carb question

[87glsubie]

ok so most people will say put a weber on it. well from what hear and read its the best. I like to experiment with different things and try to not follow the crowd. just for gits and shiggles. wouldnt throwing a bigger carb off of say a z24 nissan do the same thing. More cfm = more air + gas which =vroom.... cuz i can pick one up for like 30-40 bucks. also...... why would the weber boost power so much more than the hitachi???

[GeneralDisorder]

You need a good book on carb theory.

 

Bigger is not always better. It causes huge driveability issues - especially progression from idle to main circuit and proper functioning of the idle circuit. The small engine does not create enough vacuum through a large carb to run the idle circuit, and similarly is not able to cause the progression mechanisms to function properly.

 

You can put a huge carb on it - but without a matching race cam, and properly flowing heads you will see no benefit. But it will act exactly like a race motor in one respect - it won't idle for beans and it will have a huge flat spot off-idle. High RPM it could probably be jetted down to work - but unless you plan to drive around at 4 grand all the time I wouldn't sugest it.

 

If you could find small enough jets and rods, something like a qaudrajet could probably work alright on the primary's, but I doubt you could get the secondary's to function with the availible parts as they are designed for V8's and large 6's.

 

The Weber 32/36 is the right size for the engine. It's not much larger than stock and it's performance comes less from it's size and more from it's progressive linkage - the ability to open both barrels instantly from idle to WOT gives a boost in low-end torque or at least the rate of it's application. More than anything it just gives it a sporty feel and makes it a lot easier to service. They don't increase the ultimate HP at all without supporting mods. They are just a lot easier to maintain and tune when you *do* add supporting mods.

 

A bigger carb will get you nothing without giving the engine the ability to use more air and fuel. As they sit, the Subaru engine's get all they can use from the stock Hitachi - if it were restrictive then you might have a chance, but they aren't. We use them because they Hitachi's are junk - not because they are too small.

 

SPFI is better though as it requires no tuning.

 

GD

Edited January 21, 2010 by GeneralDisorder

[87glsubie]

dont need the carb theory anymore hah you jsut gave me the summed up version