Edelbrock 800 AVS2 Tuning

[SlinktRR]

I have run an Edelbrock AVS 800 (1812) for a few years now on an RB 499ci stroker. It dyno'd at 600bhp and 625 ft-lbs torque and runs really well with a ported holley street dominator and trick flow 240's, 18 initial 34 total timing. Cam is Comp XS290 solid, so 10" vacuum most of the time. My wife keeps complaining about the fuel smell. The AVS I have tends to run lean at idle, so I've been adjusting here and there to clear that up. Full throttle, idle performance, in gear it runs great just the lean stink. I bought the 800 for super cheap used years ago so I figured hey I'll buy the new AVS2 800 from summit, it should just bolt on and go.

I put it on and tried to set idle. It idled beautifully, 10" vacuum on the gauge at 1000 rpm. The old 1812 came stock with .113 jets, but I changed those to .104 when I first got it and tuned to 7052 metering rods which is how the 499 engine liked it. The new 1912 AVS2 comes with .104 main jets but stock calibration has 6552 rods and orange 5" springs. So I ran it like that and it idled smooth. Idle screws 2 turns out, like the old carb.

Then I put it into gear and it would die. Checked plugs, lean. I had to go 5 turns out on idle screws until it would idle in gear, which I have never had to do on an AVS. Also put in yellow 4" springs. Still rough in gear but wouldnt die. Around town it ran terrible so I used the edelbrock chart and started changing rods. Any change and the idle would go bad in gear. I had to do other things at home so I set back to stock drove back and parked it.

I'm going to go through the old AVS and clean it up, recondition it to put back on if I need to. In the meantime I'm going to call Edelbrock to see what ideas they have and also ask FBBO for some help. To sum up, only change was AVS to AVS2. Jet change? I may need to deviate a lot from the edelbrock tuning guide for jetting. The good news is the lean stink is gone, but it runs like *** so not a good trade off. The 5 turns out idle screws also threw me for a loop which makes me think there is something wrong in the idle circuit of the new carb.

 

[4mulas]

I have the 1913 carb. Only Diff is e choke I think.

Engine- 451 with Hughes SEH3236bl-10, changed to 6557 rods and left orange springs in. Stock jets. No problems here. 3550’ elevation....

 

[ruffcut]

Curious to see what you learn. I have a new 800 AVS2 onmy 512 stroker build. Hasn't been started yet. ruffcut

 

[Bee1971]

I pulled the top off my brand new 800 AVS 2 right out of the box a few summers ago

Just to verify float level and drop and check things over

Glad I did - I don’t know if it would have even ran , the primary float was barely letting the needle off the seat

And one of the float baffles was not installed in the slots or grooves

I said , wonderful - Anyways this was replacing a pretty damn near perfect running 1970 Carter AVS 750cfm that I rebuilt and converted over to Edelbrock Jets and Needles

Back to the Eddy 800 AVS 2

Have it set up as 5/16" float levels instead of the recommended 7/16" using a drill bit underneath the middle of both floats

1" float drop on both

I run the pink springs , as I have around 13" vacuum at idle (Comp XE275 HL)

Played with primary Jets down to .101 at one point , but back to factory .104 P .104 S

.068X.052 Needles

Around 1.5 turns out on each mixture screw for max vacuum

I run the exact same timing as you do

383/432 Stroker - E Street 75cc Heads

Idles in gear around 600/700 RPMs all day long , instant throttle response off idle
Can destroy the 275/60 Rear Tires off idle from Green Bay to Chicago if I wanted
LOL



Best street carb I have ever bolted up

I would imagine you guys running 500 C I D Strokers would or might have to go richer

If yours is dying in gear , needles and jets won’t fix that , and five turns out on screws

Something else is going wrong

 

[SlinktRR]

I forgot to check the floats, for sure. And that has happened to me before with an AVS. Check floats, air bleeds and blowing out the idle circuit is my plan for now until edelbrock calls me back.

 

[SlinktRR]

Update: went through the entire carb but no dice. Something very wrong with the idle circuit that I could not clear up. Lean everywhere. RMA back to edelbrock, summit gave me full refund.

While messing with the 1912 I rebuilt the 1812 completely with a carb dip in dichloromethane and new gaskets, now the bastard runs like new. Lot of varnish in the idle passages and air bleeds. 12" vacuum at 800rpm and no lean stink. The wife is fine riding in the car again hallelujah. The 1912 annular boosters fit the 1812, too bad edelbrock doesn't sell these separately!

 

[CoronetDarter]

Glad to hear you got the 1812 running. I recently swapped my FiTech FI for the 800 AVS2. I'm absolutely amazed at the idle quality and part throttle response. The motor runs better than on the FI. Something must've been wrong in your carb.

 

[Bee1971]

Anyone ever flow test one , with these huge annular boosters hanging up front

Dyno test numbers say on a 500-600 HP Stroker Big Block with this 800 AVS2 compared to say a Thunder AVS 800 or a comparable Holley


Just curious if anyone has actually tuned one and what they learned versus driving around on the street

 

[moparedtn]

The 1912 is in Fred's immediate future, unless someone can talk me out of it.
The old raggy 1812 this 440 came with (which I've doctored and nursed through a lot) has about
had it and it's time for a proper carburetor.
Glad to read the positive reviews of others, thanks!

 

[lewtot184]

This isn't apples to apples but I tuned an 1813 for friends big block Chevy. Ended up with .107 up front with 68-47rods, orange springs and 104's in the back. Runs and drives very well. I was impressed. Be sure to check the idle jets, should be around. 040".

 

[ruffcut]

After getting my build running, had to lean the carb by 7 or 8 % and seems to be much better. Most would think a 512 would want more fuel! Go figure.

 

[lewtot184]

You may have a fuel delivery problem and not a lean jetting problem.

 

[ruffcut]

IT WAS TOO RICH OUT OF THE BOX

 

[Geoff 2]

If I was selling a 'universal' carb, I would make it rich to avoid engine damage, which can occur if the mixture is too lean.

With the carb in this thread, I would raise the float level 1/16". The actual level of fuel in the bowl depends on three things: fuel pressure, n/seat orifice size, n/seat design [ windowed or not ].
Edel says 7/16" for the f/level, but that is with 5.5 psi fuel pressure.

 

[Bee1971]

Running a A/F Gauge ? I would assume primary circuit , jets or just metering rods

After getting my build running, had to lean the carb by 7 or 8 % and seems to be much better. Most would think a 512 would want more fuel! Go figure.

 

[ruffcut]

Running a A/F Gauge ? I would assume primary circuit , jets or just metering rods

Can't say as it was last year, but may have been both jets and rods. I've been using Edelbrock carbs for 30 to 40 years,and have them on multiple vehicles and fine tuned them to what the vehicle liked.
I have 2 750's on my MW race car (AVS carbs) and they were good right out of the box. And yes, there's A/F gauge on there as well.

 

[Bee1971]

You may have a fuel delivery problem and not a lean jetting problem.

Yes , in the secondary circuit

After verifying fuel pressure like mentioned , fuel flow to the carb , throttle linkage , throttle plates fully opening

Verifying the .104 secondary jets , going to .107 with no change

Removed the secondary jets again , tried carb clean thru the passages with no luck , removed the secondary boosters , flow thru those alone , just couldnt get decent flow thru the passages , even compressed air

Edelbrock Quality Control

Told him to return it back to Summit Racing

Verified by bolting on my old Carter Weber Competition Series 750 cfm on his stroker motor - Ran AWESOME on top end , ran pretty good everywhere honestly - Other then that weighted air door that i hate