: new STS with true dual exhaust???

09-30-04, 08:08 PM
Omg...last night I was walking around the cadillac dealer b.c I wanted to check out different rims that come on the STS that I think look a lot better. well I came across the new STS and was checking it out and got on the floor....it was like 12am LOLOL...and Ichecked underneath and saw true dual exhaust. one pipe came from one manifold, and the other seemed to come from the other, to a H pipe then came close together and seperated at the Y again...I was like wow....if it has the same 4.6Liter mounted engine...how in the world did they do this??

does this mean it could be done on our 99 STS's for a little more of a power increase??? id do this in a heartbeat....

Night Wolf
09-30-04, 08:47 PM
I can't tell you if it is or isn't....

but the new STS is RWD... MUCH more easy to get true duals on... the previous gen STS (which, IMO look much better) are FWD, and it is VERY difficult to get a nice, true dual exhaust setup with FWD... just the way the enigne is in sideways, and trying to get 2 exhaust pipes etc....

yeah, it is better for performance, and just to say you have it... but in reality, it is not worth it on the FWD... plus, most people see the tips on both sides of the bumper and think that is dual exhaust...

09-30-04, 09:01 PM
ooh so the new STS has the motor mounted sideways instead of front mounted like my 99'?? thats why it has truw dual??

Geno Castellano
09-30-04, 10:56 PM
The STS with the FWD Northstar from 1993 thru 2004 has the engine mounted transversely (sideways) and the FWD transaxle beside it. It is almost impossible to get a true dual exhaust system on that arrangement as the exhaust from the left (front) bank of cylinders has to cross from the left bank to the right bank to exit the engine compartment. There just isn't a lot of real estate to do this in. The Northstar FWD drivetrain passes the left bank exhuast between the engine and transmission which limits the attempt to put a true dual exhaust on the car. If the exhaust went over the engine it would creat too much heat in the engine compartment and there is not enough ground clearance under the transmission to run the front bank exhaust under the trans to the rear.

The new STS for 2005 is a rear wheel drive vehicle with the engine mounted longitudinally in the chassis i.e the engine is lengthwise in the chassis instead of sideways. This makes more sense for a rear wheel drive car with the prop shaft exiting the rear of the transmission toward the rear of the car. Now it is much simpler to put a true dual exhaust system on the vehicle since there is a bank of cylinders on each side of the car.

Caddygirl - Per your comment, the engine in your 99 is sideways. "Front mounted"? Do you mean front wheel drive? Both of the applications are "front mounted" as the engine is in the front of both cars. The 99 is front wheel drive and the new 05 STS is rear wheel drive or all wheel drive if you check that box.

Geno Castellano
09-30-04, 11:01 PM
If you look under the hood of the earlier FWD STS cars or view the exhaust system from underneath the car you can plainly see where the front bank of the exhaust joins with the rear bank of the exhuast at a Y shaped take down pipe that leads to the cat. It is possible, with some custom exhaust work, to split the exhausts at the Y pipe that is just in front of the firewall and take the separate banks to the rear of the car in a "true dual" configuration.

Not worth the effort in my opinion due to the restriction of the "cross thru" pipe that has to take the exhaust from the front bank in between the engine and trans to the rear bank. But it could be done and would be "true duals"

You would also have to deal with the O2 sensors and add another catalytic converter and such and it would set codes but it could be done.

09-30-04, 11:27 PM
wow thanx for the info anthony. you really know your stuff. well i guess that clears that up. haha.
i wish corsa fell right into my arms...ugh!!!

10-01-04, 09:06 AM
I just bought my Corsa system, but I haven't installed it yet! :crying2:
I can't wait though! :D

10-01-04, 09:29 AM
Caddydaddy, please give us a report when you get the system installed..


10-01-04, 09:33 AM
Caddydaddy, please post a report once you install your new exhaust system. Once I stop spending money on the house I want to get the Corsa system too.


10-01-04, 09:34 AM
Oops, sorry about the double post.


10-01-04, 10:44 AM
OK, hopefully Monday I can start on the install. By looking at the directions, it's very easy to do, just cut the exhaust off at the cat, and bolt the new one on! The hard part is going to be getting my STS up on jackstands!

10-01-04, 10:31 PM
I wanted to run true duals on my '98 STS. But, after looking under the car it's pretty much a waste like most of you said. The pipe runs back along the undercarriage nicely since there is no driveshaft. The rest of the under carriage is not indented like the middle. So, I'm sure you'd see the pipes running all the way down the car. Not to mention the front pipe coming from the front bank of cylinders. Also, if anyone has ever considered bigger piping be careful. I had my exhaust done awhile back. And when they welded everything back on the long pipe after the resonator is not centered. Which means it will bump the side of the undercarriage when going over bumps. I can't stand it!!