Any impressions on the Edelbrock AVS 2 series of carburetors?
12-27-2017, 11:35 AM
#1
Racer
Thread Starter
Any impressions on the Edelbrock AVS 2 series of carburetors?
Has anyone fitted an Edelbrock AVS 2 carby on their C3 vette and what was their impressions? I have the Quadrajet, supposedly rebuilt unit, but has a major bog issue and mpg is in the 7 - 9 range on hwy (L82 original motor, rebuilt, 79 Vette). Yeah, I could rebuild it (again) but then I like the fact that with Edelbrocks you can do some tuning as an end user w/o having to disassemble or even take the carburetor off the engine. Thanks!
12-27-2017, 11:48 AM
#2
Has anyone fitted an Edelbrock AVS 2 carby on their C3 vette and what was their impressions? I have the Quadrajet, supposedly rebuilt unit, but has a major bog issue and mpg is in the 7 - 9 range on hwy (L82 original motor, rebuilt, 79 Vette). Yeah, I could rebuild it (again) but then I like the fact that with Edelbrocks you can do some tuning as an end user w/o having to disassemble or even take the carburetor off the engine. Thanks!
I consider them to be a very well designed modern carburetor that is perfectly suited to street engines.
12-27-2017, 01:28 PM
#3
Dr. Detroit
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The AVS 2 is just the previous model with annular style boosters.
I have tuned The Edelbrock a thousand times and here is what I have to say:
*) DO NOT run more than 6psi to the inlet. It will bleed down excess pressure AFTER the engine is shutoff sending raw fuel down the intake throat.
*) DO NOT use an adapter to adapt it to a spread bore Q-Jet manifold. The distribution from the mis-match on the primaries is awful and you will never get it to run right......it reverses through the venturi and turns everything black......buy a Performer 2101 manifold to go with it...(or equivilant).
*) Do play with the spring loaded secondary flap......it is much like a Q-jet in this regard......you can adjust it.
*) Listen all you want to people who slam these units.......The Q-Jet IS a better mixer overall.....but cores are dried up and what is left out there is junk. Refurbishing a used up core is big $$$$$..........and yes Lars is a genius with these.......I myself was very good at them at one point but have not touched one in years as there just plain ISN'T any around anymore.
*) Read Edelbrocks manual....everything you need to know is in there.
*) A carb mixes fuel......if you bolt a new one on and it runs like **** then check elsewhere.....ignition and or timing.
*) I ran an AVS on my 66' 327/350 (Car in the Avatar) for years and it after I tuned it....it ran perfect....never an issue and ran like F.I.
This was on a 2101 Performer with an MSD distributor and box......it was astounding how it hit instantly with the key and how it pulled down 15-16 MPG.............
*) 400 horsepower and about 12 inches or lower of vacuum and these carbs are done.....the metering rods get confused and the air horn is just plain restrictive for moving air. Anything below that is fair game. The Eddy is an excellent street piece and nothing more.
Jebby
I have tuned The Edelbrock a thousand times and here is what I have to say:
*) DO NOT run more than 6psi to the inlet. It will bleed down excess pressure AFTER the engine is shutoff sending raw fuel down the intake throat.
*) DO NOT use an adapter to adapt it to a spread bore Q-Jet manifold. The distribution from the mis-match on the primaries is awful and you will never get it to run right......it reverses through the venturi and turns everything black......buy a Performer 2101 manifold to go with it...(or equivilant).
*) Do play with the spring loaded secondary flap......it is much like a Q-jet in this regard......you can adjust it.
*) Listen all you want to people who slam these units.......The Q-Jet IS a better mixer overall.....but cores are dried up and what is left out there is junk. Refurbishing a used up core is big $$$$$..........and yes Lars is a genius with these.......I myself was very good at them at one point but have not touched one in years as there just plain ISN'T any around anymore.
*) Read Edelbrocks manual....everything you need to know is in there.
*) A carb mixes fuel......if you bolt a new one on and it runs like **** then check elsewhere.....ignition and or timing.
*) I ran an AVS on my 66' 327/350 (Car in the Avatar) for years and it after I tuned it....it ran perfect....never an issue and ran like F.I.
This was on a 2101 Performer with an MSD distributor and box......it was astounding how it hit instantly with the key and how it pulled down 15-16 MPG.............
*) 400 horsepower and about 12 inches or lower of vacuum and these carbs are done.....the metering rods get confused and the air horn is just plain restrictive for moving air. Anything below that is fair game. The Eddy is an excellent street piece and nothing more.
Jebby
Last edited by Jebbysan; 12-27-2017 at 01:29 PM.
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Lagonia (12-27-2017)
12-27-2017, 04:49 PM
#4
I just put an AVS 2 on my 75 L82 and I love it. It’s been in the 30’s up here and it still runs amazing. When I got the car it had an old Edelbrock 1406 carb on it that was leaking fuel out the side leakage, I didn’t feel like rebuilding a carb that wasn’t original to the car so I threw a AVS 2 on it. Best decision I made. It runs smooth and doesn’t have any dead spots when going from idle to moving.
