i am thinking of doing an exhaust delete to my o4 monte carlo. I heard it makes a huge difference and makes it a little bit faster, but that it makes it sound way too loud? is it a good idea to do that delete?

 

It's a great idea and the mod doesn't make the car sound any louder. Now if you delete the resonator it's a different ballgame and the exhaust will be louder/sound like crap. If you go the ZZP downpipe with the Ubend delete and high flow cat you'll be better off. You will get an O2 code due to the high flow cat but you can have the code deleted with a tuner or get an O2 sim for it and the code will go away.

 

You mean to tell me if you take out the mufflers it doesn't make the car any louder?? WHAT?!!? Maybe we're talking about two different things.

Okay, so what do we mean when we say "exhaust delete?" That's really a very wide term!! Just taking the rear mufflers out and straight piping out? I did this for 2 years. I had a glasspack in place of the resonator (which a man in an exhaust shop told me a resonator isn't much more than a glasspack, and he's used glasspacks as resonators. Right now I'm running my stock set of mufflers with a glasspack and it sounds just like stock.) It was pretty loud, but only at certain RPM's inside hte car.... I can swear to you the car was quieter inside at 80-90 mph than it was at about 45 mph climbing a hill. Don't ask why, but around 2000 rpms or so the cabin drone was there, and people in the back seat, well, they had to yell at you for you to hear them. I didn't mind it when it was just me, but now I'm tkaing my girlfriend around in it everywhere with me and one day we went on a double date and I said "That's it"

Are you wanting to take out your catalytic converter? This will make you a little louder but it will also make the cute little check engine light come on unless you get this thing from I think ZZP that plugs into the oxygen sensor and constantly reports a perfect cat.

Another thing that people on here love to do with the '00-'05 model is a U-bend delete. Before the catalytic converter, just after the engines downpipe, is a cute little thing that bends down and actually tightens up so that the oxygen sensor could go in. You may have to do some hunting to find an exhaust shop to take this thing out, but what you can do is cut out the section, get a piece of straight pipe welded in and have the O2 bung welded into the side so it goes in kind of sideways, and the computer will never know the difference. I went to three exhaust shops before a 4th one finally said "I'll do it." All three shops that denied swore to me it would throw a code and it wasn't really restrictive anyway. Who's right? Well I can't feel it very much to be honest, but I sleep better having mine deleted.

Here are a pair of pictures of it...





Now while it looks like it widens out some, it also looks like it collapses down. If you run your fingers inside of it after taking it out, it really does feel weird, it's like the whole thing just caves in from all directions and gets pretty tight. It feels like it actually gets narrower and shorter. This is probably the weak link of hte whole exhaust system. Maybe if you left everything else alone, it wouldn't matter, but I have a feeling if you change out the cat and take out the resonator (or put in a high flowing one) and louder mufflers, this would be the weak link that keeps you from really feeling hte performance in the car. IT only takes one place in the entire exhaust system to hold the whole thing back, and I'll have to say this is probably that weak link.

 

I believe I said the resonator and not the mufflers. Removing the mufflers isn't a good idea in any car unless you are building a track car. The op mention the exhaust and I thought he meant the DP/resonator since he wasnl't being specific, but if he meant the whole exhaust system then he won't be able to drive the car on the street.

 

I would leave the exhaust on your car- its going to be very very loud without any kind of exhaust on the car. I've driven my monte before running open downpipe (no cat) - and I definitely wouldn't consider that daily driveable.

 

The stock cat-back on these cars are good up to something like 450whp.
The only reason to change the mufflers, resonator, or anything else after the downpipe is if you want a different sound.

The u-bend that Cowboy showed is probably the biggest restriction in the stock exhaust.

You can have an exhaust shop weld in a piece of pipe in place of it, but like he said, some may turn down the work for whatever reason. ZZP also sells a pre-made section, where you would just cut out the u-bend and weld theirs in place. https://www.zzperformance.com/grand_...=504&catid=110
You will want to keep a bung for the o2 sensor in the replacement, as you will throw codes, and I don't think that the o2 emulators work on the '04 and up cars.

You also have the option to replace the whole downpipe, which is a pretty good idea on the supercharged cars. The downpipes that are available usually bolt in place of the stock downpipe, which is literally four bolts and is very easy to change out yourself.
An aftermarket downpipe would replace the catalytic converter, the u-bend, and the restrictive pipe section between the rear manifold and the cat which effectively takes care of the three biggest restrictions in the stock exhaust.
Note that some downpipes are weld-in and may not completely replace the stock downipe, as you can buy just sections of downpipe.
https://www.zzperformance.com/grand_...=551&catid=110
For a supercharged monte, you would want a 3" downpipe, and you would need one with the rear o2 bung installed. Whether you run a cat or not is really up to you, but it is illegal in most states to not run a catalytic converter.

Another big restriction you can work on is the front manifold. The design of the stock manifold doesn't really allow for porting, but there is a replacement option here https://www.zzperformance.com/grand_...ts1.php?id=208.

Also, you could replace the stock manifolds and downpipe with a set of headers as well, which would be your best bet performance wise.

As far as sound goes, headers, a powerlog, or downpipe won't make the exhaust any louder, but they will very slightly alter the exhaust tone.

-Riggs.

 

Dont run a filter on your intake or exhaust. Im putting down 240 hp on an otherwise stock NA engine with that setup.

 

enzo are you being serious? theres an exhuast filter? lol

 

Exhaust filter = catalytic converter...

 

wait what brock??