kevsmu4

I want the JBP vortex header, but not sure what would be best after that as far as cat. or no cat. cat-back piping and finally the exhaust and exhaust tip.

Since the header only comes in 3" I would think you would want no cat 3" cat-back with 3" exhaust? Suggestions on size and what manufacture would be great!

ooo lastly, where is the most reliable/cheapest place to buy the JBP?? I know usd autosports have it for $550.00......

1 more thing, is their just 1 sensor in the exhaust system from header to tip or more???

theneelster

Yeah you'd want 3" exhaust header back, but you're ears will tell you different. It will sound like ****. No...it will sound like **** coming through a microphone.

If you're supercharged without the harrop you will lose power with 3" exhaust versus a 2.5 or 2.75 setup. 3" is for turbo applications or above 350 or so.

Buy it from a member.

2 sensors. 1 on header 1 after cat. Why would there be any more on a 4 cylinder vehicle?

HunterKiller89

iTrader: (1)

i personally say 3inch header exit. 3 inch downpipe inlet to cat, cat to 2.5inch and 2.5inch downpipe to 2.5inch catback

btw, just guessing by your post, you sound a little confised. the exhaust IS the catback

you'll want a cat...cats rob maybe a horsepower or two at most...and make the car sound MUCH better, and honestly, you wont feel 2HP...thats the equivalent to 5* temperature difference outside.

CobaltSS422

wow $550 is cheap for the JBP header. I think JBP sells it for $900 or some craziness like that. The look of it is really cool but do some reading i've read about it touching wires and what not because its such a tight fit with that header.

Gabi

thats whats i will be doing
i got that header and order the dp 3inch inlet to 2.5 inch and will get a 2.5 cat back

kevsmu4

what's the stock exhaust on the cobalt??? How does it differ that a turbo can use 3" and a s/c can only use 2.5" when they are both pushing in the same amount of air???

I just did a little research. Back pressure is not what you need to worry about. Having a 3 in exhaust makes the air/fuel ratio a bit leaner increasing the chance of valve burning. Now on some cars the computer will detect this and correct this by injecting more gas. So a s/c can run 3" exhaust all the way through without power loss given the air/fuel ratio is correct. So I guess the question is; is the cobalt's computer capable of correcting the air/fuel mixture as stated above?

I may also add that switching from 3" to 2.5" or the other way around will disturb the flow of exhaust gases causing a higher "back pressure". If the pipe is to large the air may be prone to cool down causing the exhaust temp to decrease making the air much denser and heavier which also in turn causes a high back pressure.

Sooo, for starters I think I need to decide on a single size to be used through the entire system. Now if I were to go with the JBP headers which collect to a 3" flange I would indeed want a 3" down pipe with 3in cat-back exhaust. Now the next question would be whether or not I want to run a cat or no cat. No cat would mean greater directional velocity in exhaust flow but at the same time is not emissions legal and may not acquire the sound desired. On the other hand running a cat may take away from "rasspyness" and meet emission standards. I think the solution to the cat would be a high flow cat designed to lower back pressure over a standard cat.

HunterKiller89

iTrader: (1)

^^ i like him....he does his won research

hes a little behind in the info, but thats ok....atleast he actually looks stuff up himself

Silv3r

Ermmm you got half of it right.. but around the wrong way...
Your exhaust has nothing whatsoever to do with your a/f ratio. It has to do with air velocity, and as you mentioned, backpressure (which is a factor in your exhaust velocity). Take a look at this post, it's stickied in the general section, and it'll straighten out what you've heard.
https://www.cobaltss.net/forums/general-cobalt-68/simple-explaination-intake-exhaust-resonating-camshafts-operation-68523/

And don't go catless. It sounds horrible. You won't like it.

kevsmu4

I disagree, if you are making the intake and outtake of exhaust less restrictive more air is able to flow through. That is more air with the same amount of fuel. So having a greater amount of air with an equal amount of fuel would make a lean mixture.

but perhaps my thoughts will change upon reading that sticky....

Sharkey

iTrader: (1)

thing is in a mass air flow system you have a pre-determined amount of fuel being injected for the amount of air being ingested. if you are flowing more air through the motor the MAF picks up the airflow and injectes the fuel required for it. that is one forgiving feture of a maf system, 14.7lbs of air ingested, 1lb of fuel is injected (unless in power enrichment)

kevsmu4

As far as coming to a conclusion on an exhaust setup I have:

JBP headers --> JBP downpipe/cat--> cat-back Hahn exhuast

3" all the way through. It's gonna cost roughly $1500.00 but after looking around I can't find a better setup out there.

