I'm going to remove my main cat soon (in preparation for a single turbo) what's the quietest midpipe out there, or quietest way of removing the main cat? I fear that the car will be too loud so in the process i'm also going to remove my N1 dual exhaust and replace it with a racing beat what else can i do to make it quieter though?

 

What about a resonated midpipe, I hurd those wern't quite as loud. RX-7 Store has a few for around $300.

 

I don't have a midpipe, but I've seen that many people use a Borla XR-1 muffler with the midpipe. If you are that concerned about noise (I would be too), get a high flow cat instead (unless you've already ditched the air pump).

BTW, I think Jimlab found that a resonated midpipe doesn't really have much more power than a high flow cat.

 

quiet midpipe is a oxymorron...

but get a reg one and weld in a xr-1 it will be the quietest...the resonated ones only drop like 4-5 db at that..they sound nice but dont kill that much sound...


really ex noise is based on your cat back..

if you have a n1 style you will prob want resonated(i have blitz nur spec and like the non resonated pipe)

but i had a greddy sp and with a reg midpipe i found it to be quiet...

 

duuurrhrhh i need to learn to read...

a reg mid pipe with racing beat should be fine...a xr-1 with a racing beat and you may be considered a "sleeper" hehehe

 

Put on a high-flow cat

Seriously, a friend has a resonated midpipe--can't remember if it's Shane Racing or Pettit. It's quite a bit quieter than my setup (w/midpipe).

I've heard the Borla XR1 welded into the midpipe is a viable alternative...

 

Close...

A resonated midpipe isn't much quieter than a standard midpipe is what I actually said.

 

If that. I don't believe that the resonated midpipes make that big a difference in noise level. An XR-1 stuffed in the midpipe definitely will, though, without harming flow substantially.

You can also "stack" XR-1 mufflers sequentially, and run more than one. Brian Richards (M2) uses them on his race cars. Three in a row, if I remember the conversation correctly.

 

I have a resonated midpipe from SR. To my ear, it isn't much louder than when I have my cat in place.

I have an older Apexi RS catback, so that probably helps a bit.

-Matt

 

I should state that my experience with Pettit's resonated midpipe is on non-sequential cars, which will obviously be louder than a sequential car below 4500 rpm. It's entirely possible that the resonate midpipe will quiet a sequential car much more effectively.

 

I heard that the resonated Midpipe isn't much quieter than a normal midpipe, it just gets rid of the droning which is common to most FD's with the midpipe in. Ivan has a petit resonated midpipe, and his car is still loud as a mother..

 

can't a more restrictive muffler help out the sound by a lot?

 

Exhaust mods ==> DP, MP, Apexi N1 Duals

I have a Borla XR-1 (16 inches) welded into the midpipe.

At IDLE: It quieted it down (loud but not stupid).
While CRUISING: No droning, especially on the highway.
AT WOT: No difference that I can perceive, ie. very very loud.

The difference at idle and crusing was enough that my gf noticed right away and asked what I changed on the car, but under hard acceleration still loud enough to attract all the cops for miles.

I am probably going to change catback to either the Racing Beat, or M2 catback and keep the resonated MP.

Somebody else posted about hammering in a silencer available from JEGS into the MP to quiet it down. That probably works by restricting flow, but should still flow better than a catalytic converter.

thesaint

 

Exhaust mods: downpipe, Pettit resonated midpipe, GReddy Power Extreme cat-back and I'm still sequential. The difference between the stock cat and the resonated midpipe was noticeable, even below transition and at idle. It wasn't bad however and was tolerable. Once I go through turbo transition, it's a different story. Car gets LOUD. Enough so that I was pulled over two nights ago for excessive noise. He let me go. Got a "stern" talking to, and was told ANY modification to the exhaust in Florida is illegal (it's not) but I didn't want to push the issue and get a ticket. Also, cruising down the highway, there's a big increase in noise at say 70mph. Even more so at 80mph. I actually used an Apexi silencer for the GT in the GReddy. Drilled a hole and installed it. Worked a bit, noticeable difference in power however. I've managed to misplace it since I moved however. I'm going to try the XR-1 next as a single isn't too far off.

Bottom line, resonated midpipes do make a small difference over a straight pipe which is greatly affected by your choice of muffler and the state of your turbo setup.
Michel

 

where do you get a Borla XR-1

 

You can get the borla xr-1 from Jegs.com, I ordered myself one just this morning, just want to quiet it down a bit in town. The nice thing is it's straight thru 3" pipe with stainless steel casing so should hold up well. I got the short 12" version but comes in 16 or 18" too I believe. The 12 inch one was 150bucks with 2 day shipping to ks.
art

 

I have the stock twins, and just installed an SR resonated midpipe.

Along with a racing beat single tip
and downpipe, it's more quite than
with the stock cat. I'm pleasantly
surprised. Only downside is fumes at
idle.

 

Summitracing carries the Borla XR-1.

I went with a 16 inch 3 inch inlet/outlet centered, oval silencer.

About $126 when I got it last year.

Worth it. Had it welded into a custom MP (mandrel bent 3 inches for $80 CAD).

thesaint

 

Borla XR-1 is a whole line of mufflers. The two that we are interested in are the XR-1 Race and the XR-1 Sportsman.

The XR-1 Race is the quietest XR-1 muffler (ironic, considering the name ) and splits the exhaust into three smaller straight pipes through the silencer. It is supposed to flow well and be quiet, but it costs more, like $180+ for the 16" oval.

The XR-1 Sportsman is one straight-thru pipe. It should flow well and is cheaper than the Race, but probably doesn't quiet the exhaust as much.

-Max

 

My bad, I have the XR-1 sportsman

 

The Borla XR-2 is Titanium, can that be welded to SS? I'm not sure if JIC & Kakimoto come with a Ti' MP but HKS is 4" & the XR-2's are 3' & 3&1/2".

I'm sure it changes the tone/sound but are you really only getting a wieght benefit? ...does M2's setup pass smog?

 

This morning, I just installed a MagnaFlow Straight Through muffler in place of the cat with 3" piping. The power kicks hard during the 2nd turbo and it did not make any difference in sound.

 

Of course not, the cat is removed.