I know there are getting to be a lot of Walker converts - so I thought I'd share this.

I did the "cheap method" A/f meter, pg. 13 http://bob2000.com/carb.htm.

'Got the sensor from NAPA for ~$20, swapped it into the Walker O2 bung, ran the wire, hooked it to an old analog meter I have (~$10). 0 - 2.5 volt setting.

It works - although the readings were poor below 700mv - probably because of the cheap sensor - or maybe the distance from the engine.

At any rate - I'm glad it only cost me $20, instead of $130 for the "trick way".

And it helped confirm that "plug reading" is still a good way to check your A/f ratio...

 

kickass, i might have to do this went i get my headers and new exhaust on. thanx for the tip.

 

Well, I just bookmarked that.

 

'Made a couple of rig runs - and got to observe my fluctuating A/F ratio "meter". It's kind of neat to see the needle jump when the power valve opens. It'd be nice to have a sensor that wouldn't "drop out" at lean cruise, but according to Forgnone (the tuner guide author) , "the expense and complications involved (in using a heated sensor) are not worth it for carburetor tuning."

One thing to note - I'm running water "injection", which has a cooling effect, which in turn causes false "rich" readings. Since the water injection offsets detonation, I'm not too concerned about the (cruise/decelleration) times when the meter drops off (indicating hot, over-lean). I'm not getting "lean miss", and my plugs aren't white, so I know it's just inaccuracy in the A/F "meter" . What did I expect for $20 .

I bumped the water ratio up to about to about 1:16 and got nearly 15 mpg - doing 70-75 MPH most of the time, for about 350 total miles. I had to lean the idle mixture screws to get rid of a subsequent "miss". Normally, my MPG's suffer some at those speeds (lucky to get 14.5 on Summer gas, 13-ish on Winter "crap"). As a side effect, I was cruising up lesser hills without any noticeable drop in speed/change in pedal position.

Water injection: more power, better mileage, & cleaner emissions. & Too much "trouble" for most folks...

I can hardly wait for "Summer" gas, to see what I can get with it. (usually 10-15% better MPG's).

 

3rd fillup totals: 676 miles, 44.7 gallons of gas, ~3 gallons of water...

Most recent: 313 miles/20.5 gas/~1.75 water

 

could u explain this "water" injection thing some more...

 

There's simple, and not so simple. I went the simple route. I have an old Marvel Mystery Motor Oil "injector" that was originally intended to bleed MMM oil into the vacuum advance line. The intent was to provide additional lube for the upper cylinders.

The unit has a valve, which controls the rate of fluid flow. The flow rate can be observed (dripping off of a brass "post") through a small sight glass.The original came with a 1 quart Mason jar reservoir. It is tied, by a single line, to a "T" in the dizzy's vacuum advance line. The vacuum basically "sucks" in a controlled amount of oil (or whatever).

After reading up on WI a bit, I decided to use the "oiler" and switch fluids - to water ( w ~10% alcohol in the Winter). The quart jar didn't give me much range, so I adapted a 2-1/2 gal poly tank from a common garden sprayer. The reservoir's top water level MUST be lower than the carb inlet - so no syphoning can occur.

Mine is mounted along side the radiator, on the driver's side ( I built a little aluminum platform, & secured the tank to the radiator dam with large HVAC clamps. It is trial & error to get the rate. Drive ~100 miles, observe water used, adjust, repeat..

Immediately upon getting to 1:20 or so, I began to see better mileage & feel more power. Other advantages are said to be a cleaner burn, and removal of carbon buildup.

The more complex way involves pressurizing the fluid and injecting it though a jet or jets. A vacuum/boost monitor, or a throttle micro switch activates the pump. These setups can run $300-$400, but are one way to deal with detonation under high boost, or when boosting with a high compression engine. Ther are a couple of companies that offer kits, but there are also a number of DIY articles (see WI in Big Six - over at FSP).

A very simple set up could be ANY container, some fish tank air line, and one of the valves they (pet stores) sell to split the air flow.

 

thats pretty dam interesting...will it work with an EFI?

 

I don't see why not.

The carb's vacuum advance line provides the perfect inlet. How's THAT work with EFI? The trick is to get into the base of the venturies, not direct to manifold vacuum.