Carburetor Annular vs Downleg Boosters

Whats the difference between annular and downleg boosters? Which one is better? Is there a real difference between the two? We'll take a look at both and put them on a little flow fixture to see exactly how the fuel is pulled through the system.

#edelbrock #holley #boosters

[SteelSurgeon]

Your videos are awesome bro! Keep it up. A lot of us newbs need all this info and you are good at dumbing it down for us.

[johnhenderson]

This is a fantastic explanation of booster comparison and how they work. Best video I have seen on youtube explaining this. Thank you very much.

[magdump]

I came to appreciate the annular design when I bought my first cheap Summit Racing carb.
Haven’t looked back.

[edwardojr]

I love your carburetor videos!
I'm considering a Mighty Demon with the annular boosters myself

[edsmachine]

Very good video.
Thanks for sharing.
Take care, Ed.

[corey_]

Nice video bro, I learned a lot. I’m throwing a Mighty Demon 850 w/annular boosters on a LS3 crate engine. Super excited about it

[vermiciousknid]

I used to have an Edelbrock 650 off-road version, but it always ran too rich. I replaced it with an AVS 2, 650 & the difference is impressive. Acceleration is much smoother around town with much better gas mileage & no loss of power. At low throttle it drives more like fuel injection, but still slams me back in the seat when I step down hard.

[kenjarabek]

Currently restoring back to being a daily driver; 1980 GMC Caballero with: 305ci/5.0L engine, Carter Quad 4bbl, 350 Trans, 64k on the engine, runs very good.
Part of my restorations intentions will include elimination of CarterQuad, Smog sensors, air pump, catalytic converter, etc., and simple additions are hugger headers, dual exhaust (haven’t decided on mufflers yet) and either a 600 or maybe a 650cfm Holley or Edlebrock.
Would appreciate your feedback.
Cheers and thank you.

[bigblockjalopy]

Thats why engines with intakes without a heat crossover and without a working heatriser in the ex manifold MUST have a carb with an anular booster. Best is to have both.

[Torquemonster]

I switched from a well optimized Vacuum secondary 750 cfm Holley to an out of the box 850 cfm Holley double pumper with annular boosters. Holy Cow !! Could not believe the difference in the cars ability to accelerate from a dead stop. It was night and day. That carb made my 440 powered B-body pull like I had always thought it should. Why every carb does not use annular boosters is beyond me.. production costs I suppose. ?... excellent video btw. 🍻

[ricardoflores]

Great demonstration. The downleg booster has a curved shape that places the booster lower in the bore and increases the venturi pressure. The term, pressure drop, used on this video is misappropriate. The pressure is drawn downward, but does not drop, it actually increases as it gets deeper into the intake.

[steelcitycaprice.]

I recieved great understanding and appreciated the post.👍😎

[cutlsenc]

I’m running a tuned 1406 and it runs fine....but I can’t seem to get rid of the slight loss of power as you accelerate. I’m sure the avs will most likely cure the issue, just not ready to shell out the scratch just yet.

[tooljunkie]

Great demo!!!

I have an AVS Edelbrock carb, and i asked Edelbrock if the Annular booster could be sold separate and if it would would cure the bogg....

Edelbrock said nope, you need to buy the new carb..

Thanks for the video !! As always explained well, and makes it clear to understand

[kevinwestmoreland]

I've read that with an annular booster signal being stronger, fuel flow is quicker and slightly leaner jetting can be used. Is that correct? I have a holley 84010 on my 350 in my truck and the stock jetting of 67 PRI, 75 sec, and 65 over seems a bit RIC.

[ryanpaasch]

I have a Carter 625 with a bar that is like the annular? I have a 360 mopar around 400 hp it struggles a little wide open us the carb to small? Any thoughts

[DanMiller-xwyz]

I am in the process of installing an Edelbrock AVS2 with the annular rings. My previous carb is an Edelbrock Performer 1406 - 600 cfm. Yes, I have had that nuisance off-idle hesitation from that carb. I did many tunes and mods to help the problem. I am hoping that the new AVS2 will completely solve that problem. Was wondering in the video, you showed the annular booster from the AVS2, removed. Do you know if Edelbrock sells those annular boosters as a possible upgrade to an older Performer ? They boosters look very similar.

[brianfrancis]

i have fe360 with 390 intake and heads bored 30 over stock c6 trann with 468 comp cam what be best set up carb put it in galaxie f street

[triumph]

I've watched several of your video's today. Seriously considering swapping out my 950 DP Holley for the 800 Edelbrock AVS2. I've got a 468 BBC and while it runs fine I feel the 950 is too much for the street. I want to thank you for helping me make the decision to switch. Always wanted too try a annular discharge carburetor and your video's are very helpful and educational. I now understand why I could never get an Edelbrock carb to run right. Thanks again.

[britdragster]

Can you swap from a regular straight leg or down leg booster to a annular booster in a 4150 style carb?