Another Suburban Question

[RxCowboy]

I see alot of you posters know much more about vehicles than I do so here is my question. I have a 1995 Suburban 1500 with a 350 V-8. I can only get about 11-12 mpg whether I am pulling my 18 foot Smokercraft Ultima or just highway driving. I have had it tuned up and keep it up well.
I bought it used in 1996 and the guy I bought it from put one of those powerchips in the computer system. Would this bring the milage down? People I know get around 15-17 mpg with the same year Suburban. What kind of milage are you guys getting??
Thanks for the comments.

[Husky]

Did the person you bought it from give you the old chip? If so, you might try replacing it and see what kind of mileage you get. Had a '92 Yukon with a 350 and was geting about 15-17 , if that helps. Some reports I read on the aftermarket chips do indicate both losses and increases in general mileage, as well as overall performance. Hope that helps.

[Dave in Mpls]

I'm getting 13-14 in my '94 whether I'm towing or empty, but thats comparing apples and oranges. My 350 utilizes a TBI (throttle body injection) system which uses two fuel injectors. Your '95 is (I believe) the first year GM ran the VorTecs in the 1500 series. The VorTec uses eight fuel injectors, one for each cylinder.

In regard to the chip, everything I've read (adds composed by the manufacturers) suggests that gas mileage should increase with the use of the chips. Of course, I've bought into advertising claims before!! Anybody need any Marvel Mystery Oil or J.C. Whitney engine rebuilding pellets!!

Regards

[shotgunbilly]

It could all depend on how the rear end was geared for also, highway driving or geared different for pulling. such as pulling boats and trailers,( trailering package ). believe it or not some people have subs and don't pull anything. When bought new there are about 4 or 5 different gear ratios that can be pick at
the time of purchase. hope it gives you something to think about. P.S. I own a 90 sub and get about 13 miles to the gallon, but when pulling a 22' travel trailer it drops considerably. about 8 ouch....

[Phil T.]

Stop by a dealership and have them determine the axle ratio. There used to be a tag on the differential housing that had the code for the gear ratio, but I'm referring to GM trucks older than yours.
When you know that, adjust your non-towing speed accordingly. Keep the engine rpms around peak torque, and your mileage should improve.
An extreme example is my late father's last pickup. It has a 454 under the hood, a Turbo 400 auto transmission, and 4:10 gears. He used it to haul a 27' fifth wheel trailer around the continent in his retirement. When he drove it empty, the old leadfoot insisted on driving over 70mph (he never got caught speeding in his life). The mileage was a dismal 6mpg.
At his death, I took the truck and had it reconditioned. One of the things I added was an aftermarket tachometer. Oops, peak horsepower (2400rpm) is at only 50mph! Drive it below peak hp, and the empty mileage is at 15mpg. When carrying 3000lbs of slide-in camper, groceries, bedding, and clothing at reasonable speed, the mileage drops to 12mpg. Add 2500lbs of boat, motor, and trailer, and the mileage is around 8 or 9mpg. Still better than speeding empty.

[cmb]

no experience with GM products, but you may (should) be able to determine the rear end ratio by looking at the build tag inside the door jamb on the drivers door. It should be listed as a code that you can look up in your owners manual.

[Eyez]

95 should be a TBI also.(at least it is in the pickups). My local chevy dealer explained to me that the vortech 350 wasn't EPA approved soon enough to get it into the 95's. My father has a 95 and he gets about 12 mph towing the boat, and about 14-16 the rest of the time.


Eyez

[AquaMan]

I think that your gas mileage is in par with the rest of us. I have never gone better then 14, but never worse then 11 either. Most rigs that are set up for towing with the correct tranny and rear diff ratio will/should get the same mileage towing or empty.

Adding chips, etc are really for improving empty weight performance at the sacrifice of your towing mileage. Your are altering your power band.

The only real improvement is aspiration (Intake and exhaust). Better filters and pipes can improve that but at a high cost to out put ratio.

Change your engine, tranny and rear diff oils at their scheduled times, keep tires properly inflated and keep up with the repairs/tune ups...that will do more to maintain good performance then anything else.

AquaMan~~~~~~~~~~~~~

.·´¯° --- "It all begins and ends at the water's edge"

Eric@crowncomputerinc.com

[RxCowboy]

Thanks for all the responses. I am learning alot. The gentleman I bought the Burb from was pulling a 22 ft travel trailer and thats why he put the chip in.
I live in Northen Montana and have a short boating season. Should I get an original issue chip and put it in to help with milage the for the nine months of the year I drive it to work?

Thanks again for the responses.

Scott

[Chevy4sur]

Does the Vortec 350 consistently get better gas mileage than the pre-95 TBI?