Is there ANY way you can make a 90' Suburban V1500 4x4 700r4 350 Tbi V8 gas Fuel Efficiant some?

[blackandgold51]

is there any way you can make a 350 tbi gas engine fuel efficient?

I have a 90 suburban v1500 700r4 transmission with a 350 TBI gas v8. I want to sell it to get a diesel suburban for fuel economy(6.2 Diesel same year or 89 to 91). However some people say" stick with gas because it's cheaper "and Diesel engines are not east to work on and expensive "and such.

I was wondering if diesel engines are not easy then why not I find a way to make a 350 engine fuel efficient almost?

By the way I use premium gas mostly . gas here in new orleans for premium is around 2.30 to 2.60 a gallon. Same goes for diesel .

I even read and/or heard that 6.2 engines are not good.

 

[diesel4me]

I own two 6.2's--they are OK as long as your not going to tow a lot of weight..low HP,but pretty high torque..they do have their problems,like the cranks sometimes breaking without warning,and the usual glow plug and fuel system woes usually caused by neglect...
I personally dont think they are an "easy" engine to work on compared to a small block,but many here disagree with me..
I'd rather do a water pump on an old 350 than a 6.2 any day!..

I only get around 17-22 mpg,mostly 17 and less more often than more--I have had small blocks from 283's to 400's that came close to 17 often if driven properly...I really dont think a 6.2 is that much more economical than gas--diesel still costs 40 cents more than gas here (2.39 vs 1.99 a gallon yesterday),so its almost a break even deal as far as mileage..

Oil changes cost more,you need almost 2 gallons and 15W-40 diesel oil ,and that can add up..

It is when the diesel needs something like an injector pump or glow plugs it'll bite ya--whatever you saved on spark plugs,wires,cap & rotor and carb rebuilds will vanish..many mechanics here shy away from diesels if they aren't used to working on one too..

The diesels do have some advantages though too--they are usually more durable and last longer if maintained,and poor weather doesn't affect them much--you'll appreciate having no distributor or wires to get wet and stall it out,and no carb flooding or choke troubles ,it'll go uphills off road that would stall a carbed engine,and it runs good from a dead cold start...

About all you can do to peak the mpg of your 350 is to tune it up good,drive it like grandpa,and take your time going places--I got almost 5 mpg more at 50 mph on back roads vs driving on highways where everyone was going 70+..these old trucks are not very areodynamic and it only takes a few more miles per hour to cause a drastic drop in fuel economy..low gearing will reduce mileage especially at higher speeds..

I know a few guys with 90's GM trucks with 350's ,efi,and an overdrive automatic,that consistently get 18+ mpg commuting in them,so it can be done..

 

[blackandgold51]

I own two 6.2's--they are OK as long as your not going to tow a lot of weight..low HP,but pretty high torque..they do have their problems,like the cranks sometimes breaking without warning,and the usual glow plug and fuel system woes usually caused by neglect...
I personally dont think they are an "easy" engine to work on compared to a small block,but many here disagree with me..
I'd rather do a water pump on an old 350 than a 6.2 any day!..

I only get around 17-22 mpg,mostly 17 and less more often than more--I have had small blocks from 283's to 400's that came close to 17 often if driven properly...I really dont think a 6.2 is that much more economical than gas--diesel still costs 40 cents more than gas here (2.39 vs 1.99 a gallon yesterday),so its almost a break even deal as far as mileage..

Oil changes cost more,you need almost 2 gallons and 15W-40 diesel oil ,and that can add up..

It is when the diesel needs something like an injector pump or glow plugs it'll bite ya--whatever you saved on spark plugs,wires,cap & rotor and carb rebuilds will vanish..many mechanics here shy away from diesels if they aren't used to working on one too..

The diesels do have some advantages though too--they are usually more durable and last longer if maintained,and poor weather doesn't affect them much--you'll appreciate having no distributor or wires to get wet and stall it out,and no carb flooding or choke troubles ,it'll go uphills off road that would stall a carbed engine,and it runs good from a dead cold start...

