The resonated pipe without the cat would be quieter from my experience the high flow is just as loud as the cat delete pipe.

Anything on power gains??

hfc just as loud as the midpipe? anyone have opinions on a hfc with the ms dual can exhaust?

this thread needs videos / soundclips. C'mon guys, I'm sure a bunch of you have them.

My recent searchign has led me here... I'm thinking that in retaining as much warranty, emissions leagality, and sense of hearing, that a HFC installed on a virtually stock car is about he best $400 I could spend. Any opinions to sway me one war or the other. Essentially I'm asking, is with a stock exhaust does it get SIGNIFICANTLY louder, will I get a "noticable" gain in power and will I have no issues passing MD emmissions and having any warranty work performed? Also should I wait for the Cobb AP to lean out my A/F ratios before or concurrently to get max gains? I.E. 5 hpish from HFC alone, 10 hp ish from EMU programming and 18ish together? Does that make sense?

I know this thread ended long ago but I am buying the rx7store hfc and I was wondering if they had done any emissions testing on it? Thats the only thing I need to know. Will it pass MD emissions (or any state emissions for that matter)? I don't have a stock cat to replace this unit with so if I get it its all I will have. I know the RP highflow cat will pass a "smog test" but I don't know if thats the same as the emissions test. I need to know so if anyone can help that would be great... I will try calling the store once you west coasters wake up over there.

I have the HFC on an RB exhaust and it does substantially change the exhaust note. Not extremely loud, just more grunt at the lower end.
As for noticable gain; probably not while driving but you might free up a few ponies on the dyno.
AP would be a great choice once you start modding your car and you know which direction you're taking with it. (ie; prioritized mod list)


Not sure on MD emissions, but I remember reading a while back that someone passed CA smog with it. (we have some pretty strict laws) Not sure if they do a visual inspection in MD and whether they'd give you shit for it.

Cool thanks Jedi. That gives me a little hope at least.

We have changed the design of our resonated midpipe a little. We went with a longer magnaflow resonator to help keep noise levels down.

I have burned my cat and will cost me 2500$ to purchase a new one in Norway....I have catless midpipe, but it gives me CEL. I hate CEL!!!

Does your midpipe still runs without CEL???

I what type of midpipe did you purchase??

Thanks for your help!

hey guys does anybody know if the high flow cat is legal? and do you need to weld it? or is it hard to install? and will I be making more noise if I only put a highflow cat and leave the stock exhaust??

I need a race pipe buy this weekend and so far you have the best price. How fast can you ship to 89117? or 89169? what ever is cheeeeeeper :)
Also I have the OBX cat back, will this just bolt right up? or do I need to have a shop install it?
Thank you for your time,
-Gilbert

Dont know about "legal" but you may not pass smog ;)
Dont know if you need to weld it. I kinda just asked the samething, "If I need a shop to install it".
You will need to lift your car up, if you dont have the space or tools have it installed. If you do have the space or tools its not that hard. Realy.
You will make more "noise" stock. But not as bad if you had after market exhaust ;)

no welding is involved. you can install this with simple hand tools.

Jason, thinking about getting your high flow cat and the MS single muffler cat back; have you seen any info or testing that indicates it will pass standard fed emissions testing? How about info needing to flash ECU with these mods? Can't imagine it would make all that much of a difference to disrupt the ECU settings, but curious if anyone has needed to do this with similar mods

I have the same question as corky regarding emissions testing.

PM sent.

ok guys a few more questions to the this thread......

does anyone know if it will void my warranty if i install the high flow cat????

and is this highflow cat durable???? I don't wanna buy it and 6 months after it gets burn or somethig....

is there any increase in sound if I just install the highflow cat and leave the stock muffler???

or what do u guys think its better..... buy a midpipe and a muffler and intall it leaving the stock cat??? or the high flow cat and a muffler??

Midpipe without cat will not pass emissions.
I'm not sure if the high flow cat will pass emissions.

Pending the answers to our questions, street legal way to go would be high flow cat & muffler, off road use way to go is midpipe.

does the '3 inch stainless steel high flow cat' fit perfect with the JIC exhaust? also how much is it in total including shipping to Sydney, 2125 Australia.