chevy mechanics Silverado question (spark plug, fuel, tires, MPG)

[Rtom45]

I have a 2005 Silverado 4WD with the 5.3 liter hi output Vortec engine. Engine puts out 310 hp and gets 17 miles city, 20 miles highway, I drive conservatively. My question is: Can I improve my gas mileage by having dual exhaust installed? Are there other fuel saving improvements I can make? Before anyone suggests a smaller truck, I live in Erie and I'm in charge of snow removal at a local institution. I'm out before the plows and have to drive in some really bad weather, I need the full size truck.

[Bummer]

Not a Chevy Mechanic here, Rtom45 . . .

However, I realized a significant improvement in both PERFORMANCE and GAS MILEAGE after having a full dual exhaust system with "performance" mufflers installed in my 4X4 Silverado with a 350 V8.

Good Luck

[studedude]

Headers would also help the engine breath better. There are also a variety of air filters, intake & injector improvements. Contact one of the large mail order performance parts houses. They can be very helpful.

[Roaddog]

Originally Posted by Rtom45

I have a 2005 Silverado 4WD with the 5.3 liter hi output Vortec engine. Engine puts out 310 hp and gets 17 miles city, 20 miles highway, I drive conservatively. My question is: Can I improve my gas mileage by having dual exhaust installed? Are there other fuel saving improvements I can make? Before anyone suggests a smaller truck, I live in Erie and I'm in charge of snow removal at a local institution. I'm out before the plows and have to drive in some really bad weather, I need the full size truck.

If your getting 17 and 20 I wouldn't touch it, your not going to do much better than that, in fact you can hurt the milage by messing with it. I added a 3 inch exhaust and cold intake system to a pickup and I lost a bunch of low end power, I gained in mid range but it didn't change the gas milage at all.

[M3 Mitch]

I'd try the following:

1 set of NGK sparkplugs in the correct heat range. You could consider opening the spark plug gap a little more than factory spec, but don't get carried away. It may or may not be possible/practical to "index" your sparkplugs, so that the ground electrode "points" towards the intake valve. This does help with the old cast-iron SB Chevy V-8. What's important is that the ground electrode not point *straight* at the exhaust valve, so that it interferes with fresh mixture getting into the spark gap itself.

2 use the thinnest grade of synthetic oils compatible with your owner's manual recommendations in engine, tranny, and rear end. I particularly like Red Line Oil, it's expensive but damn it's good.

3 If your fuel filter is due for a change, change it, I have seen many modern cars that were running "fine" pick up a little MPG with a fuel filter - but these cars were overdue. In fact any deferred maintenance should give some improvement if you do it. How old is your oxygen sensor?

4 consider adding maybe 2-3 more PSI in your tires than the factory recommendation.

5 Techron or similar injector cleaner may help a little if they are dirty

6 a flush-fitting cap on your open bed may help a little, particularly at highway speed.

7 This being a Chevy it's almost certainly an automatic. But if not, try opening the throttle *a little* more and shifting up *a little* sooner as you accelerate from a stop. BMW did some research in the '80's that showed this can improve economy at the same level of performance. Don't get carried away and lug the engine.

As said, 17-20 is pretty good for this kind of rig so you won't do much better. All of the above will help a little, but if you did all of it and got 2 more MPG I'd be surprised.

[Rtom45]

Is there any fuel savings gained by putting taller tires on the truck?

[M3 Mitch]

If you don't usually carry a load, probably. Particularly if you drive on the highway a lot.

I think this truck can be "programmed" with tire rolling diameter so your speedo/odometer stay accurate.

If not, realize your mileage per the odometer may get worse, since the truck will travel further than the odometer indicates, yet your fuel burned measurement will remain accurate.

I think the stuff I posted before will be more cost-effective for you than the tires, particularly the fuel filter if it needs changing. If it's more than say 30K miles old I would start there.