stock 1982 q-jet tune

[bob69]

Looking for suggestions on increasing the jet/rod size for a stock 1982 q-jet. It's the original q-jet on a 1982 camaro z28 four speed car. Original carb, never modified. Engine is also original and stock.

With today's gas, the carb is running lean. Does this carb use the same jets as the older version.

[Cliff Ruggles]

What is the carburetor part number?

It should be a computer controlled unit if it was delivered in the US....

[bob69]

The carb is 17082203 0692 FFW. Original carb, no modifications. It is a CCC carb. Calif specifications. I'm the original  owner.

[Cliff Ruggles]

Running lean where?  Idle, light part throttle, heavy throttle w/o the secondaries, or WOT throttle?

[bob69]

The engine will surge when cruising at light throttle. Not too bad but noticeable. I feel it mostly at freeway speeds. You can hear the engine "cycling".

The car will sometimes buck really bad when running at low rpms it in stop and go traffic. This is a manual transmission car. But it does not happen all of the time. Sometimes not at all, other times the bucking is really bad. I have to disengage to clutch to stop the car from jerking. The next time I drive the car it does not do this. Very strange.

I recently had the transmission rebuilt and did a clutch change. Under the car I noticed the exhaust down pipe had a blue discoloration. At the point where the two pipes merge and for about a foot down.

WOT is ok for a stock 305. I think it was factory rated at 160 hp. WOT is only good for about 4000 - 4500 rpm.

[Cliff Ruggles]

The MC solenoid should be taking care of that for you.  Might want to raise the upper limit for the metering rods so it has more "range" to richen it up a tad.  This assumes it's working correctly right to start with.....

[bob69]

How much of an adjustment would you recommend. The 1982 camaro shop manual says the bottom lean mixture screw should be between 2 7/8 to 3 3/8 turns. If not, turn the lean mixture screw to 3 1/8 turns. Depending on what I find, how much should the lean mixture screw be raised: 1/ 8, 2/8 or 3/8 turns.

The plunger travel should be between 3/32 and 5/32. The default is listed at 4/32 travel. Should the travel be increased or just increase the lean mixture setting and keep the total travel within the stock range.

[Cliff Ruggles]

I always raise the stop so the metering rods have full travel on those units.  Then I test them and bring the stop down until I just notice the engine speed starting to drop (tip in test at apprx 2000rpms).

Never once got one back or had a complaint doing this on CCC carbs built here.  I also slot the adjustment screw in case further adjustments are needed after it gets to it's new home, but never once has anyone called with running lean issues or asked about making any adjustments.....