I was thinking of getting a front Dutra exhaust manifold and running 2.25 dual exhaust straight from the front and rear manifolds (3 cylinders per pipe)...might even sound cooler (btw, if someone here has a sound clip of a true dual exhaust, please post it up), but I don't know if that would be better or worse for performance gains. Can someone with experience please let me know what you think. Thank you!

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-Brodie

1977 Dodge D100 stepside, slant six/3 on the tree
2002 Chrysler 300M Special (daily driver)

There is a blue Duster or Demon on Youtube with true duals. It does sound nice with Flowmaster 40's. Not sure how old you are but if your like me I would put an Flowmaster HP2 in front of the 40's. I don't care for the loud rasp of a 6. I like a mellower sound like you get at an idle all the way to 6000 rpm.

wjajr has true duals on his yellow Dart. Maybe he could post a sound clip sometime. He added the 12" HP 2's in front of some Walker Turbos for a nice sound.

Most folks don't go for the sound but instead build a "Y" pipe to connect the two manifolds since the system is lighter and easier to maintain.

On a daily driver I would go with Doug's set up with Ceramic coating or for racing, the long Hooker headers with ceramic coating for more torque and "X" pipe and true duals with 18" FM HP2's and FM Delta 50's in stainless steel. I have heard them and they sound nice....!

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Aggressive Ted

http://cid-32f1e50ddb40a03c.photos.live ... %20Swinger


74 Swinger, 9.5 comp 254/.435 lift cam, 904, ram air, electric fans, 2.5" HP2 & FM70 ex, 1920 Holley#56jet, 2.76 8 3/4 Sure-Grip, 26" tires, 25+MPG

This is from an in car video last year. Erson 280

This is a pass at Medford. OCG 34 Cam.

Thisis a cold start with the OCG 34.

You can use this as a comparison to recordings with Dual exhaust. I'm running Dual Dutra Duals into 2-1/4" Head Pipes with thermal wrap to a Y pipe. Single Xlerator fully welded muffler. 2-1/4" Single all the way out. The note is still fairly loud at WOT.

The second video I'm racing Fopar. He has Clifford shorties into a Y pipe, then the muffler. His car makes a nice sound. (Six 1bbl carbs.)

CJ

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Part of Tyrde-Browne Racing

Hi slantin_77,
I've got true dual 2" via dutra front manifold on my (otherwise stock) super six. It definitely sounds louder than stock and allows the slant to get into 2500+ rpm range easier. I do not recommend glass packs unless you want the most offensive rasp around the 2000 rpm range under load. It's really bad... But I digress. Performance wise, I think it was worth it. Here are two videos, one at idle, and one on the road. I've been running this setup for a year now.
Www.youtube.com/watch?feature=c4-feed-u&v=RyNdvBVvRw0
Www.youtube.com/watch?v=IKIMcmi8dzo&feature=c4-feed-u
Good luck,
aspen76

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76 Dodge Aspen
225 Super Six w/ Dutra True Dual Exhaust

http://i1245.photobucket.com/albums/gg5 ... AG0095.jpg
http://www.youtube.com/user/BZuko1?feature=guide

There is zero performance improvement with duals over a proper single exhaust system. Duals are more expensive and weight more. If you want the look and sound that's fine, but don't do it for performance.

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Joshua

True duals are for V engines... For an inline, you should be proud to use a single exhaust and you can get as good or better performance from it vs. true duals out the back. Why hang 20-35 lbs more tubing and muffler on the car to get no better performance?

Lou

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Home of Slant6-powered fun machines

My buddy Bill has duals on his Dart off of Clifford shorties. It sounds awesome, but it is a real pain in the kawk to work on the driver's side of the motor or trans.

I've got headers in my small block truck. I even had a dual inlet/single outlet system put on it.

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Official Cookie and Mater Tormentor.

Hmmmm...so are there any gains to be had by porting the original manifold at all? I guess I don't want to spend money on a Dutra front manifold if I don't really have to. The vehicle I have is a '77 Dodge D-100 regular cab/step side and I was wanting the exhaust to come out directly under the side steps (like where the stacks are on the Lil Red Expresses, but not stacks...just exiting out the side under the steps) so basically it would be better to have single, then "Y" it out to both sides of the truck?

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-Brodie



1977 Dodge D100 stepside, slant six/3 on the tree

2002 Chrysler 300M Special (daily driver)

Or instead of getting a Y pipe, I guess I could go with a muffler similar to this:

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-Brodie



1977 Dodge D100 stepside, slant six/3 on the tree

2002 Chrysler 300M Special (daily driver)

Me quoting Ted:
[quote]wjajr has true duals on his yellow Dart. Maybe he could post a sound clip sometime. He added the 12" HP 2's in front of some Walker Turbos for a nice sound.[/quote]

I have no way to post sound clip until late spring and then only if Mrs. Wjajr will allow her iPad to be pried from her tight grasp long enough to capture a few notes, car is tucked away in winter repair/upgrade mode. I installed Walker OEM type mufflers, replacing nasty sounding burned out Turbos. True duels have a funky unbalanced sound when used in conjunction with a lumpy cam. Two cylinder pulses from one side followed by one beat from the other pipe, than the opposite, and so the song goes. Personally it kind of grated on my ear, and before installing the two HP 2’s the mid 2000 rpm drone was unbearable due to tire size and rear gear ratio landing running in speed range of 80% of operation.

