Recommended Posts

 

 

They said it couldn't be done. Pete at Discount Mufflers in North Little Rock, Arkansas took that as a challenge and used his 30 years of experience as a pipe bender to make it happen. We even up-sized to 3" pipes after the tight bends around the gas tank. The dual catalytic converters and H-pipe will be installed in about a week during a second visit.
The fit is tight, but I have driven the car since the installation and there is no rattling of pipes and they do not bump against the underbody when turning or stopping. 
Note 1: The low spot in the installation as the pipes curve around the gas tank was done at my request since the tank is made of plastic. 
Note 2: the key to this installation is in making a clamp-on slip joint on the crossover pipe prior to the flange for the down pipe. This is because the right side of the factory Y-pipe is what holds the left side in place. It's a very tight area to work in and welding is not possible there without lowering the engine cradle.
Note 3: this job took a full 8 hours to complete because of the design work and installation of the crossover's down pipe flange. Pete stated that now he has designed the modifications, future installations will be faster. 
Note 4: My car was the experiment. My price is not your price. Call Pete at Discount Mufflers to get a quote for your Northstar true dual exhaust system. Be sure to identify if your car requires bends that go around the gas tank like mine did.

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

Oh man, love what you are doing.  

How did the alignment go?, did I miss that in another thread?

I wonder why the no charge llight flashed at 6K rpm?, it stayed on also.   Have you checked your alternator out?  Check codes and see what comes up.

How did you handle the O2 Sensor, at the H or one bank? If one bank instead of at the crossover, does the O2 sensor operate adequately?  Does your year have pre and post cat sensors or just pre?   In my mind, the O2 sensor set up becomes the problem..

Have you considered getting a Northstar Performance PCM tune?  I believe they can tune the 2002s now on the 96 through 99 he adds about 55 HP and tweak a bunch of settings. @NorthstarPerformance Jake, are you into 2002s yet?, and what parameters can you change?, this member is doing some interesting modifications and you might be able to kick it up a notch for him. Check out his threads, he installed Corvette calipers and rotors on his Eldorado.    I would always want to keep my original PCM to revert back, if I wanted to do this, if I purchase a reconditioned PCM can you mod it with my vin? Are there high performance PCMs out there that I can purchase, you know faster processor, etc, rather than going reconditioned?    I suppose I could go to your web page, but I wanted to pull you into this.. Hope all is well.

Please post photos of the muffler system.    Very cool


Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

Share this post


Link to post
Share on other sites

Hi, Bobby, Jake is aware of my car build and has seen many of the pictures that I took. I had forgotten to return to this thread and finish it. It's been a busy week.

I actually posted a thread in Cadillac Hell (Cadillac Owners Forum) today, because many of the members have been told that true duals are not possible on this car. That myth has been dispelled now.

I though about posting this thread in the Cody's build forum, on this site, but it doesn't have many viewers anymore.

I don't blame the people for unfollowing because the progress has been so slow.

I'll address the O2 sensor issues during the course of the thread. I have three O2 sensors and the post-cat sensor is the only problem to overcome.

So, I'll begin this thread again in the next post and continue with details and include more pictures than I posted in the other forum.


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

0501180956-1-1.jpg

The goal of this installation is to obtain a high performance (loud, fun-to-drive and race) TRUE dual exhaust system in my 2002 Eldorado. 

To make any real power gains, the restrictive factory Y-pipe must be deleted. There should be no problems with the ehaust flange bolts since the engine was just installed and that's a good thing, because if one of these bolts is rusted and breaks, the installation gets aborted and an exhaust leak will be there until the engine cradle can be lowered for the repair.

I'm going to have the muffler shop install 2.5 inch true dual exhaust (with dual catalytic converters) from the down pipes passed the gas tank, then up-size the diameter to 3 inch pipes (for an increase in the exhaust's bass tone) to the new mufflers. I also want no trouble code generated by the rear oxygen sensor.

I have no online data to draw from for this particular installation, except for a general consensus that what I am attempting cannot be done..... Let the fun begin!

