auxilary Posted June 19, 2004 Share Posted June 19, 2004 I bought a Pro XS stainless muffler, center/offset configuration. Very free flowing, non-chambered. it's supposed to be 3" in / 3" out, but that's just the goddamn endtanks. the actual inside perforated tube is 2.4" in diameter!!! grrrr . even the box says 14x9.5 oval 3" /3". Nowhere on Borla's page does it mention the tube shrinking, nor does it show it in the diagram! Quote Link to comment Share on other sites More sharing options...
johnc Posted June 19, 2004 Share Posted June 19, 2004 Supposed to be that way for a street muffler. If you want performance, the Borla XR-1 raceline is about the best. Loud at idle but actually quits down under power. Quote Link to comment Share on other sites More sharing options...
auxilary Posted June 19, 2004 Author Share Posted June 19, 2004 I've got a high flowing turbo, and a rotary... backpressure = not good. What would you recommend for a streetable muffler that has an inner diameter closer to 3"? My original plan was borla xr-1 in the middle, and this muffler at the back. Also, I'd like to try to keep the costs down more Quote Link to comment Share on other sites More sharing options...
johnc Posted June 19, 2004 Share Posted June 19, 2004 That's a tough one to figure out via a message board. Get on some RX7 forums and search. Maybe go to a local autocross and talk the to rotary guys who drove their cars to the event. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted June 19, 2004 Share Posted June 19, 2004 Grab a magnaflow 3" and you are set. No necking down, and guarenteed for life. (even their aluminized mufflers have a lifetime guarentee, and have SS interiors) Quote Link to comment Share on other sites More sharing options...
Heavy Z Posted June 20, 2004 Share Posted June 20, 2004 Moroso spiral flow would be my choice since you got the hi-temp issues of a rotary: Quote from Jegs: "innovative baffles are specially tuned to reduce the backpressure of high-volume exhaust systems. Spiral baffle design is unaffected by heat, less restrictive, and more efficient than fiberglass/steel wool packed mufflers. Manufactured from high grade steel with continuous welds for leak-free sealing. 4'' diameter, 12'' body, 18'' overall length." Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted June 20, 2004 Share Posted June 20, 2004 i cant see how that sprial muffler works to reduce backpressure when theres "stuff" blocking the flow... not that i really no anything about them so i cant talk but i would like to know how it works better. because its pretty cool i think. so when the gas hits the fins it makes it like a vortex and speeds up the air... right? mike Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted June 20, 2004 Share Posted June 20, 2004 drax 240z i beg to differe.... i have a 2.5" in and a 4" out (tip) on my magnaflow street series muffler, but the inside tapers to like 2" i was pissed after i bought it, but it's still loud as s*** and looks good so i kept it. -Ed (but now i want it quieter) Quote Link to comment Share on other sites More sharing options...
strotter Posted June 20, 2004 Share Posted June 20, 2004 Isn't that how it muffles? I mean, if there's no necking-down and rise in pressure, there's no reason for the gasses to pass out of the tube into the main chamber - the gasses will just pass through unobstructed and unmuffled. I think the idea is that the gasses, under high pressure at the neck-down point, pass through the cutouts into the main chamber, take a couple of bounces around trading kinetic energy (sound) for thermal, and then return to the center pipe at the rear. Or have I got that wrong? Quote Link to comment Share on other sites More sharing options...
