I just went to a 2" diameter pipe basically straight back to a muffler. It seems to be the best overall. I had a 1.25" straight pipe and the car really sucked with it on there. I think a small tip might help out some but not overly small or long. The factory cars had a pipe that looked around 2" diameter but had a tiny little tip on the muffler. I figure they had to have some reason to do that so I will probably made a slip in reducer to cut the size of the opening down on my replacement muffler's 2" tip.
I don't think a convertible is ideal for FE(prob the worst) but with the top up it seems to do pretty well. I will eventually get some coastdown testing done with it and figure out the actual numbers. I am not sure what one is better shape wise though sedan or hatchback. I would guess sedan but I am not really sure if anyone has actual numbers to compare them.
|