3inch single exit exhaust too big for N/A
 

Anyone has this set up? Im planning to do 3inch single or 2.5 single exit? anyone has dyno chart with 3 inch single?

It won't be a problem... Depending on a few things, I'll be running FI LTHs with my 3" single exhaust with a HKS Hi-Power muffler.

Thanks, I notice on your pic your single is on the driver side. any reason why? Im planing doing mine on right

No particular reason...that's just the way the piping was ran.

Wow FI LTH plus 3" single HKS exhaust? Must be loud as hell :) and you have the power to back up the screeeeaaam.

wouldn't it flow better through two separate exhausts than routed into one?

Most JDM exhaust like Amuse used 3 inch mid pipe then connect to 2 canister.

370ZTUNE.com

im guessing same flow but lighter. I just want lighter exhaust without going TI.

for a single turbo setup a large single exhaust is ideal of course you then need to either live with the extra bumper cutout or fill it somehow.

I doubt it. To be honest, I keep wondering why every company keeps putting out the same 2.5" exhaust. It's almost as if people are afraid of 3" exhausts.

In the civic community (8thcivic), everyone ran 2.25-2.5" exhausts for years because of these claims that a 3" was 'too big'. Finally a company came out with a 3" and showed that it gained everywhere, with no losses, and now no one wants an exhaust that isn't a 3". I suspect the gains would be just as great (greater) here. I really don't get all of the FI guys who are running 2.5" DPs/exhausts. That one really boggles my mind.

dual 3" WILL lose you low end torque. back ressure creates torque. sure u might gain slight hp up top but the butt dyno will feel like there is less power because of the torque loss.

and before anyone asks "how do u know if a 3" will lose power? have u tried it?"... well no i havent, but i understand how cars work...


"Horsepower sells cars, torque wins races".

-Enzo Ferrari-

^ not sure if you're talking to me but i want single exit 3 inch exhaust.

i was more responding to awkwardturtle above. comparing a single 2.25" to a single 3" doesnt mean it would work on duals.

i think a single 3" would work great on our cars tho. our engine would definately create enough exhuast gas take advantage of that type of setup

just making sure lol... btw how do you like your cnt catback w/ test pipe? loud?

not too loud at all. very low rumble at idle actually but really opens up up top.

here's a vid to give u an idea

370z CNT cat back and test pipes - YouTube

to be honest nobody that has heard it has even noticed im running test pipes

damn sound really good. what kind of test pipe? is your check engine light on? notice any hp increase?

You sound EXACTLY - like word for word - like everyone used to on the 8thcivic forums. "We need backpressure or we'll lose power down low". That was the mantra for at least 2-3 years. Everyone chanted it. One day a 3" comes out, proves every single person wrong.

Maybe you are right, maybe your'e wrong. Someone should actually test it before saying that, though, because everyone used to be like you until it was proven wrong.

Nissan 370Z Z34 Infiniti G37 Coupe VQ37VHR 3.7L 08-11 Exhaust Test Pipe Pipes | eBay

those tp's (or some similar to that with the o2 extender).

no check engine lights, and after driving a stock z then hopping back in this, this definately feels waaay more responsive and getting those cats out really helps the engine breath better up top

thanks for the info... now im really leaning toward CNT Catback.. did u install the test pipe urself ive heard those bolts are pain to remove?

i actually did not do the test pipe, only piece i didnt do actually. i think it will prolly come down to how many miles u have on your car to determine if the bolts have gone thru a ton of heat cycles or not. the less miles u have, the better the chance it will come off without fighting u.

I ran test pipes, a TopSpeed Y pipe, into a 3 inch pipe through a 3 inch hks muffler. It was loud as hell. I gained 3hp up top, but it did feel like I lost torque lower in the RPMS. I now have a Nismo exhaust with a custom X pipe and resonated TP.. to me it is the best of both worlds... The extra 3hp didnt make up for my hatch rattling from the exhaust noise.

nice.. u have video?

Yeah, I'd definitely like to see a dyno of the 3" vs. stock. Here's a dyno of a 70mm exhaust vs. a 3" exhaust on a measley 2.0L Civic SI motor. No tuning:

http://i663.photobucket.com/albums/u...ed/carlos2.jpg

You can see that the 3" gains probably 5 whp up top, and maybe as much as 10 ft lbs of torque at the vtec crossover.. and it loses maybe 2 ft lbs of torque down low. That's with zero tuning. If a 2.0L 4 cylinder motor can benefit from a 3" exhaust, it stands to reason that a much larger motor such as the Z's can as well. Enough with the backpressure nonsense, we need to see some dynos!

