Exhaust ?

[TXOlds]

Anybody have any ideas for new mufflers ? Us Texan's like to hear our cars rumble a bit. Throw some ideas this way.

[kobalt]

Corsa makes a Caddy exhaust that can be fitted to the Aurora with little modification. A pair of Flowmasters would not sound bad either.

[Marc]

Aurora40 installed the Corsa system on his 2002 4.0
some years ago. He thinks that that system is excellent.

________________

GM!!! BRING BACK OLDS!!!

[Aurora40]

Yup, I got the Corsa's about two years ago and they still make me giddy. It's a great setup. Jim has some Magnaflows on his car and it sounds great in the clips.

I believe the other guy who put their money where their mouth was when I did was from Texas. So if you see a new style 4.0 with some stainless tips and a great sound, that's probably the guy.

[Krazy Kyle]

What kind of performance gain could one get from the stock Aurora with an exhaust set?

[JimW]

Corsa is probably what? 25-30 crank HP extra? I bet my Magnaflow catback is anywhere from 20 to 25HP.

Its pretty substantial, my figures may be generous, I have yet to dyno the car, maybe once my 80mm TB and intake system goes on.

[kobalt]

JimW your figures sound realistic once you do some work to the intake side.

[JimW]

Yeah I agree, however I do have a gutted intake w/K&N, adding about 5 HP or so.

Once the RSM intake goes on, then the full potential is there

[stevensolds]

i dont do K&N because of blowby dirt that gets by. my friend has a mustang cobra (and it smokes my aurora, too) and he lifted off the filter that whole bread box was caked with crap.

anyway i want to get a flowmaster delta 40 series muffler and Bassani x-pipe but i dont know if i can do that to this car. One shop quoted me at $385 installed for a dynomax x-pipe system w/cats and stainless Flowmaster tips, but im not sure if thats going to sound good. The price is my range, however.

has anyone else added any aftermarket exhaust? i like flowmaster and dynomax the most.

[SupaStealth]

Yeah, i have the Dynomax Turbo mufflers along with catback 2.5" piping on my car along with the resonator taken out, i like the sound, everyone complements the sound of it too. I still have yet to record it though, but i promise i will soon. i honestly think they're a bit quite, but if it was any louder the passangers (especially the older people) would probably be uncomfertable, so i suppose it's just right for me.

[stevensolds]

can you tell me where you got yours installed and did you have to call dynomax to get it custom made? i wish they had universal ones like they do for every other car. i want dynomax though

[SupaStealth]

I Bought the mufflers from Napbco (or Bumper to Bumper, same thing) for 35 bucks each, 2.5" in and out. then I bought the pipe from the local exhaust shop and had them install it and they custom bent it and everything. total cost was about $240.

[stevensolds]

thats what i was wondering about, custom bent.

would any auto shop do that for you, or special ones?

[SupaStealth]

just find a muffler shop in your area, i would ask around and see if anyone you know recomends a place, because a more local shop could have really good service and cheap prices compaired to a "midas" or other name brand places, or on the other hand could have bad service and high prices, so just ask around. Any exhaust shop would be able to do it, they might charge a bit more since they have to make the y-pipe in the back though. A lot of shops should provide free quotes on the price too.

[scottydl]

Supa, I'd really like to hear your Aurora's exhaust note and WOT when you get it. I had the same mufflers (Dynomax Super Turbos) installed on my '69 Executive, when the duals were put on several years ago. They sound good, but a little loud for my tastes after being broken in. That's on a 400ci (about 6.55L) monster engine, so perhaps our 4.0L Northstars are different. If so, you can't beat the price for the Super Turbos.

[SupaStealth]

are super turbo's the same as turbos? yeah, i'll try and get some sound files of it soon, i'll do it in park, and i'll set it up so you can hear it under load too. i'll probably have to set my laptop up in the trunk or somethin' since i don't have anyting else that can record sound digitally.

[scottydl]

SupaStealth said:

are super turbo's the same as turbos?

Hmm, that I don't know for sure. I bought mine by mail-order thru JC Whitney, back in the days before internet shopping. They have a lifetime warranty against corrosion too. According to the Dynomax website, the muffler models they sell are Race, RV, Super Turbo, Ultra Flo Welded, and Ultra Flo SS... so that would seem to indicate that the Turbo = Super Turbo.

www.dynomax.com/mufflers.stm

SupaStealth said:

i'll probably have to set my laptop up in the trunk or somethin' since i don't have anyting else that can record sound digitally.

