Ok so I have a multi-part question...woth fuel prices not going down I was thinking of a few ways to improve my mpg......I check my rear gear ratio and my code is GU6 so that means I have 3.42's right?......so if i swapped to a set of the 3.08's would that increase MPG?.....I know i would lose some of the get up and go but this is a SUV not a drag car......also is there a way to install a e-fan to replace the mechanical one?......oh and in case it doesn't show up on the sig I drive a 1996 2wd blazer....4.3W engine auto.....also is there any other ways to improve my MPG???....thanks guys

 

3.08's will help a little, especially if you do a lot of freeway driving...and e-fans are easy.....i got the 16" one from advanced auto and just wired it to a switch, install wasn't too bad but it will be easy if you take out the radiator. i also found a 10" fan on ebay and mounted it as a pusher on the condenser and just spliced into the A/C wiring so it turns on when i turn on the A/C---total cost for everything was about $125

 

I have success with upgrading air intake with kits from AEM, or K&N.Maybe add a throttle body spacer. Also upgrading, replacing ignition components (wires, coil packs ect.) will help. I gained 2-3mpg by doing this. You can also clean the injectors (I hear seafoam is good for this) and more expensive install a new free flow cat. converter (say from Gibson). I have read reports on the later which indicate a mpg increases but I have not tested it myself "yet".

I had an "old timer"[:-] tell me, the more air in and the more air out, the better performance. Seems to be working so far.

 

Throttle body spacers will only work if you have a true TBI system. My 2000 4.3L vin "W" does not so putting a spacer under the throttle body will not help.

I did notice that when my thermostat was stuck open and the temperature was not going above 150-160 I was getting 2mpg better than i am now with the stock 195* working. I am considering replacing with a 180*.

Also you could replace the stock filter with a K&N Drop-in, also clean the MAF sensor just behind the air box. Simple not hard did it to mine takes less than 30 min's (you will need and electronics parts cleaner in a spray can).

Place a can of seafoam in the gas tank to help clean the fuel injectors. And get another can to run through the intake to remove carbon from the upper combustion chamber. To do this you need to read the instructions on the can, or find the procedure on the forum...

Also keep your tires inflated to the proper pressures, I usually use the readings on the door sticker and add 2 psi since the numbers on the door are for a softer more "comfortable" ride.

 

I have already been getting 21-22 mpg on the ave I would really like to get better of course wouldn't we all.....as for the e-fan I was thinking maybe a unit from a camaro or other GM car in the JY to keep it on the cheap.....I was also thinking about next time it's tune-up time using a new accell coil and some 8mm wires to see if a better spark would help any at all.....any other suggestions are very welcomed....thanks for the input guys

 

The wire and coil are a good way to go I have MSD in mine.

As for spark plugs I think you will find many different "opinions" there alot of people that stick with the tried and true OEM and others go for the fancy denso iridium, I think it comes down to what you want. Unless there has been a good independent comparision test of the plugs, to prove that one is better than others.

You can go to powerdyne . They have many spacers 92-02 vehicles which may fit your application.

While replacing your stock filter with a K&N filter will give you a small increase you will still have air restrictions from the OEM equipment, the cold air systems from AEM, K&N , GMS, (all of which are available from JEGS), will give better results.

If the e-fan fits it will work, you may not receive many positive remarks about electric fans due to all the problems that can occur with it, thus causing overheating and damage. This is especially true with the off-roaders. (I'll probably tick off alot of people with this one )

 

if your the kind of guy wuo can find time to get serious abuot your engine i found a site that has some interesting ideas thinking .i have a 84 fullsize blazer 350 4 barrel its a plow for winter only so i have time to play with it im going to try it . go to (somender-singh.com-home) read his idea carfully it makes sense to me. good luck.

 

Thats kinda funny. That dyno on the TBI chevy 350 is a complete farce. He takes a motor with a 9.0:1 compression ratio, hacks the intake ports up with a dremel cutting blade, decks the heads, uses a thinner head gasket, and arrives at a 10.2:1 compression ratio. Not only is there no correlation between the two graphs since it's an apples to oranges comparison, but those grooves are way too deep and WAY too far away from the valve to make much if any difference. He could have probably gained more by gasket matching the intake and head than cutting those grooves in.

I have done a lot of computational fluid dynamics in my schooling and for work. Building up a turbulent boundary layer does increase flow, but it needs to be consistent.

Ok so I thought it was time to weigh in on this subject since I have been kinda called out.

Anyway... I have never said anything bad about iridium plugs, only that I won't use them until more is known about them as far as plug life. I want to know that the iridium plugs are worth the cost. From what I have read recently on them, they offer the benefits of a copper plug (stronger spark) with the life of a platinum. Maybe the next time I change plugs in the Bonneville I'll give 'em a try. It'll be next year. Just dropped in a set of 1 heat range colder NGK's a few weeks ago.

My negative comments on plugs have been made squarely at the Bosch +2/+4 line of plugs which are nothing but a gimic.

Now onto how you can save fuel...

One of the best things you can do to save fuel is to change your driving habits. Coast down hills and don't try to power back up hills if you don't have to. Coast to stop signs or lights if you are going to have to stop. Don't try to beat the lights. There are numerous other ways to save fuel by simply changing your habits.

Also, keep your vehicle in tip top shape. Make sure your plugs are properly gapped and are clean. That your wires, cap, and rotor are in good condition. Run a bottle of fuel injector cleaner through your tank at each oil change. Clean your MAF sensor. Try a can of seafoam through the intake to clean it out. Check your tire pressure and make sure that they are up to the proper pressure. Keep your alignment in check. If your vehicle starts to pull in one direction, it'll burn more fuel as you keep it straight. Keep your brakes up to par. If your sliders seize, you may be driving around with a brake pad against the rotor, introducing more drag.

I have heard good things about running synthetic fluids in your diffs and how it affects fuel mileage. I can't comment on that yet, but I have Mobil1 75w90 in my rear diff, but haven't changed the lube in my front diff yet. Plus I don't really drive the truck much in the summer time.

A throttle body spacer will tend to shift the torque curve down lower in the RPM range so you have more torque available off the line at the expense of higher rpm torque. If you tend to keep the rpms low, you should notice an increase in mileage.

And as always, if you are concerned with your mileage, don't race other people on the street.

 

If you spend $125.00 on gears, 12.00 on gear oil, and a $8.00 gasket, you would need to own the vehicle a very long time to just make up that total. I would just leave it alone. IMO

 

well i was more thinking about hitting the local JY and getting the entire rear from a GU4 coded blazer for 40 bucks..... and then 12 bucks on oil for it......and I'm fully aware of driving habits effecting MPG I have changed those alot over the past 15 years of driving my 21-22 mpg ave. should attest to that.....And as a mechanic I always keep my cars in tip top shape.....As for seafoam I have heard many good things about it but it's not for sale in Germany and can't be shipped over here either... I honestly would be happy if i could ave 25 mpg or so.......