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duel exhaust

Printed From: TheAMCForum.com
Category: The Garage
Forum Name: AMC 6 Cylinder Engine Repair and Modifications
Forum Description: AMC-made I-6 engine mechanical, ignition and fuel from basic repair to high-perf modifications
URL: https://theamcforum.com/forum/forum_posts.asp?TID=70809
Printed Date: Mar/28/2024 at 10:13am
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Topic: duel exhaust
Posted By: amchornet1970
Subject: duel exhaust
Date Posted: Jun/12/2015 at 6:33am
 How many people have it on there six and do they like it.....any sound clips to go with?

I have a pace setter header with duel outlets I am thinking of installing...with glass packs....lol


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Joe
1976 hornet sedan 258 4.0 head mpfi
1985 Eagle sedan
1993 grand jeep Np242
http://s12.photobucket.com/user/amchornet/profile/



Replies:
Posted By: Ollie
Date Posted: Jun/12/2015 at 7:22am
Good question...I will answer as soon as my headers and dual exhaust are installed....Hope mine sounds like a nicely camed up Mopar 340, one of my favorite engines...but I doubt it ....hehehehe
waiting for your sound track..
Ollie


Posted By: uncljohn
Date Posted: Jun/12/2015 at 8:01am
Sorry Ollie,
I am not a personal believer in headers. They are a very expensive exhaust manifold and while they can be some addition to performance, they generally are more of a cosmetic item on a street engine A six can perform pretty much at it's maximum with a decently sized single exhaust. One way to think of it, a six is about 1/2 of the displacement of a large V8 so if one half of the large v8 can work well, than a six should too.
I have on one six, a single exhaust steel tube manifold that I purchased used from a Jeep junk yard and it was configured to bolt into the existing exhaust system used by AMC on their 6 in that case, a 1980 Spirit. The rest of he system being that of a high flow catalytic converter and a 16 inch glass pack.
Another six I used the oem EXHAUST manifold but cut the heat riser off and welded a plat over the hole. The object was to keep exhaust heat away from the intake manifold.
With the same objective in mind, my latest six uses the AMC uses an Eagle exhaust manifold which does not contact the intake manifold and I will configure a large diameter single exhaust with it.




And I took the money not spent for an expensive exhaust system and built it with a 4bbl carb and intake and an Iskenderian 270 HL Cam and some dress up goodies.

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70 390 5spd Donohue
74 Hornet In restoration
76 Hornet, 5.7L Mercury Marine Power
80 Fuel Injected I6 Spirit
74 232 I-6, 4bbl, 270HL Isky Cam


Posted By: warweapon762
Date Posted: Jun/12/2015 at 8:26am
I've found in a few cases that running the late model manifold combined with a larger exhaust pipe diameter is more than adequate for a I6. These engines don't spin at high enough RPMs to utilize performance headers properly.

If you would like a good exhaust tone, split the pipes with a y-fitting at the transmission crossmember and have one of the split pipes longer than the other. It makes the tone sound like a good dual exhaust system at a fraction of the cost.


Posted By: Bart R. Orlans
Date Posted: Jun/12/2015 at 9:08am
I put a single-in, dual-out muffler on my 232+powered Marlin. The muffler is an OE replacement from the parts store.

https://youtu.be/yxdEFkTiync

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Bart R. Orlans



They call me daddy at home


Posted By: tyrodtom
Date Posted: Jun/12/2015 at 9:20am
When I put Clifford research headers ( Viper) on my 232 years ago it took more of a performance jump than when I'd put the Offy dual-port with a Holley 390 on the engine. But I think it was because it allowed the intake and carb to work better. It made enough difference that I hade to rejet the carb to get the plugs looking right.

I used 2 stock exhaust systems going out side by side, with 2 stock type mufflers, where the stock muffler went, but I turned them on end, instead of flat as stock.

How did it sound ? Who knows, that's a personal judgement, the sound I like someone else might hate.

