Trans Brake vs Foot Brake

I am just wondering:

While on the T brake, the carb is held WOT and the accelerator pump is not needed, but the engine can load up the plugs because of the rev limiter cutting cyl's to control rpm.

When launching with the foot brake, the carb controls RPM and the accelerator pump needs to provide a shot on launch.

How does the carb handle the T brake launch with out the acc pump? Is it just due to the low air flow and then it increases the A/F supply as RPM goes up? Do the plugs stay cleaner launching with the foot brake?

Sorry if these are dumb ??'s but I'm just trying to get a better understanding.

Bill

on the t brake WOT there is airflow pulling fuel from the boosters.......main circuit already in play.................part throttle not so much so.

OK, thanks Jon.

I guess with the rpm's held lower, the air flow through the carb is lower too.

Bill

Foot braking, you've also used some of the pump shot, how much depends on where you're holding the throttle.

I wouldn't worry about loading the plugs. These days, rev limiters will alternately skip the plug, then fire it during every other revolution. With the engine already "spooled up" to your chosen rpm, it's already at WOT and under load pretty much at the release of the TB. The car leaves like a truck hit you from behind. It's a good idea to minimize the time that you have the brake engaged and the throttle open, too. Being on the chip and on the brake really builds heat quickly in the converter (about 100 degrees per second according to JW's). The guy you see at the starting line with his thumb on the button and his foot on the floor while he waits for the other guy to stage....is the same guy who wonders why he has so many converter and trans troubles. Best to practice so that you can get up on the chip a second or two before launch time.