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Discussion Starter · #1 ·
I ordered an intake which should be here on thursday and it's my first performance mod ever. I planned on finishing the intake system and buying the 2.4 IM and TB but I think I'll wait and see if a non-plastic IM ever sees the light of day. In the mean time I figured I would study up on my next mod which is the exhaust. I studied the crap out of the intake before I decided on which one to buy and I plan on applying that here.

Can you guys basically cover the exhaust for me, from the EM to the tail pipe? I have no idea what parts I need, what a cat back is, or a down pipe. I don't know if you can have a dual exhaut or if that is pointless on our cars. I also have no idea why people cut half their exhaust off for just sound... believe me I've seen it... does that do anything for power? I know it's illegal to say the least. We really need an in depth writeup of the exhaust system on this site.

Also, now that I'm onto my second mod. I keep hearing how boltons move our powerband up. What exactly does that mean? And is having it move upward to the higher RPMs a good thing or not? Is it possible to way too high? What doeps an intake and exhaust do for our powerband?

Aaaaaand go. :bigsmile: But really, thanks. :toung:
 

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basically you want to replace your whole exhaust at some point. The piping in the header and downpipe is really restrictive. Replacing those would help you with power. But your header connects to the engine, the downpipe is next thing that connects to your header and contains the catylatic converter. then you have your piping. If you would go with a catback exhaust that would replace everything from your downpipe back. And getting more power through your powerband is good, that basically means that you are going to have more power throughout your RPM range... right now you only have a certain amount of power throughout your powerband, generally on the lower half you have a good amount of torque and a decent amount of horsepower on your top end of your powerband closer to redline around like 4k rpm is a good rpm when you start to get a good amount of power.
 

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Great Response SHINKLEMAZDA. I would replacethe header and downpipe before the catback. Only cuse the stock downpipe on the N/A cars is extremely restrictive and some parts of the catback are as small as 1.8 towards the downpipe. Also a header improves the flow of the exhaust as well. up t 13%. I would reccomend you going with a 2.5 exhaust all the way through. The dual exhust isnt gonna give you better gains, you might actually lose back pressure actually and its more for show with these cars. Remember that backpresure is a key factor in exhaust. So make sre you go with the right diameter of piping for best flow.
 

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Discussion Starter · #4 ·
Ok I heard you use a certain size exhaust depending on if you're NA, TC, or SC. If I go bigger than I need to I lose back pressure or something? What size would you guys recommend for NA and a supercharger build?

So header connects to the engine, then comes downpipe, then I can buy a "catback" and that is the remainder of the exhaust system? I can choose to replace them individually if I want, in any order, but the header should be the first to go? If the header connects to the engine then WTF is an exhaust manifold?

The last thing I want is a fart can ricer sound. What part does that to an exhaust so I can stay the eff away from it lol.
 

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Eventuallythere all gonna give you performance gains and if you wanna get the one that you will fel most go wit the downpipe first. Then the Header and finally the Catback.
 

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Yeah I've researched all there is to know on the bolt ons for this car and the general consensus is to do your whole exhaust system at once.

I'm sure the OP is curious, but what would be the best bang for the buck full exhaust kit for this car- headers/dp/catback and the cost roughly for everything.
 

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I would say that the best deal would be to go with a zzp shorty header and downpipe combo and then get a custom exhaust that is mandrel bent... and then get a random muffler... that would be best. And for a car that is n/a you could get a 2.25 to 2.5 inch exhaust even with a supercharger build, if you go with a stock m62 supercharger. Now you could go with a 3" exhaust if you go with a supercharger build. The three inch is good and allows for exhaust flow to the max and I have one myself hooked up to a custom muffler (aka Modified stock one) lol
 

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Back pressure is a myth.. The truth is, what you want out of an exhaust system is velocity and scavenging. With each ignition of each piston, there is a "pulse" in the exhaust. Each pulse is a high pressure pushing out the exhaust system. In between each "pulse" there is a negative pressure. This negative pressure helps pull the next "pulse" from the motor through the exhaust. So basically you need an exhaust system that is be enough to keep flow, but still have velocity and scavenging. When the exhausts is too big, you basically lose all of your scavenging and velocity because the air is basically bouncing around in the exhaust piping. (for lack of better words)

For a N/A 4 cylinder with minor boltons, 2.25" is best. For a fully bolted 4 cylinder, 2.5" is best. For a fully bolted car with stage 2 cams or more 3" is best. (check out cobalt tom's idle video!) When it comes to boosted cars, turbo's need more flow than supercharged cars. (helps the turbo spool faster and higher) A stock SS/SC is fine with a 2.5" exhaust but with major upgrades, a 3" exhaust is beneficial..

