back pressure n/a exhaust

[MHLIGGINS@aol.com]

<<how necessary is it?  anyone know?>>

     With the n/a engines the back pressure is what 
produces most of what low end torque there is. 
     We put some significantly larger pipes on my son's 4K and moved the power away from the bottom end. Had plenty of midrange and a bit more top end, gained a few revs at the top as well. The car was tough to get launched, but did well after that. 
     The analogy I can think of is that it made it behave more like a two stroke engine. Like the 
difference between a two stroke dirt bike and a four 
stroke dirt bike of the similar displacement.

     Later.
     --ml