I just bought the ultimate man vehicle: 1989 3/4 ton Suburban.  Now I can't afford to drive it.  I'm looking for ways to improve mileage- best is about 13.5 mpg so far.  I added a K and N filter already.  I have been looking at the MSD ignition controller, and the Flowmaster exhaust.  I just want the most bang for the buck with gas mileage- anyone have any experience with either of these products?  Any other suggestions?

Synthetics, like Amsoil, in engine, tranny, and differential.

Do what Tate says. Synthetic oil increased my fuel economy by about 15-20%.

89 was the newere body style correct? well you should be able ot take the restricter baffel from the air intake under the hood. Will increase air flow and power. Always go for exhaust/ Flowmaster if you like noise. Ive got a dynomax on my 92 'burb. little less sound but still a good tone. also try and hypertech chip. the combination of the chip and intake and exhaust will make a difference. as far as ignition, i would replace all the basics first. ignition wont make a big difference till other things are done anyways.

350 or 454?

There is a great exhaust kit for motorhomes which would be perfect for your application - I think it was by Gale Banks, but I don't recall. A friend put it in his BAGO and got 2 mpg improvement as well as dramatic improvement on hills. - It cost, but he claimed it was well worth it.

'89 was two body styles back, '92 was the change.  3/4 ton has a lower rear axle ratio (3.73 or 4.11).  If you want mileage at the expense of towing capacity get a 3.42 or a 3.23 rear end at a junk yard.  If you have a 454 you're f*cked.  Those things need their own pipeline.  But they will pull stumps.  Basically you've got a barn door driving down the road.  Keeping the speed down will help.  I run K&N, Mobil-1 and a chip but all that stuff is chump change when the vehicle weighs 6000 pounds and has the aerodynamics of plywood.

Now see, if you opted for the diesel engine...  [;)]

the_reject

what about that Tornado thing advertised on TV??
supposedly makes air flow better, thus making it more fuel efficient. i was almost tempted to buy one, but everywhere i go, luckily enough, is downhill, so i didnt need it. come to think of it, i dont think i need a car!

...you'd be walking on the side of the road.

[;)]

Hey!  I can get in on this conversation, I have a 1987 Suburban (gas, 8 cylinder Model:RCH), we use it just for plowing the driveways, I pulled it out of storage to get ready for winter and it doesn't turn over, I charged the battery, but all I get is a clicking sound.  Lights work, horn is good, but nada on turning over.  Ran fine when last used.

Any ideas?

Justlearnin

Sad thing.  You're learning the hard way.  With all the things people have suggested, you're still not likely to get much more than 15mpg out of your Suburban.

'bang for the buck gas mileage' is completely unachievable in such a hulking vehicle.  Beat your chest and stomp around because you got the 'ultimate man vehicle' but never go anywhere because you can't afford the gas.

I'm not picking on you personally, but I just don't like the attitude that leads people to buy those huge vehicles.  If you have a professional use for it (hauling a dozen co workers or equipment, or towing 3 tons of crap on a trailer) that's all fine and dandy.  Pony up the cost to use it, and it's a business expense.  However, I strongly dislike the 'ultimate man vehicle' mentality.  Get the BIGGEST, UGLIEST, MOST POWERFUL (purely wasted potential) vehicle you can because it's cool, and trendy.  Your wallet will regret it every time you're at the pump.   That mentality is like buying a .50BMG to shoot squirrels, when a .22 would do fine, and be more efficient.  

Despite my disdain for the attitude, I will tell you this, I gained a lot of experience with what will affect your gas mileage by driving the most fuel efficient vehicle in the country.  My tips are:

Try synthetic oil, be sure to change it regularly, as well as a GOOD quality oil filter.  

Get a good air cleaner.  I wouldn't recommend the K&N, because they let a lot of particles through.  Check out Amsoil, see if they have one that will fit.

Run your tires a few pounds higher than recommended.  This will make them harder, and they will resist rolling better.  Under heavier loads, run them at recommended.  Mind them closely for wear.

Get your alignment checked.  Poor alignment can eat your gas mileage noticeably.

Don't speed.  For ever 10 mph faster than about 50mph, resistance from air DOUBLES.  You're driving a vehicle that has the aerodynamic efficiency of a cinderblock.  The faster you go, the harder your engine has to work.  The ONLY thing going for you in that department is sheer mass.

