A&Q about 350Z
Q:
ok people,so far i got my nismo side sills, my rear underspoilers on and my 19" Volk GT-7 Diamond Black wheels which are on their way.I'm thinking getting the HKS hi power dual exhaust system a lot of people told me its the best exhaust out there for the 350z,can you guys verify that? who has it on their car in here? results? Thanks
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A:
If you are turbocharging or supercharging your car get this.
APS 3" exhaust
APS 3.5" test pipes into APS 3" exhaust- underneath.
If not forced induction you don't need something this large, consider the APS 2.5" exhaust and 2.5" test pipes. I'd get the HKS exhaust moreso for naturally aspirated. If turbo or supercharged, APS rocks! You would not believe how many forced induction owners (with other aftermarket hi flow exhausts) I have heard say, "I'm having trouble getting full boost, I'm having trouble getting full boost. PLEASE help", then get an APS exhaust and say, "Had to get car tuned to turn down boost, had to get car tuned to turn down boost". HKS is a real good exhaust though. APS for forced induction will give you more flow for less cost and both APS and HKS are super quality. APS exhausts are engineered and tested from the get go to run serious boost is the key.
Post Edited (Jun 25, 1:26am)
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Post Edited (Jun 24, 11:32pm)
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drivenZ is right. There is not a whole lot of difference powerwise in the best aftermarket exhausts if you are staying naturally aspirated. You are looking at maybe 8 to 10 hp increase with the best exhausts. The exhaust only makes a big difference if running boost. And to tell you the absolute truth he is right about that as well. It is the first 20 inches of exhaust immediately following the turbocharger that is the most crucial. That is where the hi flow cats will help you a LOT and the big test pipes as I mentioned will help you even more. That first 20 inches is where the exhaust is the hottest and you need to be large so the back pressure does not create a bottle neck (i.e. catalytic converter and turbos get along like cats and dogs or more like cats and mice, ha)
Then after that as you get downstream of the turbo (I am still talking forced induction here) and the exhaust is cooling, it needs to taper down somewhat smaller for fast exhuast flow. That is why the APS test pipes I showed you are a massive 3.5 inches and then taper down to a still massive 3" exhaust. But that set up is loud, perhaps too loud for street use - even though I love it for the track and ultimate turbo power.
Truth is the APS 2.5" test pipes (down pipes) into 2.5" exhaust flow great, are less expensive and the massive 3.5"TP/3" exhaust do not help you (power wise) vs. the 2.5"/2.5" until you are running 10 to 12 psi of boost. Now a real good intermediate strategy, if not going above the 10 to 12 psi, is running the massive 3.5" test pipes into the 2.5" exhaust. This setup will be less LOUD and flow very well.
I know a 350Z guy running the the APS 3.5" test pipes into 3" exhaust with an APS twin turbo. A new C-6 vetter pulled up to a stop light after he (the 350Z) was already sitting there at idle. Now this massive exhaust is not that loud at full idle. The vette guy smiled and revved his v-8 engine on my buddies lil' v6 350Z. So he reved his 350Z with this monster test pipes/exhuast and the vette guy was shocked! Blew the 6L V-8 away soundwise and deeper pitch wise. This exhuast is not for the weak at heart! Problem is I am afraid some cops would pull you over for this on general principle. Running without cats is illegal on the street. (on my old mitsu eclipse turbo I could go from cats to test pipes in about 5 minutes as they pop right off and the test pipes on and vice versa in about 5 minutes at the track.)
Now I don't know if you even care about hearing all this gearhead bull$hit that I ruminate about, but a guy in Chicago is trying out running an apexi active silencer with this massive APS 3.5" test pipes into 3" exhaust for the street (again legally you should run cats on the street) to quieten things down to less than a sonic boom. Now of course that will mess up some of that massive exhaust flow for twin turbo. He said he would run it on the dyno (with and without the apexi active silencer) when he gets a chance to see how much the apexi component lessens power with the twin turbo. He anticipates that the apexi component will cut down hp on this setup about 20 to 30 hp (at 12 psi boost) but when you are running 600 + engine hp that might not matter too much on the street, ha. To again be honest with you, most people would get sick of the loudness of the APS 3.5" into 3" after about a week. It may even give you headaches. Other people say this is what God intended a 350Z to sound like, ha. Sounds like you mean business! If the apexi thing works as hoped, you could run that on the street, you'd still be plenty loud and just roar like an F15 fighter (without the apexi) on full afterburner at the track. Legally you should run hiflow cats on the street and the massive test pipes at the track. The apexi component comes out via a screw in about 5 minutes for both sides (one per side of dual exhuasts).
Again, If you aren't turbo and running at least 10 psi on a built engine, you don't need this exhaust set up. anyway. A good 2.5 " exhaust is plenty big vs. our stock 2" exhaust.
By the way, though, as I said this monster exhaust does make a difference with boost. A guy has APS twin turbos with the APS 2.5" test pipes into 2.5 inch exhuast. He was tuned at 8 psi boost on stock engine internals. He bought and had installed the massive 3.5" test pipes into 3" exhuast and doing nothing else, his boost jumped to almost 12 psi from the lessened back pressure. They had to immediately tune him back down to 8.5 psi boost or that would soon blow your unbuilt engine at 12 psi. You really should not run over 8 to 8.5 psi on the stock engine. So what was the point of going to the big exhaust without building the engine and running at least 10 psi.??? Exactly.
Post Edited (Jun 25, 12:41pm)
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Thanks for the info More power i think i'm going with HKS not 100% sure yet will see!!!
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I had an HKS extreme off road exhaust (test pipe could be exchanged with cat very qickly) for my prior turbo car (mitsu eclipse gsx) and it was pure quality. Sounded great (like stock but a deeper baritone growl) and I never had a moments problem with it. i.e. Fit great, increased my performance, never rattled. Like OEM only better. I am sure you will be happy with it if you go that route. Best of luck.
Post Edited (Jun 25, 9:14pm)
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'05 350Z Chrome Silver Touring
'73 240Z
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sounds sick justin!!
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