Need some Holley 390 help

Bubba, I wonder who else uses the 390 besides us Jeeps guys? We alone might not be enough demand.

 

I was thinking the same thing.. trying to come up with as many escuses as I can to throw at them to produce such an animal.. I would say that it would work well on the 258 and 232's also and maybe even some of the other small displacement off roaders such as the yota FJ's and such It susre would be nice cuz according to all accounts I have heard that carb is the cats @$$ off road.. I would even consider trying to make my own if I knew exactly what the differences were other than the crossover vent tube and notched floats..


BUBBA

 

Well I replaced the vents... They just pull out. Bought some copper tubing and made my own vent to connect together. Also got the spring loaded needle and spring.(spendy little guys) Wnet ahead and dry adjusted the floats to get me close. Getting closer to installing the carb. Got some linkage issues to deal with and some other pinter junk. Maybe later this week Ill get to fire it up.
I got ahold of a one of the parts guys here at my local parts store and he says he used to be in the carb repair biz for 20= years. He kinda did a quick run thru of what I needed to do. Will see. Thanks again for the info.....

 

In our favor I would say the carb is already out there (on the market, reasearch done, etc), now they just need a 390 version, or thereabouts anyway.... the market for an off road carb is already there, this would just expand their offering in that area....thinking about it, it almost seems strange they DON'T offer it......

 

Technical Services Document Library
http://www.holley.com/TechDocs/Instructions/Holley/Holley.aspx

 

Do you think a 470cfm Truck Avenger would be too large for the 225?

Holley Truck Avenger 0-90470
http://www.holley.com/TechDocs/Instructions/Holley/Sheets/0-90470.pdf

 

Update: Well I finally got all the stuff done and got to finally start up the jeepster. After messing with the floats and dialing in the mixture its running pretty good. Its definitely got more power than before, and its running alot smoother. My only problem is a slight flat spot right off the start. If I stomp on it in 1st(automatic) it flat out flys with no flat spot, but if I do a half throttle start then the flat spot occurs.
Not sure if the secondaries are kicking in either. I dont have the kickdown switch working yet.
Not sure where to start as to fixing the flat spot?

 

I have a similar problem, very slight but there. Not sure where to start either. Not sure if adjusting the accel pump would help or not. Also wondering if it could be a timing thing, inside the dist or even a loose chain. Haven't had time to fiddle with it, and not bad enough to make it an priority. Would be interested is suggestions as well though.

 

Forgot to add maybe my slightly lowered float and homemade vent tube might be combining with other factors to give me the problem?

 

I am thinking yes? Somewhere there is a chart that lists CFM requirements based on CID and RPM. This is going to vary some depending on the engines volumetric efficiency, that is how well it flows air in and out. Most engines are in the 80% range, with some race setups approaching 100%. Turbo or Super charging can put the number past 100%. If the chart is based on 100%, the required CFM flow will actually be a little high, and it is kinda like gears, go lower on the CFM to ensure good throttle response, and a little higher for max HP(RACE). I'm sure a search would turn one up somewhere.

 

Accelerator pump. Get the tuning kit and go to a larger shot or longer duration. Half throttle means you half the pump shot.

 

http://www.affordable-fuel-injection.com/off-road.htm

They say they figured it out. I haven't talked to them about the kit, I'm assuming its $$$. FI would be nice, but I'm still trying to fix everything else. Maybe someone will try it out and report back.

-Brian

 

Those flat spots you're getting at mid throttle are from an incorrect power valve. You need a lower numbered valve so it doesn't lean out momentarily in mid range acceleration. I think I used a 6.5 on my 225. The number relates to the inches of mercury vacuum needed to open...lower number, less vacuum, more gas.

 

electricontr, thanks, I am going to look into that. I am heading out for a month long training op this week, but plan to llok at it when I get back.

 

Ill check that too. Had to go back and take off the intake cause I had a major oil leak in the back. Guess I didnt seal it good enough.