Maximizing B2200 carby fuel economey

So I bought a 90 b2200 5 speed that needs a rebuild... Smokes like a 2 stroke. This is going to become my daily driver for my 60 mile round trip to work everyday. All highway 60-70 mph. While I have the engine out but before I buy parts I'm lookin to get some input on producing the maximum mpg and reliability. The obvious question is weber 32/36 yay or nay and pacesetter yay or nay. I do not need to pass emmisions where I live. I am already planning on going efan and deleting the fan pulley and replacing the crank and alt pulleys with aluminum ones to reduce weight assuming these are internally balanced motors due to a lack of "balancer". I also planned on deleting the secondary cat. Another idea I came across was changing out my gear box with that of an rx-7 for a better overdrive ratio. With the weber I'm interested in its economy and reliability along with deleting the maze of vacum lines. Since I wouldn't be using the stock o2 I was going to invest in a air/fuel ratio guage to tune my carb in. As of right now there is seemingly nothing wrong with the stock carb. I drove the truck 15 miles home mosquito fogging without any issues. Any input is greatly appreciated. Even small amounts of info like degrees of timing is a help. Thanks in advanced

Honestly these things are crazy good on gas. It would take you years to recoup the money you spend on doing all of that stuff in gas savings. I would focus more on your top speed on the highway to save gas. Mine was best at 110 kmph on the highway, if I went 120 I noticed that my tank didn't last as long. Only thing that I dont know about is the carb as most of ours in canada are fuel injected.

My main reason of interest in the weber and pacesetter is deleting the gobs of emmision tubes hoses and devices cluttering up the engine bay but it's not worth it to me if it's going to hurt mpg. I'm lookin for at least a slight improvement not miracles.

Do you know whaty your current mileage is?

The stock carburetor if working properly will give about 24 mpg. I know there are going to be people on her who will agree and disagree, but that is what I got. I also know that the weber is not an electronically controlled carb, so it won't do as well as that. If your stock carb is working, you are getting the best mileage you can using it.

You have to keep the O2 sensor though.

No idea...I only drove it ten miles and with the way it was smokin it probably wasn't good lol. Seemingly the stock carb is working fine. I was going to put the factory o2 in the pacesetter if I kept the stock carb. What emmisions devices can I remove when keeping the stock carb? Recirculating tubes are going to scrap with the stock manifold. I'm asking about the millions of vacum devices.

Hi Guys, I bought a Mazda B2000 1987 and I invested alot of time diagnosing the fuel economy issues. It now gets 28-32 MPG on the highway at 70-75 mph. I have 425,000 miles on the rig currently - the engine has 275k on it since new (it is a Japanese takeout engine - Magnum).

I am a computer programmer and very familiar with the electronics on the b-series truck, O2 sensor and computer. To improve the mileage, I connected oscilloscope up to the O2 sensor and monitored the waveform generated as a function of speed driven, throttle position and such as I drove the truck and could tell immediately what modifications resulted in an improvement. What I found was my truck was always running full 100% rich above 60 mph and was running somewhat normal below, so I set out to determine why and fix it so I could cruise and 75 and still bag 30 mpg.

Everything is 100% stock on the truck.

What I did to improve the mileage was:

1) replaced the mixture control solenoid - these go bad and will cause a truck to get 20 mpg when it should be getting 30 mpg.
2) disconnected the altitude compensator hoses (this helped a couple mpg)
3) replaced many hoses in the engine to fix vacuum leaks (THIS IS VERY IMPORTANT)

What I did which had only a slight effect on mileage was:

1) took the carb apart and cleaned it and replaced all the seals.
2) adjusted timing
3) new air filter
4) High end spark plug wires from Napa (not the base OEM quality)
5) leaned out the idle mixture
6) replaced the cat converter (these can get plugged up with age)


The things that have no effect on fuel economy :

1) Exhaust back pressure - it has no coupling to mileage as long as cat is not plugged
2) O2 sensor replacement - these seem to last forever despite the guys selling them claims, Mine was working fine with 200k miles on it.
3) Spark plugs - I tried platinum and OEM and both resulted in equal performance and efficiency and mpg
4) disconnecting the EGR - despite everyone complaining about all the emissions overhead I found no significant emissions related issues to fuel economy.

Just a tid bit of info - the computer controls many solenoids on the carb and if it detects any kind of problem (such as a vacuum leak) will cause the mixture to be full rich = 20mpg. Also until the engine gets above about 175 degrees, the computer runs the engine in full rich mode.

My advice - if you have a stock rig, and it is getting less than 28-30, you should be able to fix it for low $ and I see no valid reason to ever go to a Weber carb setup. I would not buy a truck with the Weber.

A few questions. Do you live at higher altitude or lower? And I'm assuming that disconnecting the altitude compensation houses and plugging them will make it run leaner?

I have a Weber 38/38 and pacesetter along with a catless exhaust. My fuel economy is about the same as before doing so, I get on average 25-30 mpg and drive daily 25 miles at 65-70mph. The only thing that changed is performance and the fact that if I really get on it for a while I see a big drop in fuel milage... But that's to be expected. Also this is on a motor with over 200k miles with some issues...





Fred

Thanks for the input. So I got the motor all torn down and it has a decent amount of piston to wall slop (expected for the amount of smoke and 233k) some nasty scoring in cylinder 4 and head gasket blown between 2 and 3. Head is at the machine shop getting decked and checked along with the flywheel getting surfaced. I'm thinkin I'm going to have to go .040 over to clean up these cylinders...any one gone this big? I'm curious as to if they have head gasket or overheating issues with thin cylinder walls.

Thats a good question: I noticed if operating at elevations below 1000 feet disconnecting the altitude compensator started to have no effect. At 2000 feet where I live it does have an effect. So if you live near sea level it wont help much. The original altitude compensators have a air sealed expandable chamber which opens a valve relative to ambient pressure. I believe over the coarse of decades air slowly leaks from these chambers and they no longer function. I tried replacing the altitude compensator with several others from the junk yard and none worked. A new one is too expensive to justify. So I simply disconnected the hoses and found it improved fuel economy and ran better. (I know its not ideal to leave hoses unconnected but in this case it works - I have put 100k miles on it this way and no issues)