exhaust questions

whiterider00 · 02-01-2011, 02:11 AM

so ive had my header (2.4) in my trunk for literally almost 2 years now, and i finally have the money to redo my entire exhaust. gonna be pacesetter header to dynomax muffler (as resonator) to magnaflow cat to borla muffler. pretty sure the pipe size after the flange on the header is 2.5in, but i may be mistaken. also, i think my current muffler is 2.5 in. i was thinking of doing 2.5 all the way, but from what ive read, 2.25 might be better, to help keep some backpressure. also the muffler thats on now is a single in/out with a half assed "T" on the tail pipe to give me dual exhaust outlets. would it make any difference at all in flow if i were to get a single in/dual out muffler like what would be used on a camaro/firebird? basically would those 3 extra 90 degree bends make any difference at all?

sorry for the novel i just wrote, just want to make sure i get what will be the best for the car. thanks.

whiterider00 · 02-02-2011, 12:45 AM

no opinions?

xXManwhoreXx · 02-02-2011, 01:10 AM

2.25 would be best for your setup. However I would run a real resonator insted of a muffler.

whiterider00 · 02-02-2011, 02:04 AM

ill look into that, probly b cheaper anyway.

AleroB888 · 02-02-2011, 02:30 AM

Quote:

Originally Posted by whiterider00

so ive had my header (2.4) in my trunk for literally almost 2 years now, and i finally have the money to redo my entire exhaust. gonna be pacesetter header to dynomax muffler (as resonator) to magnaflow cat to borla muffler. pretty sure the pipe size after the flange on the header is 2.5in, but i may be mistaken. also, i think my current muffler is 2.5 in. i was thinking of doing 2.5 all the way, but from what ive read, 2.25 might be better, to help keep some backpressure. also the muffler thats on now is a single in/out with a half assed "T" on the tail pipe to give me dual exhaust outlets. would it make any difference at all in flow if i were to get a single in/dual out muffler like what would be used on a camaro/firebird? basically would those 3 extra 90 degree bends make any difference at all?

sorry for the novel i just wrote, just want to make sure i get what will be the best for the car. thanks.

CAT has to go in stock location, put the resonator after the CAT, I'd go 2 1/2 mandrel bent pipe, backpressure is almost never good. Bends make a difference in flow, but the dual out mufflers are not bad. Straight in and out flows best. In general, the better flow, the louder it gets.

whiterider00 · 02-02-2011, 03:14 AM

i think im gonna keep the muffler ive got. i cant find a borla in the inlet/outlet configuration i was looking for. im hoping with the new resonator and everything that the sound calms down a bit. i think i might have developed a very small leak somewhere, because over the past few months its gotten quite a bit louder, so hopefully replacing everything helps. and ya, i forgot the cat is first, im gonna keep it that way.

xXManwhoreXx · 02-02-2011, 07:12 AM

Look into a greddy dt muffler they are quidt until you WOT than a valve opens and they roar

whiterider00 · 02-19-2011, 01:39 AM

so i finally got this done, and im kinda pissed i went with the regular resonator instead of the muffler. my exhaust is so goddamn loud, i can barely drive the car. so im thinking of getting the dynomax muffler i originally planned on getting, and just adding it in to the exhaust. this should help absorb some of the sound (i hope). its not raspy right now, just ridiculously loud. i didnt think it would be such a change in sound from adding the header and using bigger pipe, but it is insane. if anyones got any other suggestions, please let me know. thanks.

also, the other thing i noticed, is that i actually lost both low end and top end power. the only time i notice any gains is when at wot and then its so loud it may just be the sound playing tricks on me. so over all i am quite displeased with the turn out. but hey, only spent $400+ and they had my car for 3 days. ok, all done ranting.

widbyj · 02-19-2011, 03:02 AM

Sorry I missed this before... I'm running a pacesetter on my 2.4 also. High-flow 3" cat, straight back to a 3" resonator before the axle and then some bends into a 3" Hushpower (by Flowmaster) muffler. This thing is pretty loud all the time in the car but not so bad outside until I get on it (S/C doesn't help). Probably will make it quieter later, not sure. The tone is very low and sets off car alarms when I cruise past - lotsa fun!

For N/A builds 2.5" is probably best. A bigger cat might help, this one is rather small and very porous (you can see a lot of light through it). A cherry bomb style muffler would probably be better than a standard resonator without blocking any flow. A Dynomax VT muffler is similar to the greddy, at normal driving it acts like a real muffler but at high flow a valve opens and it flows straight through. Price is much better, $100 at Summit, and is fairly small.

The performance problem is probably due to the placement of the O2 sensor. They located it too far down, usually the wire doesn't even reach, and it never heats properly. This causes the ECM to mis-calculate and generally cause a very lean condition. To correct either change to a heated (4-wire) sensor -or- have a bung installed in one of the tubes about 4-6" from the head. I blew a set of rings cause it ran way to lean under boost with this header, be careful.

