Why do you want to know? It's a 2.75" exhaust. That's pretty big, even for a Type R. Refer to the exhaust sizing chart in Tuan's articles to make sure ya wanna do that. Also, I know Tuan has that catback. In his articles he told how it was and why he liked it for other than performance reasons. If I were you I would check into a Hytech exhaust system....ask SurferX...
I don't think they are all that expensive. Both SMSP and HyTech's catbacks are around $700. That's less than Mugen or Spoon and if you want to talk about something that's not worth the price I would talk about those two instead. SMSP's exhaust dynoed 2whp gain over running open header. I doubt any mass-market exhaust would flow well enough to do that. It was also the exhaust used in the great header test.
SMSP's 2.5" cat exhaust kit. Assembly required.
HyTech's 2.5" catback exhaust (plus cat in this picture).
My personal opinion I think the HyTech is the better deal here. It's pre-assembled and ready to bolt on (my car was the prototype for this thank you very much hehe) and everything on it is custom and not just plain Magnaflow. Not that Magnaflow is bad, but quality-wise I'd go with John's hand-build pieces over Magnaflow pieces if the prices were close to equal.
700 bucks is very very over priced for 2whp over open header and the fact that if you don't flow enough open header will do nothin....I am probably goin to go with a smaller diameter that just is straighter cause the smsp and hytech system have resonators and I don't want one(SRM or N1)
The exhausts made dynoed power than open header...that's no exhaust at all. How can someone not be satisfied with that? Doesn't that show that these exhausts provide no restriction and will accomidate whatever N/A package you can throw at it? That's what it shows me. Most will dyno an increase in power with open header vs closed exhaust because their exhausts do not flow well enough.
Resonators usually are not restrictive. In the case of the Kakimoto it does put some obtrusive pieces of steel in the flow path which is why I don't really like the exhaust. With Magnaflow resonators as well as HyTech's custom resontor, they are straight-through and wouldn't make a difference in performance, just in how much noise you want to make.
again, an exhaust does not make hp. An exhaust system does not make power either. the exhaust system releases power that was already there. this is a very hard concept for people to let go of.
proper exhaust system sizing releases or uncorks power that was already there but was being held back. The engine generated that power but contamination of exhaust gases in the chamber and a lack of scavenging reduced the combustion efficiency. You were capable of making that power in the first place: you had enough air and fuel going in, your CR was set right to generate the right cylinder pressure, but you shoot yourself in the foot by contaminating the burn processs...this is seen moreso at the upper rpms when one cycle finishes so fast before the next cycle starts that a problem in one cycle dramatically affects the next one..they inter-twine since there is very little recovery time in between at higher and higher rpms.
If you look at my graph (actually it's guru Jim McFarland's ...I just borrowed it) comparing the torque curve to the volumetric efficiency curve, the reason the torque does not match VE at the upper rpms is due to inefficient removal of burn gases out of the chamber.
BTW the problem is even worst if you throw in FI or N2O into the mix. You are stuffing more air volume and the importance of removing all that extra air once it's been burnt out of the chamber becomes even more critical. There's an even higher chance that more burnt gases will stay behind in the chamber, instead of leaving as they should, with a piss poor exhaust system sizing, when you do a SC or turbo. More stays behind, more dilution occurs, less combustion efficiency, less power.
The biggest bling bling gain in an SC car (after the SC itself) IS the properly sized exhaust system.
repeat after me: an exhaust system releases power and doesn't create it...an exhaust system releases power and doesn't create it...it's a good mantra to understand....
the newbies that whine over the 2 whp "gain" they got from their $800 great sounding exhaust are the ones that missed the big picture. they can't see the forest from the trees...