what is the most approprite exhaust size for a 998s engine?
 

for example running with revised cam timing and approprite ecu?

what is the most aproprite axhaust diameter to run with the above,
one place tells me 60mm the other tells me 57mm and that 60mm is too much?

It would be good to hear from anyone who has run either system, even better if youve ran both at differant times on the same bike.

im looking at buying a bigger system and anm not sure which to focus on?

Depends what your planning to use the bike for? Th bigger bore will breathe better but will knock out some midrange, usually about 5k ish.
The other thing you need to bear in mind is swingarm clearance. The 60mm will more than likely not fit with the stock arm. The 57mm will be tight!

its not for racing just trackdays. i have a mag arm so clearnce is hopefully no longer be an issue.

Was this prompted by the 60mm system thats just appeared on fleabay? ;)

Ive been wondering the same...

The guy who's selling the 60mm system says it doesnt come with the "short manifolds." Not quite sure what he means?

no but I have seen it.
more prompted by a 57mm system ive been offered, that fits the stretta motor. there does seem to be a few 60mm systems around if you look hard enough!

Are there? Tell me more!

http://cgi.ebay.co.uk/Ducati-Termi60...QQcmdZViewItem

The short adapters/headers will be the manifolds that bolt to the head and looking at the exhaust they will be Testastretta ones as the header pipes do not have the duel inlet as per 916/996.
And from previous experience with Testastretta manifolds for the 998 I doubt if you'll pick up a set cheap, so check with someone like Nelly, JHP or Moto-Rapido first and get a price.

Kev, do you mean standard 'Stretta manifolds? Like on a 996r or 998s?

Standard ones on a S or R are only 50mm, the ones for the 60mm exhaust should be bigger, Dallas has a 63mm Exhaust for his tuned 998R and the manifolds are a lot bigger than standard, I think they taper out from the 4 bolt flange that bolts to the head to the full 63mm diameter of the down pipe

these manifold/headers are 680quid.