bogging problem

[tdag]

1982 camaro 5.0 the car has a rochester quardrajet, a holley high rise manifold single plane and a cam that is one step up from stock, the car runs good until I open the secondarys then it totally boggs out. I replaced the rochester with a new holley 670 street avenger and its does exactly the same thing, totally boggs out when I open the secondarys can anyone help me with this problem? thanks

[public]

Are you running a with a distrubitor? or the newer DIS system? Your vacuum advance could be stuck if you have a distrubitor.

[RandomTask]

on the note of your manifold-- what are you running, like a holley strip dominator?

High rise single plane intakes are generally for higher RPM's only. They are horrible for city driving and on a motor, they tend to starve cylinders 7 and 8 on fuel. The only way they come into play is if you can really get the rest of the motor flowing. (heads and a high duration cam) which eventually leads to none streetability. On your setup, I would reccomend going with something like a weiands stealth (http://store.summitracing.com/ part # WND-8016)

I would also reccomend putting some more voltage to your plugs-- try getting an HEI coil. But mostly, I believe your problem is your intake, the motor just can't flow enough for what it wants to dump in. Good luck!

[curtis73]

Three possibilities:

1) the secondary jets are too lean. No carb is a bolt-on unit no matter what they tell you.

2) the accelerator pump might not be giving enough of a shot, or giving up all its juice too soon not saving any for the secondaries.

3) incorrect power valve.

You've also made your task ten times harder with that high-rise single plane. It gives a very poor vacuum signal to the carb which makes tuning it a nightmare. You're also killing the torque production of the engine.

If you want my best suggestion for curing the bog, get a dual plane intake like a Performer (not the Performer RPM) and put the Qjet back on it. The Qjet is a far better street carb and you'll see the same power with much better fuel economy and drivability.

Your bog is not easy to fix because the mismatch of parts is so great that solving these issues is usually an exercise in futility. You have a displacement, bore, valve shrouding, poor factory heads, and a cam that is designed to support 150 hp, and an intake and carb that is designed to support 650 hp, and the vacuum drop is so intense that your carb can't work under those conditions. You're giving 670 CFMs to an engine that only needs 450 and it is reducing the signal to the carb so much that its not drawing air through the carb efficiently enough to even draw fuel.

You can get that 305 to perform some, but the small bores limit breathing. Better heads or port work on your current heads will help. You're probably dollars ahead to slip a 350 under all of that and then the head choices are vast.