But running headers on a street car is a high maintenance project. Mine didn't drag, and those Viper headers were made out of thicker, higher quality steel than most headers of their time. This was in 1973, you could get a set of Hooker headers for a SBC for less than $60., these Clifford Research headers cost me over $120. I had these headers on a daily driver for over 15 years, but those last 10 years was spent constantly repairing rust thru on them. By the time I took that car off the road, there wasn't much left of the original headers.

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66 American SW, 66 American 2dr, 82 J10, 70 Hornet, Pound, Va.


Posted By: farna
Date Posted: Jun/12/2015 at 10:48am
I recommend a 2.25" or 2.5" single exhaust. Much cheaper than two of everything! I run 2.25" on my hopped up 4.0L with a generic turbo muffler. I've had people think it was a small V-8. Not very loud, just a nice sound. Glass packs usually have a "rap" to them when you let off the gas real quick after accelerating. You might like it.

If you go duals use small pipe. Stock exhaust is 1-7/8", so a pair of them would be about right. If that size is hard to find go to 2", but I wouldn't go any larger.

The single in dual out muffler with 2.25" or 2.5" in, and two 2" (or a bit smaller) out would be good. Have that type muffler on my truck, sounds good (4.7L Tundra V-8, 2003 model). I bought the truck with a flowmaster and it had to go!! Couldn't hear yourself think!! Replaced with a one in two out turbo, but it wasn't much quieter. A stock replacement (generic) muffler with dual outs sounds just right! You might want to pursue that direction...


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Frank Swygert


Posted By: tached_out
Date Posted: Jun/12/2015 at 11:44am
If you want a good idea what it will sound like, watch some you tube vids of Jaguar E types. They came with 3.8 and 4.2 litre sixes just like AMC. Those cars sounded beautiful. Pure and rich. 

They had twin exhaust manifolds. The two separate pipes ran parallel and each had a muffler side by side under the car and they each had a pair of resonators near the rear. You could see a lot of the system from the rear of the car. The pipes were 2'' if I recall correctly.

Some thing to note; the two pipes exited together still side by side. This is what gives the car such a pure sound. As you separate the pipes it begins to sound more and more raspy. If you exit on either side of the car it will sound like a three cylinder from either side. If you use an X pipe it will sound smoother but you'll lose that beautiful Jaguar sound.

I have an exhaust shop and I have worked on these cars. It's in my opinion, the the sweetest exhaust note there has ever been. 

If you have a dual outlet header, I say RUN IT. Ignore the boring people here telling you to do otherwise. 


Posted By: Ollie
Date Posted: Jun/12/2015 at 12:12pm
[QUOTE=uncljohn] Sorry Ollie,
I am not a personal believer in headers. They are a very expensive exhaust manifold and while they can be some addition to performance, they generally are more of a cosmetic item on a street engine exhaust.

I agree with you 99.9%, the increase performance is at upper RPM. I have built vehicles with and without headers. In a cramped engine compartment I like to avoid them and the ton of issues associated with them.

I bought the Clifford Package because of the carb upgrade and the easy Lokar hook up for the 727 transmission kick down. The headers were just for as u say...eye appeal and some sound improvement. I plan on staying with 1 1/2" pipe and my X pipe will be side by side going thru the big bolt on frame support. Plan on the discharge in front of the rear wheels.
Ollie


Posted By: Rogue401
Date Posted: Jun/12/2015 at 12:37pm
I  tried dual exhaust with two turbo mufflers on my new 4 speed Pacer and it sounded terrible. Just annoying. I went to a 2-1/4 single system with as long of an OE style muffler that would fit and that sounded and ran better.

I've had 2 or 3 different cat back systems on our Cherokee and never liked any of them. Annoying in that big box on the highway. I finally went back to a stainless Walker QuiteFlow with mandrel bends and it sounds and runs great.

