Looking for help building a Gas Vapor system

[racprops]

Originally Posted by tf4624

Carbs are great. We should have them still.. (we could tinker easier with it than the computer controlled fuel injection)

You cannot get the control a good FI system can give...

I like how my FI car drives great cold and hot and how much power my little 4.6 Ford makes and then can do 30MPG as well.

[racprops]

Originally Posted by tf4624

Carbs are great. We should have them still.. (we could tinker easier with it than the computer controlled fuel injection)

First I used to rebuild all major 4 barrels carbs and did some rejecting of a quad...smaller jets and thicker metering rods etc.

BUT a FI with a set of electric controls can be TUNED on the fly, on the road, you cannot do that with a carb, and with again the right test gear you can see what happens when you make changes within a mile of two.

I will take a FI system any day over a tear down and guess and drive a tank of gas to see if it worked carb.

I grew up with cabs and points and so on...I can fix of rebuild every part of the car BUT for a automatic transmission. I can rebuild stick shift trannys, I go so far back I used to rebuild starters and generators, turning down the commutators and replacing brushes.

I know how to energizer a generator and regulator system...

And I kept up and can work on FI now as well.

Rich

[oil pan 4]

I have a vacuum gauge and wide band O2 meter.
Takes about 95% of the guess work out of tuning a carb.
The thermostatic air intake eliminates about 4 more of those 95%.

[racprops]

I have had a vacuum gauge in all my cars, and know that at 10 Inches and below, the metering rods of a quad are full out and your running on your main jets.

I know the higher the reading theoretically the better the MPG, but for the pumping loses....

BUT that does not really tune the carb as good a FI system electronically controlled.

I know they used to super tune the carb and the timing systems but it took a lot of time and work...

And it was NOT cheap either.

Rich

[oil pan 4]

I used a wide band O2 meter too.
The vacuum gauge kind of just lets me know if the metering rods are up or down or if the secondaries are open. The key is the wide bans O2 meter.

[elhigh]

I won't argue that FI gives far greater control, but it appears to me that in most cases its main function is to improvement power and driveability while maintaining the existing level of economy compared to a similar, carbureted model.

As to cold weather performance, I don't think the advantage is as great as you think it is. My truck is ready to drive immediately upon starting even down to 0 degrees. And it isn't one of those weird "electronic feedback" carbs, either. I think if I had one of those I'd just replace it with TBI because a couple of friends had one on their vehicles and hated them with a deep, abiding passion.

[racprops]

Well as I am 68 and have been driving from 14 (scooter) I could NEVER fully trust a carb to not stumble at say a light: cold.

I am blown way how my FI cars and Vans do not have that stumble.

And sadly I do agree with the MPG part.

BUT I have not found any way to fix it a A/F ratio of 16.5 was as far as i can take my car and that is only good for 4 to 6 MPG...now if it was programed in like the lean burn of the old OBDI Camaro it would be great, but at this time I feel the $400.00 to get it to do that not worth it.

Rich

[oil pan 4]

The biggest difference between cold starting a carb versus fuel injection in the cold is the fuel injection needs about 20 seconds for the exhaust manifold to warm up.
But most people remove the heat riser so they run like poop in the cold until they start to warn up.
With the thermostatic intake I can get mine to run a fairly consistent 16:1 or leaner air fuel ratio.

[ThermionicScott]

My carbed VWs run pretty well in the cold, but I figure they're running richer than stoich even when the automatic choke has fully opened.

This thread has gotten me interested in adding a wideband O2 sensor and gauge to my '67 Bug when I start playing around with it again. It's so cherry that I don't want to radically modify it, but it would be interesting to see what the AF ratio is most of the time and maybe play around with rejetting.

[oil pan 4]

If it's running rich you could nearly double the fuel economy.
When I got my 7.4L suburban it was getting 6.5mpg. The carb was running very rich. When I pulled the motor it was getting nearly 13mpg in mixed driving then between 16 and 18mpg on the highway. Most new suburbans don't even get 16.