About all you can do to peak the mpg of your 350 is to tune it up good,drive it like grandpa,and take your time going places--I got almost 5 mpg more at 50 mph on back roads vs driving on highways where everyone was going 70+..these old trucks are not very areodynamic and it only takes a few more miles per hour to cause a drastic drop in fuel economy..low gearing will reduce mileage especially at higher speeds..

I know a few guys with 90's GM trucks with 350's ,efi,and an overdrive automatic,that consistently get 18+ mpg commuting in them,so it can be done..

What if I get a double are(or cold air) intake that has two air hoses go to the front on each sides of the radiator, along with a set of longtime headers, double exhaust with straight pipes, 4 barrel fuel injection, MSD coil with MSD wires, take off the 02 sensor, put in a K&N air filter(which I already have) and maybe a supercharger? Also my gear ratio is like before the transmission shifts to 2 gear the engine rpm goes up high or higher before the red line before it shifts gears quick

 

[blackandgold51]

I own two 6.2's--they are OK as long as your not going to tow a lot of weight..low HP,but pretty high torque..they do have their problems,like the cranks sometimes breaking without warning,and the usual glow plug and fuel system woes usually caused by neglect...
I personally dont think they are an "easy" engine to work on compared to a small block,but many here disagree with me..
I'd rather do a water pump on an old 350 than a 6.2 any day!..

I only get around 17-22 mpg,mostly 17 and less more often than more--I have had small blocks from 283's to 400's that came close to 17 often if driven properly...I really dont think a 6.2 is that much more economical than gas--diesel still costs 40 cents more than gas here (2.39 vs 1.99 a gallon yesterday),so its almost a break even deal as far as mileage..

Oil changes cost more,you need almost 2 gallons and 15W-40 diesel oil ,and that can add up..

It is when the diesel needs something like an injector pump or glow plugs it'll bite ya--whatever you saved on spark plugs,wires,cap & rotor and carb rebuilds will vanish..many mechanics here shy away from diesels if they aren't used to working on one too..

The diesels do have some advantages though too--they are usually more durable and last longer if maintained,and poor weather doesn't affect them much--you'll appreciate having no distributor or wires to get wet and stall it out,and no carb flooding or choke troubles ,it'll go uphills off road that would stall a carbed engine,and it runs good from a dead cold start...

About all you can do to peak the mpg of your 350 is to tune it up good,drive it like grandpa,and take your time going places--I got almost 5 mpg more at 50 mph on back roads vs driving on highways where everyone was going 70+..these old trucks are not very areodynamic and it only takes a few more miles per hour to cause a drastic drop in fuel economy..low gearing will reduce mileage especially at higher speeds..

I know a few guys with 90's GM trucks with 350's ,efi,and an overdrive automatic,that consistently get 18+ mpg commuting in them,so it can be done..

And as for the diesel, it's best to stick with gas since I don't have to worry about caring for it too much(although I do take care of my cars such as changing the oil every 3000 miles with either 10w40 winter or 20w50 hot summer)

 

[diesel4me]

Best thing to do is leave it bone stock--any mods like dual exhaust,larger EFI throttle bodies.and "deleting" any emission items like the O2 sensor will only cause mileage to drop more--it may perform better,but those mods wont help mileage any--the supercharger will lower mileage too...it takes HP to run it and its main purpose is to stuff more fuel and air into the engine,which will use up the fuel faster..plus you'll be tempted to boot it more often,instead of driving it gently,which gives the best MPG..

 

[blackandgold51]

Best thing to do is leave it bone stock--any mods like dual exhaust,larger EFI throttle bodies.and "deleting" any emission items like the O2 sensor will only cause mileage to drop more--it may perform better,but those mods wont help mileage any--the supercharger will lower mileage too...it takes HP to run it and its main purpose is to stuff more fuel and air into the engine,which will use up the fuel faster..plus you'll be tempted to boot it more often,instead of driving it gently,which gives the best MPG..

So it's best to keep what I have.

Although I have been thinking about converting it to a diesel like a 6.2 or Cummins but that is expensive however

 

[Big Ray]

So it's best to keep what I have.