If you look under a MB or BMW straight six, there's a ton of engineering to get the tone and performance they do from the factory.  My 93 Benz 3.2 straight six has split manifolds, dual cats and pipes all the way and dual inlet/outlet center and rear muffler. If I was going to build a hot six, I would try something like that.

The best my dual 6 cyl. Pacer sounded was with small Pacesetter resonator tips added. That took some of the "raspberries" out of it. I think the biggest problem with the pacer was it had something like a 2:56 gear so it was always under load and sounded like a UPS truck. Maybe with another gear, the engine would have freed up and sounded more happy.


Posted By: tached_out
Date Posted: Jun/12/2015 at 2:18pm
This video pretty much sums up what I was saying. 

https://www.youtube.com/watch?v=Fiwx44X7UqE


Posted By: Rogue401
Date Posted: Jun/12/2015 at 2:22pm
That's nice! Classic six sound


Posted By: 232jav3sp
Date Posted: Jun/12/2015 at 5:32pm
Mean sounding Gremlin with true duals:

https://www.youtube.com/watch?v=NoKIowRiQQ4

Another built 258 in a CJ:

https://www.youtube.com/watch?v=JASRzty037w


Posted By: Rogue401
Date Posted: Jun/12/2015 at 5:54pm
Wow, I can't believe how nasty that Gremlin sounds! Lot better than my Pacer ever did.


Posted By: 232jav3sp
Date Posted: Jun/12/2015 at 6:48pm
Heck yeah it does! I expect that my 4.6L will sound similar. I know that my 232 won't because I choose Comp's 260H cam. Smooth idle.


Posted By: MarlinSteve
Date Posted: Jun/12/2015 at 7:31pm
Originally posted by 232jav3sp 232jav3sp wrote:

Mean sounding Gremlin with true duals:

https://www.youtube.com/watch?v=NoKIowRiQQ4

Another built 258 in a CJ:

https://www.youtube.com/watch?v=JASRzty037w


That gremlin was done by Nick Alfano and my son Jerry Orton.

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Posted By: Snotty
Date Posted: Jun/12/2015 at 8:09pm
Never done it but wanted to the one time I did own a straight six car. I heard a 225 /6 Mopar with the split header and was running small chamber Flowmasters. I thought it sounded sweet!

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Son's car: '73 Gremlin X, 401, T-10, Mopar 8.75 rear with 3.23 sure grip. My car: '70 Newport Convertible, 440 automatic


Posted By: FSJunkie
Date Posted: Jun/12/2015 at 10:57pm
Why.

Too much effort for not enough results and 3 cylinders per pipe sounds weird.

You need to be careful with inline six exhaust or they can sound like a rice burner, and nobody wants their 40 year-old car to sound like a Honda rice bomb.

Single pipe, 2" to 2.5" with a single chambered (Flowmaster) or turbo muffler. Most places hand you a turbo when you ask for a stock replacement, so that's an easy way to go. Glass packs or any kind of straight-through muffler (Magnaflow) will sound like a rice bomb on a six.

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1955 Packard
1966 Marlin
1972 Wagoneer
1973 Ambassador
1977 Hornet
1982 Concord D/L
1984 Eagle Limited


Posted By: Cooper12
Date Posted: Jun/13/2015 at 8:57am
I bet dual muffler pipes on a single exhaust would look pretty good

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JASON FLOYD


Posted By: amxdreamer
Date Posted: Jun/13/2015 at 1:55pm
A friend of mine had a Hornet he had just purchased with duals that he fired up for me at his house. It sounded angry and I asked him what V8 it had...it had an I6! The car went like a bat out of h e double hockey sticks!


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Tony
Vancouver, BC
1970 AMX
1972 Badassador
AMO#10333


Posted By: jsprengeler
Date Posted: Jun/13/2015 at 6:57pm
John,
     That's an awesome looking 6 you've built! What are you putting that into?

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Posted By: 70BBOAMX
Date Posted: Jun/13/2015 at 10:02pm
2.25 or 2.5 single with a  Walker dynomax and a megaphone tip.



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