Drax240z Posted June 20, 2004 Share Posted June 20, 2004 Maybe I should be more specific. All the magnaflows I've used have been straight through. I typically stick to the round bodied ones in 14" length or so and they are straight through. Then again none of these have a polished tip or have much bling at all... they just plain work! Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted June 20, 2004 Share Posted June 20, 2004 The pipe does not muffle by going to a smaller diameter, it's the same theory as insulating water pipes, it absorbs the noise that flows through. What matters is peforation size, length, and packing material. (honestly i can't se SS packing material absorbing much noise.) Yes the magnaflows are "straight through" but mine has a taper. but no complaints. -Ed *Edit* I would think the reason for the taper is to create some backpressure, 1 for low end torque, and 2 with the taper at low rpm, the reduced exhaust speed, caused by the backpressure, i would think gives it more time to absorb sound, but once your revs pop up.... say 3k or more then i think it acts like a sprinkler, you have pressure behind the taper, and it necks down to a smaller size thereforce accelerating through it faster. which would explain why my muffler doesn't really muffle at high rpms. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted June 21, 2004 Share Posted June 21, 2004 Uh, I don't know that I'd go the XR1 route... I've got that setup on the Vette and it is loud LOUD LOUD!!! But in a good way when you aren't droning on the highway!~ Mike Quote Link to comment Share on other sites More sharing options...
Heavy Z Posted June 22, 2004 Share Posted June 22, 2004 The moroso spiral flows have a hollow tube that runs thru the body of the muffler on which the fins are attached - your idea is correct ON3GO about the flow. I have two of these in 2 1/2" that feed into a Y-pipe back to a 3" hooker aerochamber. I am very pleased with the unique sound this package produces, and without the drone Mikelly talks about. Quote Link to comment Share on other sites More sharing options...
wheelman Posted June 22, 2004 Share Posted June 22, 2004 Heavy, Do you have any sound clips of your system? I tracked down a sound clip of the spiral flows but it is a little louder than I want. I like the overall sound but want less volume. I'm installing a 95 LT1 and plan on using 2 1/2" with the spiral flows to a Y pipe like your but wasn't where to go with it next. Wheelman Quote Link to comment Share on other sites More sharing options...
Heavy Z Posted June 22, 2004 Share Posted June 22, 2004 Mine ultimately feed into this 3" hooker aerochamber. Sorry I don't have any sound clips. The combo resulted in a system with a great tone at idle and IMO never gets too loud. My old Z used to let cops know I was around two blocks away, this is just stealthy enough but still sounds plenty mean. On the freeway you can easily hold a conversation without having to yell, but you will hear it, as well as the wooshing sound of exhaust moving through the spiral flows under your legs. Quote Link to comment Share on other sites More sharing options...
auxilary Posted June 22, 2004 Author Share Posted June 22, 2004 Grab a magnaflow 3" and you are set. No necking down, and guarenteed for life. (even their aluminized mufflers have a lifetime guarentee, and have SS interiors) Drax, do you happen to know which model that magnaflow makes? I need it to be free flowing and SS - rotary heat will burn out most mufflers I am going to send the muffler back and get a refund,a nd pick up a magnaflow unit Quote Link to comment Share on other sites More sharing options...
Drax240z Posted June 22, 2004 Share Posted June 22, 2004 Take a look at magnaflow PN 14619. Not sure you saw it, but the aluminized magnaflows have a lifetime guarentee as well and use all SS on the internals. The only difference is about $40 and the polished SS casing. Quote Link to comment Share on other sites More sharing options...
auxilary Posted June 23, 2004 Author Share Posted June 23, 2004 Gotcha... does it muffle sound at all? Quote Link to comment Share on other sites More sharing options...
Drax240z Posted June 23, 2004 Share Posted June 23, 2004 Not so much muffle as change the frequency to a range that is much more pleasing on the ears and lower in the audible range. Most turbo cars sound pretty darn good with only a straight through magnaflow in my experience. Not too loud at all. I can't imagine why this would be any different on a rotary. (except it might sound like a 2 stroke!) Quote Link to comment Share on other sites More sharing options...
auxilary Posted June 24, 2004 Author Share Posted June 24, 2004 Have you ever heard an industrial chainsaw with no cover on? Imagine that sound if it was made by 1.3 liter rotary making over 300hp. If you have a wankel with a test pipe for an exhaust making 400hp, and a 1000hp bb chevy with a blower running straight pipes, you won't heart the bbc winding out as much as you're gonna hear that wankel screaming Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.