This is for you carburetor guys,
I run a 570 cfm Holley Avenger Carb. I used to work good but then I had trouble getting the secondary's to open until finally the secondary's wouldn't open at all. It ran really well with just the two barrel side. You could kick it and it responded instantly and ran real smooth. Today I fixed the problem with the secondarys. I had a bad diaphram. Where I had taken it off once before I crimped the diaphram and put a hole in it. So I put a new one on it and fixed it.
NOW. Every time I kick the gas it bogs. No matter what gear, no matter what speed, when the secondarys kick in it bogs for an instant and then goes like it's hair is on fire. I'm using the black spring ( heaviest of them all ) in the diaphram housing.
I'm reading every thing I can get my hands on about this problem but I thought maybe some of you guys went through this before. The power valve on this carb is #85 and the primary jets are #54 W/ #65 secondary jets. Remember that the car ran great on two barrels and the horsepower is just @ 270. Jim
Not up on the Avenger. If it has a secondary acc pump maybe the cam need changing that
actuates the pump. Had that with 660's.
Ron,
I fixed my problem. The idle circuit was too lean and I installed the blue accelerator pump cam. When I put the vacuum guage on it, it only read 15" manifold pressure at 600 rpm. I set the idle screws and got 19" manifold pressure at 600 rpm. (I don't know how it moved. I always set those to highest manifold pressure.) Anyway, it doesn't bog now. The tech from Holley thinks I need a 670 cfm carburetor. I would agree other than the fact that I've drove it for three years now too dumb to know that the secondarys weren't kicking in and I have been tickled to death with gas mileage as well as the way it ran. So putting on a bigger carburetor seems a little futile for a 270 hp engine. I'm happy having the 570 cfm i've got now instead of the 250 cfm I've been running. Jim PS. The Street Avenger carb secondary has no accelerator pump. It gets it's secondary gas by sucking the gas out of the secondary bowl by the air flowing through the secondary venturi.
It must feel like a race car now! :burnout:
Ron,
I find I have less time between shift points now. Wah-hoo . Jim PS I'm running the black secondary spring but I'm also running a 63 390 snorkle air cleaner which makes the black spring in reality a plane spring. If the bog happens to reappear I'll use a 14" open air cleaner.