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Cadillac STS (98) & CTS-V (05) 2006 Lotus Elise II
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Discussion Starter #1
I know somwhere in the many threads this question has been asked and answered. i just cant seem to find that information. I have a 1998 STS i just bought and i was looking for a performance exhaust, cat back. i looked at Borla but they dont make a system for the 98 N*. i also looked at Corsa but they start at 1999. is there anyone who has a suggestion as to what performance exhaust to use for the 1998 STS? any help would be nice.

thanks
Ben
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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:rolleyes: Up in N Central MD there should be a few shops willing to mandrel bend up an entire s/s system...go with 2 1/2 pipe from the cat to the Y, then 2 1/4 each side of the Y to mufflers of your (or recommended) preference. (leave out the resonator if you choose, but most of MD IS an emissions state for exhausts) Go with mufflers that are recognized as sounding good, but will not drone you out of the car at 55-70. A pair of Borla, Edelbrock, or CORSA tips will finish it off. Duplicate the rods and hangers from OEM, and spend time centering the system or it will vibrate in the center tunnel during turns. You're fooling with a 281 c.i. engine, so there's not a lot of exhaust flow to start with.....Too much pipe and you'll lose some low-midrange torque, just where 98% of your driving is done. Flowmasters seem to have a drone, if this forum is any indication.......Look at $500+ to do it RIGHT.
 

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2001 cadillac sts
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Those specs are stock for a 98....use the corsa specs, to get HP. Dont listen to anyone saying KNN filters will hurt you, they wont, They will give you some added HP, especially with the exhaust done....other than that, theres not alot out there yet, but check the northstar tunning thread, there is an individual in the preliminary stages of a PCM tune for performance.
 

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2001 cadillac sts
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No offense jadcock...Im just saying , with a little exhaust work, the added airflow of a KNN, does increase HP, it is a fact.....maybe with stock set up the paper filter gives a better low end response.
 

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White Diamond 2001 STS
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Do you have dyno numbers?

With a K&N filter on an otherwise stock engine, performance was unsatisfactory, and fuel economy dropped. Engine lost low-end power and part throttle response was soft. Going back to a real filter "fixed" it all back to where it was when I started, $60 richer. :)
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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:rolleyes: FWIW, I installed a CORSA on my STS in 11/06. There are pix of it and the OEM in a couple of "exhaust", CORSA", and similar threads from 01/07. I still have the entire OEM in 1 piece standing up by a tree next to my pistol range. Just went out and did a little memory refreshment measuring. The OEM main pipe is just under 2 1/4" OD from the cat outlet, through the resonator (which has baffles) back to the Y. The muffler pipes are just under 2" OD, with significant reductions from the roll bender. I have no idea of what the inside of the mammoth mufflers looks like. The Y is a stamped 2-piece weldment. The tip pipes sre 1 3/4" OD. On the other hand, the CORSA is 2 1/2" ID through the Y to 2 1/4" ID all the way to the tips. The resonator and mufflers are straight pipes with resonance holes cut in the pipe sides in the resonator and muffler cases. No baffles. You can see through the whole system with a flashlight. CORSA is exactly correct when they advertise "Quiet when it needs to be................." It's loud as hell from 4,000 to 6,250 with your foot in it. Dead quiet on the highway. Nice rumbly idle. Search Hitmoney's threads, too.........also, FWIW, after the CORSA, a trial K&N unit screwed up my low and midrange response, so I'm back to the swiss-cheesed stock airbox and panel (WIX) filter.
 

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Cadillac STS (98) & CTS-V (05) 2006 Lotus Elise II
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Discussion Starter #9
Is there a main difference in the cat back system from a 1999 to 1998? i know Corso makes a nice exhaust system but only for the 1999 and up. i called them and they told me that the 1999 system wont work on my 1998 STS? is this true? I have called some local custom shops and they said to go with Flowmaster V-series and leave the stock pipe just add the mufflers with tips? Does this make any sense?
 

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Cadillac STS (98) & CTS-V (05) 2006 Lotus Elise II
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Discussion Starter #10
SUB 409, who do you recommend up in N MD?
 

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2001 cadillac sts
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Benb870, the flowmasters will be too loud, and mufflrs only, do very little for HP. Have a muffler shop enlarge the diameter from the cat back just a bit. Not sure if corsa makes it for 98. I thought 98 and 99 were the same set up. Im not sure though.
 

