: Hi Flow Cat converter to go with Corsa Exhaust, which one?



Rob S
03-10-06, 08:58 AM
Anyone running a Hi Flow cat with there Corsa exhaust? I have the Exhaust and would like to install a Hi flow cat at the same time. Also allowing me to reinstall the factory exhaust if needed a few years down the road. Figured that would save me from cutting the pipe on the factory exhaust. I look forward to installing the Corsa exhaust, just waiting to figure out which Cat to use, any recommendations??

zonie77
03-10-06, 10:01 AM
There is some info on the web about quality and flow on the replacement cats. I didn't save any of it though. You should be able to find it easily.

Patrick7997
03-10-06, 11:18 AM
Rob, let us know what you end up doing, and how you like it.....

I am in serious contemplation of just such a project....

mmayer
03-10-06, 09:14 PM
You might want to try and contact Random Technologies in Georgia. I talked to them and thats where I'll probably get mine from. Some people on this website have also used a Magneflow brand hi-flow, but I am not sure what kind of performance gain they are seeing. Make sure your measure your cat flange before you call. If you find any other sources make sure and post it.

danbuc
03-11-06, 01:31 PM
Hmm....I know one guy that used a Magnaflow Cat and got some decent results (with the Corsa). He said it was a little louder, and that he "felt" more pickup down low I believe. Of course, the ole' butt dyno isn't the most accurate, but who knows. Is there any way that you could test it before and after (i.e. track run, dyno run,..ect). That would be nice to see if it really does make an improvement.

Rob S
03-11-06, 09:43 PM
Well, guess I need to do a little more research. As for actual HP improvements, well, that would involve me using stock cat, then aftermarket cat, both on actual dyno's. To be honest, it wont happen. Main reason I want to use aftermarket cat is to keep from butchering the stock exhaust. So my only before and after will be with total stock, then with all aftermarket.

I will however keep everyone posted on what I chose to go with, and the results.

danbuc
03-12-06, 02:40 PM
What do you mean by "butcher"? Whether or not you keep the stock cat, you will still have to cut the original exhaust system off. If you keep the stock cat, then you'll cut the system after it. If you go the aftermarket cat route, then you'll have to cut before the cat. If you put a new cat in, you'll have to spend the extra money having the shop weld in two new bungs for the O2 sesnors. Keeping the stock cat would save you money by not having to do that. Of course and aftermarket cat may help performance...by how much, I have no idea.

Rob S
03-12-06, 08:32 PM
What do you mean by "butcher"? Whether or not you keep the stock cat, you will still have to cut the original exhaust system off. If you keep the stock cat, then you'll cut the system after it. If you go the aftermarket cat route, then you'll have to cut before the cat. If you put a new cat in, you'll have to spend the extra money having the shop weld in two new bungs for the O2 sesnors. Keeping the stock cat would save you money by not having to do that. Of course and aftermarket cat may help performance...by how much, I have no idea.

From reading the instructions (havent been under the car to confirm) it appears the cat bolts to the Y pipe via a flange. Is this not the case? I will climb under the car to verifiy this. I figured I could unbolt it prior to the cat and remove the exhaust as one unit. If it needs cut I will more than likely just use the stock converter.

danbuc
03-12-06, 09:56 PM
The exhaust is welded together into one piece at the factory. There are no clamps holding the system together. To install the Corsa system, they give you a specified length of pipe you must leave after the cat when you cut it (STS, and DTS use different lengths), in order for the system to properly line up under the car. The Corsa system is then designed to simply bolt on to the existing pipe coming out of the back of the cat where you cut the old exhaust system off. I myself had to have it welded on, because apparently the design of the cat used in '98 is ever so slightly different than the cat's used in the 99+ cars.

On the other hand, you are correct in saying that the cat does bolt to the Y-pipe. Unfortunately your talking abotu the wrong Y-pipe. The one that the cat bolts to, is the section of pipe where the right and left bank exhaust manifolds join, just at the back of the tranny by the rear mount. The cat does bolt to that section of pipe. However, the other side of the cat is just welded pipe which runs to the Resonator, then out to the rear Y-pipe which feeds the two factory mufflers. Everything from the cat back is welded.

edit: I just looked on their website since I didn't remember how the install process was laid out exactly. Here's th link for the PDF document with pictures. http://www.corsaperf.com/InstallCadillacSTSDTSSys.pdf As you can see, the replacement resonator actually has the aft O2 sensor bung welded right into it. Thats' the end that goes on the piece of pipe that sticks out the back of the cat that would have gone to the old resonator.

edit2: you might have to copy and past the link in your search bar and then hit enter or click you search button or whatever, for the browser your using. Just clicking the link doesn't seem to be working.

Rob S
03-14-06, 04:24 PM
The exhaust is welded together into one piece at the factory. There are no clamps holding the system together. To install the Corsa system, they give you a specified length of pipe you must leave after the cat when you cut it (STS, and DTS use different lengths), in order for the system to properly line up under the car. The Corsa system is then designed to simply bolt on to the existing pipe coming out of the back of the cat where you cut the old exhaust system off. I myself had to have it welded on, because apparently the design of the cat used in '98 is ever so slightly different than the cat's used in the 99+ cars.