Have someone stand behind your car and hold the laptop/microphone, while you idle and rev. Then the obligatory "GO!" shout from your helper, and you smash the accelerator and take off. ;D

[stevensolds]

yeah i really want to hear some sounds. i hope its in stereo too. anyway, would you be able to get a race muffler for this car? ;D also did u have to buy cats with that package as well.

i know my cats are gonna go soon anyway, so thats why im asking

[SupaStealth]

i did a cat back system, so nope, stock cats still

[stevensolds]

since i just got my inspection in sept, maybe ill just run no cats for a little while ;D its MASSIVE power. theres a guy i know leads a group of racers he has a 2002 honda civic Si, and without cats he said he gets 15 horses at the wheels back. if thats true or not, i dunno but i might try that. im sure the service engine soon (SES) light will come on though. i will just get one of the SES bypass modules or something

[JimW]

A few words of advice for those who dont want a cat converter

1. Dont get caught.
2. You will experience a lose in backpressure.
3. You will fail emissions tests (if applicable)
4. EPA will nail you to the ground if someone reports you, and there is a "squealers" reward

Personally, I dont like cars that run without a converter, its not environmentally responsible. High flow is the way to go IMO.

[1badaurora]

Is it possible to get under the car and put a hacksaw to the mufflers and remove them and just add some straight pipes to make up for the lenght of the muffler?
That is for some of us budget folks
because I would like some rumble, just not a rumble that doesnt match with this type of car, something maybe low pitched, but thoaty, like a Mustang....I guess that wouldnt be very lo pitched...
Input please?

[kobalt]

1badaurora - It is possible but I would not recommend it. You will loose low end torque due to backpressure loss, the car will be at least 10X louder and will not pass inspection in most states due to lack of mufflers and the noise. For the sound you're looking for save up some $ and get a muffler shop to install some nice high-flow mufflers for you.

[JimW]

It invariably comes down to two things...is sound more important then performance?

Cutting off the mufflers to create straight pipe exhaust is an option, however I believe that GM exhaust systems need all components in order to maintain necessary back pressure.

It is possible however.

[Aurora40]

Man, I wouldn't run without cats or without mufflers. If you were willing to put up with a horrible ride for some extra performance, why would you even drive an Aurora in the first place?

And if you really want to get some extra performance from the exhaust system, get some headers, don't just gut the current system. You could improve flow with headers and a different exhaust system and still keep cats, still be legal, and still have a car that's not obnoxiously loud.

[JimW]

Headers would be nice, and something I looked into but apparently the header design on the L47 (4.0L) is pretty good, according to R&D at RSM, the cost vs performance gains doesnt make it a worth while mod.

Thats how it was described to me anyway.

[Ted C]

The Y pipe is the costly part of the system. When stevensolds refers to "especially the older people" is he referring to me?

I'd would love to hear all of these exhaust set ups! Ideally for me, it would be nice if it was quiet at idle and when I don't get into it, but then ;D...

After all, I do sometimes have clients in or near my car...

[JimW]

Mine is dead silent at idle and rumbles nicely on the roll, anyone with a webserver willing to host, I have a whole bunch of vids (most of you have seen em)

[Aurora40]

JimW said:

Headers would be nice, and something I looked into but apparently the header design on the L47 (4.0L) is pretty good, according to R&D at RSM, the cost vs performance gains doesnt make it a worth while mod.

The caddy engineer guy on caddyforums mentioned once about some flashing and such in the stock headers, which isn't surprising. One could have the stock ones extruded or something to smooth the passages and probably make some decent gains. Then there would be no cost of new headers and no fitting issues.

[SupaStealth]

I had my car without the mufflers for a few days before i put my current exhaust on. i actually enjoyed it, it wasn't that loud to me. I didn't notice any significant loss of low end torque, but did notice an increase on the top end. it was more or less a nastalgic sound when i had a 64.5 mustang with mufflers. i was sad when i heard it after the mufflers were installed, because i can hear the air getting sucked in is louder than the actual exhaust note because of the air intake when i had my friend drive it as i stood outside of the car. But i'm sure this is because i'm teenager .