Although I have been thinking about converting it to a diesel like a 6.2 or Cummins but that is expensive however

I'd do an LS swap if anything. I have a 90 burb 3/4 ton with the 6.2. I like it well enough. It has 285k on the clock, and I recently bought an I.P. and injectors for around $550 or so.

Keep oil in it, it's damn near bulletproof. As far as the cranks snapping, that's an issue with the harmonic balancer. The stocker has rubber that deteriorates over time, causing it to be out of sync with the power impulses.

As far as mileage, it gets 14 or 15 mpg. That's with the TH400 tranny. An overdrive tranny would help pickup a few more mpg. As well as a turbo.

Just keep in mind the GM 6.2l was designed for mileage, not power.

If you decide to go with diesel, buy a diesel truck. It's just not worth the $$ to swap a 6.2l in your rig. IMO...

 

[blackandgold51]

IsE="Big Ray, post: 3578172, member: 53280"]I'd do an LS swap if anything. I have a 90 burb 3/4 ton with the 6.2. I like it well enough. It has 285k on the clock, and I recently bought an I.P. and injectors for around $550 or so.

Keep oil in it, it's damn near bulletproof. As far as the cranks snapping, that's an issue with the harmonic balancer. The stocker has rubber that deteriorates over time, causing it to be out of sync with the power impulses.

As far as mileage, it gets 14 or 15 mpg. That's with the TH400 tranny. An overdrive tranny would help pickup a few more mpg. As well as a turbo.

Just keep in mind the GM 6.2l was designed for mileage, not power.

If you decide to go with diesel, buy a diesel truck. It's just not worth the $$ to swap a 6.2l in your rig. IMO...[/QUOTE]
Which year is the best LS engine? Also is it cast iron block? Because I don't like aluminum because cast iron last long

 

[blackandgold51]

Hmmm. ...... I was wondering of just getting me a second hand vehicle like an accord and keeping it on standby just in case fuel prices go up and keeping my gas suburban

 

[Stomis]

This is the age old debate. You're willing to spend thousands of dollars on mods, or a second car + insurance costs. All that money could just go towards fuel and you'll be in the same place driving the truck you like. Dont get me wrong, having a second set of wheels can be very beneficial in other ways also, and obviously we all love to mod stuff but lets be honest here; people really harp too much on the mileage they're getting. The quantity of money you are willingly and enjoyingly dumping into a 30 year old truck just goes to show that return value isnt that important to people like us.

Drive the wheels off you're shit and stop cringing at gas costs. The only way to really come out ahead is to ditch the truck and trade it in for something fuel efficient. Only then will you really be saving anything. It takes years to catch up getting 10 more mpg via a $5000 investment.

 

[campfire]

This is the age old debate. You're willing to spend thousands of dollars on mods, or a second car + insurance costs. All that money could just go towards fuel and you'll be in the same place driving the truck you like. Dont get me wrong, having a second set of wheels can be very beneficial in other ways also, and obviously we all love to mod stuff but lets be honest here; people really harp too much on the mileage they're getting. The quantity of money you are willingly and enjoyingly dumping into a 30 year old truck just goes to show that return value isnt that important to people like us.

Drive the wheels off you're shit and stop cringing at gas costs. The only way to really come out ahead is to ditch the truck and trade it in for something fuel efficient. Only then will you really be saving anything. It takes years to catch up getting 10 more mpg via a $5000 investment.

The value of fuel mileage will depend on how much driving you do. When I look at the mileage that I've put on my 40MPG Saturn during the last 10 months, and consider what it would have cost to drive a typical gasoline-powered Suburban each day, the cost savings has been enough to pay for the car and put a new roof & siding on my house. And then some. So it doesn't have to be overly expensive having a second car, and Suburbans are serious overkill for just driving one person to work. But if you drive 2 miles each day to work, the fuel cost is probably going to be significantly cheaper than buying another car. So the pendulum can swing either way, depending on your particular needs and driving habits. My answer does not necessarily fit your lifestyle.

 

[black dawg]

What kind of mpg does the suburban get now? Does it need premium fuel?