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Lagonia (12-27-2017)
11-19-2018, 06:24 PM
#5
Heel & Toe
Avs 2 carb
*) 400 horsepower and about 12 inches or lower of vacuum and these carbs are done.....the metering rods get confused and the air horn is just plain restrictive for moving air. Anything below that is fair game. The Eddy is an excellent street piece and nothing more.
Jebby
11-19-2018, 06:35 PM
#6
Dr. Detroit
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hello, I have a question about this statement. Does that mean if you have 400 or more hp then this carb will not work? Long story short I have a 383 and on PAPER it should have about 400. I know paper isn’t real life but let’s just say it does. I should not get this then? I thought about getting it cause my stock q-jet has a wot lean miss and I believe it’s due to lack of fuel in the bowl with the secondary’s opening. I asked edelbrock and summit and both said it would work. Thanks
Now the 400 horse number I threw out there has a few things about it that you may want to consider......
1) A lot of small blocks that make 400-425 horsepower do not make 12” of vacuum.....this is changing as modern heads become more accessible to the backyard guy/gal.....it is easier to make good power now with less cam.....but you need 12” of vacuum or better for these carbs to meter correctly or they just go pig fat......top that off with a super restrictive air inlet on both the primary and secondary......these carbs create a LOT of turbulance when they start flowing real air.
I had a 650 AVS on my 66’ 327/350 and it was amazing.....but that car made maybe 380-390 horses and made 13” of vacuum.
2) The Holley DP or the HP are real performance carbs with real tunabilty.....they are designed to move air....and with four corner idle it is as good as it gets...they are much better suited for low vacuum situations and move clean air/fuel at WOT.....
The Edelbrock May work in your application.....but if you have too many issues with it.....sell it and move on......
Jebby
Last edited by Jebbysan; 11-19-2018 at 06:36 PM.
11-19-2018, 06:53 PM
#7
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Has anyone fitted an Edelbrock AVS 2 carby on their C3 vette and what was their impressions? I have the Quadrajet, supposedly rebuilt unit, but has a major bog issue and mpg is in the 7 - 9 range on hwy (L82 original motor, rebuilt, 79 Vette). Yeah, I could rebuild it (again) but then I like the fact that with Edelbrocks you can do some tuning as an end user w/o having to disassemble or even take the carburetor off the engine. Thanks!
I love the smaller primaries and the gigantic secondaries of the Quadrajet which tends to give better gas mileage than I have experienced with my edelbrocks. It sounds like you have a very rich mix if you are getting such poor gas mileage or your timing is way off. I would determine your timing setting, get it set to about 14-16 at idle and make sure its about 34 or 36 all in by 2500rpm. If that checks out, look at your secondary flap setting and maybe set it a little tighter to get rid of the bog. If you are not the original owner or cannot confirm that no one has changed the rods in your carb, then You may want to send it to Lars. It will cost less than the AVS2 and it will be better in the long run.
I do ALL my own work on my vette from rebuilding the engine and tranny down to all the wiring and alignments, but I left the carb rebuild to Lars to make sure i had a good working unit and that it was done right tthe first time. I have 2 other Quadrajets I'm going to take apart and try rebuilding myself to see if I can get it close to as good a job as Lars does, If not I'll send them to him, again.
11-19-2018, 06:59 PM
#8
Heel & Toe
I should just make a new post about this but maybe you can help. Long story short I have a 383, I forget the exact cams in it but it has trick flow heads, mild comp cam(can get spec if needed) 10.1:1 compression na. I put a blower on it due to getting from a family friend and he always planned on putting a blower on it. I have a 142 and running 2lbs of boost and with my calculations I am at about 11.8:1 (I know I’m not over the 12:1 for pump). I have a stock 750 qjet that has a wot lean miss with that due to wrong carb and bowl size. But I want to drive it and don’t plan on racing it so I want to stay away from a blow thru carb espectually when I’m not putting much boost in it and the mrs already hates the projects on the car. Do you think a double pumper 650 will work fine then?
11-19-2018, 07:01 PM
#9
Le Mans Master
You mentioned you have a pretty OEM L-82 and are looking for a carb to replace the Qjet. I have had a Holley 4175 650 CFm vacuum secondary Qjet replacement carb on my L-82 since the 1985. It is a fabulous carb with great tune ability, excellent performance, very similar MPG to a qjet (maybe 1 MPG less..who cares?) and easy adjustment and rebuild ability. I now use this very same carb on my upgraded rebuilt L-82 355 with 425+ gross hp with minor jet changes (super easy) and the same vacuum secondary spring kit from 30 years ago (lightest secondary spring). All tuning can be done on the carb on the car! My 4175 has serviced the OEM L-82 all the way to a strong L-82 355 with AFR heads and roller cam with 10.2 compression. THIS IS A GREAT CARB. The 4175 even has small primaries and giant secondaries just like the Qjet,,,,,,,
The Holley 4175 spreadbore carb is almost an exact replacement for the Qjet spreadbore fitting perfectly on the l-82 aluminum intake, vacuum hoses, and throttle linkeage. The only glitch is a slight mod to the fuel line to fit the 4175.
