HFC or Shorty Headers and axle back (sound request)

[rich2342]

Hi all,


Is anyone running mostly stock with the exception of HFC's and a simple axle back?



I am thinking about shorty headers or more likely HFC's to add to my magnaflow axle-back mufflers.



I want a slightly deeper tone without much added volume on especially no rasp. The car is a DD in the summer so over the top monster driving into work is not what I'm looking for even though I would love it.


Does anyone have any drive by clips with HFC's and exhuast WITHOUT HEADERS?



Please let me know feed back if you have experience with both as well.


Thanks!

[pnwdan]

Personally I'd do long tubes and HFC. Just as easy. Better gains.

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[rich2342]

That's not what i'm looking for.



It would be too loud and my state's inspection process is the most stringent.



So, Per above request folks.

[VR Baron]

I ran shortys and hiflows for over five years. Just put stock cats back on as they are getting more crazy on the laws out here in Kali. You add volume with hiflows. No rasp and sound more mean, but is just right for the street. If you have a magnaflow axleback like I did for awhile , the sound will be muted. The shorty headers may have added a deeper tone but not sure as they were installed at the same time. If you add a 3” catback like I did I find low rpm boomy sound to much and lost back pressure and responsive up to 2500 rpm. Keep the 2.5” catback.
Hp gains with hiflows will be 15 at about 5600 rpm, about 11-12 at 5900 rpm peak. Tq will be 10 from 2500 rpm on up to 4800. These numbers were on a before and after test I did.
Shortys were worth about 6 tq at peak and 9-10 peak hp

[sixty9fordkiller]

shorty headers are a waste of money on these cars. they will not result in any mentionable performance increase all while costing you time, money, and possible a broken bolt or 2 when you try and remover the OE cats from the factory manifolds


if you're gonna pull the trigger, get LT headers and if you want HF cats, then get them too.

[rich2342]

I'm most interested in one over the other not the combination of both.

Hfc's most likely, but like I see here everyone want lth and rarely has HFC and exhaust only, primarily what I am interested in hearing.

[sixty9fordkiller]

id imagine you would hear increased valvetrain sounds more than anything

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[VR Baron]

Originally Posted by sixty9fordkiller

id imagine you would hear increased valvetrain sounds more than anything

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No, you hear louder exhaust sounds with hiflows. It’s not tons, but is very noticeable. Shortys got maybe a bit deeper sound. I now can hear my vslvetrain with the new valvetrain, but mostly since I removed the Intake cover and insulation. Sounds like a sewing machine..lol
Shortys do add power. Several friends and I on same dyno got about 10. But that being said, dynos,and difference in the pulls and temps could be 5-10, so who knows.
For seat of the pants feel from my tests you will notice the hiflows. Shortys I doubt it

[SSEssence]

Shorty headers won't change the exhaust note by a lot, but once you throw on those HFCs, the change will be drastic. At least it was for me with my x pipe and muffler deletes.

[ZED SLED]

This is my 2010 LS3 with Borla S axle back and shorties and CAI, Inc. I added HFCs a few months later along with a scoop for the CAI. The cats produced even more sound, but was still deep and throaty. This setup made 417tq/419hp on a Dynojet before tune. If you are only doing one, I would go for the cats.

[rich2342]

That sounds great, man.. Do you have any driveby vids? Curious how it sounds at various speeds?



The magnaflows seem to drone a bit on the highway. I don't know if the Cats would worsen that or not. I probably could add a resonator potentially. The car seems to have the stock H pipe removed and two cherry style mufflers instead when I bought it last year.

[ZED SLED]

Sorry, only vid I have of that car. Traded it 2 ZL1s ago. Borla droned really bad at highway speed as well.

[VR Baron]

Originally Posted by rich2342

That sounds great, man.. Do you have any driveby vids? Curious how it sounds at various speeds?



The magnaflows seem to drone a bit on the highway. I don't know if the Cats would worsen that or not. I probably could add a resonator potentially. The car seems to have the stock H pipe removed and two cherry style mufflers instead when I bought it last year.

Shorty headers, hiflows, stock h pipe catback with magnaflow axleback, which is quiet, had no drone on the freeway, and little sound for that matter. When I added the 3” catback The sound was more, not drone , but just more sound due to the 3” pipes. Hiflows never droned. When I had outlaw mufflers, those droned!

[rontammy0]

Op.....I ran Jba shorty headers with Solo hi flow cats for years. I had the Magnaflow muffler delete axelback.Im now running longtubes. PM me for info...dyno#s etc. Your going to get the same comments regarding shorties as I did. But since Ive had both i can give you more facts....not just comments.