Hmm, now you are scaring me. I have a Top Secret exhaust and am going to put on a Top Speed Y Pipe and Berk HFC's soon. I hope it doesnt get annoying loud.

I dont have a video.. I may be able to post up a dyno chart however... Let me e-mail my tuner and see what he has on file. With non-res tp and the topspeed y pipe into a muffler that was pretty much a straight pipe was very loud. I think with HFC's you will be happy. It will be loud but shouldnt drone as much.

No more turbo?

Thanks... I think I'll go with ARK grip or CNT.

Strong source....runs weren't even made on the same day, made by the manufacturer of the exhaust, and they are comparing max power runs rather than averages. Besides, the flow characteristics of the k20a are completely different...it's an freaking inline four.

3" exhaust on the z makes sense if for some reason you go single, or dual for FI.

I do not understand why someone would run a single on the z(single turbo build notwithstanding) in the first place. Might as well take advantage of the scavenging afforded by an x or h pipe. The firing order across banks supports it, and the gains are proven by systems like berk. Hell, even the nismo picks up a couple horses through the h.


EDIT: People that truly believe there are gains to be had do it themselves, they don't post about it asking others to do legwork for them. I look forward to seeing your dyno results when (if) you ever do it.

Somehow I knew you and your "expertise" would chime in on that, lol. Do you just troll 8thcivic all day looking for **** on there to wing back at me? lawls. Btw, f20c? No...

You really think an exhaust producer would fake those gains? GTFO.

I have been a vendor on there since the forum started bro

it has never happened before:ugh2:


there is a reason people don't believe gains unless they are seen on a third party dyno. Motordyne (and many other reputable shops) offer dyno credits for people to independently verify...and those are the only circumstances you can even begin to believe the claimed power gains.

:iagree:

It would be stupid for a company to show that their exhaust gives minimal gains. They're not going to sell many like that.

^ So then you don't agree, because I'm arguing the point you just made, and you just agreed with the guy arguing against that point.

No, I was arguing against the point where you said no exhaust producer would fake those gains. I gave a reason why they would do it. There's a big difference between why a manufacturer would do it and whether it should be believed.

same principle applies to posting numbers that don't show losses.


FWIW, the IP dyno showed losses with that exhaust on both FG2s I saw run it, but that is not really relevant here.


For the curious, the 370z substantially benefits from running a crossover of some sort. Almost every aftermarket exhaust that shows gains has one, and that is honestly where they get most of their gains.

cylinder banks on the VHR look like:
135
246

with a 123456 firing order. The alternating pulses are ideal for a crossover exhaust, and can get funky flow characteristics if routed to a single pipe. These of course can be minimized by bring the join point farther back.






The backpressure issue is a little misunderstood by most. The engine doesn't so much need backpressure, at the risk of low end torque, as it experiences bad flow characteristics generated by the exhaust gases cooling en route.

You basically want zero backpressure from the collector back, coupled with maximum flow(not actually implementable, but not hard to get close). The header design does need to generate backpressure, as well as provide sufficient velocity that the system does not back up under overlap (won't ever happen at high rpms, will happen at low)


dual 3" is either going to create an eddy at the header output/cat/tp output, or require running a non-optimal header design (at best, a staged header diameter)


Vizard's numbers say the Z with full boltons needs about 720CFM of exhaust flow to prevent restriction. A single 3" pipe flows over 1000CFM, which means that it is in no way contributing to increased restriction, and any issues are in your muffler. 2x2.5 offers over 2000CFM of flow....

Any gains that come from different exhaust designs are mostly due to removing restrictions (cats, muffler), or tuning of exhaust pulses, not from increasing pipe diameter. Increasing pipe diameter is mostly likely to create funky flow characteristics due to either messing with the header piping, or creating eddies...as well as allowing exhaust gas to cool and back up.

Motordyne mentioned some of those same things in the reasoning for the design of their upcoming exhaust :tup:

Are you kidding me? lol

Look a the dyno. It shows almost no or negligible gains throughout the majority of the revs. You act like I put up a dyno where the car gained 30 whp and then believed it to be credible.

I didn't say anything about that specific dyno, I barely even looked at that one. I was just talking about in general.

so, if gains are believable, the default is to believe the manufacturer completely?

Hell yeah! Buy up those 60+whp chips on eBay!

I'll order two just to be safe. No reason they can't be stacked as long as I run an extra battery, right?

It's called using common sense... something that is clearly in short supply these days. If you think Go-Power, a reputable company, is falsifying a 4 whp gain, suit yourself bud.