Do yourself a favor and check out the Holley 4175 first before considering anything else.........I really wonder about all the different carbs folks use on fairly stock engines when replacing the Qjet when the 4175 will fit the bill for most applications with very minor installation adjustments required, easy tune ability, and with certainly the same performance or Better than a Qjet
The Holley 4175 spreadbore carb is almost an exact replacement for the Qjet spreadbore fitting perfectly on the l-82 aluminum intake, vacuum hoses, and throttle linkeage. The only glitch is a slight mod to the fuel line to fit the 4175.
Do yourself a favor and check out the Holley 4175 first before considering anything else.........I really wonder about all the different carbs folks use on fairly stock engines when replacing the Qjet when the 4175 will fit the bill for most applications with very minor installation adjustments required, easy tune ability, and with certainly the same performance or Better than a Qjet
Last edited by jb78L-82; 11-19-2018 at 07:15 PM.
11-19-2018, 07:11 PM
#10
Dr. Detroit
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I should just make a new post about this but maybe you can help. Long story short I have a 383, I forget the exact cams in it but it has trick flow heads, mild comp cam(can get spec if needed) 10.1:1 compression na. I put a blower on it due to getting from a family friend and he always planned on putting a blower on it. I have a 142 and running 2lbs of boost and with my calculations I am at about 11.8:1 (I know I’m not over the 12:1 for pump). I have a stock 750 qjet that has a wot lean miss with that due to wrong carb and bowl size. But I want to drive it and don’t plan on racing it so I want to stay away from a blow thru carb espectually when I’m not putting much boost in it and the mrs already hates the projects on the car. Do you think a double pumper 650 will work fine then?
Jebby
11-19-2018, 07:20 PM
#11
Heel & Toe
Yea I mean it’s not a super built engine with insane power. Internal balanced 383 4 bolt main 12-2463-3 comp cams, 23 degree trick flow heads and a blower. The blower is the only reason I’m switching carb, great carb til the blower. I’ll check that one out though. Thank you
11-19-2018, 07:28 PM
#12
Heel & Toe
One more question. Thanks again for all your knowledge. Will not having a choke cause problems being a street car other than having to warm it up before starting to drive which I do anyway? In relation to the 750hp I’m assuming your recommending this one right https://www.summitracing.com/parts/h...28-1/overview/
11-19-2018, 07:30 PM
#13
Dementer sole survivor
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A choke is only for cold starts in cold weather. If you get it started and let it get up to operating temp then it would be in the off position if it were installed anyway. So you will be okay
11-19-2018, 07:31 PM
#14
Dr. Detroit
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One more question. Thanks again for all your knowledge. Will not having a choke cause problems being a street car other than having to warm it up before starting to drive which I do anyway? In relation to the 750hp I’m assuming your recommending this one right https://www.summitracing.com/parts/h...28-1/overview/
Not having a choke is a cold weather thing.....I don’t use them here in Texas.
Jebby
11-19-2018, 07:41 PM
#15
Le Mans Master
I ran 750 double pumper on many cars in northern virginia years ago and never used a choke on any of them.
I agree the holley spread bore is a good carb.Edelbrock put a band aid on an old carb that everyone in the 60's and 70's used as a dor stop. Or send your q jet to lars.
I agree the holley spread bore is a good carb.Edelbrock put a band aid on an old carb that everyone in the 60's and 70's used as a dor stop. Or send your q jet to lars.
11-19-2018, 07:43 PM
#16
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we got 8 inches of snow last tuesday, and we are supposed to get 2-3 more tonight into tomorrow. Its supposed to be 23*F high on thanksgiving. No driving here locally until spring.
Last edited by Rescue Rogers; 11-19-2018 at 07:44 PM.
11-19-2018, 07:44 PM
#17
Heel & Toe
Car doesn’t see cold weather anyway. It goes away around sept here in pa. I knew it was cold starts just didn’t know if it would be hard to start being cold in general.
11-19-2018, 07:47 PM
#19
Heel & Toe
I ran 750 double pumper on many cars in northern virginia years ago and never used a choke on any of them.
I agree the holley spread bore is a good carb.Edelbrock put a band aid on an old carb that everyone in the 60's and 70's used as a dor stop. Or send your q jet to lars.
I agree the holley spread bore is a good carb.Edelbrock put a band aid on an old carb that everyone in the 60's and 70's used as a dor stop. Or send your q jet to lars.
11-19-2018, 07:48 PM
#20
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I love the people that get a SUV then go 80 mph down the highway in a snow storm. Its quite a show a few miles later