Exhaust Sizes

[JuGgInRoCk]

i just decided that i'm going to probably get a catback exhuast system....anyone got any guess on prices? also, what is the opening from the pipes coming off the headers/cat? what's a decent priced, and nice sounding exhaust....i don't want to be considered an oversized weedwacker

[sheek360]

Everyone seems to like the magnaflow. I believe its 2.5" all around. Its bout 500 dollars, heres a link to a good vendor. www.turbotechracing.com
I still have a stock exhaust, hopefully some of the other Redliners will be able to help you out.

[zfactor]

there is not a huge sound difference from what i have heard between 2.5 and 3".. i went 3" for future upgrades... its up to you. i say the best bang for the buck complete system if the 2.5" magnaflow though if you want 2.5" for 3" i would buy the cti system from the vendor here on the forum.... this is what i own and will have on my own car. later

[Keyser Soze]

hey Z...with all the debate on size that I have seen on here. What do think are the mods that would benefit from the 3" exhaust? I know there has been quite an ordeal on several different threads and I am probably starting another one here, but oh well.

Here is my question...I am going to do CAI, SMS headers, ?exhaust?, and Stage 2 (probabaly the injectors from GM with the 2.9 billetflow). With those mods only would it be worth it to run a 3" or do I need to have more mods to really benefit from it?

Let the debate begin.........

[sheek360]

To run a 3", seems to me. That those Mods would be enough. Not to sure about the header though. Since we are SC and not turbo'd I'd believe that we will need some back pressure. I'll leave that open to anyone else here because I might be wrong. I figure the 3" makes the gasses go quicker, so the engine will need to breath-in deeper<CAI>. And the pulley would help with the immediate breathing. OK need another beer. If im wrong please feel free to correct me.

[Sp00ner]

Oh god... not this again... here's all I have to say. Here's a 3" dyno, and a 2.5" dyno. Different cars, different places. So we're not really looking for total power numbers, only the increase from stock. You tell me. Cars are otherwise stock. Becareful with the 'gains' posted on the charts. They're a little subjective about where they pick those numbers.

[Sp00ner]

I would love to see more charts posted, but these are the two best I've seen so far, I know at least one other person has a 3" dyno with simiar gains...but from these charts, there's no way that you can choose a 2.5" for ANY power reasons, the 3" makes more power over pretty much the entire RPM range, compared to the stock dynos, than the 2.5". If we get more charts, and this is incorrect, I'll be more than happy to change my mind. Until then....

[Sp00ner]

Originally Posted by sheek360

I figure the 3" makes the gasses go quicker, so the engine will need to breath-in deeper<CAI>. And the pulley would help with the immediate breathing. OK need another beer. If im wrong please feel free to correct me.

Actually, the 3" will make the exhaust move slower...

[mgm1979]

This is interesting that this is being brought up today...some may know I recently installed the 3" CTI header/exhaust system. Until this week, no problems. This week I've had the "lean" code and just today three a code for the Cam Position Sensor Performance. The Tech's first thoughts were "put it back to stock" - they're thinking the lack of backpressure is the cause of one or both of the codes. I don't know enough to debate with them, but my "novice" thinking is to say b-s...Willy at CTI thinks it's crap too. When I took the car off the lot today, both codes were cleared and in the little driving I did the rest of the day, I've yet to see either code appear. Stay tuned...

[Sp00ner]

I'll disagree all day. The cam sensor is a magnetic pick up, maybe optical, that simply spikes a voltage when the 2 sensor parts rotate near each other.

The lean code COULD be from too many mods... you have to understand though, if you were running way too lean all the time, you'd start having bigger issues.