I found two shops in central Arkansas and one in Northeast Arkansas willing to attempt this project. The shop in the Northeast was the only one willing to work with stainless steel pipe and true mandrel bends, but the cost would have been three times what I could afford. The other shops would bend 2.5" and 3" Aluminized steel pipe. The flow rate of 2.5" bent pipe is approximately the same as 2.25" pipe with true mandrel bends, which is acceptable for my 4.6 Northstar in stock trim, and will be adequate to handle future upgrades.

From the many measurements I have taken, I know that some tight clearance areas will have to be modified and that is okay. 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

I can't believe how restrictive they built these for a Northstar:

0501180908.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

With the old system removed, we studied all available space and clearance issues.

0501181040.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

This is why the factory Y-pipe is so restrictive. The left pipe (2" crossover) protrudes into the right 2.5" pipe to form the "Y". There is turbulence as well as flow restriction which compounds the problem.

0501181029.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

The biggest problem with true dual exhaust on a Northstar car is that the left side of the Y-pipe locates the right side which mounts with a slip-over pinch flange.. When you remove it, there is nothing to mount the left downpipe to and no room to weld without lowering the engine cradle.

I was very glad that Pete of Discount Muffler has 30 years of experience and has built headers.

 0501180948.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

It took 3 hours of work to design a solution for mounting the left pipe. Pete designed a slip-over, clamp-on, downpipe with flange to work around the stock location and angle of the right pipe. He then had his assistant (pictured) finish it and prep it for installation.

0501181008-1.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

Seems like an odd angle at first, but when the other side gets bolted up, the difficulty level is apparent

0501181027.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

Normally, this would be the point during installation where you would place the dual cats and the ballance tube in whatever location best fits the available space. The final location of the cats may depend if you want your ballance tube to be an X-pipe or H- pipe configuration.      NOTE: Use an X-pipe if you want a higher pitched exotic sounding exhaust note with the benifit of the horsepower gains in the upper RPM range..

Use an H-pipe if you prefer a deeper tone with more of an American hotrod sound and want to place the power gains at the lower RPM range.

I was not expecting to do the whole exhaust system on this visit, so I had not yet ordered the dual cat setup I had been watching on Ebay for the past 3 years. Discount Muffler does have high flow cats, but no body can beat the price that I could get a set for. So, to make sure there were no surprises when I made a second visit with cats in hand, Pete used two 4" diameter pipes to test fit where my cats would be placed. He also wanted to do the H-pipe at the time of the cats installation. 

0501181153.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

After the necessary clearance was made with a hammer and reciprocating saw, Pete bent and placed the right pipe as one piece from the flex pipe all the way to the up-size point where the system will continue with 3" pipe for the purpose of creating a deeper bass note.

0501181249.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

Then the left pipe was also bent as one piece and placed. Care was taken to keep the pipe away from the plastic gas tank.

0501181339.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

The left section of 3" pipe was created as one piece from the up-size point to where it would connect with the muffler.

Note: my goal is to open up enough space between the mufflers that I can build an under-trunk battery relocation box to help with the front-to-rear weight ratio.

I also wamt the mufflers visible under the bumper like they are in late Mustangs.

We had to mount them at a slight angle, however, because of the plastic charcoal canister behind the left rear wheel well.

0501181429.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

I provided my own mufflers, red polyurethane hangers, and angle cut resonator tips, but Discount Muffler also has a selection in stock.

0501181441_HDR.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

I had to leave my car with Pete and go to work. This had been an 8 hour installation so far.

This picture was taken the next morning at the alignment shop.

0502180858.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

The myth that you cannot put duals under a last generation Eldorado has officially been debunked!

0502180858b.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

This low point in the exhaust was my preference to make more room between the pipes and gas tank.

0502180859a.jpg

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

Here is a before and after look at the exhaust system so far. I will be getting the dual cats and H-pipe installed shortly.

before%20and%20after%20dual%20exhaust.jp

 


Click here to visit the main directory for my subforum about my 2002 Eldorado build for autocross racing:

http://caddyinfo.ipbhost.com/index.php?showforum=96

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.