Oh! after whole system done up, less speed? But usually at top end, fully open is best, unless engine not enough power, probably need to change back something.....Seems another member in ZTH had the same problem.....

You mention only with extractor you could hit 200kmh, but after whole system only 185kmh, so with full system is slower.
Probably the mid or rear box robbing it's power....

familiar issue with my Civic FD1. Previous top speed 210kmj, after some other mod, mid range increase but top died at 185kmj. The air filter/air sensor is the culprit.

Just sharing, as the air/oxygen sensor is related to exhaust system.

Probably ECU check

guys, need professional opinion here..
my current exhaust setup is:
4-2-1 (wegow)
twist bullet right after the pipe joint (after flexipipe) =2.0" inlet/outlet
oval midbox after bullet =2.0" inlet/outlet
everco s-flow muffler = 2.0" inlet
1.6" piping

may i know what effect should i expect if i change to straight flow muffler?
or a long 4-1?
btw, car is 1.6l campro auto
current setup got nice pickup but top slightly suffers (quite heavy near 170kph onwards)
please advise, thanks

bro, where can i get powerzone 421 extractor for gen 2?

You mean there arent any workshop outside which sells it ?

yup...dats y people said hotbits for more to pick up, n powerzone more to high rev.... powerzone stuff r all matchup.. not sure ab others but for 4g13/15 is like dat. they manipulate wat they hav on drag race to wat they sell... basiccally, all their cams,extractor, head job, plenum, piping, r towards max feelin at 5k rpm...
weber... prepare at least around 1k include all tapak n etc..

edited: typo

errmm... u mentionin camshaft or cam pulley?
pls see back few pages back my comment ab powerzone cam.......

Why going back to original??

Yup 

---

Added on December 26, 2011, 10:53 pm
12 inch and 15 inlet?    So big?

my setup also same like yours but not noisy at all.. i think you need to change to better quality midbox perhaps?

I agree with u,bro wandzul. But my setup has no mid-box... I use tornado inlet designed bullet only. It's quite for my proton wira. Just a bit bass sound only when the rpm above 3k,below 3k same as stock muffler. 

Because of your mid-box and bullet. Last time I also just change my muffler only, it's noisy. After i have replaced my stock mid-box into a good bullet, the sound is nice and as you said abv 3k rpm just a bit bassy sound only. I have used it around 3 weeks already. I feel the car have better mileage. Need to refill my tank just know tomorrow 

what brand is your midbox? is it oval or round in shape?
get an oval shaped midbox full of fibers with internal design which able to retain some backpressure.
in general, a quality midbox should be quite heavy.

and yes, an AT car can use single midbox only, provided it can retain some backpressure. and low end will suffer a bit. i used this setup before and then added a bullet later (improved low end, top end suffer a bit but im not gonna do 180-190kph all the time anyway)

using stock piping?

even tehre is no power loss, but physiologically, u will felt ur car not as power as b4... bcoz d sound is lesser. wit louder sound, it gives u mental boost...lol..

1.7inch?