Mine are JMM.

hey guys I dont actually have any headers atm but just curious as to why would the paccies comp headers have a smaller secondary pipe (44mm) to the standard paccie headers (48mm)? is bigger better or isnt it?

Fiddie

Oh by the way id be gettin paccies ceramic coated headers

Hey Fiddie,

Bigger isn't always better. Comps are better tuned to deliver better mid to top end torque and are better suited to racing. Standards are designed to deliver more low down torque and are designed for the street.

AFAIK, it's got to do with how they Scavenge. This is from the pacemaker website.

What is scavenging?

Scavenging is one of the most critical parts to a design of a header. The tubes volume (diameter and length) is chosen to represent a discharge of spent fuel or pulse being discharged from the engine at a given rev range (usually mid to top end), without competing with the next charge. This pulse then enters the collector cone with a greater volume than the surrounding connected pipe(s). This creates a low pressure (or vacuum) at the exit of the next pipe. This vacuum then in turn sucks at the next pulse travelling through the next pipe in the sequence, vacuuming or scavenging the cylinder bore clean. This aids towards an unpolluted cylinder bore, ready for the next clean dose of air fuel mixture.

Well put Doogs, I was gonna reply something but couldnt word it like that, or be bothered to raid the pacy site

Mate, I don't mind going the extra yard to help someone out.

top stuff :D

thanks guys for the help then that leaves me to wounder about the JMM headers if I remember correctly aint they even smaller than the paccies standard? why did JMM go down that path? mayb I should call them and find out but any way thanks again guys

XRchic has the JMM headers, and her mods list includes pacies....what do u make of that? XRchic do u think they are holding u back?

I had talked to her about her JMM Dev3 kit and she says that she got hers pretty much when they first came out (dont quote me on the wording, my impression only) and when I talked to Jim him self a while back apparently they seem to be bigger and better so im not sure whats the go but ill have to call JMM tomorrow to find out the exact details

I have the jjm extractors and 3inch metal cat with redback 2 1/2 exhaust works well for me 157 rwkw

Neil