Hey everyone, I was just wondering what a high flow cat would sound like with the stock exhaust. I am really interested in getting the RT cat, but at the same time don't want my car to sound too loud. Somewhat louder is ok but I don't want it so loud that its hard to have a conversation while driving my car. I have an 05 AT, so i'm assuming changing the cat would make quite a difference. Any thoughts guys?

 

you'll be fine, hi flow cat isn't much louder

 

If you have plans to add a CAI, exhaust header–along with the RT cat; then, you would see a nice little gain in HP and response for your 05. The RT alone wouldn't accomplish much without the other mods. Sound would increase with all three components, to a nice growl–but nothing near, deafening with the stock mufflers.

 

With the stock exhaust, it won't sound noticably different.

If you add a performance header and a catback exhaust, it will get louder and raspier.

 

The stock exhaust does a great job to muffle the sound. Even with header and high flow cat, it will be hard to notice. Aside from yourself or someone that sits in your car a lot, normal people will not hear the difference. With the windows up, you will not hear a difference.

I had header and cat with stock exhaust for a while so I know.

 

RT's? why not Fastline?

 

sure...why not Fastline?

 

I am also getting a SRI for my car, do you think it would make more sense to get headers first before the high flow cat?

 

You will be pulling in hot air off the engine compartment; once the car warms up with an SRI. You would want to keep the air intake as cool, (dense) as possible, i.e., Injen, K&N, Fujitsu(?) CT-Engineering-all, reach for the cooler air from in front of the wheel well. But, I did the CAI first, header and then the RT cat-which I, and about 3000 others (RT cat owners) on AZ recommend. I followed it all up with a Tanabe exhaust just for the fun sound of it. Order doesn't matter–if you are eventually doing all 3. Its just the CAI (not to mention the Hondata Reflash) showed a most noticeable performance gain.

 

difference in noise is neglible

 

I totally agree with you that cool air is favorable and a CAI is one of the best ways to do it, but i'm not sure i'm totally sold that you're pulling in "hot air" from the engine if you have an SRI. If the car is not moving, the hot air from the engine would be an issue, but when cars are driven, doesn't the colder air enter the engine bay? The engine bay isn't completely sealed off and i'd imagine that a fair amount of air comes in from the grill and such when being driven.

I have a APEX'i SRI and recently removed the resonator box and tubing. The stock intake pulls air from inside the engine bay pretty close to where the battery is.

Although I have no experience with a CAI, I feel as though the "hot air" in the engine bay isn't as bad as people say it is. Sure it's hotter than the air a CAI gets, but its not so hot that it defeats the purpose of getting a SRI.

SRI + resonator delete + heat shield is a good alternative to a CAI in my opinion.

Feel free to correct me if I'm wrong.

 

The engine bay, especially that area (where your SRI filter is) doesn't 'flow' very well even when moving. Even if the car is getting some air, most of the airflow does not even make into the engine bay, it hits your condenser/radiator. What is worse is that your radiator's fans are in your engine bay....

You could test it pretty easily. Just tape a thermometer inside close to your filter. Go run an errand/drive. Check the temp. Before driving back, relocate the thermometer to behind your foglight/cover.

 

Get a Scangauge or something else that allows you to monitor IAT (Intake Air Temperature). I have both a Scangauge, and an Injen CAI/SRI which I have used extensively in both modes, so I've done the comparison.

For the below, note that I have vented out my driver's side foglight cover to improve airflow. Also note that my car is supercharged, generating much more engine bay heat (however, I noted similar discrepancies in IAT while my car was NA).

Once the car is moving, there's not a huge difference. In motion with a SRI, IAT would be appx. 10-12* higher than ambient air temperature. A CAI, while in motion, keeps you within 7-10*.

At a stop, however, there is a world of difference. Driving in traffic, or sitting at a light, etc, the Scangauge allowed me to watch the IAT rocket up with an SRI. We're talking 120* on a 75* day. With the CAI, it doesn't creep much past 90-95* in similar conditions.

A SRI's real benefit is the ease of cleaning/changing the filter. That is it. The miniscule risk of hydrolock isn't enough to justify running an SRI, to me. Yeah, it's a pain to have to remove my bumper twice a year to clean my air filter, but I'll pay that price for feeding my engine much cooler air.

"Hot Air Intake" isn't just a clever name; it's essentially what a SRI does.

 

^^ Good post

 

 

i think you only hear the difference with the OEM exhaust if you're really pushing the car and revving high.

i noticed my car got a bit louder after the ct-e header and RT cat were installed, but if you're driving relatively normal (3-4K) or at idle, you don't really hear a difference with the stock exhaust.

 

thanks for setting me straight. maybe it's time to get something else...

 

Just a heads up we just released our new TSX converter made by RT. 2.25" IN/OUT and 300 cell substrate. Same quality, better performance.

http://store.excelerateperformance.c.../i-262544.aspx