The 4x4 trucks will generally get worse gas mileage due to the added weight of the transfer case and front drivetrain. There is also more drag due to the fact that the front drivetrain is always spinning.

 

I average about 16mg city/highway in my '99 5.4L 4x4 expy. Out on the freeway I usually see about 18mpg. I've got a K&N CAI and the stock muffler + tail pipe hacked off and in their place I have a borla XR1 race muffler with turn down. Sounds very nice, its very mellow and throaty. One of my friends thinks its sounds like a chevy truck lol.

Shane

 

You need new friends...

 

one correction to the comment from MisterCMK about the 4x4, at least with respect to the 2003 expy. The front drive train does NOT turn all the time. There are automatic hubs that engage when put in 4x4 and the transfer case does the same. The front drive shafts are not spinning unless the selector is in a 4x4 mode. Mine does allow for "4x4 auto" which engages the front hubs but only engages the transfer case in the event of slippage.(pretty much a worthless feature in my opinion)

 

I get 11-12 city 15-16 Highway

9.5-11 Towing 6300lbs

 

Stock 03 5.4L Expy with K&N gets about 14 city and 18 highway - I can nudge 19+ on the highway if I really baby it and keep it under 2K rpm. There is a big difference in driving 65 vs 75+ though, especially if you have a fairly straight and flat interstate for hours in front of you (like I10 through Texas).

 

Is this true of all Expies?

 

I've got an 03, 4x4, 4.6L. Xcal tune, AF1 CAI and efans. The best I can do is about 17 mpg mostly highway. Also use royal purple oil and keep up on maintneance. Thinking about ways to reduce load on the egine such as underdrive pullies, maybe an exhaust.

Also thinking about ways to improve the aero drag coefficient. Anyone ever try something called airtabs? They are self adhesive vortex generators that go along the top and sides of the rear edge of a blunt ended vehicle. Designed for tractor trailers. These things create a vortext of air that is stable and extends beyond the end of the vehicle effectively reducing the turbulence and hence drag coefficient. Lots of testimony on their site about truckers who notice better handling, cleaner rear ends and better visibility during rain -all indicators of better streaming of air. They make claims to 2-4%, sometiems more, improved fuel economy. Wondering if the scale of an Ex compared to a semi might give it proportionally higher improvements?

I am thinking about getting a set (2.50 each +s/h). need about 8 across the top, maybe 4 on each rear side window. Not sure about the looks though

 

Can you post or pm me a link? those air tabs sound interesting let us know if they work.

 

www.airtab.com or do a google for airtab (one word).

There are clear, black and white. All are ABS self adhesive. They can also be painted. I'd like to get the clear ones. I measured across the top of the rear - should fit 8 tabs. Could also put about 3-4 on the trailing edge of the rear side windows.

 

And the styling really adds to the Honda CRV in their reader ride section!!!

 

No Kidding!!! I'm all for improved performance, but that is over the edge. I'm ok with doing the top. My side windows I would probably scotch tape them in place to see what they look like before doing a more permanent mount. I'm thinking a bigger vehicle would make the tabs look a little less conspicuous, especially if they are clear. Could also do the black ones on the side windows.

 

I can't see adding that to my expy.And to be honest I never seen Big Trucks with any of those airtabs on them here. Looks like another gimmick to me. Good luckif you decide to do it.

 

Yeah, I'm a little hesitant. The roofline doesn't bother me. The side of the truck might. But, they're fairly cheep. If I don't like 'em or they don't help, off they come.

Having said that, I have been doing a lot of reading about drag coefficients, hp required to over come drag, etc. The concept of a vortex generator is not new. Aircraft use them on the wings to keep the airflow from separating off the top of the wing. Mitzubishi also did a detailed study on the concept (do a search for Mitzubishi vortex generator on Yahoo; it will be the 2nd link to a pdf file). You can buy the Mitz style vortex generators on ebay for $20.

There is a lot of research being done by the trucking industry on reducing drag to reduce fuel consupmption. Those of us with big blocky trucks can only benefit from what they are learning, as long as we are willing to learn too!

 

Man if I knew I could have gotten better mileage in an Excursion I might have gone that way instead of my expi...


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