On the other hand, you are correct in saying that the cat does bolt to the Y-pipe. Unfortunately your talking abotu the wrong Y-pipe. The one that the cat bolts to, is the section of pipe where the right and left bank exhaust manifolds join, just at the back of the tranny by the rear mount. The cat does bolt to that section of pipe. However, the other side of the cat is just welded pipe which runs to the Resonator, then out to the rear Y-pipe which feeds the two factory mufflers. Everything from the cat back is welded.

edit: I just looked on their website since I didn't remember how the install process was laid out exactly. Here's th link for the PDF document with pictures. http://www.corsaperf.com/InstallCadillacSTSDTSSys.pdf As you can see, the replacement resonator actually has the aft O2 sensor bung welded right into it. Thats' the end that goes on the piece of pipe that sticks out the back of the cat that would have gone to the old resonator.

edit2: you might have to copy and past the link in your search bar and then hit enter or click you search button or whatever, for the browser your using. Just clicking the link doesn't seem to be working.

I have the link for the install, been reading over it. I think our exhaust systems do differ. My cat bolts on via four bolt flang at the front of the cat. I would like to replace the exhaust from that point back, therefor keeping the factory unit in one piece. I am going to place a call to Corsa tomorrow, see what they recommend. I'll let you all know what they say and how it goes.

WoodShoe
03-14-06, 09:15 PM
I have the manglaflow cat. Made the whole setup 3 times louder. Although they had to cut the flange off my original cat and weld it onto the magnaflow one, because the OEM flange is larger.

MrEr1c
03-14-06, 09:17 PM
I have the manglaflow cat. Made the whole setup 3 times louder. Although they had to cut the flange off my original cat and weld it onto the magnaflow one, because the OEM flange is larger.
3 times louder? wow!

do you have any soundclips? And how much of a differance is there at idle/not on the throttle?

WoodShoe
03-14-06, 09:27 PM
At idle not much noticable difference ( no sound clips sorry ) wait..maybe dave still has my vidclips from back in the day. Altough im not sure if those ones have the cat yet or not. Anyway mostly noticable at WOT. (check davesdeville's website)

AlBundy
03-14-06, 10:20 PM
I'm looking researching on doing a corsa exhaust but I'm looking for performance sounds only when I want others to know it. The low rumble is good enough until I WOT it.

Rob S
03-14-06, 10:42 PM
I'm looking researching on doing a corsa exhaust but I'm looking for performance sounds only when I want others to know it. The low rumble is good enough until I WOT it.

I have to agree, I'm not looking for anything too loud. Just a nice strong sound. The sound clips on Corsa's website are perfect.

WoodShoe
03-19-06, 07:58 AM
I have to agree, I'm not looking for anything too loud. Just a nice strong sound. The sound clips on Corsa's website are perfect.

I was initially worried that it would be too loud. Being a Cadillac and all, didn't really seem right to have exhaust on it. Now that I have it, I wish I could get it louder :) the idle is amazing, and WOT scares most little cars out of racing you :want:...which kinda sux...oh well

Rob S
03-19-06, 08:33 PM
I posted on the Corsa vendors forum... He said that adding a cat other than stock will alter the sound. I really like the sound clip on there website, want to keep that. So I will keep the stock Cat and install the exhaust. Infact going to do that tomorrow (Monday). I'll let you all know how it goes :alchi:

AlBundy
03-19-06, 09:03 PM
Could you please post their website. I curious to hear it.

davesdeville
03-20-06, 05:29 AM
http://www.corsaperf.com/autohome.htm

And there are a couple videos of N* Cads with exhausts including my ETC and woodshoe's STS on http://www.500caddy.us - click videos on the left side navigation bar.

Rob S
03-20-06, 08:04 PM
Installed the exhaust today. Went real well. Corsa is a very well engineered product, everything went together perfect. I am real pleased with the exhaust, high quality. It is an expensive exhaust, therefore I had high expectations..They were met and then some. I kept the stock Cat, and followed the instructions. The tips look great :eek: They add the performance touch to match the sound. Anyone looking to upgrade there exhaust, I highly recommend this system, its top notch all the way across the board. Spend the extra cash and you will thank yourself in the end. :worship:

mmayer
03-22-06, 01:28 AM
One thing I found out about the Corsa exhaust is that it gets quieter as it ages. I have had mine for 3.5 years and the 6-12 months the loudness has really diminished. It is a possibility the cat (117k miles) is part of the reason, but it may be the inside of the pipes are getting coated with carbon. I called Corsa and talked with them about and was told that I am not the first customer with this concern. I encourage anyone else with this observation to do the same. One tip for any Corsa system owner - keep up on cleaning the inside of your tips, it gets alot tougher to clean them when soot has mixed with condensation and formed a black coating that can be very difficult to remove.