rookie696

iTrader: (2)

Hello, I recently bought a mugen pressure chamber set for my mrx4x and to my suprise it is just a hollow tube. Before I bought this I read a few things about them and what I read stated that it was supposed to keep pressure in the fuel tank. After I found out it was hollow I contacted Mugen Racing to ask about this, I was told "It supposed to be hollow. It supplies cleaner air to the tank and saves on fuel line." Ok hello, How is it suppose to keep pressure in the fuel tank if their is nothing to keep the pressure in? How is this suppose to supply cleaner air if their is nothing in it to clean the air? How is it suppose to save on fuel line when you have to use more to install it? So if some one could help me understand how the pressure chamber works it will be greatly appreciated. Thanks for your time and info.

Gseventeen

Dear racing rookie, as far as i have had it explained to me, the pressure chamber is there to equalize the pressure ,in other words when you excellerate more pressure comes through your exhuast, thus sending more fuel to your carby.Less pressure less fuel,so when it is equalized by the chamber it is constant pressure thus saving fuel and making motor easier to tune.Any experts please correct me if i am wrong?

kmh

Thats about right. I was wondering the same thing. The guys that do not use a pressure chamber,compensate by using more fuel tubing wrapped in a circle between the tank and pipe. Thats why the chamber uses less tubing. Try both and see what works for you.

impalabob64

iTrader: (2)

Orion makes one i hve seen Joel Johnson running it at the US Open .He said it seen to do the perfectly.

Scott Fisher

iTrader: (28)

The Orion one is adjustable.

razzor

The pressure chamber adds volume to the line with out having to make it too long hence why they say you save on some fuel tubing.
The ideal pressure line length is said to 8/9 inches so some guys loop it due to the length while others fit a pressure line to make things a bit tidier.

rookie696

iTrader: (2)

i want to thank eveyone for the input. i understand how it works now thanks.

jameslow

iTrader: (1)

Btw:

What will happen if i never use the pressure chamber and my fuel tube is only about 4 inch long?

- too much fuel will get into the engine when full throttle?
- but if the pressure is too low, will it lean the engine n cause it to overheat?

keavze

too short, the pressure will be greater and not 'smooth'...
might cause nitro foaming and maybe a bit rich?

MugenDrew

iTrader: (36)

Something that you can see/learn on a break in bench are the effects the pressure line has.
Short pressure line; at the beginning of the tank no issues. From about half full to empty the fuel will foam terribely and the engine will lean out. If you richen the engine up to compensate for this you will then be running WAY to rich at the start of a full tank run.
Long line; what I have experienced is that the length to see actual changes at the half tank mark is excessive at best and would be a bit troublesome to fit in a car. As the line gets longer more resistance will be presented to the pipe outlet slowing its ability to quickly build pressure in the tank=lean bog.
Something else is going on here and from what I can figure it has to do with the same sound waves that make your tuned pipe work. The pressure chamber will take that pulse and slow it down (transition from a small area=fuel line inside diameter=fast) to a large area=slow=inside of pressure chamber then transitions back to a small resistive area to pressurize the tank. So we slowed the pulse down and took away some of its force.
I never needed one of these with .12. The pulses as observed on the bench with a .21 are quite violent. However the off-road 5 port and less engines do not need the chamber either.