Been doing some reading on this. The myth says you dont need backpressure. Somy question On a 1/2 mile circle track running z24 2.4L can i run just a header with no pipe or will I burn the valves?


fast cavy

I would run an open pipe the same diameter as the collector to at least behind the drivers seat, if not to the rear axle.

MadJack wrote:I would run an open pipe the same diameter as the collector to at least behind the drivers seat, if not to the rear axle.

this. and it's not a myth. backpressure is the enemy of proper flow.



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Backpressure is bad, exhaust velocity is good.

Unfortunately when you increase the size of your exhaust pipe or run a cut-out you are reducing backpressure but also exhaust velocity at the same time.

You won't however burn the valves, as this was a problem with carbureted cars and running to lean when they were run open header.

You will however lose some torque at the bottom end.

I would at least run the pipe to around the drivers seat as mentioned tho.

So really running a without a pipe and blowing right off the header isnt gonna hurt anything. Except loose low end torque. So really racing on a 1/2 mile dirt track running 7,200 rpm isnt gonna hurt nothing but low end torque I guess is my question?? thanks


fast cavy

You don't run 7,200 rpm all the way around, so you will need some low end.

Pretty close when yah get up too speed I'd say it doesnt drop below 6k. But on the starts your gonna need the torque.
Thanks for comments


fast cavy