Next will be 2.8" pulley/hub, smaller belt, belt tensioner, 60lb injectors, wiring harness, NGK iridium IX spark plugs, and cooling mods.

cooling mods are still undecided but am looking at:

-dual pass end plate
-heat exchanger
-meth injection

For the meth injection I am looking at Devil's Own kit or AEM kit....

Yea, I don't know what I was thinking earlier when I asked if the cobalt's computer could correct an increase in exhaust and intake flow lol. I have been up all night studying for a midterm so I am a little out of it. But the intake and exhaust do have an effect on a/f ratio or their would be no need for sensors in the intake/exhaust. Anyway, I forgot to add that my setup listed above is going to have a custom tune.

theneelster

Hehe...this is a nonstarter. The disparity between the low end and high end headers and downpipes (even catbacks) is likely less than 2-3 hp. But if you want to spend the extra dough then more power to you...err...maybe not.

HunterKiller89

iTrader: (1)

please dont get a 3" exhaust.....its DEFINITELY not needed for anything the stock M62 can make...

Scythe_Snake

Either a 3 inch to a 2.5 or 2.5 all the way through. Either is good, my personal choice is 3-2.5

kevsmu4

I really don't like the idea of going from a 3" to a 2.5 because it disrupts exhaust flow. And for the headers, I have listened to basically every video post on the internet of the cobalt ss s/c and exhaust mods and I know it's just a video and not the same as in person, but I have not heard anything quite as nice as the JBP headers or hahn's exhaust. Everything else sounds like a fart can when compared to those two company's.

oh, and cancel the NGK plugs, just read that are stock plugs are iridium tips and the NGK are nothing but over priced garbage.

http://www.youtube.com/watch?v=Jr2MQlJ0GM0

I will take a lil rasp over fart any day

hmmm perhaps a 3" header to a 2.5" high flow cat to a 3" cat-back exhaust would create some sort of venturi effect lol.........

HunterKiller89

iTrader: (1)

^^ trust me dude.....you'll regret gooing 3" all the way. loud as **** for minimal gains vs a 2.5" setup

CobaltSS422

A full 3" setup is useless on our setup unless you were turbo'd. I also agree with the 3" to 2.5" setup

mrams8ss

im thinking to put a 2.5 inch exhaust on my car (magna flow) i was wondering wat would be the best header and downpipe combo would it be jbp header or slp idk help me out....????

ShortStack

really... theres more choices than just the most expensive systems out there...

look around a little bit, you find the same quality and performance for hundreds less..

look up clearimage auto.

mrams8ss

ok kool thanks....

kevsmu4

My theory on what makes the JBP a better header then anything out there is the length and bends of the header. Going in a straight line from point a (your engine) to point b (your cat) is the shortest way possible. A short header will give you less restriction but minimal velocity. JBP curved the headers to to make a greater velocity, but made the bends large enough in diameter so the greater velocity was not outweighed by the restriction of the bends. So you get a little more restriction, but a lot more velocity.

The large velocity allows 3" exhaust to be ran. Running a short header with 3" exhaust and you get little velocity....

mrams8ss

so do u think the jbp would be the best combo with the magna exhaust

kevsmu4

The setup I am going to run is the following:

-JBP Headers
-JBP down pipe/cat
-3" hahn exhaust

possibly a resonator to cut down on rasp although not sure because I don't know much about resonators and am currently researching....

HunterKiller89

iTrader: (1)

^^^ gonna be loud as all hell....and the piping is way too big unless your running 350whp...
longer primaries do not increase velocity (to the best of my knowledge) all longer primaries will do is shift the power band down.... the midlength ZZP header and the Vibrant header also both have longer primaries, and would do the same thing...without the crazy price. all the JBP does diferentkly than either of these two headers i just mentioned is it has more bends (bad), and allows it to bolt up to a standard size downpipe...but the ZZP comes with its own downpipe, and i believe the Vibrant one does as well. Not to mention the ZZP has a LOT of customizable options, and i think the Vibrant might have a few options as well.

this is just my .02, but the JBP just seems waaay to pricey for what it is.

also, regarding the exhaust....i have a ZZP header, 2.5" DP, and 2.25 GMPP exhaust, and i still think my car is on the loud side.. 3" all the way back would be deafening and actually result in a LOSS of horsepower....

kevsmu4

Listen to your zzp vs. the JBP on youtube, it is night and day. To say 3" would loose power is easy to say, do you have proof of this?

zzp headers, no cat, 3" cat-back video
http://www.youtube.com/watch?v=viY8jnZfVL4

JBP header and 3" exhaust
http://www.youtube.com/watch?v=cvZhG...eature=related

Like I said night and day.