So….. ever over carburate?

[B3422w5]

I'd honestly agree with you, with a converter that footbrake stalls at X RPM, and trans brake set at same X RPM, shouldn't matter. In my experience however, my trans brake cars have always managed to launch at a higher RPM, as footbrake stall is generally lower, and you're relying on the cars brakes to hold it back at least some.

We aren’t talking about the same thing. Where the car begins to creep with your foot on the brake has nothing to do with the flash of the convertor, more to do with how loose it is, and or how good your brakes are.
Say you give your convertor guy the specs on your combo and it’s set up to flash at 5300( not untypical for a hot drag race smallblock)
Whether you launch off the foot at 1500, 2000, or even 2500, the convertor still flashes to 5300.
Now say you have a brake, say you set the two step chip at 3500 or 4000, it still flashes at 5300.
Yes, you are always gonna get the car to move off the foot at a lower rpm, because unlike with a brake, you don’t have gears locked together.
But you are still basically going right to that 5300 almost instantly, either way. The only difference is reaction time. Obviously if you leave with the chip set at 4k, you have less rpm to get to the flash than if you leave at 2k off the foot. But this makes zero difference in how the car will ET, just literally how your spot on the tree needs to adjust to be green.
I have found off the foot, the car is going to ET similarly no matter where you hold it at( it’s still going to go instantly to the 5300) I only adjust that leave number to adjust my reaction time, higher = quicker reaction time, lower = slower reaction time.
Unless somebody is having an issue being really late all the time, I have found zero benefit to pushing the footbrake car up against the brake to gain rpm at launch. In fact, you are playing Russian roulette for nothing, brakes could slip, suspension could tense up and not work well( happens often with a leaf spring car) etc.
Anything I have ever had, using foot I leave at 2k, and adjust my reaction from there. Simply because it doesn’t push at that rpm, and the tach needle is easy to read at an even thousand rpm. Anywhere else I have tried doesn’t impact anything regards mph or ET

 

[Johnny Mac]

I don't

We aren’t talking about the same thing. Where the car begins to creep with your foot on the brake has nothing to do with the flash of the convertor, more to do with how loose it is, and or how good your brakes are.
Say you give your convertor guy the specs on your combo and it’s set up to flash at 5300( not untypical for a hot drag race smallblock)
Whether you launch off the foot at 1500, 2000, or even 2500, the convertor still flashes to 5300.
Now say you have a brake, say you set the two step chip at 3500 or 4000, it still flashes at 5300.
Yes, you are always gonna get the car to move off the foot at a lower rpm, because unlike with a brake, you don’t have gears locked together.
But you are still basically going right to that 5300 almost instantly, either way. The only difference is reaction time. Obviously if you leave with the chip set at 4k, you have less rpm to get to the flash than if you leave at 2k off the foot. But this makes zero difference in how the car will ET, just literally how your spot on the tree needs to adjust to be green.
I have found off the foot, the car is going to ET similarly no matter where you hold it at( it’s still going to go instantly to the 5300) I only adjust that leave number to adjust my reaction time, higher = quicker reaction time, lower = slower reaction time.
Unless somebody is having an issue being really late all the time, I have found zero benefit to pushing the footbrake car up against the brake to gain rpm at launch. In fact, you are playing Russian roulette for nothing, brakes could slip, suspension could tense up and not work well( happens often with a leaf spring car) etc.
Anything I have ever had, using foot I leave at 2k, and adjust my reaction from there. Simply because it doesn’t push at that rpm, and the tach needle is easy to read at an even thousand rpm. Anywhere else I have tried doesn’t impact anything regards mph or ET

I don't disagree, I was thinking in terms of a dominator on a SB car with only 408 CID, if you have a 4000 Chip/brake, you've already got the air pumping past the blades at that volume. If you F/B the same car, and can only F/B it to 2500 (made up numbers) you don't have as much air already churning through the engine (and through that big ol carb plenum). Maybe I'm scientifically incorrect but that's how it works out in my head, and my one experience with a 4500 on a S/B.

 

[Owen 340+6]

Someone once told me that every motor with a cam and intake swap will like a 1050 dominator. Can't remember where I heard it but always said there's never to much carb for an engine... That's all I have for this convo

 

[B3422w5]

I don't

I don't disagree, I was thinking in terms of a dominator on a SB car with only 408 CID, if you have a 4000 Chip/brake, you've already got the air pumping past the blades at that volume. If you F/B the same car, and can only F/B it to 2500 (made up numbers) you don't have as much air already churning through the engine (and through that big ol carb plenum). Maybe I'm scientifically incorrect but that's how it works out in my head, and my one experience with a 4500 on a S/B.

If you read my post upthread about racing in a .400 pro tree index class using a brake, and running in a footbrake bracket race class every other round basically, I had at that time an 1100 pro systems dominator. I played around killing timing and or shift points to get it to run high 9.90’s, depending on weather conditions. I dialed the car exactly the same racing it off the foot as what it would have run flat out in the 10.0 race. Not sure about all the air blade stuff. I have never seen anything much on a time slip difference wise, unless the convertor isn’t close to being right.