Yeah, i have read that rich idle is a common issue.. how has it been since you sorted it?
Edelbrock 800cfm AVS2
- Thread starter Jeff Seighman
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First test drive showed a significant difference in power. After adjusting the transmission kickdown linkage, they were chirping 2nd gear. Overall, very good carb once it's calibrated correctly.
Rich at idle? Shouldn't the idle mixture screws take care of that as long as the carb is working properly and the fuel pressure isn't blowing fuel past the needle and seat? I can see a little extra initial timing might help with that.
Nice, thanks for the reply... i am prolly gonna end up going with a 800 and pray for the best
This carb was rich everywhere. At idle. Under acceleration. You name it, it was trying to drown itself. I only mention at idle because that's when my eyes were watering the most. Lol
These neighbors are from Monmouth CA which is at 7,000ft. We're now at 2800ft. I don't think they ever adjusted the carb while living at altitude, so this motor was trying to drink itself to death from the day it was installed. Their initial timing was around 9°-10° if I remember correctly. It was a dog. Once we leaned it out, that old girl was chooching!
Ohh man.. that red one is a dream carThis carb was rich everywhere. At idle. Under acceleration. You name it, it was trying to drown itself. I only mention at idle because that's when my eyes were watering the most. Lol
These neighbors are from Monmouth CA which is at 7,000ft. We're now at 2800ft. I don't think they ever adjusted the carb while living at altitude, so this motor was trying to drink itself to death from the day it was installed. Their initial timing was around 9°-10° if I remember correctly. It was a dog. Once we leaned it out, that old girl was chooching!
800 AVS on my 10.5-1 - 340, ported aluminum heads, RPM, etc..Nice, thanks for the reply... i am prolly gonna end up going with a 800 and pray for the best
Works excellent.
Thanks. been researching all moring, think i'm gonna go with the 750 street demon..
Jeff Seighman
aka jeffnmo
No I have not, with my back giving me fits and moving I haven't had time, but to answer one question I did put on a fuel pressure gauge and it is fine. I do have a kit now and will let you know what I had to do to make it right.
damn.. been months, sorry bout your back.. I am actually gonna go with a Street demon which is pretty much a new design thermoquad... will see how it turns out.. good luck!
Jeff Seighman
aka jeffnmo
The AVS 2 is a great carb from all I've read, just needs a little dialing in.Nice, thanks for the reply... i am prolly gonna end up going with a 800 and pray for the best
I have always run a carter or holley.. never a TQ and the design is pretty interesting.. should be fun to play with
Jeff Seighman
aka jeffnmo
Thanks, but it's my fault, I've been trying to do to much and need to slow down.damn.. been months, sorry bout your back.. I am actually gonna go with a Street demon which is pretty much a new design thermoquad... will see how it turns out.. good luck!
Not necessarily with a metering rod carburetor. If there's a lumpy cam with a low vacuum signal, the metering rod springs will be too strong and put the metering rods in their rich sections at idle. That's why tuning these type carburetors with a vacuum gauge is so important. You install a spring rated at an hg reading lower than what your idle vacuum reading is. Like on Gladys, she has 6hg at idle and bounces around a little because of the erratic idle of the cam, so I chose the 4hg springs and that keeps the metering rods on the lean step at idle. As soon as vacuum drops under 4hg, they get into the rich step for enrichment.
Man, I've been nursing a hurt back for months now. It gets better, then I re aggravate it. Rinse and repeat. I caint just stop doin stuff.
Yeah.. i'm hating getting old... i have had 2 pinched nerves in my shoulder/neck for 4+ months now.. arm randomly goes to sleep or just hurts... been a lot of fun
I can sympathize with that, TOO!Yeah.. i'm hating getting old... i have had 2 pinched nerves in my shoulder/neck for 4+ months now.. arm randomly goes to sleep or just hurts... been a lot of fun
That’s enough cfm.
Now do you have a TQ or is this in reference to the ST Demon carb? While it has some similar items, they’re not exactly the same.I have always run a carter or holley.. never a TQ and the design is pretty interesting.. should be fun to play with
Note to all, that have not had one in my hands…… yet…..
