G35Driver - Infiniti G35 & G37 Forum Discussion

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- G35 Sedan V35 2003-06 (https://g35driver.com/forums/g35-sedan-v35-2003-06-15/)

- - HFC's + aftermarket exhaust (https://g35driver.com/forums/g35-sedan-v35-2003-06/187567-hfcs-aftermarket-exhaust.html)

HFC's + aftermarket exhaust

If you have an aftermarket exhaust and HFC's on your sedan please chime in. I would like to know if there is a big difference in performance by adding HFC's to your exhaust system. Also how much louder did it get. I currently have the gen2 stillen and looking into getting a quality set of HFC's but I don't really want it that much louder. Sound clips will be helpful also. Thanks alot guys.

i have the HKS muff and a set of test pipe's that i turned into HFC , and i love how it sounds .

soad- do you have any sound clips? How did it alter the original HKS sound when you added the HFC's? thanks

I had a set of Kinetix HFC's on my Borla for a little while. The did make it louder by a decent amount. I didn't like the sound.

dont get the Random Technology HFC they Rasp Horribly , Test Pipes will get even louder unless they are Resonated Test Pipes I think more free flowing compared to HFC.

It's expensive but I have found that two turbos and test pipes sounds the best. About as loud as the standard borla with a better tone.

well the sound only got a bit louder over my HKS . in the mornings its strats out a bit raspy , but it get better after it warms up .

Quote:

Originally Posted by vulcanraven1

dont get the Random Technology HFC they Rasp Horribly , Test Pipes will get even louder unless they are Resonated Test Pipes I think more free flowing compared to HFC.

i have never heard anything good for "Random Technology" . i had bought a set of ebay special test pipes (hated them, they made my car sound like a 4 cyl Honda with a pepboys special exhaust) so after i took them of i bought a set of magnaflow high flow cats and welded them in on to the test pipes .

Fast Intentions HFC ftw...

i don't have them but know someone who can vouch for them if they decide to chime in...

Quote:

Originally Posted by joaquin03

Fast Intentions HFC ftw...

i don't have them but know someone who can vouch for them if they decide to chime in...

those are exactly what i made . i already had the test pipes so i decided to make my own . since i can do my own fab work and i get a deal on magnaflow part,that is what i mad . a set of knock of FI HFC

here is my exp - the quotes are from this thread (in case you want to read the whole thing):
https://g35driver.com/forums/intake-exhaust/150701-crawford-hfc-installed.html

Quote:

Originally Posted by OCG35

Not sure yet how I feel... low end TQ feels a little stronger. Off idle and all the way through 3K or so feels decent... but mid and upper isn't as strong - in fact, feels slightly de-tuned, almost gutless at some points.

Is it possible that the A/F has changed to the extent that timing is being pulled? I am getting the ECU re-flashed (again) tomorrow - and I really haven't driven it that much yet, but I'm hoping someone can chime in... Maybe the ECU needs to adapt?

Quote:

Originally Posted by OCG35

Yeah!!! Got TQ:D

Went to TS, was a little lean (15)... Tadashi got it dialed in A/F is now right about 13 steady... he also loaded an updated version of the drive by wire software to give a little better throttle response.

All the issues I had yesterday and this morning are gone! It pulls strong across the entire RMP range no more sluggish response!

I’m much more satisfied with the HFC now… I’m perplexed though that they aren’t as loud as I thought (not that that’s a bad thing) – it is a little more deep tone, but not much different than before (Stillen exhaust)

I'm happy:D