Hope this was helpful...

whiterider00 · 02-19-2011, 09:09 AM

Quote:

Originally Posted by widbyj

The performance problem is probably due to the placement of the O2 sensor. They located it too far down, usually the wire doesn't even reach, and it never heats properly. This causes the ECM to mis-calculate and generally cause a very lean condition. To correct either change to a heated (4-wire) sensor -or- have a bung installed in one of the tubes about 4-6" from the head. I blew a set of rings cause it ran way to lean under boost with this header, be careful.

Hope this was helpful...

this was quite helpful. i noticed they did have to extend the wires to the o2 sensor, and it looks like its just twisted together and wraped in electrical tape. no codes, but i will look into the heated sensor. and definitely gonna get some sort of muffler, and put it in to quiet it down. thanks for the help, ill update when i get it done.

Ttop191 · 02-19-2011, 11:32 AM

wait a second, they lengthened you o2 wiring??? where did you have this done, that is totally going to eff with your signal it's sending back to the PCM

Greencoupe2.2 · 02-19-2011, 11:41 AM

Las I heard the o2 sensor had to be mounted in the factory location and thosse wires should be crimped and heat scrhrinked especially since there under the car

Ttop191 · 02-19-2011, 11:49 AM

^ they shouldn't be tampered with at all...if you extend them or shorten them it changes the resistance in the circuit, and thus throws of the voltage reading the PCM receives...causing you to run rich or lean depending on what you do with the wires

whiterider00 · 02-19-2011, 04:07 PM

ya, i was kinda skeptical about the wires being lengthened. the place that did it is a local place that does mostly custom and stock exhaust work, and ive heard nothing but good about them. so i dropped the alero off tuesday morning, and they said theyd call when its all set, should be before the end of the day. no call that day. called 8am next day, and apparently they had a lot of work tuesday and didnt get a chance to bring it in to work on it at all. said it would be in soon and theyd call by the end of the day. no call that day either. called thursday morning, they said its in the shop now, hes just "finishing installing the header and everything else underneath". isnt the whole exhaust underneath...? anyway they call just before i go into work asking "did you want a muffler on the car?" wtf? of course i do, it would be ridiculous with out one. they say to come get it. the manager calls me like 5 min later asking the same thing. do i want a muffler on the car cuz its really loud right now. i tell him, yes, the borla muffler that was on the car when i dropped it off is staying and the header, resonator and hi flow cat are going on with 2.25" pipe. "oh, ok ill have to put the muffler back on, i just ran a "y" to the tips after the cat." i told them when i got the estimate and when i dropped it off what i wanted. they obviously didnt remember. finally go to pick it up yesterday (friday), and they charge me $20 more than estimated. i was pissed ab out everything at this point, but so sick of driving my dads focus that i just paid and left. got home and checked everything out, and thats when i noticed the wires from the o2 sensor:

so im gonna try to not drive it much til i can get some other sort of muffler on it to quiet it down, and until i figure out what to do with the sensor issue. if theres any issues because of the spliced wires, the shop will definitely be hearing from me.

whiterider00 · 02-19-2011, 04:15 PM

hoping something like this will work to quiet it down. cant really fit a full sized oval muffler anywhere.

whiterider00 · 02-19-2011, 04:30 PM

sorry for the triple post, but i found this:

http://www.aleromod.com/forums/showt...ght=2.4+header

and now dont know which one to believe. should i worry about how they extended the wire? should i shorten it up a bit and solder it? id really like it if my engine didnt blow the eff up cuz its not running right.

Greencoupe2.2 · 02-19-2011, 05:03 PM

what the hell kind of wiring did they use, a house extention cord and house hold wiring nut, looks like the biggest hack job i have ever seen. I i were you i would get some wire loom and some 16 or 18 gage wiring and wire it the right way. I would solder the connections and use some heat scrink to seal it up. And shotening up the wires wouldnt be a bad idea either. It doesnt even look like your cat is connected to your headers.

whiterider00 · 02-19-2011, 05:25 PM

ya, it looks like its a bit bigger gauge, and the wire nut things are just those crimp on type. im gonna call them monday morning and ask what the hell they did to it and why it looks like shit. so im gonna shorten up, and solder the wires for now, but ive heard others have switched to a heated o2 sensor to fix issues from installing the header, so ill check on that too. to fix the noise issue im gonna get the above muffler and get it on asap. this whole thing has been a huge pita, im just hoping to get it fixed quickly.

widbyj · 02-20-2011, 12:02 AM

You CAN safely extend the wire on the harness side using any good quality wire, soldering is best due to vibration.

You should NEVER cut the white wire that comes out of the O2 sensor itself.

From the pics it looks like they totally cut the original connector off of bothe ends and then just wired it all together. IMO they owe you an O2 sensor that hasn't been raped and the necessary mating connector to attach to the factory wiring. Not a shop I'd ever go back to...

As for the heated sensor - must do if you want it to work right. The exhaust may cool enough by the time it gets to the collector to cause issues, mine does. I'm going the wideband route instead, found one that also feeds out a signal appropriate for the ECM to monitor. Good luck!

Cliff8928 · 02-20-2011, 12:35 AM

If you wanted, I could make plug-in extension for your oxygen sensor that looks factory original. Either to use the original sensor or a heated (v6) sensor.