AGreenZ

Hey guys I currently have a 2008 350z HR with K&N Vortex air intakes and im about to straight pipe it. I have some questions though about that. I have seen plenty of post from people saying that it does increase HP in the vehicle but I have also seen some where people noticed a HP loss.. Im only doing it from the cat back so idk if that will be a gain or loss so i figured I would check with you guys!

SQuaLZ

Is this a track only car?

Straight pipe will not be fun on the street.

For the street I would look into Tomei or Agency Power.

AGreenZ

No it isnt a track car... But I had the muffler off the car last year for a week while I was doing some stuff to it and loved the way it sounded and everything! So i was thinking about just straight piping it from the cat back but I just want to make sure ill only be gaining hp and not losing any.

Emski

Straight pipe is going to be FAR louder than muffler off only.

dkmura

iTrader: (64)

You will not gain much HP with just a straight pipe. My SCCA T3 HR Z33 has test pipes and is VERY loud with a magnaflow exhaust. Needed multiple runs at UpRev on 100 octane fuel to find any gains. You'll eventually tire of the drone and attention from cops...

AGreenZ

Well I was thinking atm I have the vortex intakes so I have the extra air intake but im not getting rid of it any faster. SO I would assume that straight pipes from the cat back or just getting rid of the cat all together would be a nice hp boost. From what I have heard though straight pipes without a cat do not sound very good.

dkmura

iTrader: (64)

Do a bit of research around here and you'll find CAIs deliver very little gains. As for the exhaust, you'll still need a tune to take advantage of the straight pipe and in any event the upgrade will be mild (5-8 hp). It won't be discernible unless you take it to the dyno...

travlee

iTrader: (8)

op just needs to quit being cheap and buy a good exhaust and get a tune

NiLL

Long tube CIA do more for preventing heat soak and keeping you at max power then adding it. With the injen (2006 revup) long tube CIA my charge temps got very low and stay there according to a ODBII scanner. if your intake is still pulling from the engine bay I'm willing to bet you are losing power after 20m of the car being on and the stock airboxes to a decent job keeping out soak.

MicVelo

If it's all about sound, do whatever you want. And don't expect any sympathy from anyone when you get pulled over for noise.

BUT, if you are interested in actual gains of power, do as others have suggested and invest in a "real" exhaust system that is designed to maximize scavenging by USING the exhaust pulses to their advantage. You will see some nominal gains with such a system but don't expect to feel them that much.

Here's what to realistically expect with a pipe only exhaust: A significant change in the torque curve, especially so on the already higher curved HR motor. Your power will move further from the low end that you NEED for the street and higher up into the "canyon/track running, hold the gear longer realm of operation. While this may not be objectionable - that much - just warning you that the car will FEEL completely different like there's no one home in the engine compartment for a while.

Your choice.

AGreenZ

Has nothing to do with me being cheap... I don't know a ton about this stuff and have heard different things. Hence why I am here asking about the HP gain. If getting an actual exhaust is my best option then I will do that. But I have seen and been in 350z's that had straight pipes and they just sounded so mean!

travlee

iTrader: (8)

but is mean legal?

AGreenZ

In Florida I believe so we have no emissions test here and I have seen tons of straight piped cars.

MicVelo

"Noise" and "Emissions" are mutually exclusive.

You sound like you've made up your mind. Straight pipe it.

Trav, you tried.

dcains

iTrader: (15)

Here's to hoping this idiot lives nowhere near me.

travlee

iTrader: (8)

bet he joins the camber kids before long. you know OP there is such a thing called noise pollution.

when i had my 08 with art pipes and tdx2, i got pulled over for several times for being loud

AGreenZ

Nah dont worry I live on the nice side of FL. Further more why would you call me an idiot? I didn't say im 100% going to straight pipe it. Im doing my research now and looking at different options. I like the sound of the straight pipe more so I am kinda leaning that way but I still haven't made up my mind yet.

AGreenZ

Nah I dont like the camber and would it be very loud even if I did just from the cat back?

travlee

iTrader: (8)

it is called a muffler for a reason

Fridge Gnome

To me, the loudness isn't so much a turn off as the raspiness is.