header will make it louder...



Vosko had header w/stock exhaust on his 89GTU...



I had bonez high flow cat and Apexi N1 catback on my 91 n/a...



his was louder

on a N/A rx-7 if you go too wide you will lose back pressure, if you don't have enough back pressure the 5th and 6th port actuators won't open causing you to lose 25 horse after 3500 rpm. honestly I wouldn't go any bigger than 2 1/4 or 2 1/2, I have 2 1/4 on mine with straight pipe exhaust, intake, and air pump removal with 5th and 6th port wired open and I run really well, but it is really loud, if you're not looking for loud, leave in the air pump and don't hollow the cat and it will sound good.

also nimrod, where and for how much did you get your rb header for???

Depends on the condition and type of exhaust you previously had.I know this one guy here that has a Series 5 N/A and he said he was able to feel it when he put on his catback system.

I didn't really feel any difference with the catback but then again there was nothing wrong with my stock cat back, I just wanted aftermarket.



If you have for example a header into a straight pipe with no cats into an N1 single, you will likely have problems with your 5/6 ports opening and lose some low end power like Diablo was saying.... not to mention it would sound ridiculous.



I remember driving with an open header on some back roads and it was so loud I was damn near deaf. When it backfired, it sounded like a bomb went off.......now that is the ultimate perfomance, I'd say I was pushing 220 at the wheels... maybe 230 since the header was a JDM Monza https://www.nopistons.com/forums/pub...#>/biggrin.png

Yeah you should see Vosko's GTU now...my roomie bought it and it's louder than anything I have ever heard...Runs 15.4 at the track all day long, with no mods besides exhaust. Springtime should be even faster https://www.nopistons.com/forums/pub...IR#>/smile.png

I had to cancel the RB header after I found out how long it was and sat there staring at my new cat thinking how I could possible cut and re-weld it to fit. I already ruled out Apex and i'm ordering the SS RB exhaust. I know it isn't gonna give me any power but I don't want anything stock on this car. Plus if I don't spend my money on my car my girl will want it all -=)