Josh:
[quote]There is zero performance improvement with duals over a proper single exhaust system. Duals are more expensive and weight more[/quote]

All true, save several hundred bucks, and a few pounds with two into one properly sized system.

Zilla:
[quote]My buddy Bill has duals on his Dart off of Clifford shorties. It sounds awesome, but it is a real pain in the kawk to work on the driver's side of the motor or trans.[/quote]

Second that statement (different Bill), it is real tight along left side of transmission with all that plumbing occupying all available space. Also there can be ground clearance issues where second pipe crosses over to right side.

Slantin_77:
[quote]Hmmmm...so are there any gains to be had by porting the original manifold at all?[/quote]

Some have hogged out stock manifold a bit too fit 2 1/4 – 2 1/2â€￾ exhaust pipe, similar to Super Six factory method, to muffler, and reduced to 2 inch after muffler to keep hot gas velocity high out to bumper. More on this exhaust sizing and reasoning can be found via “Searchâ€￾ button.

If you don’t have over sized valves, high compression, 4v carburetor, and a high lift high rpm lumpy cam, a single Super Six exhaust system will do the job just fine.

Below are a few photos of a truck that has become a regular at local shows utilizing stock manifold, Super Six exhaust into single muffler, exiting with two bent side pipes under passenger’s side step. Looks nice, sounds nice with a bit of lope, and window down low noise driver friendly…

Bill

[img]http://i294.photobucket.com/albums/mm87/wjajr/odd%20stuff/002_zps8ff58452.jpg[/img]

[img]http://i294.photobucket.com/albums/mm87/wjajr/odd%20stuff/006_zps22d251fa.jpg[/img]

[img]http://i294.photobucket.com/albums/mm87/wjajr/odd%20stuff/003_zps2471fbb9.jpg[/img]

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC

This is definitely true for a stocker, if the engine has been modded (high compression, porting, large valves, cam, 4 barrel), then it will help with the improvements. The only other item to note, is that if you have duals, you can put an oxygen sensor in each pipe and if running a 4 barrel carb on an intake manifold that was "split", it would help dialing the engine tighter for street/mileage...So unless you have built a 10:1 engine with all the goodies, it's not worth it except for sound and presentation. I can say that I have run my duster with the same engine on two runs and the engine with the dutra duals ran 16.5's...same setup with the stock single manifold and 2 1/4" single pipe ran 17.3's...(but that is a 10:1 engine with porting and O/S valves and more cam)



There are a little, and upsizing the pipe to 2 1/4" will help a bit too.

With split exhaust manifolds you can tighten the manifold bolts higher than the factory recommended 10 ft/lbs without the risk of cracking due to thermal expansion. The reason the bolt torque spec is so low is the long exhaust manifold is designed to slide as it expands and contracts. In my opinion, this is a pretty weak element of the inline six design.

This is the primary reason I went to Dutra duals after my stock exhaust manifold cracked. Once you tighten the manifold combo tighter, I think you will find cold start up drivability better as there is less chance of minor vacuum leaks when cold. That being said, you must keep the rear stock heat riser with a carb or cold start drivability will get worse. Of course if you go with headers, the cracking issue goes away, and the bolts can be made tight, but you will still lack carb heat.

Whether you go true duals or not is personal choice of course, and what you are trying to do. A pair of small duals are quieter than a single larger exhaust pipe, and offer less restriction than a single small pipe. I had a single large pipe on this car years ago, and the resonance that got set up in the rear pipe, behind the muffler, was extremely annoying on the highway. And I drove this car a great deal. It was my daily driver in my piano service business. It was so annoying, my wife would not ride in it on the highway with me. Quiet has since been my logic all along. If you are just after noise, a large single exhaust can be pretty intimidating.

Sam

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Sam,

Just wondering, what do you mean by a "pair of small duals?"

I would surmise that a single, 2 1/4 or 2 1/2 fed by a Y pipe from the split manifolds would be much quieter than duals...but, I did think that I wanted to try dual 2" pipes that run down the driver side and into a dual 2" in, 2" out turbo muffler and then over the axle and out the dual tails on the driver side. No resonator or X or H pipes intervening, just each bank getting a 2" all the way back through a dual turbo (maybe a crossover turbo, but not necessarily) on the driver side (why run extra pipe to the passenger side when the exhaust manifolds are on the driver side?).

I did have a conventional dual setup previously with an X pipe, resonators before the mufflers and the drone was horrible at 2000-2500 rpms. I removed the resonators and it really made no difference, the X pipe was the issue it seemed. It gave me more power, I know this because I took it out of the system and got a noticeable drop in power (not just noise, but actual get up and go).

Just wondering....

Brian

My true dual setup sounded awesome at idle and cruising at 60+ mph, but the drone at certain mid-range rpms was absolutely horrible....

It's a space issue, for guys with an automatic there is more room under there on that side (although you may want to look at you E-brake cable routing on a '67 since it's a little different than the late guy's cables) and access to the tranny shift linkage when you do run that...For us manual transmission guys we don't have a big fat pan under there to hog the room, but we make up for that by putting all the clutch and shift linkage in the way...I ran dual 2" to each side then to the rear on my car, it was easier to work with than going to long tube headers (3 into 1 x2) that ran both collectors to about the position of the clutch fork and then tried to make it fit right...

-D.Idiot