Should be about 11-12 city 14-16 highway.
One 6.2 burb I had averaged 20, the other only about 17, both same drivetrain.

 

[campfire]

I have a 90 suburban v1500 700r4 transmission with a 350 TBI gas v8. I want to sell it to get a diesel suburban for fuel economy(6.2 Diesel same year or 89 to 91). However some people say" stick with gas because it's cheaper "and Diesel engines are not east to work on and expensive "and such.

I was wondering if diesel engines are not easy then why not I find a way to make a 350 engine fuel efficient almost?

By the way I use premium gas mostly . gas here in new orleans for premium is around 2.30 to 2.60 a gallon. Same goes for diesel .

I even read and/or heard that 6.2 engines are not good.

6.2 engines are good. Compared to an sbc, they require slightly different (not particularly worse) maintenance, and they aren't drag racing engines. They are designed for mileage and 1980s-era towing. They are very simple and dependable. It has the simplicity of a 1-wire engine with the dependability of fuel injection. No sensors, no tuning, just put 12V on the fuel solenoid and it runs. As a rough comparison, there are about a 1/2-dozen specific issues that can arise with a 6.2 engine. If you look at your current TBI engine, and start counting sensors, you'll find that it has a couple dozen potential failure points. In neither case do you expect all of them to fail, but you know that some of them will eventually.

I don't think you'll be any less happy with a 6.2 than you are with your current engine. You should expect to change a set of glow plugs (like spark plugs, but less often). If you buy an older one (pre-1988) you may have to learn how to mechanically prime the fuel system at some point. Harmonic balancer should be replaced if it's loose or knocking. But that's true for any engine.

You may or may not find the 6.2 a good fit for your purposes. But don't go around thinking it's hard to work on, or that it's a bad commuter engine just because it won't beat a 454 in a quarter mile. And definitely don't go around thinking it's an overbored 350 block that likes to blow up. Not sure how that rumor got started.

 

[campfire]

If you're thinking you wanna DD a Suburban, and you want better mileage, and you're willing to go play with exotic mods such as turbine setups in that pursuit, switching to a 6.2 engine (stock) will probably beat any mods you'll put on a TBI 350. You may get close, but I have yet to hear of someone who did pull 25-27MPG out of a TBI 350, and I have seen several 6.2 trucks pull that range (including one of mine).

Swapping a 6.2 into a TBI truck should not be terribly difficult, but it would be a whole lot easier to simply buy a truck that already has a 6.2 engine. Instant mileage boost. And if you want more, there are some small mods that can be done to 6.2 engines to squeeze more out of them. Adding a turbine setup is pretty common.

Keep in mind that a lot of non-engine factors affect mileage. Don't expect 20MPG out of a Suburban equipped with a TH400 and 4.56 gears.

 

[Blue85]

The biggest MPG gain could be from a gear swap. You could do better with a fancy MPFI setup, but some of those cost as much as a used LS engine (which would get better mileage). So if you're thinking engine swap, look at a 4.8 or 5.3 and not just the 6.2. Removing the O2 sensor would be a step in the wrong direction.

I know a 5.3 can get 20MPG in certain GMT800 setups, but they are more aerodynamic than our square noses. You might query some of the LS-swappers here and see if anybody has some confirmed DD MPG numbers for reference. May be hard to find, since many of these swaps are performance oriented and may also be more trail-oriented.

 

[black dawg]

The other day I had a 90 v1500 burb on the lift, and right after it I had an 05 1500 4x burb on the lift. There was a noticeable substantial weight difference between the two. Wonder what a 6.2 would do for mpg in one of them?

 

[campfire]

The new ones are noticeably lighter?

 

[black dawg]

yes, and it seemed like a bunch.

 

[tRustyK5]

Curb weight on a 90 burb and a 2005 burb is roughly the same. Both between 5200 and 5500 lbs. Apples to apples, 1500 4WD burbs. For every place they saved wegith as they get newer GM added some other heavy crap...

 

[blackandgold51]

Thanks to all the answers. And sorry that I ask a lot of questions and if I am bothering you. I think it is good to get all the information I can along with the history of this particular engine(6.2 diesel).