Sorry about the cats/testpipes.
custom true dual, Just like the stillen exhaust for the sedan except mine has true dual muffler.
So do u think rasp will get louder or no?

 

Well, you've got a system not really designed for the flow characteristic you've now introduced...hence the rasp. It's hard to say if it will get worse...typically it will get worse as parts break down over time. Also, sometimes as they carbon up a bit and season, they mellow out.

You now have mufflers and resonators that are getting more than they originally bargained for...let it all run for a few hundred miles...

Rick

 

^thanks, any idea on that wisteling noise whe the rpms are coming down at 2300 rpm ?

 

^^^ the exhaust fumes are making your ears hallucinate

 

lol, it is pretty bad though especially when coming to a sudden stop.

 

you smelled my Crawfords... maybe you shoulda gone with them?...

 

I wanted to with testpipes instead of HFC. I figured resonated pipes would be the best way to go. I am going to shawn's to retune my car next weekend.

 

I'm still gonna beat you

 

does anyone know if you can pass smog in cali with HFC's ?

 

U are going down next CS day!

 

a day like today would be perfect weather!!!! I won't be going till decent weather - I might have cams & headers by them, you better watch out

 

prabably the sniffer, but possibly not visual... Crawfords look kinda OEM so they might? you can always put OEMs on prior...

 

Expect it to get louder and possibly most raspy. Thanks to the VQ's firing order, you're going to have sorts of interesting sounds coming from the exhaust under various loads and rpms and most of those sound are not pleasing. You'll probably see the following:

1) A metallic rattling/pinging/buzz sound from 2200-5500rpms. This sound is often mistaken for a loose cat brick, loose metal, etc. It's not. What you're hearing is some of the funky exhaust sounds from the VQ's firing order.

2) A heavy buzzing/rattle when coming off the throttle at high rpm, while in gear. The sound gets progressively louder as the rpms fall. VQ Maxima owners can the sound, "bee's in a can".

 

As for the OEM cat design, it's a two stage cat. The aftermarket HFCs are single stage. The OEM design employees a precat and a regular cat. The prupose of the precat is to improve cat light off on a cold start. The HFCs just have a main cat which means the emissions will be slightly higher on cold starts, but once warm, should perform like stock.

The VQ Maxima/Altima uses a set on precats just downstream of each exhaust manifold and then a standard large cat just after the y-pipe junction. A popular mod with the Max/Altima crowd is to add either headers or a non-precat y-pipe, but to leave the stock. It's basically the same setup as the HFCs on the G/Z.

 

+1, today would be awesome!
BOOO on ur cams Post it up when u get done though. Im still waiting for someone to make power over 6200 rpm with DE engine.