Backfire when cold

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thanks for the replies everyone, i have my booster vacuum hose hooked up to the side of the tunnel ram top (see pic), do you think i should block it there and instead run the hose to the back of the rear carb?
20191212_132353.jpg
 
ozmoparjoe said:
do you think i should block it there and instead run the hose to the back of the rear carb?
Click to expand...
I try not to think of tunnel rams at all,lol.
If your booster works, it don't matter where it's hooked up to.
The thing about vacuum is that it's just pressure less than atmosphere, not a vacuum at all.
And the first law of pressure is that in a closed system,pressure is equal every where in the system.
But on a running hi-perf engine that is just not true. In an individual runner, the pressure is being jack hammered by the action of the opening and closing valve. So in that runner the pressure is fluctuating wildly . But if you connect all eight runners to a common plenum, then it smooths right out, cuz the pulses sorta get lost in the volume of said plenum.

Now as to the booster; it has a minimum working vacuum, and if an individual runner only makes that minimum for a few microseconds once every other revolution, the booster will take forever to charge, and it has to maintain some minimum vacuum during every brake application, in order to give assistance. So sometimes with a bigger cam at low-rpm for instance, it requires more than one runner to make the minimum.
So;
If yours is doing that; giving assistance on every brake application, then it is getting the minimum required vacuum, no matter where it is plumbed to.
 
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AJ/FormS said:
I try not to think of tunnel rams at all,lol.
If your booster works, it don't matter where it's hooked up to.
The thing about vacuum is that it's just pressure less than atmosphere, not a vacuum at all.
And the first law of pressure is that in a closed system,pressure is equal every where in the system.
But on a running hi-perf engine that is just not true. In an individual runner, the pressure is being jack hammered by the action of the opening and closing valve. So in that runner the pressure is fluctuating wildly . But if you connect all eight runners to a common plenum, then it smooths right out, cuz the pulses sorta get lost in the volume of said plenum.

Now as to the booster; it has a minimum working vacuum, and if an individual runner only makes that minimum for a few microseconds once every other revolution, the booster will take forever to charge, and it has to maintain some minimum vacuum during every brake application, in order to give assistance. So sometimes with a bigger cam at low-rpm for instance, it requires more than one runner to make the minimum.
So;
If yours is doing that; giving assistance on every brake application, then it is getting the minimum required vacuum, no matter where it is plumbed to.
Click to expand...
That's a great explanation thank you!
Yes the booster works fine every time, I also replaced all the plugs and I think I will leave it alone now as it is all working as it should.
 
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