what mufflers and diameter pipe???

[joey]

well..now i am in need of advice for my exhaust...the motor is still in the process of a rebuild..it will ba a 318 with 360 heads rebuilt, bored .030 over, cam, headers, 4-barrel and intake...i want to know what mufflers are loud yet smooth and will command respect...also what size pipe should i use to achieve optimum flow and sound...thanks for your time

[nitroman88]

Sounds like your rig is a street car or truck. With a mild small block you are looking for 2 or 2-1/4" pipes. Mild big blocks work well on 2-1/2" pipes. Don't let anyone talk you into shelling out the bucks for a 3" system unless you plan on building this thing into a drag car.
Mufflers? If you are going to drive this thing a lot, go with turbo style muffs. They sound cool, they are inexpensive, and your ears, brain, neighbors, and girlfriend will thank you. Some people prefer Flowmasters, but I think they sound kind of tin-cannish. Straight-through style muffs and flowmasters sound GREAT - don't get me wrong. I ran them on a daily driver with a mild 440 in the 80's and had to swap them for turbos to save (what was left of) my hearing. Later.

[Christopher]

If it were me,I'd run what I ran in a 318 Duster that I had for my first car.2 1/4" pipe,Street Hemi mufflers for a B-body car,and a crossover pipe.Nice mellow sound but not so loud that you can't hear the stereo or anybody riding shotgun.

[Hoov]

I have a 360 Volare RR dualed out with 2 1/4" pipes and turbo mufflers and no crossover myself. Nice sound when you punch it, but at idle and cruising it is just a small rumble. I put a catback Flowmaster system on our 95 5.9L Ram and it sounds great, but the rumble is quite a bit more noisy.

[The Dartman]

I personally feel that Flowmasters sound the best on a hopped up street car. There are several variaties (straight through, dual chamber) and you should be able to find one that has the qualities you want. Since these are expensive, I would recommend next just getting a pair of turbos (15 - 45 bucks) from your local exaust shop when they put it on.

As with ANY exahust job, I always use aluminized pipe. It has similiar qualities as stainless at a fraction of the cost. It will last a long time (forever?) and will continue to stay shiny and will not rust (other than the welds). This is especially important if you live in the Norhtern half uf the US. I recommend getting a 2 1/2 inch aluminized system, since if your going to do it, you might as well do it right.

I run 2 1/2 aluminized pipe to side exiting Stainless Supertrapp Mufflers. I have always loved the look and sound of SuperTrapps, and since they're adjustable, I can make the car quieter or louder in just a few minutes. My exahust system cost me about $230 for the pair of Supertrapps, and $55 for the exahust work. I also installed a set of swap meet $20 Dump tubes for easy access to mucho power.

[RAM MAN]

DARTMAN:

I have always wondered about SuperTrapp mufflers - several people originally told me you could get better for the money - but sounds like you are a satisfied customer.

I was considering putting a pair on my 98 RAM Quad cab.

So on your set up - did you just run the aluminzied pipes from the cat (or headers) to the SuperTrapps ? Ever have trouble adjusting the rings ?

Just curious. . . .

[340king]

Hey Joey, obviously your not from Australia. Super Stock and Drag Illustrated, A.K.A. Drag Racing Monthly recently did an article based on best street mufflers. The resluts were quite surprising. They flow rated mufflers just as you would carbs, heads, etc. They also dyno'd them to judge sound attenuation. It would be worth looking up the results. Gary Vizard did the testing and I have found his work to be very good and objective, not the typical infomertial that you get with most high performance mags. I will look through my archives to see if I still have it.

[The Dartman]

Supertrapps are NOT the best muffler for maximizing performance (AKA 99% Drag Car). Since they are tuneable (tunable? tune-able?) that is a benifit, but they cannot come close to the near zero loss of performance that you get with the best flowmasters or Dynomax racing mufflers.

Although, the Supertrapp people ran a test on a NASCAR car with Supertrapps (disks only - no glasspack) and found that there was NO loss in performance and a decrease in Decibals (?) of 50 to 75 percent.

I have always loved the look and sound of Supertrapps since I saw a couple local cars: a "Rat Fink" '56 Chevy that runs 12.20's, and a friends Pro Street Trans Am that ran 11.80's on street tires (licience plates said "Y TRYIT"). The Trans Am guy now runs a 6 second FunnyCar.

As far as adjusting the number of disks, it is important to put ANTI-seize lubricant on the threads to ease the removal of disks. The process itself is slightly complicated since the bolts are small allen head screws and there is a ton of them in each. A cordless screw driver helps this process go faster. I don't really need to adjust mine since I have Y pipe dump tubes directly off my headers though. They re mostly there for looks and driving to my local track (and maybe a cruise night or two).

