My concern is from an episode I had today.
I made a U-turn and had to gun it because I needed to make enough room for oncoming traffic.
The noise I heard was more like a small muffled poof when I accelerated hard. Kind of like a short muffled fart, being serious though.
This could be 'normal', as now there is more sound coming through from the opened up exhaust, but really not much more. As such, it might be letting me hear sounds that already existed under certain conditions but were silenced before with just the catback.
I would say the tone also has changed a hair to the lower end, with a tenth of one decibal going higher.
My pedal effort is less reflected sound wise through the exhaust, like the motor is not having to work as hard for the same excelleration in comparison to the older catback only set-up. This is the best part, because now people dont think I am racing everyone with the more aggressive sounds I had for less excelleration. I swear, people think OMG I hear his exhaust so I will show him what flooring it is all about. Even though I am not flooring it. This is not always the case, I just get a lot of this though with my wife's car.
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Anyways, the sound was very short in duration, and not loud but audible all the same. I hate hearing 'new' noises, it usually means something is going wrong.
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This post is prompted because yesterday is when I went ahead and got a 2 1/4 inch cat, 2 1/4 mid pipe with sensor mount and a 2 1/2 resonator for my wife's car to complete the exhaust. I dont want a header at this point.
The shop suggested the 2 1/2 for the resonator because the baffle restrictions on the inside of it reduce the inside flow, so 2 1/2 on this resonator should flow with equal backpressure as a normal 2 1/4 straight through pipe.
This was all done to match the 2 1/4 catback exhaust with 2 1/4 turbo muffler.
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My question is:
Now that the car has a 2 1/4 inch full exhaust, do I need to be concerned with running lean?
Do I have to get the computer tuned with this set-up?
This is a 2003 2.2 Ecotec Sunfire...
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I did reset the computer before driving home from the shop.
I did the standard 5 minutes with the positive lead off the battery.
Then putting it back on, starting up the car and let it find the idle point for 5 minutes.
Then shut off the car, start again and drive.
The only other mod on this car is the drop-in K&N filter.
Even people with Sunfires are reporting CAIs popping CELs so I didnt want to mod the intake side of the motor much.
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I am not currently getting a CEL, and hopefully wont.
I went ahead and put some 91 octane in the tank immediately after I heard that poof noise. The tank has about 8 gallons of 87 with almost 5 gallons of 91.
I know high octane is a waste of money on a stock set-up, but I am not sure if I over stepped the limit of this 2.2 ecotec by going to the full exhaust.
I just know that a backfire causes major damage to the motor's internals.
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Just for the ones who want to know:
The upgrade from catback to full exhaust made a HUGE friggin difference in excelleration. The catback alone was nice, but I did not think it would make THIS much of a difference.
Why? Because on other cars it helped, but didnt make 'this' much of a difference. All cars react differently to mods.
The torque even on the freeway is felt! I tap the gas and my head gets pushed back good everytime. For a 4 banger naturally aspirated, I am very impressed.
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I had a V-6 Mustang 3.8 race me on the freeway, and I only had to push the gas to the middle (seriously) and the guy kept looking over and had that look of hope on his face. So I floored it and seriously, the guy was 10 cars back when I let off. Yes, he was trying, his engine made that over excellerated whine sound followed by excelleration and that sound of build up from the exhaust once the tranny kicked in.
V-6 3.8s are slow, I know, but they are like a 9 second 0-60 and I didnt have to floor it to match him flooring it with my wife's 2.2 Sunfire.
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All this up and go is great, but I dont want the motor breaking as a result.
My Cobalt is bone stock, but who here has their Cobalt with a full exhaust and has there been any backfires or weird sounds or problems that have arisen from this upgrade?
Thanks
Wow man, that's a long post.
You won't run lean with an exhaust with an otherwise stock car.
It sounds to me like you're just hearing more of the engine's popping. I wondered about that too.
No need for 91 octane, 87 octane will do nicely.
Nice Mustang kill...
Admiral Jedi wrote:Wow man, that's a long post.
You won't run lean with an exhaust with an otherwise stock car.
It sounds to me like you're just hearing more of the engine's popping. I wondered about that too.
No need for 91 octane, 87 octane will do nicely.
x2. that's what o2 sensors are for.
JBO Stickers! Get yours today!
now you have to bore your tb out !!!!
DO IT !
yea its ok, the pop you hear isnt your motor being destroyed just with less restriction that's what happens
Quote:
yea its ok, the pop you hear isnt your motor being destroyed just with less restriction that's what happens
The way this is written out, it could be picked up as the motor is being destroyed, but just will less restriction.
Do you mean that or?
Today I drove the Sunfire again and it wouldnt no matter what reproduce that sound.
It was more like a wimpy fart than a pop. If I backfired full blown, I would be chewing nails.
