Originally posted by Snorton Norton
Beautiful car there SK-SXT!
But I MUST ask something. I see that you have dual exhaust on there. Obviously something you changed/added. My question involves the fact the at least on my R/T, and I presume your SXT, that the factory exhaust is a TUNED exhaust. Aren't you really degrading performance by removing the tuned single exhaust and installing a dual exhaust?
As well, at least in the environment of building 2 cylinder motorcycle engines, changing the exhaust to a single tuned pipe has always proven to be the best way to increase horse power over any other pipe arrangement. Doesn't this hold true in our environment as well?
Negative on the degrading of performance!
The two cylinder exhaust into one pipe is simply the start of a header. This helps the vacuum created by the pressure pulse from one cylinder to help pull the pressure pulse from the other cylinder.
Any time that you can reduce exhaust back pressure on a multi cylinder 4-stroke engine, you will benefit! The sound levels may go up though.
The 2nd gen. 3.5L tuning increased the flow rate of the engine by about 23 – 28% through the intake, heads, exhaust manifold and exhaust. This accounted for most of the increase in HP from the 1st gen. engine.
Remember also that any products from the factory must also meet sound regulations and in this case where most of the buyer market is “older”, they wanted to have a silent exhaust. My research also found out that on some of the newer mufflers that Chrysler is specifying for use on these cars, are also using a material like fiberglass to wrap the internals of these mufflers for sound deadening. Some of the aftermarket muffler manufacturers have been doing this since the fifties. (ie Glass packs)
As for how the exhaust was “dualed”, I had a Dynomax 17739 installed in the place of the second muffler and then added two tail pipes with the longest 3” chrome tips that were available in the shop at that time. 4" chrome tips like the 300M Special were not available. I left the front muffler/resonator in place. The OEM muffler and resonator weight 25 lbs. The Dynomax and tail pipes weighted about 22 lbs.
This same idea has been in use since the Camaro first came out. The Dynomax muffler offered the most flow without the most noise in the passenger cabin (Of the mufflers that I had to choose from.).
For those a little more adventurous, you can leave the first muffler/resonator on and install a “Y” pipe at the rear axle area and then route the two tail pipes out the back.
Remember that you may need ear plugs for any highway trips after the “Gee I love that sound” idea wears off. I know! I have a very high flow exhaust on my Neon R/T (Header, no cat., 28” long glass pack, mandrel bent 2.5” exhaust pipe to a Rhino Ultra High Flow muffler made for the Neon’s.). I also used to run the headers open on my Camaro’s once in a while until my GF/wife informed me that I was cut off until I made the sound “decently livable”(The police were happier also).
Do a search in these forums for Dynomax and you will find some sound clips and pictures of how this was done by the others. Check out http://www.geocities.com/custom_LH/index.html
for some good ideas and pictures. I love the true duals!
PS. Has anyone else had the police called by the neighbors for have too loud of an exhaust while the car was in the garage with the doors closed? We were not even revving it up! (67 Camaro refitted with a open chambered head 427 cid RAT motor with a 1050 cfm Holley, etc. It ran with the front wheels about a foot off the ground on a hard launch)