Hey guys and gals. Just had a full system put on my 83. Its 2.5 semi mandrel bend with a flowmaster and Pacesetter header. I need to silence it a little more. The way i have the system setup now is the muffler is welded right to the header and obviously the tubing after. Ive been looking at the racing beat universal pre silencer. But i was wondering will it work after the muffler? Or do i need to lets say get ride of the Flowmaster and put in the pre-silencer and a cat and a different muffler? I searched but found nothing about runnin a pre-Silencer after the muffler. Thaks

 

do not run a presilencer after the muffler. its designed to be run before the muffler..hence the name PREsilencer.

at any rate, a presilencer is needed to cut down noise and raspiness. flowmaster mufflers are really not a great choice imo for the 7, though some guys may debate this. the best way to go exhaust wise are products from racing beat. the pacesetter header is prone to rusting quickly, warping, and not providing as good of flow or overall durability as the racing beat unit.

i would personally save the cash and buy a RB header, presilencer, and muffler. if you go that route you will have to have two pipes fabricated. a small pipe from the header to the presilencer and a pipe from the presilencer to the muffler. another alternative to to purchase the street port exhaust system from racing beat. best sounding and most durable exhaust on the the market.

 

The thing is they may call it a Presilencer but i was wondering if it work the same before or after the muffle. The Flowmast was free, And Its gonna help a little with my turbo setup and the turbos spool a lill faster with flowmaster. I would love to get a RB setup. kinda of a lot and its the same about i bought for my car....... Ill probly end up putting a cat and Presilncer on it and probly a diff muffler. Just trying to see if i can rattle any Rotor brains here first

 

Pardon my ignorance, Verneuil, but how does the flowmaster help the turbos spool faster? Do you have a rear mount turbo setup; something like Squire's makes, and the flowmaster allows more gases to flow to the turbo than different mufflers? As I don't know what turbo setup you plan on using, I'm just curious to hear (read, I suppose) your thoughts on this matter.

~Devon

 

i don't believe he isn't using a turbocharger

 

A presilencer works after the muffler just fine. All a presilencer is is a small-bodied straight-through muffler. However, RB presilencers don't actually do that much muffling; they're more for tone. You're better off with something like a Magnaflow oval to bring down the decibels. Actually, though, if you really want to run a Flowmaster, it'd be better to put it at the end of the exhaust system since a) it's chambered, and b) they allow a lot of noise to leak through the walls, so using a presilencer of some sort before it would be beneficial.

 

There is a write up about the differance of mufflers on the rotary. The flowmaster keeps back pressure. Some back pressure is good for turbos. Helps to spool them faster. No i dont have the turbo's on yet. I am modifiying the 3rd gen twins to fit the 12A. Theres a long post about it. Ill look at a silencer. That may work just well.

 

Ahh I see. I haven't read the thread on the different mufflers and their effect(affect?) on our engines, since I'm too poor to purchase anything aftermarket. Best of luck making the twins work.

~Devon

 

i have a good used Racing Beat muffler I will let go pretty cheap. pm me if interested

 

how much you asking?

 

Oh No.... Not back pressure and turbos again.

Mufflers belong at the back of the system. It allows some of the intial sound to absorb and stabilize in the system before reaching the muffler and allowing it to do it's job.

I have a Vibrant 4" round, 3"in/out resonator in place of where the "silencer" would go and it's not raspy at all. Actually sounds better than my friend's with a RB presilencer.

Your choice in muffler has nothing to do with the turbo. "spool" Has way more to do with heat and velocity and turbo sizing, than it does with muffler. Why do you think turbo'd cars respond so well with larger downpipes? (hint, get's the exhaust out faster, or in your terms less back pressure.) You're also going to start busting baffles having the muffler that close. They aren't the most durable mufflers to begin with. I've taken many flowmasters back for customers over the years that have broken baffles. It seems worse on cars with the muffler before the rear axle than with the muffler behind the rear axle. Heat is all I've been able to come up with as an effect, which will obviously be amplified on a rotary.

 

Sorry, but you don't know what you're talking about. Yeah, some backpressure helps spool turbos... backpressure in the exhaust manifold, that is. After the turbo, you want as little backpressure as possible, just like in an NA system. You can think of turbos as operating off of a pressure differential between the inlet and outlet of the turbine housing. The bigger this pressure differential, the faster the spool.

Edit: ^ Beat me to it, lol.