A single exhaust defeats the purpose of headers ('would completely choke the flow), and a new Summit turbo muffler is about 30 bucks.
1. the O.P.'s car is not an I-6 2. I'm sure a single pipe of larger than 2-inches would be used on either application.
It seems that you may not entirely understand the flow physics of a header versus a cast iron log manifold because that's pretty much only true for a very poorly designed(and way too small) single system AND in only the high-mid to upper rpm ranges where the factory style muffler starts to really stifle max potential gains. And even then.. the longer primaries certainly do offer potential midrange scavenging increases despite a restrictive single piped system and poor flowing muffler. If it were just a matter of getting the most flow possible from a system?.. we'd all be running around with 4" exhausts on our 6's and 5" exhausts on our 8's. Velocity is just as important as all out flow though.. sometimes even moreso.. so that rationale just doesn't work in the real world. When you boil it right down.. plenty of folks have found more power from headers and factory singles.. than restrictive factory log style manifolds and less restrictive mufflers alone. In fact.. you'll usually see more power gained with a header and restrictive muffler.. than a factory manifolds and straight pipe so long as the pipe and muffler sizing isn't severely undersized to begin with. In other words.. the "too small" factory muffler is not the only bottleneck of such a completely "too small" system in the first place. A factory y-pipe is definitely no picnic for evacuating an exhaust no matter how big a muffler you use after it. I know this to be fact because I've done it.. and dozens of people I know have too. Not to mention the tens of thousands who've done similar as they're forced to build their exhausts incrementally(headers first.. then full duals) as they can afford it.. and/or just can't deal with having their daily driven vehicles down too long to do it all at once. Then there's the fact that theres' tons of "performance vehicles" out there with headers and single piped systems. As long as the exhaust is suited/matched to the needed velocity/flow characteristics of the engine.. it could care less whether it's breathing into a dual or single set of pipes. There's also the potential for fewer restrictive bends(air doesn't like to change directions too much) and less weight(unburdens some existing power) with a nicely designed single setup too. Anywho.. I rarely just swap ot a muffler and expect it to rock my world without complimentary components. At the very least I would fabricate an entirely new system from the manifolds back. The mileage gains alone could help pay for the cost in well under a year.. or far less than that if you drive a fair amount. Even if you were to keep the factory manifolds?.. a less restrictive pipe size from there on back would be worth about 3-4HP/5-6TQ. In the process get rid of the factory y-pipe and build your own/buy a prefab'd unit(flowmaster makes a decent one) for another 2-3HP/4-5TQ. Then run a fairly decent muffler that flows more than at least 350cfm for another 4-5HP/7-8TQ. Then you can revisit the possibility of headers later on for an honest peak increase of 8-12HP/15+TQ.. at the rear wheels. These figures would be fairly conservative for a mildly cammed motor that doesn't spin very high. If you want to cam it later on?.. there's an easy 25HP/35TQ available from a decently built exhaust system. That's a far cry from the measly "4-5HP/7-8TQ" that a muffler swap alone will give you. Course.. a basic muffler swap will make it sound like you got far more than you really did.. if that's all you're really after here. PS. To my ears.. glasspacks are too raspy.. and flowmasters can sometimes be too tinny and prone to drone. Maybe look at the Hooker Aero chambers? They are sort of a mix of a chambered and straight thru design that usually gives a "bigger than it really is" type sound without any drone.
Yeah I realized that after I posted it, left it cuz I figured you guys had forgot what it sounded like
lol.. I just realized after reading all the "flowmasters are on Mustangs".. or "Flowmasters are on Chevys" posts.. that some of you guys must not get around too much to gain newer perspectives. Flowmasters are just so "90's" anymore(despite their newest design revamps) and many are using other better sounding and freer flowing designs these days. Some may actually be considered as knockoffs.. but they're still not flowmasters either. All the fast cars I see are running straight thru designs.. and probably less than 20% of all the others combined run flowmasters any more. IMHO, there are much better alternatives these days.
i have some thrush mufflers on my torino and i like it, they sound good on bigger engines like 351s or chevy 350s but i took the flowmaster off my comet which is a 302 and put a thrush muffler on it and i hate it, maybe if i had dual exhaust or like u have glasspacks........
heres a good example on how mufflers really sound... http://www.youtube.com/watch?feature=endscreen&v=fO0fy2yBNoM&NR=1
I'm well aware of how restrictive stock exhaust manifolds are, which is why I'm running Hooker full-length headers. I also know how much of a P.I.T.A. they are to install, and the only saving grace for me is that my car has no power steering or auto trans linkage. It would be more trouble than it's worth to install headers if I was only gonna run a single 2-inch exhaust pipe. Not to mention that headers and the corresponding exhaust work is expensive, and I somehow got the impression that the O.P. didn't want to spend a lot of money (for now). So while everything you said is certainly true, it just doesn't seem practical (in my opinion) for what the O.P. is trying to accomplish at the moment. It appears to me that the O.P. is just looking for a new muffler that sounds good, which is why I suggested a Summit (or similar) turbo. If it were an I-6, I'd suggest a glasspack. Flowmasters sound terrible on 6-cylinders. A turbo may sound "okay", but I think a glasspack delivers the overall best tone. Turbos sound deep & throaty on a V-8. Of course the Hooker Aerochamber would sound even deeper.
well said.. and point taken. Obviously far more gains to be had to help make it worthwhile with bigger engines.
Ive decided on the Flowmaster original 40s after i install headers and a custom pipe setup but ima add the electrical cut outs or "dumpers" so i can have it either go through the mufflers or just straight out
very wise choice I dont know what the mufflers will sound like but Im interested in hearing it when you get it all installed
