A'PEXi WS2 on an N/A 05 6mt Coupe?
 

Hi all. I'm thinking about going with the World Sport II exhaust, due to the very low price and subtle tone. However, I'm worried about the exhaust diameter. Am I correct in thinking that the WS2 is 70mm? If so, that is roughly 2.76", much larger than stock. Will I see any drop in performance with a diameter increase like this? If so, any other recommendations on a decent low-cost cat back solution.

FYI...Z tube / Pop Charger installed now with MREV2 and MD 5/16" Copper ISO waiting to be installed soon.

Nobody can help? I don't know much about exhausts, so any insight would be appreciated. Thanks.

I don't know much about that exhaust, but most of the aftermarket cat-backs are 2.5'' because you need to maintain some back pressure, and the forced induction guys usually go for a 3''. Fast Intentions and HKS are both great, and both 2.5'' if I'm not mistaken.

Seriously, someone please school me here on exhausts. Thank you SixOneFive, but I understand the FI people go for 3.0" and I need to maintain "back pressure" on my NA engine. What I'm worried about is the fact that the exhaust I just mentioned is somewhere between the 2.5" that my engine wants and the 3.0" that FI engines want. I would go with Fast Intentions, but I'm looking for a budget system here. Since I'm not really going to see power gains either way I'd rather save for FI in a year or two.

you might see a loss of a couple of hp, but nothing really noticeable i'd say. i was running a 3" topspeed on my N/A engine and didn't really feel anything.. once I put my dual 2" invidia on, it felt more perky though so idk.. save for the FI if it's what you want

Thanks for the responses. FI is definitely not in the near future, so I'm going to continue looking for NA mods. Even if they won't net me more HP I'd rather not lose any either.

When people are saying 2.5" for NA they are assuming it's a dual 2.5". The Apexi WS2 is a single 3" and it will be fine for you. Yes, a dual 3" will be overkill for an NA car. Most aftermarket singles are 2.75-3".

You'll get better response over at my350z, i know few members their who has that exhaust. I doubt you will loose any hp, perhaps may gain lil more torque. I say go for it.

I'm liking these responses. Thanks.