weber flow rates

sen2two · 03-04-10, 09:05 PM

Heres some i found, not sure of the accuracy... but seem reliable.

Source: JayCee Ent./Perf.Tech- flowed on Superflow 600 @25" water

Weber 48mm IDA w/44 venturi-348cfm (per venturi)
Weber 51.5mm IDA w/47.5 venturi-395cfm (per venturi)
JayCee 62mm /55 venturi -633cfm (per venturi)

with 20" water

Holley 1150 Dominator (4 barrel) 1180cfm (est.) total
Weber 48mm IDA w/44 venturi-311cfm (per venturi)
Weber 51.5mm IDA w/47.5 venturi-353cfm (per venturi)
JayCee 62mm /55 venturi -565cfm (per venturi)

Source: Gene Berg Ent. no flow specs given

Weber 48mm IDA 40mm venturi-561 per carb
Weber 48mm IDA 42mm venturi-583 per carb

Source: CB Performance 1991 catalog- no flow specs or venturi sizes
I assume these numbers are @28" H2O per venturi

Dell'Orto 48mm DRLA 388.5cfm
Weber 48mm IDA 372.1cfm
Dell'Orto 45mm DRLA 329.3cfm
Weber 44mm IDF 292.3cfm
Dell'Orto 40mm DRLA 266.4cfm
Weber 40mm IDF 212.8cfm
Dell'Orto 36mm 205.8cfm

sen2two · 03-04-10, 09:11 PM

With that said, i just picked up a 48mm dhla weber. I would like to add a 44mm venturi to give me around 650cfm. I found gene berg sells them for ida webers. Can these also work for dhla? or is there somewhere else to get a 44 venturi?

how would i know what size venturi i already have?

also, i know that idf are more streetable, and ida and built more for racing. and there flanges also differ. is there a difference between a dhla and another type of sidedraff?

i plan on using these for a full PP motor. what amount of cfm should i shoot for?

1BADSP · 03-04-10, 10:24 PM

i had my weber 51 ida running 46 mil chokes,at around 800 cfm,this was on a pport 13b.

sen2two · 03-06-10, 09:01 AM

i did find parts for ida webers. and how to make a 48ida into a 51 ida. but how much do the dhla and ida differ for parts use. can i use a 44 ida venturi in my dhla?

jgrewe · 03-06-10, 10:10 AM

There should be a number cast into the top edge of the venturi, look down the throat. If not pull it apart and measure it.

Berg makes some nice parts, I don't know if you would have 'venturi' action with 44's in a 48. You may need to have the carb bored out to 51.

All my big weber experience is with IDA's and DCOE's, not real familiar with the DHLA when it comes to internals.

moremazda · 03-07-10, 07:06 AM

Isn't the DHLA the horizontal Dellorto, and DCO(E) the horizontal Weber?

sen2two · 03-07-10, 09:03 AM

^yes. i did a lot of searching and found that out. My "weber" is still in the mail. If its a dellorto, im sending it back...

rotaryengineering · 03-08-10, 11:36 AM

If you purchased a DHLA it is more than likely a Dellorto side draft. These are great performing carbs but the problem is the lack of available parts. There is a company here in the Los Angeles area that still has parts and can also make whatever you need.

European Motorworks
(310)644-8038 and ask for George or Javier

If you are looking for the highest air flow to make the most power with your P-Port I would recommend a Weber 55 DCO side draft for the price you can't beat it. They actually ship brand new out of the box with a 48mm choke which is a good starting point. These carbs are a true 55mm barrel from entry to the butterfly. These carbs are half the price of a Terminator II or Gene Berg IDA style carb. The only restriction I see is if you wanted to use some other fuel other than pump/race gas. Using Alcohol or E85 you will run into float bowl capacity issues. These is no room to extend the bowl like you can with an IDA style carb.