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More on mufflers - comparing info
https://slantsix.org/forum/viewtopic.php?t=17976		 Page 2 of 4
Author:  SwingLo73 [ Mon Jun 12, 2006 5:07 pm ]
Post subject: 
So what would your first choice be? I don't care about sound as much as performance...

I don't mind paying for whatever is going to be better, I'm sure if I tell them, " I want this" they'll give it to me (or they won't get my business).
Author:  SlantSixDan [ Mon Jun 12, 2006 5:36 pm ]
Post subject: 
That's a very tough question. There is no right answer to "Which muffler?". On a stock (or near stock, or even "vaguely sorta stock-like") slant-6, as long as you don't pick something that's way too small, muffler choice is not going to make a significant performance difference, for the slant just doesn't flow enough that you're anywhere near the flow capacity of most any muffler of roughly the right size. Much more important to performance is pipe configuration and sizing. The biggest gain over the stock setup on your '73 will come from upsizing the headpipe, either with a single 2¼" headpipe as used on the 2bbl cars and assorted others, or with a pair of 2" So, durability and sound quality become the important factors.

Me, I am very sensitive to sound quality, and have a low tolerance for noise that others might find tolerable. I also don't like having to pay for exhaust work twice—once when I'm sure I've found the perfect "performance" muffler, and then again in a couple months when I get tired of the exhaust being too loud. So, I tend to pick a premium quality, stock-type muffler, but for an engine larger than the one I've got. This keeps the system quiet over the long haul (and over the entire RPM range) while minimizing flow restriction given the gas volumes present in a slant-6's exhaust system.

I'm about to put an exhaust system on my '71 Dart, and I'm thinking I may try out an E-body setup. The E-bodies with 198, 225 and 318 engines had no oval muffler under the passenger compartment floor. Instead, these cars used a round muffler inside the quarter panel, much as is done on most late-model cars. Same muffler used for all three engines. It's been previously (and correctly) explained that as the exhaust moves rearward in the system, it cools, and any given amount of a cooler gas takes up less volume than the same amount of a hotter gas. Therefore, any given muffler will present more restriction if placed closer to the engine than it will if placed closer to the rear bumper. I'm thinking to run 2¼" pipe off the manifold clear back, over the axle and into that E-body rear-mount muffler...if there's enough room within the A-body quarter panel. (Or I may go crazy and put on Dutra Duals.)
Author:  RossKinder [ Tue Jun 13, 2006 11:40 am ]
Post subject: 
Quote:
Me, I am very sensitive to sound quality, and have a low tolerance for noise that others might find tolerable.
I started this thread looking for anything remotely near the low rumble idle so valued in the 50's and 60's. Maybe that's a pipe dream. In any case it looks like most folks here just want the noise turned off.

I despise high pitched engine sounds like an amplified model airplane engine. So I'll do what I can to be rid of them. But perhaps there are suggestions for killing those but keeping the rumble idle? It's purely an ambiance thing.

Thanks
Author:  CStryker [ Tue Jun 13, 2006 2:44 pm ]
Post subject: 
Quote:
Quote:
Me, I am very sensitive to sound quality, and have a low tolerance for noise that others might find tolerable.
I started this thread looking for anything remotely near the low rumble idle so valued in the 50's and 60's. Maybe that's a pipe dream. In any case it looks like most folks here just want the noise turned off.

I despise high pitched engine sounds like an amplified model airplane engine. So I'll do what I can to be rid of them. But perhaps there are suggestions for killing those but keeping the rumble idle? It's purely an ambiance thing.

Thanks
Like I said... cheap glass packs. There's nothing "high" about the sound of my exhaust, though it also has 2+ inch pipes (one of the few hack jobs by the PO that I actually appreciate).
Author:  RossKinder [ Tue Jun 13, 2006 3:29 pm ]
Post subject: 
Quote:
Like I said... cheap glass packs. There's nothing "high" about the sound of my exhaust, though it also has 2+ inch pipes (one of the few hack jobs by the PO that I actually appreciate).
OK, I'm going for glass. I badly need new pipe all the way back, but I think I'll take a que from Dan and have them put the muffler way at the rear. If I really hate the Cherry Bomb it might be easier to change that way. (Straight pipe?) :shock: :shock: :shock: :shock:

Oh, shouldn't 2" pipe be enough in case I put on a 2bbl?

Thanks
Author:  Andy's GT [ Tue Jun 13, 2006 5:09 pm ]
Post subject: 
the super six exhaust manifold is 2.25", i think youd probably be best going with that, but i dont know how much difference the .25 makes, im getting ready to do a super six swap in the next couple weeks or so, and im planning on getting 2.25" all the way back, thanks for asking the question about mufflers, im looking for the same sound, i think im gonna try a glasspack too
Author:  SlantSixDan [ Tue Jun 13, 2006 5:58 pm ]
Post subject: 
Quote:
the super six exhaust manifold is 2.25"
There is no such a thing as "the super six exhaust manifold". The 2bbl slant-6s got the same exhaust manifold, with the same 2" outlet size, as the 1bbl slant-6s.
Author:  Andy's GT [ Tue Jun 13, 2006 6:19 pm ]
Post subject: 
"The Super Six is made up of the following:

