Size of carb - Nova Tech
Nova Tech  
Find Nova Parts at SS396.com     
GROUND UP & SS396.com         
Official Sponsor of Team Nova
   

Auto Insurance



Engine General Engine Discussion.

Novas.net is the premier Chevrolet Nova Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old Jan 29th, 08, 12:03 PM
Stonecrest Stonecrest is offline
 
Join Date: Jan 2008
Posts: 3
Stonecrest has a positive reputation
Default Size of carb

Hello, im new to this site and i have a quistion. At the moment i have a 71 nova with a 350 and im pushing a little over 300 hp and i curently got a new intake and carb from summit. I got a elderbroke 750 carb and im experiencing stalling when i start off, my uncle checked the carb and the distributor suction and all that stuff and he said that the engine doenst have enough horse power for the carb and its putting out to much gas. I never thought you could get a "to big" carb, also when ever my friend is behind me he says he is smelling a lot of gas. So could this be the problem with the stalling when i start off? Thanks
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old Jan 30th, 08, 08:46 PM
Big Dave Big Dave is offline
Site Moderator
Dave
 
Join Date: Mar 2006
Location: Tampa FL
Posts: 17,539
Big Dave has a positive reputation
Cool Re: Size of carb

Yes you can over carburate an engine, especially if you do not use a vacuum secondary carb. 750 cfm will feed 650 horse power with no difficulty. The LS-6 450 horse 454 BBC left the factory with a 780 cfm Holley, and it would bog at the hit of the throttle unless properly tuned. A 350 cid motor will be quite happy with a 600 to 650 cfm vacuum secondary carb, and will cheerfully run up to about 5,400 RPM with a Holley 450 cfm carburetor (I use Holley because I have personal experience with them, not because there is anything wrong with the Carter AVS you have).

Big Dave
Reply With Quote
  #3  
Old Jan 31st, 08, 12:11 AM
mcarmaniac mcarmaniac is offline
 
Join Date: Jan 2008
Posts: 179
mcarmaniac has a positive reputation
Default Re: Size of carb

yes big Dave is right you can over carburate your motor. I have a 327 in my chevyII with a .30 over bore, heders, hei distibuter and performer intake, and they are telling the biggest I want to go would be a 650 so I may end up getting a 600 edelbrock. And my motor is farley stock to so I would think a 600 or 650 would work for you. Just call the support guys at summit or jegs and ask what they recomend thats what I always do, it'd best to have a bunch of opinions in my opinion
Reply With Quote
 
  #4  
Old Jan 31st, 08, 10:56 AM
jays64II jays64II is offline
Senior Tech Team *
Jay
 
Join Date: Jan 2007
Location: way far south jersey
Posts: 1,113
jays64II has a positive reputation
Default Re: Size of carb

The edelbrock 750 should be fine on that motor with th proper tune
__________________
720+ horse 385 small block with 23 degree heads.

Mazzoni Enterprises & Outlaw Autoworks
[email protected]


http://inlinethumb57.webshots.com/12...600x600Q85.jpg
Reply With Quote
  #5  
Old Feb 4th, 08, 12:04 PM
Stonecrest Stonecrest is offline
 
Join Date: Jan 2008
Posts: 3
Stonecrest has a positive reputation
Default Re: Size of carb

Thank you very much dave, Im guessing im gona go with a 600 carb and that should stop the probelms, man i didnt know a 750 was for like a 650 hp engine. Thanks for all the help guys
Reply With Quote
  #6  
Old Feb 4th, 08, 04:22 PM
Big Dave Big Dave is offline
Site Moderator
Dave
 
Join Date: Mar 2006
Location: Tampa FL
Posts: 17,539
Big Dave has a positive reputation
Default Re: Size of carb

More important than the flow rate of the carb is how the carb gets it's signal as to engine load. The boosters (those round donuts on a stick that hang out into the venturi) come in three different designs (with ever increasing price tags). The stock straight leg has not changed much since Mr. Benz of Mercedes-Benz fame invented the carburetor 160 years ago. The next improvement is found on Holley’s HP series of carbs, and is the down leg booster. It places the booster further down in the venturi to amplify the vacuum signal that often gets lost with rumpity-rump cams.

Finally, if you really want to save money on gas and maximize the power out put of the engine (by lowering your Brake Specific Fuel Consumption number) you want annular boosters on your carb. This feature will allow you to run an 750 cfm on a 350 and still have good throttle response and top end flow with fewer tuning issues (actually if you used a vacuum secondary you could run an 850 carb without issues). An annular booster nearly doubles the price of the carb but you can recoup that cost in fuel savings on a daily driver.

Look at Holley’s new carb picker software on their web site. You answer a few questions (honestly now) and it will make a recommendation as to the correct size. That still leaves you with many choices as to finish and style. The annular boosters are not available on Holley’s low end 4160 carbs, but I think you can still find a down leg.

I do not work for Colt Industries (In interests of disclosure I do own their stock, but I have bought a lot of losers as well), and I am quoting Holley only because that is the carb I have used for the past four or five decades; they are not superior to any other brand, and many other carbs have similar features.

Big Dave
Reply With Quote
Sponsored Links
Advertisement
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
slick size + finding same in street tires dgas Wheels & Tires 11 Jan 27th, 08 01:23 PM
carb make and size joe70 Performance 2 Jan 12th, 08 11:03 AM
Rebuilding Carb 1972nova Performance 5 Dec 28th, 07 12:01 PM
70 L78 carb question l88z16 Engine 0 Oct 19th, 06 04:30 PM
283/195HP to 283/220 Hp Intake @ Carb FXRS1HD Engine 3 Sep 3rd, 06 06:54 PM


All times are GMT -4. The time now is 06:40 PM.


© 2009 AutoForums
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.