Looking forward to the report.
The ST Demon... i always heard TQs were amazing IF you could get them to work.. and IF you can keep them from leaking.. i spent hours today learning bout different carbs and i like that the ST is a re-design and not just a copy and seems like a great idea all around. Time will tell.. be a few months still. I will be taking it apart and checking everything beforehand for sure though.
It's in my cart at Speedway, a 750CFM with the composite body + Aircleaner setup which i needed anyway for $536 shipped.. which is much less than other carbs i had looked at.
Cool man cool!
The TQ, being old these days, can be a hit or miss on the quality of the carb. Figure the best are the early non emission models from ‘71-‘74-ish area except truck models which have less vacuum hook ups on them since they were exempt from what cars had to put up with. That’s a lot of time!
Throttle shafts wear out but are fixable with a bushing. The main body, if available these days from Tomco, can show there short comings with to much heat applied to them, which, back in the day, in order to meet the restrictive tail pipe requirements, the factories raised the engine operating temps upwards with thermostats @195*’s. Add in summer heat.. the phenolic resin would crack under the heat.
Rule #1 w/a TQ, keep it cool, cool as possible, start with that very thick gasket the factory used!
I’ve had one warp on me and one crack. No other issues through their usage with me.
Once you have a good one, no cracks or warpage & good throttle shafts, etc…. Like any carb should be…. Their learning curve isn’t to bad. They’re different in a sense and not different.
I agree. Looks and seems like a great idea. Though I’m not a fan of having to remove the carb in order to change jets. But I guess there’s a caveat to everything!
Good move on the composite body.
yeah... doing research it seems that their jetting is VERY self-adjusting for lack of a better term so not near the narrow range like holleys.. so shouldn't need too much tuning. I never understood how the rear airdoor worked on TQs and now that i know i'm all in.. it's a genius idea that should give a lot nicer transition once setup properly.
The TQ secondary side is a combo of the air door and the side pull off. It can be a PIA getting it perfect in weird way out of stock set ups.
Jetting is never self adjusting. I get what you’re trying to say but don’t think it simplified over a Holley. Approach it in the same manor and correct with the same diligence and excellence you would in trying for the best you can get.
Jetting is never self adjusting. I get what you’re trying to say but don’t think it simplified over a Holley. Approach it in the same manor and correct with the same diligence and excellence you would in trying for the best you can get.
yeah, not self adjusting.. said it bad.. but a wider range to run for each jet size (if i was reading properly..) Either way.. will be fun to play with.
The metering rods bouncing at idle on an AFB/AVS causing a rich idle....goes in the same fairy tale book as the PV on a Holley opening at idle & causing richness.
Neither is possible IF the throttle blade/ t slot position is correct. The reason is that there is insufficient air flow past the almost closed blades; insufficient air flow means not enough pressure drop to pull fuel out of the booster.
Now, if the blades are open too far at idle, then there could be sufficient air flow to activate the main system. Easy to check: see if fuel is exiting the boosters at idle. I would doubt it veeeeeery much on an AFB/AVS single booster carb. I suspect that the rich idle mentioned above is because the blades are open too far at idle [ big cam/low vac ]. The engine is getting additional idle fuel from the greater amount of T slot exposed, making it rich. Mixture screws likely have little control over the idle. The fix for this problem is to add by pass air so that blades can be closed & have the correct t slot/blade correlation.
Neither is possible IF the throttle blade/ t slot position is correct. The reason is that there is insufficient air flow past the almost closed blades; insufficient air flow means not enough pressure drop to pull fuel out of the booster.
Now, if the blades are open too far at idle, then there could be sufficient air flow to activate the main system. Easy to check: see if fuel is exiting the boosters at idle. I would doubt it veeeeeery much on an AFB/AVS single booster carb. I suspect that the rich idle mentioned above is because the blades are open too far at idle [ big cam/low vac ]. The engine is getting additional idle fuel from the greater amount of T slot exposed, making it rich. Mixture screws likely have little control over the idle. The fix for this problem is to add by pass air so that blades can be closed & have the correct t slot/blade correlation.
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