Whats the big difference between boxing the whole carb and jus boxing the carb intake(top). what benefits does Boxing the entire carb offer?

I personally did the boxing the top of the carb thing and it crushed float and cause it to flood at full boost(15psi). I had to run a small line(from infront the turbo) to the vent hole over the float chamber to eliminate that problem.......but i can still see that same thing happening if u jus box the entire carb and don't run a small line over the float chamber.


Thanks alot for your help..
ps.Sorry if it has been mentioned before but i need some help.

Boxing the entire carby makes equal pressure inside and outside the carby. This eliminates the stress put on the carbie gaskets when atmospheric pressure is outside and positive boost pressure is inside the carbie.

Whether you box or not or run this line you speak of - your float will still crush if it is hollow.
I cant see how this line you ran could do anything for the float. The only thing I can see it doing is help reduce pressure on the fuel bowl part of the gasket, with this only creating a boost leak that sucks fuel from the bowl back around in through the turbo inlet. I cant see that fuel supply could be acceptably metered through the carbie on boost when this line is fitted.

The float is a faom filled one.
ok.....1st the carb is a rochester 2barrell carb. It has a pin size vent at the top of the carb. When the box is placed over the carb the vent is exposed to all the boost coming into the carb which is 15psi....so i had to make a plate to fit over the vent with a tube/hose running from there to infront the turbo. Since the line allows only so much air to go into the float chamber(compared to when the box was over the vent hole, wher a greater mass of air could enter). This stabilizes the float sum wat.

http://datsun1200.com/modules/myalbum/photo.php?lid=6175My Carb 'Box'

Obviously if your float can crush it isnt a solid float. You need a hard foam filled float ( do rochestors have these? i dont know.) When your float has crushed, do you need to replace it? or does it expand again? How do you know the fuel bowl floods? What fuel pressure do you run?

I still stand by what I said. The pipe you installed has only provided a boost leak. For the carbie jets to supply fuel to the engine you require a lower pressure on the engine side of the jets. If you have boost pressure on both sides of the jets, you still get the vacuum effect of air passing the jets to draw out fuel like a normal carbie is designed to operate. If you put a lower pressure line into the carbie especially the fuel bowl, you create a low pressure port for any greater pressure to head to. Naturally the greater pressure will go to it and along with it, it will draw the fuel from the bowl.

Do you have a pic of this pipe you added? or even a pic of the carbie to show where you attached it?

I would love to see that flexible rubber piping when its supplying 15psi to the carbie

The flexible hose swells out huge so that will be changed.

I think we have our terms mixed up here. when i say crush i dont actually mean the float is being distroyed, i saying the float is being kept down(like fuel is entering) by the boost causing the engine to flood.

will try and get some pics todat. How did u get that pic posted in the forum/post by the way.

Quote:

Magic

How do you know the carbie was flooding? I mean what did the car do / what did it feel like?
How do you explain boost being able to push a float down when boost is surrounding it in the fuel bowl? and how does this pipe stop this from happening.

Please dont think I am trying to prove you wrong. But from everything you have said, I dont see how any of it is possible. Thats why I ask what fuel pressure you are running and what the car felt like when you feel its flooding. Does it feel like the car hits a big flatspot?

think i'm going to try to box the whole carb and see what happens.

can i make the box out of 1mm sheet metal??? i'm planning on pushing 1 bar boost.

dont want it to be heavy.