is 350 cfm too much for a ea82??

[Subruise]

ive got a 2bbl holley nobody wants and i saw Mcbrat had a 4bbl. whitey's hitachi is a lot better with the new fuel filter but i want to know if the holley is feasible.

 

Thanx, RV

[LPGsuperchargedBrumby]

i would think a 350 cfm holley on a EA82 would be somewhat over carbed....the weber 32/36 that alot of people fit is rated at about 160cfm if i remember right

[NorthWet]

I had a 350 (360?) CFM Holley 4bbl on my 2.0L Datsun, and it did really nicely. The 2bbl is likely to behave differently, but shouldn't be overkill. (I personally like vacuum secondaries like my 4bbl had, though seemingly nobody here likes them.)

[mcbrat]

the Holley 600 I had on my ea81 had a vac secondary. it was incredible above 2500 RPMs in the gravel pit at WCSS7, but for daily driving and trail riding, it was less than ideal. it was still driveable, but too much work to keep it from bogging coming off of idle...

[NorthWet]

My little 4bbl (smallest Holley made, and wickedly expensive at the time) was great everywhere. Good idle, no off-idle bog, and good gas mileage. Vibration took its toll, rattling a booster venturi loose.

 

(Also had trouble with sunken floats until I replace the brass float with a nitrile one. Bad news when the fuel tank level is above the float level... )

[ShawnW]

the Holley 600 I had on my ea81 had a vac secondary. it was incredible above 2500 RPMs in the gravel pit at WCSS7, but for daily driving and trail riding, it was less than ideal. it was still driveable, but too much work to keep it from bogging coming off of idle...

 

That was so much fun!

[monstaru]

you will be wasting more fuel than you use..........

[Subruise]

thanx folks. i kinda figured as much but needed a for sure answer, i think i got it

 

RV

[motorhedfred]

Holy thread resurrection !

 

To answer the question, technically no carburetor is "too big". The ability of of larger CFM carburetors to effectively atomize the fuel at slower airspeeds is the culprit. Careful tuning and possibly annular boosters would get you there.

 

More pump shot through a slightly larger squirter would give you a longer steadier accelerator pump fuel supply. A 2-stage power valve might be needed as well, but it can be done.

 

This of course doesn't speak to the myriad other vacuum lines, and gizmos that were part of '80s pollution control technology.

 

Vibration issues aside, the 390 CFM 4bbl could be made to work as well if you can fab up a proper manifold and plenum for it.

 

MHF

[spazomatic]

I think a small 4v with the secondaries disconnected (rendering it just a small 2V) would work better than that 2v. reason being, the venturis on the 2v are larger than the primary venturis on the 4v. thus, making for a better vacuum signal to the carb at lower RPMs, which will result in better driveability.

 

I've toyed with this idea too. either using a small 390cfm 4V (they're made for certain classes of oval track racing) or an old autolite/motorcraft 2v (they rock off road)

 

I think though, that the weber is definitely a better fit overall and shouldn't be as time consuming to swap (I'll find out...weber's in the mail!)

[Idasho]

you will be wasting more fuel than you use..........

 

There is absolutely no way to WASTE fuel with any properly jetted carb.

 

Airflow determines the fuel flow. Not you right foot. (with the only exception being the power valve)

 

The primary players in determining airflow are displacement and volumetric efficiency.

 

 

What you would be wasting with a carb that is designed for a much larger motor is the ability for the carb to produce more engine power. Used on a small motor the potential simply isnt there.

 

Its like feeding a monkey an elephants dinner. The monkey simply cannot eat it all in one serving, so there will be much left on the plate. Unused.