well you learn somthing everday. for some reason i was thinking DOHC has 2.5 and SOHC had 2.25inch

 

sounds like you got good parts coming on the intake side, as for the exhaust, it depends where you live

in ca the best and only header worth buying that is legal is the pacesetter, the kirk is not legal here and will fail the emissions test, and get you a fine

anywhere else, use the kirk header, available on modernperformance.com, if you still need to use a cat, you'll have to get a round one and relocate it, along with the second oxygen sensor, but this is by far the best route

as far as mufflers, it depends, for the most possible power, get a 2.25-2.5 inch diameter glasspack, your choice of lengths, or go straight pipe, the less backpressure you have the better ( No Matter What Anyone Else Says, This Is True, If An Engine Needed Backpressure Then Funny Cars And Dragsters Would Have Mufflers) the only reason for backpressure is to quite it down, just dont cut it off right at the header, you still need a good length of piping (this is called tuned length)

if you dont want to go that route, then anything that opens it up more then stock will help

 

I am willing to differ. We just went over this. especially on 4 bangers. More flow=less low end torque. But it means more high end acceleration. Its a sacrafice. Can anyone back me up on this?

 

i posted on this a couple days ago, but i'll post it again


http://www.ssheaders.com/header.htm

 

so in short:cheaper route

Pacesetter headder
DOHC muffler
3.0L intake
ATX 52mm TB

Not so cheap
Pacesetter headder $130 ish
exhaust system of your choice. . . i have Pacesetter catback not the best but i like the looks $???
Iceman CAI $200+ used
ATX 52mm tb bored out to 55mm $varys got mine of ebay for $70
ported and polished intake got mine for $122
Indy head 1400 off howellautomotive.com I got a used one from someone off of NeonCanada.com for $1200 w/4000Km
would also like to sugest a UDP

 

i thought the same exact thing someone told me that the dohc has 2.5...

hmm

but i guess spud knows his neons

 

best thing to do is keep the stock size piping if your gonna use a glasspack, or upgrade to 2.5 inch if your going to use a more restrictive muffler (although less restrictive then stock), just make sure that the tubing is mandrel bent if you upgrade to 2.5 or you really wont have upgraded at all, since crush bends (which most local muffler shops use) reduces the diameter of the tube


as far as backpressure is concerned, drag racers would use mufflers if backpressure helped

road racers would not use mufflers if it wasnt for the noise concern of being in that loud of a car for hours

backpressure only changes the torque curve by choking it and reducing your engines output

tuned length (pipe diameter and length) is how you change your torque curve, bigger shorter pipes are better for low end power, which is why drag racers use large diameter short length headers

long tubes with smaller diameters is better for low end power

my dad is has a masters in physics, and believe it or not this was one of there discussions in his advanced classes because the professor was a car nut

another example is 2 stroke motocross bikes, 125CC motocross bikes have longer smaller diameter expansion chambers, because they are good for top end, where a 250CC motocross bike uses a fatter shorter expansion chamber, because its better for low and midrange, which a 250 has more of

 

http://s8.photobucket.com/albums/a36...t=MOV01243.flv



Thats a link of my exhaust system with 2.5 inch tubing bended correctly btw...with magnaflow resonator and dual tips out...

 

yup send it if it contains the items 12VOLT and the other gentleman reccomended(ie. headers).

 

Thanks for the info. I live in a small country Texas town where there's no emission testing done. It's still state law to have a cat although no one has ever looked under my vehicle to check. The only reason I still run one one my Dodge Ram P/U and this Neon is because I do not know how to bypass it and not have the CEL come on.