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By the way Jadcock, I do have before and after g-tech times.....forget the accuracy of 1/mile times, it does do good in measuring before and after mods. KNN equaled better 0-60 and 1/4 mile (with exhaust)....Have you done dyno #'s with and without KNN?....
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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:highfive: 2003 Remember my post about cutting a hole in the airbox on the outside, fender area? Take out most of the box side so it matches the sheet metal hole in the inner body/fender well. Make a foam gasket to seal the gap betwen the box and body metal. Panel filter stays as is. Filter area is 'way bigger than the engine needs........

:stirpot: BenB, let me do some research in the local resto car club. Give me a few days. You might try a Google search in the meantime........Not sure what the cat-to-Y pipe ID is for a '98, but, at the very least, replace the Y, mufflers and tips. Flowmasters can be pretty loud. There is no reason a local custom shop can't do a good job if you specify it.....and you can't do it on the cheap........
 

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White Diamond 2001 STS
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By the way Jadcock, I do have before and after g-tech times.....forget the accuracy of 1/mile times, it does do good in measuring before and after mods. KNN equaled better 0-60 and 1/4 mile (with exhaust)....Have you done dyno #'s with and without KNN?....
There's a page on Caddyinfo.com that showed questionable gains with K&N (it's K&N, not KNN). The link is down at the moment. :(

http://www.caddyinfo.com/airfilterstudy.htm

Here's another one that is as "scientific" as I've seen:

http://www.bobistheoilguy.com/airfilter/airtest1.htm

It all comes down to the fact that different cars respond to different mods differently. Like medicines, different mods will have varying levels of success and varying levels of "side effects".

Just as it would be unfair for me to say that a K&N filter WILL NOT help, it's unfair for you to say to not believe those of us who say that they were of no gains on our cars. Lots of (inconclusive) data is out there. Most of us prefer filtration effectiveness over 2 or 3 horsepower anyway, and on that note, there is undoubtedly a preponderance of data that show that high-flow low-filtration filters like the K&N pass more dirt into the engine.
 

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Cadillac STS (98) & CTS-V (05) 2006 Lotus Elise II
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Discussion Starter #15
Sub 409, thanks for the information. i will look forward to seeing what you find out. i'm not afraid of spending the $$$ for a nice system. i'm not even looking for that much as far as HP gains. I am really interested in hearing a nice exhaust note with that motor. i have heard the Corsa systems online and that is what i am seeking. to be honest with you i could care less if i gain any HP from this mod, but just a nice sound without losing any power. Have you heard of Tony's custom exhaust in Glen Burnie MD? I know they do alot of work in the MD area, but i want to make sure i go to the right place.
thanks
Ben
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Tony's was mentioned by a couple of Camaro resto builders here. Worth a try. I think CORSA will sell mufflers and resonators only.........e-mail 'em. No guts, no glory.
 

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2001 cadillac sts
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Jadcock, let me assure you, I agree with your last post, and I apologize if I sounded disrespectfull. These forums are typed so its hard to tell in what context people are posting. I was typing with a smile on my face absolutely no animosity here. I just personally have been using KNN (and I know its K&N, I just put KNN cause its quicker) for years along with other cadillac owners around here, and it has worked well.....Im sure your right, about varying results. Maybe here in South Florida, its always so hot and humid, that it works to our benefit, who knows. By the way, I am familiar with all the caddyinfo posts. I did however enjoy the second link you posted.
 

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Cadillac STS (98) & CTS-V (05) 2006 Lotus Elise II
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Discussion Starter #18
Recent update!!! Corsa does use the same exhaust for the 1998. it is the part number 14150 and it fits the 1999 & up same model STS N*. I called today and finally spoke with someone with some brains at Corsa. they said that the reason why they list the Corsa System for the 1999 & up and not the 1998 is because most or some of the 1998's have a 2 1/4" inlet at the stock resonator and the corsa system starts at 2 1/2". they told me it is EXACTLY THE SAME AS THE 1999 AND UP. STOCK HANGER LOCATIONS ETC. they said i might have to get a flange fit on from ahead of the stock resonator to custom fit the corsa at the begining of the system. any exhaust shop should be able to do this. So good news for 1998 STS owners if they want a Corsa system. it will fit!! the stock part number is 14150 you can find it on some sites for around $1045.00 thanks and good luck!
 
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