djKale Posted January 17, 2006 Report Share Posted January 17, 2006 Hey guys I own a 99STS and I am looking at replacing the cat with a high flow unit. I already installed Dynomax Turbos but would like a bit more sound from the exhaust. Do you think the high flow cat would have an impact on sound? What about performance? I don't want LOUD, just a lil more grunt. If there is a resonator, would removing it make the car too loud??? I appreciate comments from anyone with experience in this area. Kale Link to comment Share on other sites More sharing options...
djKale Posted January 18, 2006 Author Report Share Posted January 18, 2006 Hmmm....I guess this isn't the most popular mod. I will be finding out the answer first hand... Kale Link to comment Share on other sites More sharing options...
Willie Hank Posted January 18, 2006 Report Share Posted January 18, 2006 I installed a high-flow cat. and felt it improved performance, although some at this site questioned my observation. If it truely reduces backpressure performance and sound should slightly increase. It was only like $ 90 for the high-flow cat., installed ('93 STS). Link to comment Share on other sites More sharing options...
Spurlee Posted January 18, 2006 Report Share Posted January 18, 2006 kale: Tell me about intalling the Dynamax Turbo's - did it meet your expectations? Can you forward their website? Thanks! Scott 1996 El Dorado 2006 STS 2000 Corvette Link to comment Share on other sites More sharing options...
sprucegoose Posted January 19, 2006 Report Share Posted January 19, 2006 Hmmm....I guess this isn't the most popular mod. I will be finding out the answer first hand... Kale I replaced my CAT with a high flow one from CatCo. It was a little differrence in performance, but not huge. I think it sounded much better, but mine was totally shot, as the screening was rattling loose inside. If there is a resonator on your car, definitely removing it will wake up the growl in her. I plan on doing that with my Riviera once I get her thru the emissions testing here! '09 Cadillac CTS-4 3.6 direct injection, 128 K mi. '15 Chevy Tahoe LTZ, 5.3i V8, 125 K mi '70 Firebird Formula 400, Bored+.04, RAIII heads, M21 4spd., in-process restoration! Link to comment Share on other sites More sharing options...
sprucegoose Posted January 19, 2006 Report Share Posted January 19, 2006 Here is the link to my post when I did this last year. Good luck! Goose's Cat Con replacement '09 Cadillac CTS-4 3.6 direct injection, 128 K mi. '15 Chevy Tahoe LTZ, 5.3i V8, 125 K mi '70 Firebird Formula 400, Bored+.04, RAIII heads, M21 4spd., in-process restoration! Link to comment Share on other sites More sharing options...
djKale Posted January 19, 2006 Author Report Share Posted January 19, 2006 kale: Tell me about intalling the Dynamax Turbo's - did it meet your expectations? Can you forward their website? Thanks! I went with the Dynomax Super Turbos, 14" I believe - http://www.dynomax.com. I wasn't expecting much, just better sound and that's what I got. They are quieter than I would have liked, but they do have a growl when you stomp on it. There's no resonating at highway speeds either. I haven't noticed anything performance-wise but I'm guessing they were worth a couple or even a handful of horseys. I just walked into the nearest exhaust shop and started asking questions. It turned out that the owner's brother had an STS around the same year as mine and they had just done an exhaust system on his car. I originally wanted to go with the Flowmaster Delta 50s but he said that they put them on his brother's car and that they were way too loud. They ended up putting on a generic Super Turbo that he said was very similar to the Dynomax version. He also said that they did a high flow cat and that the exhaust tubing did not need to be enlarged. So I put the converter on my "to get" list and figured I'd spring for it when money allowed. I have an appointment for tomorrow... Kale Link to comment Share on other sites More sharing options...
djKale Posted January 19, 2006 Author Report Share Posted January 19, 2006 Well I'm pleased to say that the car sounds 100 percent better now! I removed the resonator as well and it's pretty much perfect. A nice growl when she starts up, then a smooth purr afterwards. Took her out on the freeway and there's no resonating whatsoever. She's quiet at idle and normal driving conditions but she roars when you stomp on it. I definitely feel a difference in throttle response as well as WOT acceleration. The cat is made by Magnaflow. I'll post some sound clips this weekend... Kale Link to comment Share on other sites More sharing options...
navion Posted January 19, 2006 Report Share Posted January 19, 2006 Here is the link to my post when I did this last year. Good luck! Goose's Cat Con replacement Did you ever replace the Goose with another Caddy? I see that you are still active on the board. Britt Britt Link to comment Share on other sites More sharing options...
sprucegoose Posted January 20, 2006 Report Share Posted January 20, 2006 Here is the link to my post when I did this last year. Good luck! Goose's Cat Con replacement Did you ever replace the Goose with another Caddy? I see that you are still active on the board. Britt Navion, I'll try not to hijack this post too bad! Yes, I replaced her, but with a Buick Riviera. See the following link for a picture (about halfway down the page). Great car, but I do miss the roar of the Northstar with the Dynomax muffs! I just love this board too much to leave it all together! Elvira (mistress of the dark) '09 Cadillac CTS-4 3.6 direct injection, 128 K mi. '15 Chevy Tahoe LTZ, 5.3i V8, 125 K mi '70 Firebird Formula 400, Bored+.04, RAIII heads, M21 4spd., in-process restoration! Link to comment Share on other sites More sharing options...
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