Anything we can do with stock exhaust to make more HP and make it a little louder

teemoney

teemoney

Member
Location
Toronto, Canada
Car
2007 Infiniti fx35
The mod bug is biting me but i'm not ready to do a complete exhaust swap yet. Is there anything i can do to make my exhaust sound a little louder and maybe gain a few horses. Would a 2.5 inch hfc help? I just don't want the rasp. Been reading about some g37's who added hfc's to their stock exhaust and it sounded good and no rasp. I will probably pass by a local exhaust shop and see what they have just want to see what you guys say first
 
HFC will give you the most power by themselves compared to changing any other individual exhaust part. (However the true gains won't be seen without a tune)

I ran Kinetix HFC on my FX35 and they were OK.

(p.s. the g37 has a different motor)
 
HFC into stock exhaust will rasp. 2.5" outlet is bigger than OEM Y-pipe inlet. You'd need to do a custom transition to make it not rasp.


Or just have your resonator removed. Will gain volume, no power of course.
 
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test pipes will give you the most power not hfc. I didnt feel much difference with hfc more of a sound difference. I felt the added hp and torque with test pipes
 
I think your best bet is to start with the mufller; custom fabrication or aftermarket. It will change the sound a lot. It's not going to yeld any gains but if you want to make the exhaust louder step by step the muffler is where you should start.

Sent from my HTC One
 
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Well not the answers i was looking for lol. Was hoping a couple hfc's would do the trick. So now i guess the best option is to save up for a Invidia exhaust or visit my local muffler performance shop and see what they can offer. If i do get the Invidia, do i still need hfc's or does it come with them
 
teemoney said:
Well not the answers i was looking for lol. Was hoping a couple hfc's would do the trick. So now i guess the best option is to save up for a Invidia exhaust or visit my local muffler performance shop and see what they can offer. If i do get the Invidia, do i still need hfc's or does it come with them
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I still stand by my HFC comment - technically yes Test pipes yield more power but you are worried about rasp, but want more power... so HFC is your best bet.
If you buy ones for a 350z they'll fit just fine. like Kinetix (like I said above)

It's also fairly straightforward to swap out the stock resonator for a louder one. You can also change the muffler. These will probably be cheaper than swapping out the cats.
couple hundred vs. cost of HFC + install price ($300+hours?)

Honestly if you just want to make it a bit louder and don't care about the numbers/performance/ just swap out the resonator. Cheapest method.

---
FYI
The invidia does not change the cats, it's a cat-back exhaust.
 
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You could always just do nothing now, and save money towards a full exhaust and just do it once and do it right, rather than deal with it multiple times.
 
I agree Stu. I don't really want to change my full exhaust until i have to though. I would love to just do hfc's but i don't like when exhausts sound raspy. So the hfc's from a 350z will give me a little more power and be a little louder with no rasps, if so where can i get them.
 
id save the money and get a catback system then move from there. a good hfc will cost you 500$ + duty fees. ill keep an eye out for you on kijiji and g35 / 350z forums.
 
Thank you, i appreciate that Viperi. So the Kinetix hfc for 350z or g35 is what i think i want. If it really adds 6-8 hp and no rasps that's good enough for me. I like our stock exhaust note a to make it a little louder is all i need. I already installed a cai and md 5/16 iso thermal copper so if a add these cats i will be happy and get a tune. I know this may not be the route most of you would take but i would be happy

---------- Post added at 07:22 PM ---------- Previous post was at 07:05 PM ----------

So even after paying a lot for the Invidia exhaust i still need to buy hfc's to go with it
 
You can find kinetic HFC for about $300 (look around) and it's well worth it... the 5-15hp gain won't be realized until a tune but you should free up a few ponies and wake up the exhaust tone by throwing them in there. Just be sure to get defoulers for the o2 sensors because although kinetic claims no CEL sometimes it happens. (I didn't need them for mine, which I bought used)
If you want more info, check out y old thread on my fx35... had a ton of the bolt ons and did tuning, etc.
To be honest the cost of tune won't be worth it if all you have is CAI / HFC / spacer. I would wait until you have full exhaust work and a few other things
 
Thanks for the info Jbaker. So when you had on the kinetix you had no rasps? I was thinking of getting a tune after adding cats but you're making me think now. Perhaps i will just add the cats and not get a tune. I am already happy with just the cai and spacer
 
teemoney said:
Thanks for the info Jbaker. So when you had on the kinetix you had no rasps? I was thinking of getting a tune after adding cats but you're making me think now. Perhaps i will just add the cats and not get a tune. I am already happy with just the cai and spacer
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There wasn't much added rasp from the Kinetix HFC. There was a little bit to be honest, but my exhaust was already so loud that it didn't really make much of a difference. it mostly made the exhaust note louder as a whole /deepened the tone a bit without adding much rasp.

example: my old FX35; with NIsmo S-tune mid pipe and muffler, z tube intake, motor dyne spacer

http://www.youtube.com/watch?v=8yyQN-ImkFE&list=UUbs-tl6OjxjW-vjK_pW99wQ&feature=share&index=9

added kinetic HFC, notice the difference in tone? Really opens it up, but doesn't really add much rasp per se. you still have that infiniti gurgle!

vids after adding HFC:
http://www.youtube.com/watch?v=H4QVRpx7Xs4&feature=share&list=UUbs-tl6OjxjW-vjK_pW99wQ&index=4
another:
http://www.youtube.com/watch?v=HDtyLcM7JZ0&feature=share&list=UUbs-tl6OjxjW-vjK_pW99wQ&index=7

Obviously it will be quieter with a full factory exhaust but this hopefully shows the difference HFC makes before and after

since I'm already vid whoring my old car... here's the "final setup" before I got rid of it.
Nismo Stune Midpipe/muffler; kakumei Ypipe; Kinetix HFC; tube intake' motor dyne spacer ( I think that's all I had that would change the exhaust tone)

http://www.youtube.com/watch?v=uvzNAF5fk1c&list=UUbs-tl6OjxjW-vjK_pW99wQ&feature=share&index=3

Good luck in your FX35 endeavors! I'm always willing to answer questions
 
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Tell me something, i noticed everyone buys Invidia, Berks, kinetix etc, are local exhausts performance shops good? Are their hfc's usually any good?
 
teemoney said:
Tell me something, i noticed everyone buys Invidia, Berks, kinetix etc, are local exhausts performance shops good? Are their hfc's usually any good?
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I don't think local shops will have high flow cats that will fit your car sitting on their shelves.... unless you want them to build you a custom one, which would cost a ton of money just from the labor alone (trust me, I just went through this with my FX50)

You're better off buying ones you know will fit and just having them installed.
 
A lot of times those companies will just buy an HFC module like any exhaust shop could get or you can get online, and then the work they do is designing it and adding piping so that it lines up with the OEM mounts. I had them added to my midpipes, so it's not hard to do, and might even be cheaper for a shop to fab some up for you if they have the right flanges and piping.
 
StuLax18 said:
A lot of times those companies will just buy an HFC module like any exhaust shop could get or you can get online, and then the work they do is designing it and adding piping so that it lines up with the OEM mounts. I had them added to my midpipes, so it's not hard to do, and might even be cheaper for a shop to fab some up for you if they have the right flanges and piping.
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This is true, but like I meant to say it depends what they have sitting ton their shelves -- and the angle for the cats is a bit more difficult than throwing them on a mid pipe -- and the hours just start to add up.
 
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