I have a new Silverado extended cab Z71 with a 5.3L and 3.73 gears that will be used for boat towing and part time communting. The best gas mileage I can do is just under 18 MPG on the highway without the boat. I'm not interested in drag racing the truck, but I would like a little better mileage. Does anyone have a receipe for tweaking gas mileage? Do any of the cat back, cold air, 160 degree thermo mods do anything to improve mileage on these puppies?

chuck

 

That sounds like good gas mileage to me but if you want to bump it up to between 18 and 19 try a UPD intake with K&N filter and a pair of electric cooling fans. Not sure about what kind of exhaust will help since some make less bottom end torque than others and you tow. Later dude.

 

I picked up a solid 2 mpg gain on the last 3 tanks of fuel I measured, IF you keep your foot out of it, if you play around any it seems to suck more gas then stock. All I have is a real catback exhaust, air intake, 160 stat and a HPP3. I would guess that the colder stat and Hpp3 may hurt mileage though.

For sure exhaust will help.

 

If your primarily after milage I'd leave the thermostat alone. All the other basic mods like a cold air intake & filter, catback exhaust,and hypertech programming help the mileage as well as provide a big torque improvment for towing. If your doing more highway driving consider a bed cover too.

 

If you want exhaust for towing and good gas mileage, consider a single 3 inch cat back with a good straight thru muffer like Magnaflow.

 

Well there let me tell you what not to do.

do not add a supercharger. Though a sc can actually increase your mileage the thrill leeds to other performance accesories and a lead foot which = no gas mileage.

Just kidding you could get some lighter aftermarket wheels, lower the truck an inch or two, remove the spare, electric fans, better exhaust/headers, intake. maybe this would help but just out of curiosity why buy the fullsize for gas mileage?

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Seagull:
<strong>I have a new Silverado extended cab Z71 with a 5.3L and 3.73 gears that will be used for boat towing and part time communting. The best gas mileage I can do is just under 18 MPG on the highway without the boat. I'm not interested in drag racing the truck, but I would like a little better mileage. Does anyone have a receipe for tweaking gas mileage? Do any of the cat back, cold air, 160 degree thermo mods do anything to improve mileage on these puppies?

chuck</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">It wouldn't hurt, but try driving around with the tailgate down and compare your mileage then. I bet you will see a difference. Then if you are impressed, you can go get a bedcover and also do the intake and cat-back mods. The mods would be like icing on the cake.

I know for a fact that the wind resistance that is created by the bed of the truck, does not help gas mileage at all.

Carlos

 

if you do a lot of highway driving and don't pull anything that is just way too heavy then you could try (just a suggestion) 3.42 gears...those 3.73 gears are great for towing but suck when it comes to everyday driving and gas mileage. Of course you would have to change front and rear and for the price you might as well try the exhaust upgrades first then a MSD igniton. THe MSD ignition helped my 1988 TA's gas and my 1993 S-10 w/ 4.3V6 gas mileage.

 

If you are getting 18 with a 5.3/3:73/Z71, you are getting great milage. Driving with the tailgate down won't have a measurable effect. A bed cover will offset the down tailgate by the added weight. The best suggestions have been made to you. An intake and exhaust should get you 1 to 2 miles better. I peaked my mpg at 19.8 hwy miles. That was with a 4.8/3:73/intake/exhaust and an HPPIII. After I put the pulley and 160*thermo in it started going back down. Now with all the mods I have, I run about 18 on the hwy, but that is also at 5000lbs with me in it. I have some heavy accesories. You can see my mods in my sig link.

 

IT'S A TRUCK. GOOD GAS MILEAGE. <img border="0" alt="[jester]" title="" src="graemlins/gr_jest.gif" /> . you want good gas mileage get a geo metro or one of those electric cars. lol.