And please, don't drive it like an a$$hole.  Don't tailgate anyone.  Don't be the hotshot in the giant truck and try to intimidate people.  

Good luck with it.  
M@

Hielo:  with an 87 Chevy, that's either a bad battery, corroded connection at the solenoid, or the starter/solenoid itself.  Take a known good battery out of another car and try it first.  If it still just clicks, check the wires where they bolt to the solenoid on the starter for corrosion, clean and retighten if necessary.  If that doesn't work, remove the starter (two bolts plus wires), and just replace the whole unit.  The solenoid will usually go bad before the starter, being so close to the engine deteriorates the solenoid from heat.  Keep track of how many shims are between the starter and the block casting...your problem is easily diagnosed and fixed, even I can do this one!  ;-)
Hope that helps.  

Thanks TheKill, I will throw a new bateryu in this weekend and see what happens.  Thanks for the response!

hielo - check the negative ground too

Is yours a 2 wheel or 4 wheel drive?  I have a '92 that is a 4X4 and have never gotten better than 10-10 1/2 mpg.  If you're doing better, you are lucky.  

And for the "member" that downed us owners for getting big gas hogs, I had a remodeling business, and kids, and drivers here drive like crap, so the more steel, the better.  Back then gas was alot cheaper.  We get the reject drivers from around the country, Tucson seems to be a magnet for them.

Now it mostly sits, except for trips to the ocean, or lake.  I have a pathfinder that I drive around town, and my ex has a new Jeep Liberty.  They are a piece of junk.  She has had nothing but trouble with it since she got it.  Less than 25k, and already 2 recalls.

Oh well, enough of my rambling.  You-with the new toy-try a free flowing exhaust (flow master is good), try better air filters (K&N is supposed to be good), and the chip like everyone else suggested.  DO NOT lift yours and add big tires, (like mine) unless you want to park it and drive the Hyundai around town, cause you can't afford to gas it up.

Good luck.

Mark

K&N is a good start, Flowmaster makes a 3 chamber big block muffler which is really quiet and lets that engine breathe. If you get a muffler system by all means 3in pipe from the catalytic back.  Get good spark plugs and wiring, headers might also help, but you either love or hate em.  Good headers will not give you any trouble, cheap part store ones will be a nightmare.  the good ones have written warranties and thick mounting flanges.  Find out what gear ratio you have, sometimes people want a faster or slower one and can get it swapped even steven.  Go easy on the pedal, use that cruise control it really makes a difference on long trips.  Around town you are destined to spent some bucks.  The suburbans are great vehicles, the old ones are easy to work on and last forever, just feeding them can be pricey.  Good luck!

Thanks all for the advice.  To MatthewQ- my daily driver is a $2500 '91 civic which gets 37 mpg.  The suburban is for getting wood, and going into the hills with the family.  Last time I got wood with my old Pathfinder, I roasted the transmission with too much weight.  The engine is a 350, and the rear end is 4.11- I would hate to change it though, as it is a positraction, and I really was looking for one of them.  I guess, I'll try the synthetecs and the better exhaust- thanks again.

Be happy with 13.5. Like psychworker said, my '92 4x4 adverages about 11.5.

Thanks for the info guys!

I've got an "89" Suburban, 4x4, 350ci, 4 speed autotrans.

The rear end just "cracked" and started rattling one day and I had to replace the internals. 3.73:1

Chip?  Where's the chip located?

It needs an exhaust system anyway so I'll check into the FlowMaster.

Where's the baffle in the intake?

My wife really didn't like it when I bought the truck but now I can't get her out of it.

Keep the pointers coming!

13.5 mpg seems to be a common in GM trucks.

My '69 C10, '72 K5 Blazer and '83 K20 all run about 13.5

If you need to shop for parts look here: [url]http://www.lmctruck.com/[/url]

Semper Fi
Dave

I'd be happy to get a consistent 13.5mpg in my 94 GMC K2500 Suburban with 4WD, 454, 4 speed auto, and 4.10 gears.

To the welfare bum who doesn't like the attitude of big truck owners; Bugger off. I like the room, capacity, safety, versatility, and capabilities of a 4WD Suburban. I've got no problem with $50 fillups. Get a better job, chump.