As for which one to do first, It doesn't matter the slightest bit.. They all need to be done sooner or later.. (in your case)
 

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Discussion Starter · #10 ·
Back pressure is a myth.. The truth is, what you want out of an exhaust system is velocity and scavenging. With each ignition of each piston, there is a "pulse" in the exhaust. Each pulse is a high pressure pushing out the exhaust system. In between each "pulse" there is a negative pressure. This negative pressure helps pull the next "pulse" from the motor through the exhaust. So basically you need an exhaust system that is be enough to keep flow, but still have velocity and scavenging. When the exhausts is too big, you basically lose all of your scavenging and velocity because the air is basically bouncing around in the exhaust piping. (for lack of better words)

For a N/A 4 cylinder with minor boltons, 2.25" is best. For a fully bolted 4 cylinder, 2.5" is best. For a fully bolted car with stage 2 cams or more 3" is best. (check out cobalt tom's idle video!) When it comes to boosted cars, turbo's need more flow than supercharged cars. (helps the turbo spool faster and higher) A stock SS/SC is fine with a 2.5" exhaust but with major upgrades, a 3" exhaust is beneficial..

As for which one to do first, It doesn't matter the slightest bit.. They all need to be done sooner or later.. (in your case)
So to prepare and knowing I'm going with full bolt ons and probably stage 1 cams, I'm looking at 2.5" to 3"... What is on my stock car now?
 

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Discussion Starter · #12 ·
That's tiiiiiiiny LMAO!!! What is the absolute best quality exhaust you can buy for a Cobalt, non custom? Also is the stock SS(any year) header, downpipe, cat of good quality or is it pretty crappy being stock also?
 

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what the difference between full bolt ons and minor bolt ons OBZ??
IMO just an intake and cat-back vs everything

So to prepare and knowing I'm going with full bolt ons and probably stage 1 cams, I'm looking at 2.5" to 3"... What is on my stock car now?
Stage 1 i would say that 2.5 is fine.. stage 2 i would go 3 inch for sure though.
That's tiiiiiiiny LMAO!!! What is the absolute best quality exhaust you can buy for a Cobalt, non custom? Also is the stock SS(any year) header, downpipe, cat of good quality or is it pretty crappy being stock also?
IMO the best catback for the cobalt is Corsa. THere seytem's are all mandrell bent for the best flow possible. Get the touring for a quieter sound, and the sport for a louder sound. There is no performance difference in either. I have the Corsa sport and LOVE it! I would recommend it to anybody!

Don't waste your time on the LSJ (SS/SC) manifold. get a real header. However the LSJ downpipe is a great upgrade for the 2.2. IMO the piping is perfect for a fully bolted car.
 

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Discussion Starter · #14 ·
OBZ do you think there will ever be a non-plastic intake manifold or should I just get the 2.4 one? I know this is about exhausts but I didn't want to make another topic to ask.
 

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OBZ do you think there will ever be a non-plastic intake manifold or should I just get the 2.4 one? I know this is about exhausts but I didn't want to make another topic to ask.
There really isnt a need to have a aluminum intake manifold unless your really pushing larger numbers of like 300+. Go with the 2.4 manifold swap.
 

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Discussion Starter · #16 ·
There really isnt a need to have a aluminum intake manifold unless your really pushing larger numbers of like 300+. Go with the 2.4 manifold swap.
I know I don't have to worry about the manifold blowing apart or anything, it just looks so... cheap to have a plastic part in a car you want to be a show car. :notrust:
 

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Thats true and if your going for show and you want to pay that money for the apperance of that then go ahead and do the damn thing hahaha
 

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Discussion Starter · #18 ·
LMFAO!!! Yeah I would if they had one made out of metal lol. I think Hahn makes one but I heard Hahn isn't very good. In the mean time I'll work on my exhaust and hope to god an aftermarket company makes one... your car is pretty sick based off your sig, I can tell you care about what your engine bay looks like as much as I do... :toung:
 

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I remember seeing one out there. I am not sure if it was HANH or who but there is one. And thanks for the compliment. I try to keep it clean. It was hard when i was living 3 blocks off the beach and the Salt deposits from the ocean breeze would build up on the car and engine bay. I contstantly had to wax the car
 

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OBZ do you think there will ever be a non-plastic intake manifold or should I just get the 2.4 one? I know this is about exhausts but I didn't want to make another topic to ask.
I highly doubt it.. Volcan (sp?) makes a pretty bad ass one, but that would be horrible on a N/A set up.. The only reason to need a metal IM is for boost. The 2.4 is great for N/A IMO
 
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