Mopar Muscle Association UK

I was wondering if increasing shooter size would help my launch.
Before I start experimenting, do I keep primary and secondary the same?
It's also occurred to me that as I wa launching at 4-5000 I bet I need to change the pump cam position from hole 1 to 2.

Most of the pump shot is done by then.

When you are at the track you may have to slacken off your pump adjustment so it delays the shot.

So is there any point playing around with pump cams or shooters?
I've tried swapping pump cams before and not really achieved anything but confusion...
I've never changed shooters, they're both 31.

What you can do is mess with the secondary pump, it's unlikely that has shot it's load by then. Bigger shooter, more aggressive pump cam and ultimately a 50cc pump are things you can experiment with. The other thing you can experiment with is the power valve, the sooner that opens the quicker it enriches the mixture, if it's a big bog that might be the only way to get rid of it.

Are you using jet extensions ?

Yes to jet extensions.
Yes to 50cc sec pump.
Yes it's a big bog!

I'm running a 4.5pv but I suspect it opens at idle sometimes as vac at idle is an unsteady 5.

I have a 2.5 I was about to try but that's going the wrong way to cure the bog isn't it?

In that case try an 8.5, it will be open at idle but you can lean it off with the idle screws. I've had a couple of instances were I had a bad bog and very low idle vacuum, worked in both cases.

Are you WOT on a Rev limited or foot brake and watching the rev counter?

Ta Blue I've heard of that trick before. I'll give it a go 😊
Watching the revcounter with the clutch let out as far as I can without moving Pete, I don't have enough feet to hold the brake

Line lock, mate.

On a race car you would have a 1st stage Rev limiter so you would already be at WOT, so the pumps would not work at all, hence the question.

I would back off both pump arms to delay the shot and try again. You could have a rich bog (but I doubt it) so at least this would prove it.

Make sure there is still sufficient cam profile to obtain a decent pump, you may have to bend the arm a bit.

Ta Pete.
I think I'd need a bit more practice to add the linelok into the things to remember on the startline, it's bewildering enough already!

I'll try the pv trick as that's easy to try out. Then I'll have a play around with the pump arms, cams, etc

Linelock is easy as long as you have the button on the shifter or the steering wheel. You could even do something fancy like releasing it via a micro switch on the clutch pedal.