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i need more mileage, its the only thing thatll save my sub from being sold!

muddysub

muddysub

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ok as some of u know im thinking about selling my suburban... primarily because itll cost me so much in gas to drive the damn thing!
http://coloradok5.com/forums/showthread.php?t=132444
i seriously need to get more mileage out of this pig if i wanna keep it... it gets about 8 mpg right now... please tell me if i ditch the old (160,000mi) engine for a new one itll get like 10-12 mpg in town... ive got another tbi 350 here in my yard i thought about swapping the whole thing but i dont know how well it runs... i also thought about just taking the heads off that other 350 and having them all done up ( valves, springs, guides, seats etc...) and putting them on my engine... HELP ME SOMEONE!!! i dont wanna sell my suburban but if i cant get a lil more mileage out of her im gonna have to... i know the TSLs dont help that but as soon as they wear down some more im puttin MTRs or PJs on it...
 
SUCK IT UP....For the payments, inflated insurance rates and all the 'extra' driving you will do with an econe car, you could buy a lot of gas....


Heck get a second job, leave the women alone, eat Ramen noodles....Guarnteed you will spend more on the girlfriend than you ever will on a vehicle....:grin:
 
Even if you could gain 3 mpg it would take a year or 15,000 miles of driving to save you $1000 in fuel.

You'd be better off spending the 'motor' money on a Honda or similar older import. With 15,000 miles you'd save $2700...

Rene
 
The only thing I can think of is to get some kind of overdrive setup of some sort (aftermarket [i.e. Turbo 400 retro fit] or factory [i.e. 4L80E]). I have read the specs on your burbon, and they are similar to my Crew Cab. My truck gets 13 - 14 MPG (around town), and the only difference is I have a 4L80E over drive transmission.
 
Gas mileage is the price we all pay fro the rigs we drive. I knew the pric eof fuel wouldnt be cheap and I knew when I got my truck I'd be fillin up twice a week. But its a trade off. I dont own anyone for my truck, insurance is cheap, shes damn reliable and I take it anywhere.

I'd consider a new motor. Im inthe kind of the same boat. Until I rebuilt my carb I was gettin crappy mileage but at 130k it is expected.
 
The harsh reality of the laws of physics....

You wont EVER get more than 12-15 mpg out of any GM fullsize truck,especially a 4x4 or a suburban!--unless its diesel,then you might get as much as 18 to 20 or so..they weigh at least 5500 lbs empty,and a small block has to grunt all the time to pull that much tonnage around!--and big blocks arent any less thirsty either..

I am considering selling one of my trucks due to no job,and gas mileage is a real factor too--at 2+ bucks a gallon,I dont have enough cash to get very far in any of my trucks,the diesel included,since diesel is even more than gas per gallon..and even if I get back to work,I cant see paying for plates and insurance on 3 vehicles that I cant drive 8 hours of the day anymore--thats a lot to pay just to let them sit...its time to trim the "fleet" down some...

But I look at it from another point of veiw--I am less likely to get killed in my trucks than a go-cart sized econobox like the VW Jetta I had a few years ago--43MPG was nice,but getting run over by an 18 wheeler isnt!--the big rigs and jerks in hummers and suv's that dont pay attention and talk on the cell phones while driving convinced me the money I saved on fuel isnt worth dying for-so I sold it.....:frown1:

-I consider a full size rig life insurance!!--one guy I know will only drive a caddy coupe deville's from the 70's,he has 3 of them too!--and he hasn't much money either,and he's always said the cost of gas isnt the biggest expense--often insurance for small sporty cars is much more than it is for a land yacht--and buying a car that gets good gas mileage isnt going to be cheap anymore--already rotted honda's and toyota's selling prices have jumped a lot here recently--you cant get one for less than a thousand bucks now,500 was the going rate a few months ago...its not going to be cheap to drive ANYTHING any more I'm afraid...:crazy:
 
That's not true... my mechanic has a full size blazer that gets about 25mpg on the highway... it's a 350 with a auto trans, but he does have overdrive.

What RPMs are you running at at about 65mph and 30mph?? To get the best mileage, get as close to idle as possible in whatever gear you run in, without bogging the truck down... if you have a stick, 2200rpm at 65 in 3rd gear or 1700rpm in 4th gear should get you the best mileage for your vehicle. If you have an auto, which is more likely in a burban, spend the money on an overdrive tranny with a nice 4th (or 5th) gear that will allow you to run at near idle for highway cruising.
 
well swapping my th400 for a 700r4 is OUT OF THE QUESTION! i know a new motor will help, and getting different tires will help... ive got 36" swamper TLSs right now and i wanna get a set of MTRs or radial PJs or IROKS...

i dunno ive gotta make some decisions...
 
There is no way a 350 powered K5 of any vintage or description is getting 25 mpg or anything close to it. Even the 6.2 powered K5's with stock tires and overdrive and tall gearing are barely able to get mid 20's...and the 350 just cannot match the 6.2 for fuel efficiency.