[Old hippie]

opinions are like belly buttons: just about everyone has one. Heres mine. I agree with Christopher 100%. A 318 does not need dual 2 1/2" pipes unless you have cammed the snot out of it and totally killed the bottom end driveability. This is a smallish engine and needs all of the bottom end help it can get. I would run 2 1/4" all the thru, meaning out the back a la 340 Duster style. For mufflers my first choice would be 3 chamber Flow Masters, off set inlet and outlets. I know they are kinda pricey but they are one hellofa muffler. Second choice would be the street hemi style which is real close to the stock 340 hi-po muffler and fairly quiet too. It seems that back in the 80's someone was building a turbo style muffler that had a longer body (18 to 20 inch body as opposed to 14 inch) to help quiet down some of the real nasty big blocks. Don't know if these are still around but they might be worth looking in to. I also like a balance tube: they help the bottom end, don't hurt top end at all and help to quiet things down a bunch. I am not a big fan of Super Trapps. Like I said....opinions.

The Old Hippie Hisself

[Tim_K]

Ok, Joey, here's my suggestion:
2-1/2" pipes full length with 2-1/2" 3 chamber Flowmaster mufflers. 3 chamber Flowmasters are supposed to be quieter than 2 chamber ones. If you want to use pipe no bigger than 2-1/4", I would definitely use mandrel bent pipe. You'll probably have to order a bunch of mandrel bent pieces of pipe and mig weld the whole system together, I don't know anyone who has the equipment to do it all already, unless you want to hand $500.00 to Tube Technologies, Inc. for one of their pre-bent systems. If you use 2-1/2" pipe, this mandrel bend vs. stock compression bend thing won't be as critical. Compare two pieces of bent pipe sometime, mandrel bend against compression bend (which is the type of bender every garage I've ever been in has had) and you'll see the difference immediately. Compression bends lose about 20% of their cross-sectional area through the bends, tight radius bends are worse than more gradual bends.
I've been 'testing' various garages the past few years, asking them if they had mandrel or compression benders for exhaust work. Almost every one either said 'mandrel' or didn't know what I was talking about. And they ALL had compression benders. 1 or 2 said 'compression' and therefore passed the test (knowing what their own tools actually were).
This is why I don't trust any mechanic to touch my cars. Incompetence. I've taught myself to do a front end alignment with a level, string, and a tape measure, and finally found one half-decent person to go to for custom exhaust work, which were the only 2 things I ever went to garages for, anyhow.
I digress. A few years ago, I had a '72 Satellite with a 318. Modifications to it were minor, just a stock '71 340 intake with a 6322S ThermoQuad, and a 2-1/2" dual exhaust with #42551 3 chamber Flowmasters. It sounded good, and wasn't loud or annoying either. Get a Summit Racing catalog for the mufflers and mandrel bends. That's where I found mine, anyway.

[RAM MAN]

Here's a site that has some Flowmaster sounds - if you want to check it what that sound is like . . .

Just my .02
http://www.geocities.com/MotorCity/S...lowmaster.html

[The Dartman]

I'll be the first one to admit that Supertrapps are not for everybody (both sound and looks).

I am still against ANY 2 1/4 performance exhaust system because of the sound and back pressure though. This does stem from having a terrible sounding 2 1/4 inch steel system with cherry bombs. With this system the car sounded great at idle, but when you got on the gas it immediatly had a harsh buzzing tone (kind of like harley meets 2 stroke motorcycle meets 6 banger sound). In fact, I had one guy come up to me at the track all happy that I was running a six cyclinder through the exhaust in the low 13's. Talk about embarrassing!!

[joey]

i really appreciate all of the advice...i think i will go with the 2 1/2 inch pipe with a crossover pipe...and use the 2 chamber flowmaster mufflers and finish it off with some megs rolled edge tips...should have a nice loud sound...tell me what you think

[Orange Bee]

