Manual trans numbered q jet on auto 455

False alarm.....Happens's to me all the time.

 

Sorry the numbers didn't pan out Speedfreak but as you said you have the correct one for your car.

What carb book are ya'll talking about reading? I sure could use some help with a condensed book like that : )

 

Thanks very much Cliff for your detailed explanation!

 

You are most welcome.

I would add here that the engine will also get a "dump" of fuel from what is available in the fuel supply passages leading up to the secondary nozzles. This happens same as the secondary POE fuel and helps prevent stumble/hesitation/bog going quickly to full throttle. Fuel is also added by the primary accl pump so the length of the pump, duration spring, and size of the exit holes will have fuel continuing to be added well past the initial opening point of the secondary throttle plates since they are mechanical, not vacuum operated.

The big key to preventing stumble/hesitation/bog is to find the right combination of choke pull-off release time, spring tension on the flap, and adding enough fuel to cover a potential lean spot as the large air flaps open all at the same moment.

The height of the hanger and type of secondary metering rods used are also players here. The single most important part in this "recipe" for smooth transition will be the choke pull-off, followed by the primary accl pump and POE.

IF the secondary airflaps are adjusted with too much free travel from the choke pull-off link it will create a momentary lean condition the instant the flaps open. This will also happen if the choke pull-off and/or link up to the air flaps is not used.

So that little diaphragm on the side of your carburetor that few folks pay attention to, or modify/adjust the opening rate of, or take up the slack in the linkage is more often than not the first place where a potential lean condition is created when you go to full throttle.

We offer "timed" choke pull-offs here, and even make adjustable pull-offs for serious tuning. We also take every single plastic pull-off apart and internally modify them as the current ones being sold are WAY too quick and make secondary tuning difficult, if not near impossible.

When you have everything in the mix correctly adjusted, you should NOT feel any noticeable transition when you go to full throttle. The entire load/speed range should be linear, or without any "kick", lunge or noticeable transition.

That last statement is difficult for folks to get their heads around as they expect the secondaries to produce some sort of huge "kick" like a small snot of nitrous or lunge like you often see when using a Holley DP carb. Although smooth transition is a bit "boring" compared to a big "kick" when the secondaries come in, it will produce quicker ET in 60' times at the track every single time.

Here is a link to my car at the track, with perfect traction, super tight converter, and 3.42 gears. Notice that the car leaves very clean and the power is linear. Not the first hint of any sort of transition when the secondaries are coming on right off the starting line. This is what we tune for with these engines.....hope this helps some......Cliff

 

Manual trans applications are a little different. You don't want as much delay in the secondaries opening between shifts. Unless of course if you shift without lifting