Dual Exhaust?

RL Chilton

The convertible is currently in the shop getting dual exhaust.  I am utilizing the 7X Splitter to go from manifold to exhaust pipes.  A few questions and y'all's thoughts are appreciated:

1.  Do I need to utilize a crossover?

2.  2" pipes all the way back?

3.  Pros and Cons on Flowmaster mufflers?

4.  Anything else I need to know?

Thoughts on the above received today would be most appreciated. 

BillUSN1

Most of this will be personal opinions so here's mine.
1. yes/no you don't need it but I like to run one to balance the sides and reduce the drone affect in the passenger compartment. H pipe/balance tube/X pipe.....
2. The son and I just talked about this last night. I planned on 2 or 2 1/4 all the way. 2" should be fine with 2 1/4 a little over kill.
3. I like my 50 series but feel the 40 series are just too annoying for a driver. May be fine for a cruise night vehicle. We also discussed just going straight pipe all the way out the back. Those old videos of the Hornets revving the engine really sound good. But for a distance driver would probably get old.
4. I like to use the new stainless braided flex connections like used on the transverse engines. they allow the motor mounts to flex and not work the header pipe connection loose. they are pretty popular now.
Make sure the exhaust is mounted with rubber hangers to limit vibration.

RL Chilton

Thanks, Bill.  Appreciate you taking the time to comment. 

GrimGreaser

If the motor is pretty mild, you may be able to get by with 1 3/4 pipes, to ease installation. If its pretty stock, probably 1 5/8 pipes. I think 1 5/8 pipes will handle about 180 HP or so. YMMV, as I'm no expert, but from the exhaust stuff I've read.

lostmind

I had straight pipes with no mufflers on a 53 hornet , 1 3/4" . I didn't have a problem with  drone, but that was 25 years ago. The wife and son thought it was cool.

The flex pipes are great idea.

Lee ODell

Hi RL

Reducing exhaust back pressure is good. Reducing velocity is not good. Velocity is important for efficiency.

1. When I added a crossover on my 69 AMX and X crossover on my 64 El Camino there was a reduction of exhaust noise. Also, there was a noticeable loss of off idle performance. Loss of velocity from increase of exhaust tubing volume.

2. Exhaust out the back will be more pleasant on the ears on a long cruise. Before adding the crossover on the AMX I increased the tube from original 2 1/4" to 2 1/2". Result: noticeable power loss at take off incre

Lee ODell

I don't know why part of my message is missing from my post.

I agree with GrimGreaser that smaller pipes might be more efficient for low RPM performane as well as easier installation.

After reading an article by a header builder that was making much more power from longer 1 1/2" headers than his competitors 1/3/4" and 1/7/8" headers on the same engine. From my experience with loss low end power on my AMX by increasing the pipe size bigger may not be better and smaller may be better.

3. My experience with Flowmaster mufflers is they are loud and annoying on a long cruise.

Glad to see your project is nearing completion.

Lee O'Dell

Browniepetersen

When I started up my 1954 it has the "glass packs" that were out in the 60's. It also has an exhaust cut out so that they could open it for drag racing. I am starting to think that this is the best of both worlds. I have opened the cutout and it is too much for driving around. It really sounds good when you are at a rod run and open it and let the car idle. I would like to reproduce the glass pack sound but I doubt that flowmasters will do it....

J Spencer

My 51 Pacemaker with Clifford headers and duals side by side I have 30 inch "Smitty"' muuflers from 

Summit.  When I first got the car it had 24" glasspacks, too loud, put 30" glasspack with resonator tips.  Much better but for my ears still a bit much. Now with the "Smitty's" on it I like lt and my friends tell me it sounds good going down the road.    Personal taste for every one I guess.     My car the mufflers are side by side in the back, guess you can't do that with  the 52-54's with the spare tire in the well.

BillUSN1

Here's a few links that may help or hurt?
The problem is most articles relate to max HP and torque(SBC) and not a driver.

http://www.exhaustvideos.com/faq/how-to-calculate-muffler-size-pipe-diameter/

http://www.magnaflow.com/07techtips/faq/question10.asp

http://www.popularhotrodding.com/enginemasters/articles/hardcore/0505em_exh/

https://www.youtube.com/watch?v=Y0Va3sDhqwI

Ol racer

F.Y.I.

I installed Duals on my '37's with 2" galvanized pipes on both cars exiting ahead of the rear wheels on 'each side'. One car has a modified Hornet with Headers and inexpensive oval mufflers from Auto Value Stores and has a nice tone at Hwy Speeds..

The other car has a 'Stock Hornet Mtr' with a 7X Outlet and two round inexpensive 'Glass Packs' from Auto Value that is so quiet that Ive'd startled people walking at Cruise In's.Neither car has a cross over pipe. I tried straight pipes on the stock Mtr car first, but the sound (in the garage) was 'tinny' so I cut the pipes & installed the Glass Packs to enhance the sound, but suprisingly, its still very quiet....

RL Chilton

Ol Racer-

My exhaust man is having trouble fitting 2" pipes to the 7X outlet.  Do you know if 2" will work or do we have to use a smaller pipe on the splitter?

HUDSONBROTHER1

My 1946 super six 2 door sedan has a warmed over 262 with a 7x style block relief,twin h and an early set of long tube Clifford headers with 2" pipes running thru glass packs and megaphone tips on the ends.Hudson six's with duals sound awesome !Nice in the car on long trips with the glass packs and tailpipes.

Chris Smith

Thinking about going with two of these chambered mufflers for my dual siamesed system and long tube Clifford headers. No glass to burn out and a straight through design. They offer a 26" length with 2" ends and 3" outside diameter.  

 

Kdancy

Chris, I'd like to hear the sound of those chambered muffles. Who makes them?
 This company?
http://www.classicchambered.com/classic/products.html

Chris Smith

Thats them, I am going to order a pair Tuesday. Should sound wicked good I hope

PAULARGETYPE

CHRIS I WOULD BE CONSERNED ABOUT HOT HAVING ROOM TO GET ROOM FOR 2 3'' ROUND MUFFLERS UNDER THE CAR BEFORE THE REAR END I KNOW I HAD A HARD TIME RUNNING 2'' PIPES FROM FRONT TO REAR ON MY CAR GOOD LUCK