I'm looking for the best bang-for-the-buck bolt-on engine mods for my 07' Coupe 6MT before I get Osiris dyno tuned.

Current mods are:
- Z-Tube + Amsoil filter
- Mrev2 & 5/16 copper

The exhaust mods I'm considering are:
- Berk HFCs
- XYZ Y-pipe resonated
Note: I have emissions testing and do NOT want a loud or smelly/polluting car

Now I'm contemplating if these $1000+ exhaust mods are really worth it. It would be nice to have these 2 exhaust bolt-ons to complement my intake mods, but since Osiris will give me the best results and improve drivability, do I really need these exhaust mods... what HP/TQ am I giving up?

 

Get HFC. The stock cats are very restricting.

 

But be prepared for the rasp of HFC's.

 

If you've tried doing a SEARCH you know that most of the restriction in your exhaust system is in the OE cats. I tried BERK'S and they lasted 9 months at best, went with FI and they're working great....with my exhaust. Problem with just adding HFCs is the OE exhaust system isn't designed for that much flow so you get rasp. Save your $$ so you can get a quality high flow exhaust like Motordyne's along with HFCs. Then you'll have a system that makes RWHP along with sounding great. Then a tune will net you 30+ RWHP along with the added torque you can really feel....Gary

 

I have been on YouTube looking at the various exhausts.......like the Fast Intentions as my personal favorite. But I will look into Motordyne's system.

 

OP - sorry if this is hijacking

Gary - do you have any opinions on the other HFC? My Sedan OEMS are going and I am looking for a pair to add to my Stillen Cat-Back. Seem to be (too) many choices: Berks, FI, Crawford, Stillen, Kintex, Random Technology. Also the manufactures don't provide a lot of info, and while searching I haven't found a lot - as compared to say exhaust systems which are compared and re-compared to death.

Also are you aware if anyone makes a resonated HFC? I understand it would be less HF than a non-resonated HFC, but might offer a RWHP increase with less of a sound increase.

Your input would be great.

Again, sorry OP - hope you don't mind.

 

For my exhaust setup, im going with ART pipes and XYZ pipe with resonator, then tune. Then eventually ill get the rest of the Motordyne exhaust or get another axleback.

 

If you want maximum power will still passing emissions get ART pipes and an XYZ w/HFC module. You will see significant power gains while limiting the volume increase and retaining the ability to pass emissions. Plus you will get a quality HFC.

Gary, I know you'll get a kick out of this - Just saw a pair Berk "Test Pipes" for sale in the classifieds. It was a HFC that blew out after 2 weeks of use lol.

 

Art pipes and MD exhaust call it a day like Mr Gary said. /Thread.

 

I've heard nothing but good things about FI HFCs and whoever designs parts at motordyne is an extremely impressive engineer.

 

I've read this (which is why I'm considering HFC as a good value mod), however I don't understand what makes the cat on the G so much more restrictive than the cats on any other car in North America? They all share the same general emissions requirements, no?

Often with cars changing the cat provide the least performance improvement, what makes the G so different?

 

Imho, this is an interesting question and looking forward to the answer. But i'll give you an interesting comparison.

I had to swap out my performance pipe to stock pipe on my super sport bike. Let me tell you the the bike performed awfully! The original pipe was highly restrictive! I could not wait to put back on the performance pipe!

 

Are you saying this because HFCs produce rasp themselves or because of the change in diameter between stock and aftermarket piping size?

Specifically this is why I was considering the resonated XYZ module (to help reduce/eliminate) some of this noise. From my searching this combo seems to be the best value option that is a bit louder/deeper, but still retains that unique G exhaust note.

 

Hfc are amazing fairly cheap and make a total diffrent sound with stock exhaust i really dont get a rasp.worth every penny

 

I was aware of the benefits of a cat, hence why it's #1 on my exhaust mod list. As a standalone mod I'd get rasp with the OEM exhaust, hence the combination of an XYZ resonated to temper this and it's also a great HP value mod. I don't have headers or mid-back exhaust on my list because from searching these provided the least gains (and full exhaust really doesn't fit my wants for value or sound).

My research on ART pipes says issues with emmissions and fumes. If this is true - not what I'm looking for