* Two barrel intake manifold
* Carter BBD two barrel carburetor, or on later models, a Holley 2280 two barrel carburetor
* Special air cleaner
* Special throttle and return spring brackets
* Shorter throttle cable (same as V8 cars)
* On automatic models, a special kickdown linkage
* Special two barrel thermostatic choke pulloff coil
* Oversized exhaust system (2.25 inches)"
"The Super Six will work fine with your stock exhaust system, but remember that the factory Super Six cars had a 2 1/4 inch exhaust pipe as opposed to the 1 1/2 to 1 7/8 sized system that came stock on most 1 bbl slant six cars. The factory did this for a reason: the two barrel carb flows more air into the engine, and thus necessitates the ability to pass more air out of the engine. If you Super Six your car it is highly recommended that you also upgrade your exhaust system."
http://www.slantsix.org/articles/supersix/article.htm
Author:  Andy's GT [ Tue Jun 13, 2006 6:31 pm ]
Post subject: 
ok, i see what your saying, the outlet is 2", but the pipes are 2.25...got confused on the article, so when all else failed i busted out the tape measure...that doesnt make any sense though, 2" outlet to 2.25 pipe, i guess once it gets there (2.25) it will flow more freely, thanks for clearing that up
Author:  SlantSixDan [ Tue Jun 13, 2006 6:58 pm ]
Post subject: 
There are some problems with the Super Six article:
Quote:
or on later models, a Holley 2280 two barrel carburetor
That's not true. Only Carter BBDs were factory equipment on the 2bbl slant-6. Holley sold an "Economaster" 2280 in the aftermarket as a replacement, but Holley 2280s were never used as factory equipment on slant-6s.
Quote:
the factory Super Six cars had a 2 1/4 inch exhaust pipe as opposed to the 1 1/2 to 1 7/8 sized system that came stock on most 1 bbl slant six cars. The factory did this for a reason: the two barrel carb flows more air into the engine, and thus necessitates the ability to pass more air out of the engine.
That's also not really true (kinda, debatably, but not really completely). The factory put a 2¼" headpipe on the 2bbl-equipped cars to improve performance, but not because the larger pipe is "necessitated" by the 2bbl. The only time more air will potentially flow through the 2bbl-equipped engine than through the 1bbl-equipped engine is at or near wide-open throttle.
Author:  Joshie225 [ Tue Jun 13, 2006 7:34 pm ]
Post subject: 
Quote:
There are some problems with the Super Six article:
Quote:
or on later models, a Holley 2280 two barrel carburetor
That's not true. Only Carter BBDs were factory equipment on the 2bbl slant-6. Holley sold an "Economaster" 2280 in the aftermarket as a replacement, but Holley 2280s were never used as factory equipment on slant-6s.
Dan,

Didn't California cars use a Holley 2bbl on the Super Six? I've seen at least two that way.
Author:  SlantSixDan [ Tue Jun 13, 2006 9:21 pm ]
Post subject: 
Quote:
Didn't California cars use a Holley 2bbl on the Super Six? I've seen at least two that way.
I've got final-edition FPCs for most all the relevant years, and FSMs for several of them, and none of them list a Holley 2280 as factory equipment on a 225. I think you're seeing aftermarket replacement carbs.
Author:  Joshie225 [ Wed Jun 14, 2006 12:14 am ]
Post subject: 
I didn't say they were 2280s. In fact I don't know anything other than they were a Holley and they bolted right on a Super Six. I thought it was special for California emissions. What an FPC anyway?
Author:  SlantSixDan [ Wed Jun 14, 2006 7:29 am ]
Post subject: 
Quote:
I didn't say they were 2280s.
That's what they would've been, if they'd been used by the factory. 2280s were used on 318s and 360s in some years during the 1970s.
Quote:
In fact I don't know anything other than they were a Holley and they bolted right on a Super Six.
And as I say: Holley marketed Economaster 2280s as aftermarket replacements for the original Carter BBDs.
Quote:
I thought it was special for California emissions.
I haven't seen any evidence the factory installed anything but Carter BBDs on Super Sixes in any market.
Quote:
What an FPC anyway?
Factory Parts Catalogue. And FSM = Factory Service Manual.

It can be tough to determine what the factory installed vs. what a vehicle owner or mechanic installed, when you're walking through wrecking yards and looking under hoods. Especially where common and widely-sold replacement parts or accessories are concerned!
Author:  RossKinder [ Thu Jun 15, 2006 3:17 pm ]
Post subject:  Update
Well, I now have a new exhaust system. From the muffler back the old one looked a lot like Swiss cheese. Made for an interesting sound.

They (Midas) put in all new 2" pipe except for the first 8 or 9 inches, and a glaspak behind the axle. They tried to sneak in what looked like a 10", but I made them put in 24". The mechanic said it didn't make any difference since it was straight through anyway. :roll:

The sound? I like the low end at slow idle. A bit rumbley. It gets a bit loud when accelerating right in the middle of the shifting range. (Less bumble bee than tuba.) It sounds a lot like the imported sports cars of the '50's and 60's. MG, Healy, Morgan, Jag... I haven't decided if that's good or bad. :?:

At highway speeds it is surprisingly quiet. Actually my Swiss cheese system did very well at highway speeds. This doesn't seem any different. :)

There is a noticable improvement in midrange power. I guess that's from opening up the pipe. (Not going to do any speed runs until I get my steering and suspension right. :shock: ) And apparently that opened pipe is also what increases the midrange sound - letting it just hang out there more. That's my take anyway.

It surprises me somewhat. I remember glaspaks as giving more of a BBBRRRRRAAAAAAPP sound. This is very smooth.
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