Turtle13

iTrader: (1)

Hey so I am thinking of removing my only remaining Cat and going straight pipe.

Truthfully I've been battling an exhaust leak, I thought I was going to fix it tonight when I added my header/down pipe gasket and new nuts. It didn't fix the problem hardly at all. There is allot of rattling coming from my cat, I can hear it every time I stop at a light or wait in a drive through. I had to go to work so I couldn't fully investigate the rattle, but its very irritating.

I've been trying to look into ways to slightly quite my car down, (problems with local pigs). Fixing the exhaust leaks would almost solve the problem, but I now think it could be the Cat leaking and not just the missing gasket in the down pipe. How much louder will my **** get if I go straight 3" piping with no Cat? its already a straight 3 with just the one last cat.

Theres a possibility that all I need to do is tighten my bolts down, add some locking nuts and that will be the end of it...but in the case that my Cat leaks and rattles, am I better off replacing and keeping it or just deleting it?

Also is there any good way to quite an FC without losing the great sound? I want the depth of my sound, but I don't need to hear it 3 miles away. My family can hear me coming for a good 5 minutes before I get home.

What do you guys think? I imagine this is something lots of people have tackled.

tuscanidream

iTrader: (6)

The cat was glowing red from becoming clogged on my girlfriends t2. I had a "test pipe" made at a local shop to replace it, and it didn't make it any louder from what I can tell. She's running 3" downpipe to oem mid pipe / exhaust. It's pretty quiet with a sporty oem sound.

Is your exhaust all stock right now?

RotaryRocket88

iTrader: (7)

If the system is 3" bolted to a stock (2.25") exhaust manifold, you'll always have an exhaust leak. Which is it? A header? Or a stock exhaust manifold + downpipe?

OEM mufflers may be enough to keep the noise down, but with better flowing mufflers, removing a cat makes a big sound difference. When my car was NA, I had a straight pipe, corksport presilencer and a main cat in there are different times. With TII RB mufflers, the noise level was:

Straight Pipe > Presilencer > Cat

Turtle13

iTrader: (1)

I think that the headers stock. and from there is 3" but I dont think thats where its coming from. In the past I would tighten up the nuts every once in awhile and it would quite things up right away. This time im pretty sure its from the cat, I dont think its clogged up. I still run my air pump, and I have an SAFC wired in and tuned. Im going to get her up tonight and look at it and see if I cant tighten it up or figure something out. But in the case that I decide to change it up, I wanna know what peoples experiences have been.

So from here I would ask, do you guys know any good links to companies that sell 3" headers (the only seemingly original part of my exhaust) so I can minimize that leak, and companies that sell the section of piping I need to delete that cat. Also, whats going to happen when I delete that cat? Should I just delete my airpump at that time too?

RotaryEvolution

iTrader: (30)

here, i'll ask it:

why do you have 3" exhaust in the middle of the stock system?

Turtle13

iTrader: (1)

It's all 3" except the one coming off the motor. Thats the only stock part. It goes from im guessing 2.25" off the motor to 3 on the downpipe. The rest is a full racing beat exhaust. Im looking to make it ALL 3"

RotaryRocket88

iTrader: (7)

There is no stock header. It's a cast exhaust manifold. Also, the NA RB exhaust system is 2.5" ID, not 3". The NA downpipe they sell is also 2.5" ID, but it still has a habit of leaking. I had one when my car was NA, and it would always eat gaskets.

Since no RB system uses cats, you also need to figure out your cat flange size and if it was extended to mate to the downpipe. RB downpipes are 3" too short and won't reach a stock main cat. They're intended for use with their longer presilencer.

List all of your exhaust components. Is it something like this? Keep in mind that the measurements are ID not OD.

Exhaust manifold (2.25") -> RB NA downpipe (2.5") -> Some sort of modified replacement cat (2.5" or 3") -> RB catback (2.5" to 2x2")

Also, this is an RB header for their system: http://www.racingbeat.com/RX7-1986-1...ers/16130.html

RotaryEvolution

iTrader: (30)

and bigger is not always better for naturally aspirated engines.

2.5" is even a little overkill for most sub 200WHP free flowing setups unless you like a very peaky power curve.