first off thanks to all that answer every little question...they help a lot
and actually help make me sounds like i know what im talking about in the parts store

anyway...am getting a new fuel pump to go with mty soon to be here dell'orto....

my question is this....

the holley red seems to be a good choice...very affordable and everything...

why do i need a regulator tho...the parts guy said that it will hold back pressure, but even without one it should just put a bit more pressure on the carb(needles and seats etc??....soo.do i need it? and why




thanls all once again.....


cheers,

Paul

 

bump

 

Each carb is designed to work at a specific fuel pressure. Having the pressure too high will change the a/f mixtures as it will take longer for the emulsion tubes to become uncovered and for the air bleeds to start working. And I can almost guarantee having no regulator will cause the carb to flood especially if the needle and seat are worn.

 

thanks man...one other thing.....i have access to a carter fuel pump..from a v8 friend of mine.....

it does 7-8 psi...should work?.....its certainly cost effective

cheers,

Paul

 

From what I've seen here on the forum, a Carter 7-8psi should be just what you need.

Someone correct me if I'm wrong

Jon

 

I just got a mikuni 44....what fuel pump and regulator should i get for this setup?


thanks..

Bluezone.

 

Mallory Comp110 and the 4309 regulator.....a lot quieter than the Carter or the old Holley blue or red pumps....something to think about if you can talk in your car when its at idle. You'll hear all the other pumps....

 

I don't think any of the carb choices for our cars require more than 6 psi. The stock Nikki has been in the range of 3.25-4.25 through the years, according to different manuals, though the carburetor emulsion tubes, air bleeds and needle & seats have not changed. Changing the fuel pressure can dramatically change the behavior of a performance carb.

The problem with fuel pumps and the specified pressures they claim is that it's dependant on alot of things specific to the car. Fuel supply hose diameter, alternator capability, accessories being on, crap like that. So if your carb wants a constant 4.5 psi, and you install a pump that will give 4.5 psi...when no accessories are on, with a specific diameter fuel line, not ever defying gravitational pull by whipping around corners and sloshing fuel all about in the system, then it should be o.k.
But that's not realistic. So you go slightly overkill, and use a regulator. The pump pumps a supposed 7 lbs, but that can mean anything from 5-8! So a regulator set at 4.5 gaurantees that flow steadily no matter what fluctuations the pump is having.

 

...And fuel pumps are fuel pumps. There are different types, and the price range is wide. But as an old school carb guy, I view them like starters or alternators- they either work or they don't.
Realizing I invite opposing opinion by that statement, I will say that if I had a fuel injected engine, or a boosted engine, I would most certainly blow the bucks on a proven good brand/model pump. In those cases, careful attention and high priority paid to the fuel delivery system is a must.

 

Sterling,
Out of complete respect for you, I will say nothing more about fuel pumps....

in this thread.

 

hmmmm...ok so which fuel pump should i use for my mikuni???

 

so whats the recommended fuel pressure for a dellorto...(and thanks sterling for the informative reply.....it helped visualize it easier


cheers

Paul

 

Damn you, sir! I have taken an oath to speak no more and you dare flaunt this question again!!

On fuel pressures, people can only give you a rough idea and then you have to take it from there. Even on exactly built engines with exactly built carbs, it will be different. Strange but true. As an example, I had my now-deceased '80 on the dyno at Alamo Autosports last year and we ran two different pressure settings while we were there. You'll have to peruse the thread yourself for the specifics...(dyno day), but what it comes down to is this....a mere half pound difference in fuel pressure meant 113RWHP @7600 rpm and the engine breaking up at 7400 rpm....the bonestock Nikki liked the lower pressure...