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Interior & ExteriorDiscussions about the interior, and exterior of your vehicle.
This is a discussion thread titled "Mileage increase with tailgate off", within the Interior & Exterior forum, part of the Technical & Vehicle Assistance Forums category.
PEID! Thank you sir, I certainly did understand your rundown and it makes perfect sense. Maybe one day I'll figure out how bad my mileage is (heavy foot).
On the tailgate up and down deal, I can completely understand how somone would think that with the gate up it acts as a wall for air to have to overcome, but the explanation from Sweetwater explains it very well. Aerodynamics is a very interesting subject, if you're into motorsports...or kites or something.
Anyway, thanks for the info PEID. I'm a new user on TundraSolutions and have owned my Tundra for 3 weeks and I love my pickup and I am starting to love this. It truly is packed full of VERY useful information.
...how do you know you filled it to the same place each time? I mean, each fuel pump cuts off at a different time and you're not supposed to fill it to the top. So, right here, we're talking discrepancies in your MPG figuring. Even using the same gas nozzle will not fill up to the same level each time...
Is it close enough for measuring a decrease or increase in MPG? Yeah, but for monitoring more precise fluctuations, no, not at all.
Originally posted by CJ ...how do you know you filled it to the same place each time? I mean, each fuel pump cuts off at a different time and you're not supposed to fill it to the top. So, right here, we're talking discrepancies in your MPG figuring. Even using the same gas nozzle will not fill up to the same level each time...
Is it close enough for measuring a decrease or increase in MPG? Yeah, but for monitoring more precise fluctuations, no, not at all.
CJ
I have never heard of not filling completely as in it is bad or anything.
As far as being the same level, when I fill mine I let it click then generally round up to the nearest $0.50 or so. Sometimes get the "Classic Over Squeeze" $31.01. But I would bet that I fill my tank within a 3-oz everytime I fill. 3 oz isn't going to make any difference on 300+ miles, unless you calculate it to the nearest ten-thousandth.
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1996 T100, 180,000 and counting
Filling the tank completely (beyond an operational nozzle's auto-off, for example) can lead to damage of the charcoal canister, as rounding can do. Not to forget back-splash.
But really, like I hit on before, these real world tests are hardly conclusive and should not be taken as having nearly as much credit than wind tunnel results. Headwinds, tailwinds, tire pressure, air temperature, engine temperature, vehicle weight, you know what I'm getting at. All that vs turning on and off a fan and lifting and closing a tailgate. A lot less variable inaccuracies when dealing with a wind tunnel.
A more accurate method of getting real world results would be to put an explosion proof fluid volume gauge inline with the fuel line between the fuel tank and the engine compartment. Yeah, more work than your method, but much more accurate.
Relax man, I'm nt interested in turning my Tundra into a rolling EPA lab or anything. I was only curious to get a ballpark idea of what kind of mileage I was getting. I'm just enjoying driving and whatever mileage I get, that's what I get right?
Just out of curiousity, what kind, if any, of tonneau covers are people using? I'm curious if anyone has installed a Peragon folding tonneau yet?
Actually - your truck IS more aerodynamic with the tailgate UP.
With the tailgate UP, a 'bubble' of circulating, volatile air is generated within the bed of the truck and as oncoming air passes over the cab, it takes the least restrictive path right over the bubble - almost as if you had a small, invisible camper shell.
With the tailgate down, or off, as oncoming air passes over the cab of the truck, it does not encounter any resistance over the bed, so it in effect presses 'down' on the bed of your truck - obviously making the truck work harder and decreasing your wind resistance - and explaining why mechanical engineers still put tailgates on trucks after all these years.
To increase my gas mileage, I've removed the rear seats, spare tire, emergency brake hardware, bedliner, trailer hitch, rear bumper, dashboard, interior light bulbs, and any cargo I may have ever wanted to carry. I'm getting .003 mpg better now! : )
I think that if you're driving a pickup truck, you need to learn to live with the gas mileage or buy a car if you don't need a tailgate for keeping stuff in the bed.
I own a 94' Chevy S10 Extended cab with a 5 speed and 4.3 liter Vortec. So far, 110K trouble free miles. But that new Double Cab coming soon looks very, very tempting.
Does anyone know exactly when it is arriving?
Also, I'm debating between a 4x or a 2x. What are the average mileage differences between 4x and 2x. Is the 4x mileage calculated while in 4x drive mode?
This is a link to a copy of an article taken from a magazine that quotes engineers from Ford Aerospace Division who did a wind tunnel test on a ford F150.I assume the results would apply to other trucks.http://truckgadgets.com/fuel.htm
I used to have a 2000 Chevy Silverado and I had to constantly check the bed for trash cause if not, when I drove, it seemed to me the wind would come in hit the tailgate then come forward across the bottom and slam trash against my cab and rear window. Aluminum cans were the worst. When I say slam I mean slam. That right there tells me there is no bubble of stagnant air in the bed. Something was slamming that stuff against my bed and window. Yeah, the wind after it made contact with my tailgate.
Havent noticed it with my Tundra, but of course I havent had it too long yet.
Maybe 10 years ago, I had a lil 4 banger Toyota truck. My best friend had an RX7. With my tailgate up, he would beat me. With my tailgate down, I could barely nudge him out.
from everything Ive seen and tried, no tailgate = better gas mileage, faster get up and go... : )
...how do you know you filled it to the same place each time? I mean, each fuel pump cuts off at a different time and you're not supposed to fill it to the top. So, right here, we're talking discrepancies in your MPG figuring. Even using the same gas nozzle will not fill up to the same level each time...
Is it close enough for measuring a decrease or increase in MPG? Yeah, but for monitoring more precise fluctuations, no, not at all.
CJ
Your correct. To eliminate as much variation as possible you would need to use the same pump and nozzle during testing, and even then there will certainly be variation in the filling cutoff. You can get a fairly decent approximation, but I would think that the error involved would be about +/-0.1g or so. Just a guess
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When filling...
Mileage between 4x and 2x?
