevin