Dura spark so intimidating

[85_Ranger4x4]

Why would he want one that's 1.02. Isn't that a little small. I ran a motocraft 2100 with a 1.08 venturing on my 2.8 and it really woke it up.

Compared to the craptacular stock carb?

The stock one is a 1.08, it is a little oversized so the computer would be able to adjust the mixture either way. Ideal would be a tad smaller if you can't cheat it with the computer.

 

[wildbill23c]

So does the smaller venturi provide better economy and power or how does that work out? Never really understood the difference in the sizes, all I know is after the answer to where the numbers were I know I have a 1.08 venturi on my 2.8L.

 

[kimcrwbr1]

The engine uses a certain amount of CFM and if the venturi is too large there is not enough static pressure (vacuum) through the venturi to pull the premixed air/fuel thru the venturi booster and atomize the the fuel. The autolite/motorcraft carbs actually premix the fuel and air before it gets to the booster The round parts center of the venturi. The 1.21 venturi works best on small block V-8s. What happens is the fuel does not atomize properly and drips down on the intake manifold and puddles there. The raw unburnt fuel then washes down into the crankcase and reduces lubrication. You can get it to idle real well but off idle you will get hesitation and performance issues. That about the best I can explain whats happening.

 

[millwrightdude]

I will be ordering one for a 1978 mustang II

 

[wildbill23c]

The engine uses a certain amount of CFM and if the venturi is too large there is not enough static pressure (vacuum) through the venturi to pull the premixed air/fuel thru the venturi booster and atomize the the fuel. The autolite/motorcraft carbs actually premix the fuel and air before it gets to the booster The round parts center of the venturi. The 1.21 venturi works best on small block V-8s. What happens is the fuel does not atomize properly and drips down on the intake manifold and puddles there. The raw unburnt fuel then washes down into the crankcase and reduces lubrication. You can get it to idle real well but off idle you will get hesitation and performance issues. That about the best I can explain whats happening.

Great info, thanks. Guess I'm good with the 1.08 Venturi then LOL.

 

[millwrightdude]

I want to thank you guys. I got it all wired and it's running good. I'm going to get the carb ordered this weekend.

I did screw up and I cut the wire to the electric choke, so I'll need to know how to wire up the choke on the new carb

 

[Baja Ranger]

What coil are you using? And, are you using the factory wiring still just tapping in?

 

[kimcrwbr1]

I want to thank you guys. I got it all wired and it's running good. I'm going to get the carb ordered this weekend.

I did screw up and I cut the wire to the electric choke, so I'll need to know how to wire up the choke on the new carb

Key on hot pretty much anywhere you want I have been running mine from the coil pos for two years with no problems.

 

[millwrightdude]

I using a coil off a 1979 mustang II

 

[Baja Ranger]

I using a coil off a 1979 mustang II

You are using a can style coil then correct? Did you use a ballast resistor and is this with or without using the factory ranger wire harness?

 

[millwrightdude]

Yes, I'm using a can style coil. What is the resistor for. Im using the factory harness and info that I got from the ranger station

 

[millwrightdude]

The truck runs so good after the dura spark conversion, But Im having one problem, When I turn the headlights on or turn signals the truck dies. So what did I do?

 

[millwrightdude]

If I unplug the little red/blue wire on the starter solenoid then turn the lights on the truck stays running

 

[kimcrwbr1]

http://www.therangerstation.com/tech_library/2_8Duraspark.html
Scrool down to the second color wiring diagram did you cut the red/ltblu wire and splice it just above the 4 wire connector.

 

[kimcrwbr1]

Also cut the light green wire from the two wire connector it is probably robbing power from the ignition. Did you wire it as the second color schematic.