Just getting the rpm's down is not enough to get good mileage. You'd be lugging/bogging the engine...it needs to be running at it's most efficient rpm at freeway speed. Much below 1900 rpm and a small block pretty much just falls on it's face and starts hunting for another gear.

Rene
 
diesel4me said:
You wont EVER get more than 12-15 mpg out of any GM fullsize truck,especially a 4x4 or a suburban!--
Click to expand...

my 77 K20 knocks down 12 with a 350/350/203 4.10 gears, and 30" tires. oh yeah, beating the hell out of it with a 7.5' Western blade on the front too. i bet i could get 15 with it easy without the blade.
 
tRustyK5 said:
snippage

Just getting the rpm's down is not enough to get good mileage. You'd be lugging/bogging the engine...it needs to be running at it's most efficient rpm at freeway speed. Much below 1900 rpm and a small block pretty much just falls on it's face and starts hunting for another gear.

Rene
Click to expand...

Agree. Best engine efficiency is at peak Torque. If you know at what RPM that is, gear the truck to run at that RPM or just a little under it at the speed you normally drive for best mileage.
 
Buy a beater

Instead of spending that next $800 bucks on a new lift or set of tires, buy a 1988 Honda Accord. I see old imports around here all of the time for next to nothing that get 25 + mpg. That way you can drive your burb on the weekends and let your import get you to work... I hate small cars but if I lived off base I would definitly get an old piece of ****, import car so I could let my domestic piece of **** (and wallet) rest for the week... As it is, my 8 mpg 77 Blazer makes my 2 mile trip to work everyday just fine...
 
ntsqd said:
Agree. Best engine efficiency is at peak Torque. If you know at what RPM that is, gear the truck to run at that RPM or just a little under it at the speed you normally drive for best mileage.
Click to expand...

i wonder what mpg a 454 tbi can reach ..because all the torque is avabl at just 1650 rpm or somehting..no need to rev it

does anyone know if a TBI engine shuts of the injectors when just coasting down a hill? cuz i know most modern carengines do if the rpm is above 1400 or so..

my mpg sucks : 8 in town about 14 on highway...the poor 350 have no power where the 2:73 gears forces it to work..before the axleswap im gonna try drive it in second gear!! i don't go that fast anyway , traffic is slow here 45-50 mph

i have read somewhere that a 305/350 TBI are good for 17-18 mpg..what is the gm ratings?
 
i have read somewhere that a 305/350 TBI are good for 17-18 mpg..what is the gm ratings?
Click to expand...

I have seen two or three local guys with 88-91 model trucks with the 305's that make near 20mpg whether standard or autos....they did something right in those years
 
I used to have a 90 Z71 reg.cab step side 305 w/5speed and 35" MTR that would get 17-18 mpg w/4.10 gears and corrected speedometer.

Currently have a 99 Sub 2500 w/454 tbi 4L80E that gets avg. 10-12mpg can get 15 on long trips.
 
My '90 Burb with a 350/700r4/241/3:73 got 9mpg on 31's, so I did a complete tune up with fuel and air filters, now I get 9mpg. Haven't checked it since I went to 33's.
 
My 91 Burb gets 14 on the highway. 350 TBI, but it has the 4L80E trans. 4.10 gears and 33.1" tall tires. It's a slug with the 33s when in overdrive ... but I spend less time at the gas stations.

I think other posts have mentioned for what you'd spend upgrading the trans (or other parts), you could buy a little econo box.

But I guess you gotta work in the cost of registration, insurance and the repairs you know a cheap, used car will need, then, figure out what you wanna do.

Eric M.
 
Zeitler said:
i wonder what mpg a 454 tbi can reach ..because all the torque is avabl at just 1650 rpm or somehting..no need to rev it

does anyone know if a TBI engine shuts of the injectors when just coasting down a hill? cuz i know most modern carengines do if the rpm is above 1400 or so..
Click to expand...
My '95 C3500 Dually TBI 454, 4L80EHD, 14BFF 3.73, and 215/85Rx16 tires is stock. I get 8-9 mpg in town. 11- 12 mpg on freeway trips running 70- 80 mph. The best mileage I've seen was returning to San Jose form Reno running 55 and driving for economy, I got 14 mpg. The truck weighs 6700 lbs empty with me in it. The truck has been well cared for and has only 66k miles on it. This truck was the last model year to have the TBI motor. The next year they came out with the 7.4L vortec engine.
 
These rigs are life insuranse! Gas is expensive but not as much as a car payment or the price of my life. Why are you talking about a new motor but a OD trans is out of the question?
When trying to get an accurate mpg rating you need to use gps. Our spedos are just not accurate enough espically if you have changed tire size. You need the most accurate distance you have traveled you can get and this can only be done using gps.
I have 37" mtrs and got the spedo adjust gear it is close but using it to do my mpg it was still off. My spedo said I was getting 11.2mpg when I really was getting 12.8mpg. 350 crate/700r4/208
My rig weighs 4300 pounds in winter with top doors and tailgate, in summer 4000 with tools spares hi lift and no top doors or tailgate. I have ripped out the ac, dash, interior, back seat, and a lot of body so the weight loss helps the mpg a lot.
 
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