Well, last weekend I installed a quadzilla XZT tow module on a guys 06 dodge cummins. At the same time we installed the fuel tank vent mod. We also cut a 4" hole in the bottom of the air box and used a flexable metal dryer vent hose to extend the air intake to under the truck front end. Used stock air filter. Also took out cross members in the torque tube. Total for all modifications = $265.00

After driving a couple of tanks off the verdict is in:
Before modifications = 17.8 MPG overhead, 18 MPG hand calculated.
After modifications = 21.7 overhead, 21.9 hand calculated.

Keep in mind he has the tank vent modification so the fuel tank is completely full every fillup. I was standing there and watching him.

This drive has been repeated over the same terrain and weather conditions and temps going 65 MPH.

Summer temps usually are 1 MPG better than winter temps so we'll see if he gets an even better MPG improvement when summer gets here.

No towing MPG figures yet.

The tank vent modification added another 4 gallons of fuel. We emptied and vacumed out every drop of fuel from the tank and then measured the fuel we put back in.

 

Nice!

where can i get info on the fuel tank vent mod?

 

http://www.diesel-max.com/store-cate...s_2429930.html

 

Your overhead isnt off? The moment I put my XZT on the overhead was way off. I have never seen a mpg increase with my XZT either.

 

So I guess the tank vent kit give more accurated calculation cause I seen a increase with my XZT but not that mutch about 1 MPG or so.

Buzzman

 

I'am going to go out on a limb here and say that on a tipical vehicle driving like most people drive now days your not going to see the improvements this vehicle did.
1. This vehicle uses an additive every tank full.
2. The tires are aired to 80 PSI summer/winter.
3. It a little over a half mile to get up to speed, instead of drag racing to speed.
4. It never idles, not even winter. Start it in neutral to get transmission fluid flowing for about 1 minute put in gear and slowly get up to speed.

But then again this vehicle was driven the same way since new and never made more than 19 MPG even in summer.

The overhead in my 05 and then this 06 are very accurate. I have found to make them more accurate you have to turn the key on at fuel pump after fueling. Then reset everything on the overhead, not just the MPG guage. Then start truck and drive.

 

Before you put the fuel tank mod in the pump would shut off, and the guy would probably round to the nearest dollar. Now after the mod he is able to put 4 or so more gallons of fuel in. So he needs to compare 2 tanks of miles per gallon #'s and then recalculate. I suspect the mpg increase is from being able to put more fuel in.

 

Nope, if he shut the pump off before the modification and then filled each time the same way the MPG would still come out the same. In other words if you used 22.2 gallons per 400 mile trip and now he uses 18.2 gallons per 400 mile trip he used 4 gallons less.
4 gallons At $3.00 per gallon = $12.00 saved per 400 miles.
$265.00 on modificatons divided by $12.00 = 22.08
22.08 X 400 miles = 8832 miles to pay off modifications.

As a side note With the fuel tank modification his tank now holds 38.4 gallons which on a short box truck the fuel tank is 34 gallons stock. The long bed trucks are 35 gallons.

 

Bottom line, there is no way you picked up 3 mpg from the XZT with exact same driving styles and conditions as before. If have had mine over 30k miles and have seen little mpg improvement with the exact same driving. I do not hotrod accelerate up to speed and I do not let the truck idle longer then 30seconds. I cut the thing off in the driver thru of banks and fast food. I hand calculate every single tank and there is very little difference in mileage with or without the XZT. That is my experience anyway.

 

Yah, I was one of those guys that didn't beleave in MPG increases either. What can I say. I was there and witnessed the whole thing.

Like I said we filled the fuel tank to the top after doing all the modifications described in my first post. I rode with him until we filled the truck up again. 21.9 MPG hand calculated. I have rode in this truck many many times and it never got over 19 MPG unloaded in the summer. This winter it was getting 17.8 MPG on ULSD. Still is winter here.

I guess all I can say is he must have been getting 21.9 MPG before we did the modifications because that's what the truck gets now.

By the way, 21.9 - 17.8 = 4.1 MPG improvement not 3 MPG. Sorry if you didn't gain anything. No need to rain on this guys parade!!

I don't need to prove anything, Him and me are as happy as a pig in Manure.

 

I have gotten about 2 miles per gallon more since I have placed on my xzt. I use hand calculations.

Ethan