blow through carb

[XFlow_Fairlane]

well I was reading up on how to mod a holley carb for blow through on turbomustangs.com and basicly all they did was remove the choke and mod the carb to handle boost (solid float plugged holes etc..) and then drill out the power valve holes to supply more fuel when under boost. well all these basic systems are present on a 1100 so I was thinking of doing the same mods to one for a blow through setup

pros
1. stock carb.....no mounts needed......already have it
2. ease of hook up of boost supply.........2" neck allow easy use of a silicon coupler


cons.

1. harder to find parts (jets, power valves)
2. may not flow enough fuel


now as long as I had it open and would be drilling holes in it I was thinking of tapping the jet hole to take a holley jet to make jetting easier

so does this sound like it might work? for my turbo I only want some more power than stock and not a strip monster. fuel economy is important to me (still in school) and for power I am only looking to get in the 150-200 hp range. or will this just be plauged with problems and melted pistons?

 

[Fingers]

I cant see any reason not to use a 2 barrel Holley for this, the cons you listed for the 1100 should be enough to scare you.
If it leans out it will cost you a set of pistons!
Does10s Falcon runs really well with the blow through Holley and I am sure he will chime in with his experience and opinions.

 

[XFlow_Fairlane]

well the thing keeping me away from the 2300 is the need for a modded head/adaptor and the cost involved. I was wanting to get the car running under boost and if the1100 is not enough carb I was going to upgrade to the 2300 (disable the turbo until switched over)

 

[Does10s]

I don't know much about the 1100. Does it have a solid float? If so then I say give it a try! Put in some bigger jets and start with very low boost levels. Work your way up.
Make sure that your fuel pressure will increase when the boost increases. Maintain 5-6psi more than the boost pressure. 10lbs. of boost = 16psi of fuel pressure.
Also pull out some timing.
Later,
Will

 

[XFlow_Fairlane]

yeah I got some solid floats for it. I was going to boost reference the pump and run a mallory reg in addition. I have a hobbs switch and a fuel nozzle from a NOS kit I was planning on using for additional fuel. so I guess if it looks liek it is going to go lean I could jsut run teh additional fuel supply

 

[Does10s]

I wouldn't worry to much about adding a solenoid to add fuel. The venturi in the carb will take care of that.
Another thing you might want to get rid of the choke assembly. Then fill the holes.

Later,
Will

 

[XFlow_Fairlane]

as far as the choke goes is it needed to get the car started? this is a year round driver adn needs to start in cold weather (around 0 or lower) so was hoping I could keep a manual choke on it? yah or nah?

 

[Anonymous]

IMO you don't need the choke. Just learn how to start your car w/out it. Useually it just takes a couple extra pumps on the peddle before starting. I've driven chokeless holley's thru many of Illinois winter.
It sounds like you've thought your system out well.

 

[XFlow_Fairlane]

is there any problem with leaving it on there? aside from a little extra air leakage past the shaft? I would like to try and run it if I can just for the extra security and ease of starting.

 

[Does10s]

With the turbo in front of the carb, it almost acts like a choke on initial fire up. You just pump the pedal a few times and it'll fire up.
If you're concerned with it just leave the choke on there and give it a try.
And just an FYI....of all the blow-thru carbs that I've seen, not a single one had a choke on it.
Will

 

[Mustangaroo]

I removed the choke blade from my Supercharged Blow Thru Holley setup and it still starts great! For what it's worth.

 

[XFlow_Fairlane]

give it a shot starting here in cold IL during the winter. I didn't know if you HAD to remove the choke on a blowthrough setup? on holleys I assume it is becuase the choke uses a pull rod and the hole needs sealed where a 1100 has the shaft that runs out form teh carb body so far less leakage issues. on teh manual choke the butterfly opens under higher flow/low vac conditions so it SHOULD open up under boost if the choke is on .....if it doesn't then the choke comes off. I figured leave it on and if it works then it stays if not off it comes.

well this is my first winter with a good carb on my car.....past two winters were with a leaky 1908? holley that would leak the fuel bowl out overnight and require a crap load of cranking in the mornings

 

[kirkallen143]

From what I have read, if you think about it, the fuel mixture is being forced into the combustion areas and not having to rely just on vacuum to bring it in. Just like there is no choke on an EFI.