STILLEN 370Z Dual Cat-Back Stainless Exhaust System

kdo2milger · 02-28-2009, 10:27 AM

Quote:

Originally Posted by spiderman

So the Stillen doesn't replace the stock converters? If you want to replace them, you need the HFC's too? What does adding the HFC's with the Stillen ultimately do?

no, the industry calls them catback exhaust - meaning from the catalytic converters all the way to the exhaust tips.

stock catalytic converters are by far the most restrictive part of the exhaust system. stock cats are for vehicle emissions.

replacing them with high flowing cats or test pipes free up a lot of power that is otherwise sufficated by the cats. your not really adding horsepower, your actually unleashing the power that is already there by a free-er flowing aftermarket setup.

so ultimately by replacing the cats w/ hfcs and a good catback along with a good cold air intake you are making it easier for the engine to breathe...better breathing equals more horsepower to the ground. and as a added bonus a much much better sound out of the exhaust.

semtex · 02-28-2009, 10:51 AM

Quote:

Originally Posted by kdo2milger

no, the industry calls them catback exhaust - meaning from the catalytic converters all the way to the exhaust tips.

stock catalytic converters are by far the most restrictive part of the exhaust system. stock cats are for vehicle emissions.

replacing them with high flowing cats or test pipes free up a lot of power that is otherwise sufficated by the cats. your not really adding horsepower, your actually unleashing the power that is already there by a free-er flowing aftermarket setup.

so ultimately by replacing the cats w/ hfcs and a good catback along with a good cold air intake you are making it easier for the engine to breathe...better breathing equals more horsepower to the ground. and as a added bonus a much much better sound out of the exhaust.

Agreed, 100%. Spiderman -- a cat-back exhaust is so named because it's from the cat, back. As in, from the back of the catalytic converter(s) onwards. A cat-back exhaust alone will yield significant results. But to go the extra distance, some people also replace the stock catalytic converters with either high flow cats (HFCs), or test pipes. Test pipes are essentially just pipes with nothing in them. In other words, you're taking out the cats entirely and have nothing to filter out the pollutants. Test pipes are not street legal, fyi. Not that I have anything against them per se. I had Kinetix test pipes on my 350. But this time around, I've decided to go with HFCs and stay 'clean'. Think of HFCs as a compromise in between full-blown test pipes and restrictive stock HFCs. Stillen does not currently have HFCs available for the 370. However, Berk and Kinetix do. If you look at the thread on the Berk HFCs, you'll see that they alone yield up to +19whp, and they alone give you a much nicer exhaust note. Here's the link to DD's group buy thread, which includes the dyno results and the sound clip video:

DDMotorsports: Berk Tech High Flow Cat/Test Pipe Group Buy!

I've decided to get both the Stillen exhaust as well as the Berk HFCs. That should really open up the sinuses, so to speak. Then once I get the CAI put on, we'll really be in business!

spiderman · 02-28-2009, 11:16 AM

Quote:

Originally Posted by semtex

Agreed, 100%. Spiderman -- a cat-back exhaust is so named because it's from the cat, back. As in, from the back of the catalytic converter(s) onwards. A cat-back exhaust alone will yield significant results. But to go the extra distance, some people also replace the stock catalytic converters with either high flow cats (HFCs), or test pipes. Test pipes are essentially just pipes with nothing in them. In other words, you're taking out the cats entirely and have nothing to filter out the pollutants. Test pipes are not street legal, fyi. Not that I have anything against them per se. I had Kinetix test pipes on my 350. But this time around, I've decided to go with HFCs and stay 'clean'. Think of HFCs as a compromise in between full-blown test pipes and restrictive stock HFCs. Stillen does not currently have HFCs available for the 370. However, Berk and Kinetix do. If you look at the thread on the Berk HFCs, you'll see that they alone yield up to +19whp, and they alone give you a much nicer exhaust note. Here's the link to DD's group buy thread, which includes the dyno results and the sound clip video:

DDMotorsports: Berk Tech High Flow Cat/Test Pipe Group Buy!

I've decided to get both the Stillen exhaust as well as the Berk HFCs. That should really open up the sinuses, so to speak. Then once I get the CAI put on, we'll really be in business!

Thanks very much for everyone's feedback, I appreciate the help! It's what I thought but wanted to make sure. I was thinking of the same set-up based off what I have been reading semtex. Quick question .. at cruising speeds, will adding the Berk HFC's be too loud combined with the Stillen Cat Back?

Frick@DDM · 02-28-2009, 11:51 PM

Quote:

Originally Posted by spiderman

Thanks very much for everyone's feedback, I appreciate the help! It's what I thought but wanted to make sure. I was thinking of the same set-up based off what I have been reading semtex. Quick question .. at cruising speeds, will adding the Berk HFC's be too loud combined with the Stillen Cat Back?

Well even on previous cars I have driven such as G35's and 350z's which had the Stillen dual with test pipes, sounded great and were not obnoxiously loud and drony as other exhausts.

In my opinion it will not be drony with the dual and hfc's. It should sound awesome

With the stock exhaust and the HFC's our 370z sounds great when you get on it and stock when you are cruising. The Stillen won't be too loud

Nikon FM · 02-28-2009, 09:54 PM

Quote:

Originally Posted by semtex

Agreed, 100%. Spiderman -- a cat-back exhaust is so named because it's from the cat, back. As in, from the back of the catalytic converter(s) onwards. A cat-back exhaust alone will yield significant results. But to go the extra distance, some people also replace the stock catalytic converters with either high flow cats (HFCs), or test pipes. Test pipes are essentially just pipes with nothing in them. In other words, you're taking out the cats entirely and have nothing to filter out the pollutants. Test pipes are not street legal, fyi. Not that I have anything against them per se. I had Kinetix test pipes on my 350. But this time around, I've decided to go with HFCs and stay 'clean'. Think of HFCs as a compromise in between full-blown test pipes and restrictive stock HFCs. Stillen does not currently have HFCs available for the 370. However, Berk and Kinetix do. If you look at the thread on the Berk HFCs, you'll see that they alone yield up to +19whp, and they alone give you a much nicer exhaust note. Here's the link to DD's group buy thread, which includes the dyno results and the sound clip video:

DDMotorsports: Berk Tech High Flow Cat/Test Pipe Group Buy!

I've decided to get both the Stillen exhaust as well as the Berk HFCs. That should really open up the sinuses, so to speak. Then once I get the CAI put on, we'll really be in business!

Semtex,

Are you going to dyno your car after the mods are in place? I'd like to do the same setup but am not too committed until I see the results/benefits. Perhaps one of the Venders who sales all the parts can do a dyno session and post the incremental results...........might motivate some additional purchases?

semtex · 03-01-2009, 08:46 AM

Quote:

Originally Posted by Nikon FM

Semtex,

Are you going to dyno your car after the mods are in place? I'd like to do the same setup but am not too committed until I see the results/benefits. Perhaps one of the Venders who sales all the parts can do a dyno session and post the incremental results...........might motivate some additional purchases?

Not sure if I want to go through the hassle and expense. I guess I can look into it. I'm not even sure where to go around here for a dyno.

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