d1drift

I was thinking about cutting the middle resonators in the middle of the car out to give it alittle more flow, performance. Will this make the car louder? Has anyone done this before?

skperformance

iTrader: (6)

What year?

cartechpr

it will make the car louder on acceleration.. not much difference when cruising.. the car outside will be louder.. if you want more power, be sure to use a true dual system. That's what i did and finally the headers feel they gave something to it. I guess i need a 3.62 rear now :P

pito

How about this...

True dual pipe work

Muffler delete

If its too loud, put on resonators instead of mufflers.

d1drift

It's a 1999, i'm would like to keep the stock rear mufflers on to keep the oem look and keep the car quiet. If I were to just cut the two resonator out and weld straight pipes would there be a noticable(big) difference in tone? I don't want it to be too loud when i'm cruzin.

PureDrifter

iTrader: (10)

do a search for "muffler delete" in this forum and you should eventually find a lextreme link.

siamiam

has anyone used electronic cutouts on their LS's?

Stefwilli

I thought about it but didn't go through with it. I will on my next car, the idea is cool.

PureDrifter

iTrader: (10)

using cutouts will harm more than help you performance wise since u most likely will lose low-end torque, something we are already screwed by since the rear end gearing is so high.

d1drift

Are the exhaust systems on California cars differ than other cars? I have 3 cats I think(two directly off the headers and one in the middle of the car before the resonators) two resonator and two muffler. way too much :-)

PureDrifter

iTrader: (10)

you have 2 cats and , 1 resonator, and 2 mufflers.

skperformance

iTrader: (6)

I have 2 cats then one center resonator , then to more larger resonators then 2 mufflers.

Looks like this

PureDrifter

iTrader: (10)

rofl, thought i missed a set.

steveski

I had my resonators cut off yesterday at my local muffler shop. It cost $80 and here's what they did using the guide from this site:

They cut both pipes just beyond the "Y Section" and ran new sections into the existing mufflers. The old resonators weighed maybe 10 pounds each. The new sections they made were fairly straight and the overall rear mufflers were kept in the same location.

The car has a rumble now. It is more pronounced under load. At idle it has more throat. It sounds similar to the GS 430 to me. It is not loud and it is not invasive to the cabin. Now it just sounds like a V8. I am glad I spent the little money it cost - sounds cool.

There was another option to run new pipe sections from the two cats back to the mufflers - the only problem for me was there was an extra cat in the middle (just like the photo pure drifter posted). Since there is an extra O2 sensor there (and on the two cats off the manifold), I figured I'd get a warning light if that section was removed - it would have given true dual exhaust though.

As for power increase man I don't know about that. The car is pretty quick either way. I don't have access to a dyno. The muffler guy said I picked up some horsepower but who knows. That is not why I did it. I have a soundclip of the car but don't know how to upload it.

Hameed

I have a 99 GS400 which is basically the same engine and almost identical exhaust setup to your 99 LS.

I removed all the piping and all three resonators from the cats up front all the way to the L-tuned mufflers at the back. I replaced all of that with 2.25 inch mandrel bent pipes and a Magnaflow 2.25 inch stainless steel Tru-X pipe - (specifically this one http://www.autoanything.com/exhausts...A2672A0A0.aspx ).

Pros
The sound is just so awesome!! The outcome exceeded my wildest expectations. It is very loud on WOT ONLY. That alone is worth the price of admission. On start up, the exhaust does not have a very deep note to it, however when you drive off and accelerate very hard, the exhaust note is pure music to my ears!!! It sounds like a more sophisticated version of a V8 mustang, however deeper than than a mid engine exotic car like a Lambo or Ferrari.

When cruising at city speeds or the highway and the tranny has shifted into 5th, you can barely tell the difference compared to the L-tuned mufflers by themselves (my previous only exhaust mod). So for example when I come home my neighbours don't know I am coming home. I was very concerned that the exhaust would be loud ALL the time, but that is not the case at all.

The exhaust gases are now flowing more freely (bigger 2.25 inch pipes and no resonators) and the X-pipe also contributes to that effect by creating a vacuum when one bank of cylinders pushes air out thus causing the other bank of cylinders to move its air out faster. The car definitely feels peppier, however I will dyno the car so that I can see what HP gains this mod made. I know I have not done a baseline dyno, however I will just take an approximate and average base number that others have done and use that as my base. Yes that is not exact or scientific, however I can't just afford to dyno the car so many times.

The nasty drone at 2100 rpm with the L-tuned mufflers is completely gone!

Cons
Some minor drone on part throttle at slow speeds (less than 30 MPH). Very minor. Not even worth mentioning, but I just wanted to share that the exhaust is not perfect that's all.

Some pics.

1. Stock Exhaust


2. Modded exhaust



Video
I would right-click on the links below and choose "Save As" and save the videos to your hard drive rather than trying to watch them as they stream as the first one is pretty big at 12 MB. I deliberately did not make it smaller just so that you appreciate the full effect better. Remember to turn up your speakers to full volume when listening.

When you watch the video, the start up does not sound that great in this video - the actual note of the exhaust is actually more deeper. I am not sure why the camcorder does not catch that. However on the second part of the video when accelerating away, it does a pretty good job of capturing the sound.

1. Start up, Drive away and Drive by
http://www.prudensconsulting.com/yah...00_Revving.wmv

I have not had a chance to dyno the car - been too busy. However based on research I did on this type of setup, I would safely guess I have gained at least 10 rwhp.

Here is a link to a similar setup on a Corvette - http://www.vetteweb.com/tech/0307vet...nfo/index.html