IAT and MAP sensor

[Ilikeoldfords]

I have been just using the odometer for mileage. It also has not been corrected for the 35in tires. How far off will my mileage be corrected? I know when my speedo says 60, I am really going about 68. I guess I didnt take this into account either. How would you correct the speedo for the larger tires? I will get a GPS on it soon though.

[98whitelightnin]

Dealer can do it or if you have a smarty you can do it.

[Ilikeoldfords]

To the dealer I go then. Do you know about how much they charge for that?

[diesel4life]

Hey Will, like Ryan says if you know someone with a smarty they are capable of recalibrating your speedo. Ive double checked mine with a gps and its spot on. If you have to go to the dealer, Im guessing they will charge you a minimum of an hours labor. Thats just a guess though Ive never gone to them for that.

[Ilikeoldfords]

Ok. I will check around for someone with a smarty. No one comes to mind though. I will still check with the dealer and just see what they would charge. I'm kinda curious.

[98whitelightnin]

After you remove the smarty you will loose your speedo calibration.

[diesel4life]

Are you sure about that, Ryan? The way I remember it is if you clear any dtc you would also reset the speedo. But I can go in and adjust my abs (speedo) without doing any other changes or downloads. And no matter what I do as long as I dont clear any dtc i will retain my abs adjustment. Now to get the high idle, you have to be able to download a catcher software, then you can remove it back to stock but you still maintain your high idle feature. I could be wrong, my wife tells me I am everyday!

[98whitelightnin]

Maybe I did it wrong. I borrowed a buddies smarty and set my tires size and all was right but when I removed the smarty from mg truck, the speedo went back to reading wrong. Can you check it out for us? If it still works I will borrow his and try again.

[diesel4life]

Tomorrow I will go out and return my truck back to stock and see what it does. Other than reading dtc codes for people, Ive never really had to share it with anyone, so Im not completely sure either. I do know that I can change tunes and not lose the abs, adjustment, I will let you know what I find out tomorrow.

[Ilikeoldfords]

Just to give an update, it was a good call on the hour labor time at the dealer. It came out to about $90 and on top of that they said they could only calibrate it for the largest stock size tire for this year and model :banghead: I think my uncle has a smarty so I will have to get with him. If someone does find out if the calibration stays or not, that would be great:hyper:. I would like to know if it wont work before I drive 3 hours away hahaha!!

[ISX]

The IAT fooler is only meant to correct winter mileage.. It doesn't make hot weather mileage better because the IAT already sees hot (ambient) temperatures. If you are over 60*F ambient, I would say you won't notice much at all. To confirm this though, could you guys all try and get on level ground and record your IAT's and ambient at say 60mph? We are all across the board so a guy at 60F and a guy at 20F would be perfect. Record boost as well since higher boost will have an affect. Oh and let us know if this is with or without a winter front. If one guy has one and the other doesn't then it will be a little uhhh yeah, skewed data.

[diesel4life]

Went out earlier and returned my truck to stock settings. Like Ryan said, it wipes out the abs adjustments as well. Actually when there is no software programs installed from the smarty, theres not even an option to adjust abs. Shows how much I run my truck at stock :whistle:Thanks for setting me straight!

[Ilikeoldfords]

Ok, so if it doesn't stay after everything is returned to stock, and the dealer can't do anything for me, the only way to calibrate the speedo is to buy myself a smarty? There's gotta be another way??

[Ilikeoldfords]

So I did a few tanks with the 2.2 ohm resister. I tried the comp on and off. The best I could make was 16. I'm gonna try the 3.3 ohm and see what happens.

[cowtipper]

You used the 2.2 on the truck in your sig? I have an 02 H.O. We dont get the great mileage that the S.O pump guys get. Curious on how high you get it.

[Mopar1973Man]

Well the big problem is fight the rolling resistance of those large tires. Then the increased wind drag for standing taller.

[Ilikeoldfords]

I understand that. What I am trying to get at is I was averaging 18-19 during the summer. Now I can't get any higher than 16.4? I know that I will never get over 20 with my set up. I am just trying to get to my summer mileage.

[War Eagle]

I understand that. What I am trying to get at is I was averaging 18-19 during the summer. Now I can't get any higher than 16.4? I know that I will never get over 20 with my set up. I am just trying to get to my summer mileage.

I am guessing you are using winter fuel now and that alone will decrease your mpg if everyhing else stays the same as your summer driving. Not sure how many mpg's that would make on your truck but on mine I lose between 1-2 mpg's.

[Ilikeoldfords]

That would just about have to explain it. I heard somewhere that there is no summer/winter fuel for diesel. For some reason they were saying we just use the same fuel all year round. Thats why I didnt take it into account I guess:doh:

- - - Updated - - -

You used the 2.2 on the truck in your sig? I have an 02 H.O. We dont get the great mileage that the S.O pump guys get. Curious on how high you get it.

I did use the 2.2 for a while. no improvement though.

[Mopar1973Man]

I understand that. What I am trying to get at is I was averaging 18-19 during the summer. Now I can't get any higher than 16.4? I know that I will never get over 20 with my set up. I am just trying to get to my summer mileage.

The other factors like winter fuels and weather will make a impact.

TIRES (235's vs. 265's)

Like with my setup I've got a set of 265/75 R16 on steel rims which weight roughly 85 pounds per tire. Then my summer tires at 235/85 R16 on aluminium rims which weight a mere 62 pounds per tire. This has a net gain of 2-3 MPG easy by shaving off 23 pounds per tire. These 265's are on there last legs and will not be used again and will be replacing with a set of 235's A/T tires for next winter. Too much loss in going big and out here the wider tires do poorly in the snow.

WINTER FUELS (Higher Cetane)

At least in the frozen north I know all fuel is a mixture of #1 and #2 to bring down the pour temp to close -20*F roughly. Then some people have this fear that their fuel will gel up so they add more fuel conditioner of some sort and most don't even measure the proper amount. Like for Power Service its 400:1 ratio so if the 35 gallons of fuel (4,480 ounces) you would add 11.2 ounce total. But still in all your raising the cetane the higher the cetane the lower the BTU's.

WEATHER (Wind, road conditions, etc.)

Like yesterday I left the house and headed for McCall, ID to pick up a few things. Since I'm climbing up hill the truck tends to warm up fairly rapidly. But with the colder weather and the winterized fuels there is less power per cycle so you need more fuel to over come the loss of the BTU's so I've been typically 13 MPG getting to New Meadows, ID where in the summer it more like 16 MPG. But my return trip is mostly down hill so I should gain a bunch back. But I don't I've been averaging about 19-20 MPG at best in the winter and then like last night SAR's meeting with the heavy winds pulled my average from the morning of 19.5 down to a dismal 15 MPG bucking winds all the way back up hill to home. I could of gained back some of this by getting off the highway and slowing down and reducing the amount of wind drag on the truck. But I wanted to get home. So the quick route cost me dearly.

And this what all the wind brought...