So what kind of MPG increase with a

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Nov 14, 2003
What kind of mpg increase can be expected with a tonneau cover on a tacoma? how about an aftermarket magnaflow exhuast? While I have some interested parties looking at buying my truck they have been lower than what I wanted to accept for an offer. So I am trying to get better mpg in the mean time. I have already done the basic stuff: tire pressure, all synthetic, slowed down a bit on the highway, guage traffic lights etc... but I can still only get a combined highway/city 18mpg. I guess thats ok for a truck but not great.
Buddy of mine just got an used 02 Pre-runner V6 4 door with a tonneau. He clocked it with 21 MPG on the highway. He drives fast and uses AC all the time.
A tonneau would help; I doubt a Magnaflow will incerase mileage all that much and the noise will likely annoy the heck out of you. Plus, 300 bucks to increase gas mileage maybe 1 mpg if any? When's that gonna breake even! If you don't carry anything in the bed most of the time, you could always take the tailgate off until you need it. That's free!
Cool thanks, so its probably not worth the $$ so it seems. I guess I am stuck with 18mpg. I have 32K miles on it so I doubt it is going to "break in" more for better mileage.
Going from 18 to 19 mpg saves 0.0029 gallons per mile. At $2.50/gallon, that's $0.0073/mile. How much does the cover cost? Divide the cost in dollars by 0.0073 and that's how many miles it'll take to break even, if gas is $2.50/gallon.
Originally posted by rpn453:
Originally posted by XB70: It's not specific to your truck, but maybe you can get some ideas from reading Aerodynamic Characteristics of General Motors Truck in which they achieved a 22.03 % reduction in drag through the use of a bed cover.
Wow. I thought taking off the tailgate would improve mileage.

You would as would I. Actually I did get about a 10% increase in mpg. Now if you were in a 1/3 scale styrofoam model going the equivalent wind speeds of 73mph, 167mph, 245mph, 337mph, and 470mph during the testing in an enclosed 5'x7' tunnel you might just see a decrease in fuel economy as the testers at U. of Mich. did. [Big Grin]
I've got a hard tonneau cover on a 2000 Nissan Frontier w/ 4 cyl and don't really notice any mileage increase. Typically tops out at 27mpg w/ reasonable freeway cruising. It adds about 80lbs to the back which is noticeable in handling. The front end and cab area is surely lacking in aerodynamics, and I was already aware that dropping the tailgate increases drag. The tailgate issue has been discussed before on this board.
your getting what you should be with that truck and thats what i get with my sc/taco and i get a little better with my 4runner..except when i'm boost happy then between 13-15 mpg.. both seems to like to run about 2200-2400 which is about 70mph on the hwy to get the best mpg. any faster and i'm just sucking it down. that seems to be the sweet spot when i'm pulling my small boat also. so your normal go up on the tires and smooth on the gas.. muddawgs
mud, I just read of some people on the TTORA forums getting 23mpg from a cat back exhaust and such. That is pretty high for our engines, but maybe they just dont know how to divide? I would love to get a Supercharger but buying premium and possibly lower mpg is scary to say the least. Although I have read that people get an increase in mileage with the URD fuel upgrades. Do you have anything to help deal with the pinging these engines get with the charger?
that 23mpg is exagerated. i've had friends tell me that got 29mpg in a xyz suv because thats what the computer tells them.. people say mighty tall things when you cant see them. i can only offer you to tell you what i know with this truck and is a real world experience. i've bumped 20 a few times but thats it and i've had a few taco's since 95 and just this 1 4runner with this motor. the 2.7's get only slightly better because its a brick also but its a dog. my mileage on all the ones i've had, have been rougly the same as yours +/- at times. my 4runner does consistantly better than my taco but not by much around 2mpg. the pinging that most everyone is complaining about is high gear low rpm. it is a issue but not quite to the degree what its made out to be. i dont drive in boost up a hill in high nor do my turbo friends. the stock fuel system now will go lean though and you wont get a ping on some trucks. i've only noticed ping when i filled with a empty tank in iowa at a kum and go. i've had my sc since the first generation and have added several fuel mods including injectors and diff pump on my own. there are some people like gadget at urd that have made a great all in one kit to do and tune the system relatively well and have many happy customers. but i dont think that even gadget would make a claim with better mileage with his kit. i've never had the ping issue except that one time to where it was unbearable as some have said. but i have had the lean issue when your into boost for a period and the fuel pressure drops. the sc was installed with less than 200 mi on the truck. so it was still fairly clean. some of the people i've talked to have the sc have had between 60/70k before they installed and have had issues with pinging. coincidence?? maybe.. your right in range what you should be. keep the tires pumped up and keep the rpms in range as i've sd above and you'll do ok. you can install a vac guage also pretty easily to help you determine whats right for your truck at what speed. but you'll get no power increase or mileage from a cat back or chip with your truck.. Some have reported better results with the deck plate mod or elbow mod on stock motors. those are both free or cheap to do. but i cant say i did better with those on my taco. good luck to you and your taco. regards, mudd
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