Joey,
STOP! Now that I have your attention, as short lesson on exhaust systems. First, my name is Marc Medina and I am a die-hard Mopar guy. I also worked at Flowmaster for 2 1/2 years as chief technical advisor among other things. When you say cam, 4 barrel intake etc., you need to be very specific. Is it a .400 lift 252 duration hydraulic cam or the Mopar .528 lift solid? What compression ratio will you be at 8.5 or 12 to 1? Which intake and carb? Which transmission? If automatic, how loose a converter? What's the rear gear ratio and tire diameter? Which car are you putting this into?
Here's the basic breakdown on horsepower per pipe diameter:
2" pipe 100 hp
2 1/4" pipe 275-325 hp
2 1/2" pipe 300-425 hp
3" pipe 450 to 625 hp
Some of these vary depending on cubic inches and intended use. Velocity in the exhaust system is very important! If you think you'll bee in the 2 1/2" pipe range, then use the mandrel bent tailpipes from Flowmaster (part# 15806) They fit all 67-76 A bodies, 70-74 E-bodies and 67-74 B-bodies, although Flowmaster won't tell you that (only because the head of R&D hasn't personally tried it himself). Never use two chamber mufflers on a REAL street car. They are designed for an engine that spends most of it's time over 5500 RPM which is not real street operation. Use the 42551's with the 15806's and you'll be golden.
Here's the deal on these stupid muffler tests:
Every gear head in the world understands carb sizing by airflow. If it flows more air, then it makes more power (or at least that's what is assumed!).Think back to the Max Wedge engines equipped with the long ram intakes.......The ram length was tuned for a specific RPM range where the cycling of the intake valve used the ram effect to "supercharge" the engine! The same thing happens in the exhaust system. Every time an exhaust valve opens, it releases an exhaust pulse into the header pipe. So your exhaust doesn't flow in a steady state like a flow bench tests! Flow bench testing mufflers is a joke! It has nothing to do with what the muffler actually does. It's like saying that a bigger camshaft makes your doors open easier! To keep this from being pages and pages long, I'll give you the Readers Digest version:
For REAL STREET CARS (true daily drivers - blowers and nitrous not included)
1) Keep the ID of the header tube as close as possible to the the exhaust valve diameter.
2) Use a cross over pipe - as close as possible to the outlet of the header collectors, and the same diameter as the pipes you are connecting.
3) Use the general pipe size guide above for pipe sizing.
4) Always use 3 Chamber mufflers.
5) ANY PACKED MUFFLER (that's a muffler with any type of fiber packing) will hurt performance compared to a properly installed and tuned Flowmaster.
For those of you who think this is a crock, here is a little story for you....
That "Muffler Shootout" article in Car Craft a few years ago showed Borlas RACE Muffer as slightly better than Flowmasters Street muffler, but it was also much louder! A few years later, Flowmaster had spent a considerable amount of advertising money with Car Craft and they asked for more mufflers for another shootout. The sales manager told them he was very dissapointed with the way they ran the last test (they asked for street mufflers from everyone, but tested race mufflers from Borla - not cool). Thier response was an offer to run the shootout agian, write the article and then NOT PUBLISH IT IF FLOWMASTER DIDN'T LIKE THE RESULTS! The sales manager told them that if they were that easily influenced that he wouldn't participate in such a shootout and that was the end of that!
Any test like that can be so easily skewed to make one product look better than another, you almost need something like Underwriters Labs to really get a good test.
If any of you have questions about exhaust or other Mopar related stuff, please feel free to e-mail me any time.
Marc Medina
Orange Bee

[The Dartman]

I vote Marc "orange bee" to be the official Mopar Chat exhaust expert.

All in favor type "I".

Thanks for the information!! You sound really knowledgable about the subject and I'm sure that many people will be asking you more questions.

[This message has been edited by The Dartman (edited November 05, 1999).]

[Hoov]

"I"

[Larry S.]

"I"

[440trk]

I


Thanks for sharing your knowledge!

440trk

[Brian Mills]

I

[Tim_K]

Way to go, Marc! We need good technical people here, especially from a company like Flowmaster. I'd like to see some more in-depth technical information on exhaust systems, maybe you could set up an example car and give reasons why a certain type of exhaust system would be best. Also, I'd like to see some more words on that whole 'exhaust velocity' thing, and flow comparisons between mufflers. Although I understand a flow bench cannot accurately simulate the operating conditions of an exhaust system, how else do you make comparisons, then? How does a 2" pipe carry a 100 horsepower rating, and a 2-1/4" get 275-325? A single system vs. dual?
I agree that Car Craft (Camaro Craft, Chevy Craft, etc.) is an inaccurate and unreliable source of information. Just look at that lousy Slant Six article they did last month. I did some research, and found out just how cheaply that guy did the buildup, and all the shortcuts he took, and then he had the nerve to be disappointed when it didn't run 15's. Anyway, I'm looking forward to seeing more hi-tech exhaust tech information.
Oh, and before I forget - "I".

[hoss]

"I"

[cudadude]

"I"
Glad to have an exhaust tech. here. I just put a set of flowmasters on my wife's (oops) 86 Mustang and we love them. They have a perfect performance tone. As for performance gains i cannot say because i just swapped to an 89 motor and the cam band is different and i am still getting used to it pulling hard from 3000 instead of 2500. Sorry for posting this obsceen story on this board

[JimG]

G'day joey,

Yet another exhausting tip: For exact location the the cross over pipe (and that little extra HP) get car up to operating temperatures and using a squirt gun or water bottle spray find the exact location where the water no longer turns to steam. Install the cross over 2" downstream from there.

I noticed a slight increase in HP going from the normal H patterned exhaust cross over to an X patterned one. It flows more betterer. I copied the idea from Mopar Action.

As well, my mufflers both have one inlet and two outlets (four tail pipes). Not sure how much zoom this added (if any) as I've had them since building the car.

Unfortunately though, my car sets off a lot of other car's theft alarms. Especially in enclosed parking structures. This has more to do with the resonance (a pulsing vibration) caused by the cam than my exhaust set up.

Hoo roo,
Jim Guckert