I wanted a quiet (almost stock) exhaust and the T1R 76S is supposed to be one of the quietest exhausts around. After installing the CBE about 3 weeks ago I was very satisfied with the sound level. It was quiet with just enough sound that you know it's not stock.

Next I installed the AMS Widemouth O2/Downpipe and everything was good; no noticable difference in sound level.

Then yesterday I installed my Mil.Spec HF Cat and wow, now things are a lot louder.

I'm not sure what my options are. The 76S already has a resonator in the straight section behind the cat. The Mil.Spec cat is right up against the forward flange in the test pipe and the O2 bungs are taking up a big chunk of the straight section (which is pretty short) of the rest of the pipe.

My goals are to run a stock frame upgraded turbo with all supporting mods to achieve around 400-420whp on E85.

I'm guessing if I run the stock cat with the upgraded turbo, I may lose 15-20whp/tq and some spool.

Anyone have any ideas how to quiet things down.

 

my HKS metal catalyzer with Blitz Nur Spec DT is quiet as stock.

 

dunno what to tell ya. removing/minimizing a cat will make any exhaust louder.

the jdm fanboi above this post poses one option, but only if you have kids you're willing to sell to africa as slaves. but the piping on those parts is smaller, so depends on your needs.

or go with my route, and install bottle type resonators at the straight sections. my exhaust (magnaflow) is quieter than a 76S, not to mention cheaper in price as well.

but assuming you don't want to let go of your 76S, you can opt for another resonator. if i recall, you should have a section long enough for one more resonator. my pipe allowed for two, but the 76S already came with one.

 

For my setup I have the T1R 76s, MXP Resonated Testpipe, AMS Downpipe. I can tell you its pretty quiet until you open it up above 4500 rpm then it gets loud. But downlow its only a bit of growl, not loud at all, sounds like performance car should. But you changed the exhaust for a bit louder and free flow, you can't always have the best of both worlds.

Putting in another resonator really made a difference for me, its helps get the rasps and some of dB out.

 

I have an invida DP with Hflow cat and a Fujitsubo catback. It is fantastic. Not loud, mild growl. BArely louder than stock under 3K RPM's. I have not experienced any droning either

 

Yup, there's not much you can do. If your goals are only 400-420whp then I'd stick the stock cat back in and deal with a little bit of lag. BTW, if you're running e85, you'll smell it all the time with the milspec cat. You'll still smell it with the stock cat but not as much.

 

Yeah it smells like popcorn...

 

Well, I just pulled off the Milspec cat and stuck the stock one back on. It's a few decibles quieter but the throttle response is bit worse. Strangely enough when I logged the difference, I actually have a bit more top end with the stock cat. I see a very small loss in spool but it feels worse than the logs show.

 

I've been driving the car for the past few days and it drones a lot. It has a horrible resonance if you are sitting at idle with the windows down. It's not bad at constant cruise at 65-70 but it is annoying around town. I wouldn't mind if it was a V8 but a 4 cylinder drone is something I'm not fond of.

My company gives me a $600/month car allowance to drive a <5 yr old 4 door vehicle to hall customers around in. I really can't drive something that sounds ricer.

I'm going to post another thread to se if I can find some resonator options.

 

Something's wrong...I have the T1R 76s with AMS test pipe (non resonated) and a T1R o2/downpipe and mine has zero drone. I can only hear a noticeable difference over ~4k at which point it has a great growl.

Here's a link of what it sounds like, you be the judge...and this is with the intake and IC pipes, both of which also add noise.

http://www.youtube.com/watch?v=YHaQ7O8qgGE

You can even hear in the beginning that at 4k it's completely quiet until i punch it...no drone.

 

I put a DP on my system last Saturday and was surprised that the system was quieter than before. My suspicion is that I didn't have a good gasket seal on the cat pipe and when I did the r/r that the new gaskets had a better seal.

Have you checked for leaks at all of your connections? Did you use new gaskets when you installed the HFC?

 

I checked all the bolts today and everything is tight. I agree that mine sounded just like yours before the Mil.Spec cat went on. Maybe because of the placement of the cat in the test pipe it is creating some resonance. I should try a test pipe without the cat to see what that sounds like.

 

Quiet is bad Its always better when its not stock

 

I have my milspec cat welded a couple inches from the front flange. It does increase the resonance in the cabin a bit more but I lose about 1psi from 6kRPM to redline. I'm leaving it off for now until I figure out what to do.

I'm leaning toward a T1R cat which has two 100 cell cats or a resonated TP.