Club Cobra Gas-N Exhaust  

Go Back   Club Cobra > Manufacturers, Engine Builders, tools, and parts. > ERA---Speak with Bob Putnam

Welcome to Club Cobra!  The World's largest non biased Shelby Cobra related site!

  •  » Representation from nearly all Cobra/Daytona/GT40 manufacturers
  •  » Help from all over the world for your questions
  •  » Build logs for you and all members
  •  » Blogs
  •  » Image Gallery
  •  » Many thousands of members and nearly 1 million posts! 

YES! I want to register an account for free right now!  p.s.: For registered members this ad will NOT show

MMG Superformance
Nevada Classics
Main Menu
Module Jump:
Nevada Classics
Nevada Classics
MMG Superformance
MMG Superformance
Advertise at CC
Banner Ad Rates
MMG Superformance
MMG Superformance
MMG Superformance
Keith Craft Racing
August 2022
S M T W T F S
  1 2 3 4 5 6
7 8 9 10 11 12 13
14 15 16 17 18 19 20
21 22 23 24 25 26 27
28 29 30 31      
  #1 (permalink)  
Old 11-29-2006, 02:05 PM
289FIA's Avatar
Proud Club Cobra Member
Visit my Photo Gallery

 
Join Date: Mar 2001
Location: North of Baltimore, MD
Cobra Make, Engine: ERA 2121
Posts: 137
Not Ranked     
Default ERA FIA undercar exhaust vs Sidepipes

Hi Bob,

Found this informative link regarding how mufflers work:

http://www.howstuffworks.com/muffler.htm

Got me thinking about the “technology” differences between undercar exhaust and sidepipes. I’m looking for a quieter note on a rather tame 302 but lately have been reading various threads of how much power can be lost with different sidepipe setups. This leads me to believe the undercar exhaust restriction would vary even more.

So 3 questions:

1) What size are the primaries pipes on both setups?

2) On a 9.5:1 compression 325HP small block, what could be gained going with sidepipes vs undercar? (probably not realistic question, right?!)

3) Considering the limited space under the FIA, any recommendations on “better” performing mufflers that could out perform the stock setup? (Borla, FlowMaster, MagnaFlow, Dynomax, etc…)

Thanks,
289FIA
Reply With Quote
Sponsored Links
Sponsored Links
  #2 (permalink)  
Old 11-29-2006, 04:10 PM
imagine2frolic's Avatar
Senior Club Cobra Member
Visit my Photo Gallery

 
Join Date: Oct 2006
Location: Orange Park, FL.
Cobra Make, Engine: n/a
Posts: 1,596
Send a message via Yahoo to imagine2frolic
Not Ranked     
Default

All of the mufflers listed except for Flowmaster are basically a glass pack. Straight through with a bit of a curve. The tubing passing through the muffler is perforated, and then the rest of the body has a packing of some sort, or another. I myself am thinking of a 289 275 HP with an under car exhaust. I was hoping to find a cast iron manifold application, but that does not seem possible, but one never knows. I was going to experiment with 2, or 3 long glass packs welded together under the car. What ever length I could get to fit before a bend. The bigger, diameter, the system, the better it will breathe. You lose your low end unless you are side stepping the clutch with a big system. Not good for everyday driving. You need to ask yourself, what kind of driving you will be doing, and then it is easy to decide on a system. I have done exhaust for 30 years, and tried most everything on most of my cars. Flowmasters are very loud mufflers, and not really the best breathing muffler there is.
Reply With Quote
  #3 (permalink)  
Old 11-30-2006, 04:43 AM
CC Member
Visit my Photo Gallery

 
Join Date: Nov 2003
Location: New Britain, CT
Cobra Make, Engine: Size 10 Feet
Posts: 2,913
Not Ranked     
Default

The primary pipes on both setups are 1 5/8", feeding into a 3" collector.

On the undercar exhaust, the collector tapers to 2 1/4" pipe for the muffler.

The side pipe has an internal glasspack. I'm not sure about the ID - either 2" or 2 1/4"

I don't know the amount of power lost through the muffler. The amount of power lost probably depends a lot on the amount of valve overlap and the carburetor. For a 300 bhp 302, maybe 20 bhp, but that's strictly a guess.

P.S. Interestingly enough, we usually use a Dynomax muffler, the internals of which are a perforated pipe going directly from in to out, which sounds a lot like a bullet muffler.
Reply With Quote
  #4 (permalink)  
Old 12-20-2006, 10:34 AM
chuckbrandt's Avatar
Club Cobra Member
Visit my Photo Gallery

 
Join Date: Jul 2001
Location: Kansas City, KS
Cobra Make, Engine: ERA # 665, 390 (to start with) Toploader
Posts: 652
Not Ranked     
Default

I'm going to try these one of these days. A pair is supposed to support 400 HP, whereas the original dynomax are only supposed to support 200 HP.

http://www.flowmastermufflers.com/pr...8b4fd29079d23d

Chuck
__________________
Build website at www.chuckbrandt.com
Reply With Quote
  #5 (permalink)  
Old 12-20-2006, 11:07 AM
imagine2frolic's Avatar
Senior Club Cobra Member
Visit my Photo Gallery

 
Join Date: Oct 2006
Location: Orange Park, FL.
Cobra Make, Engine: n/a
Posts: 1,596
Send a message via Yahoo to imagine2frolic
Not Ranked     
Default

I looked at the Flowmaster, and it looks to me like a piched down glasspack with blockage on the exit. I think for less money you can get a lot more. The most important thing is what do you want to hear, and how will you drive? Then you can make a decision. Exhaust is always give, and take. In 30 years I have not seen a muffler that gives you everything. There are several variables. When a customer comes into my shop. The first thing I ask is..."what do you want to hear, and what do you want to see." From there I can figure out something to make them happy....
Reply With Quote
  #6 (permalink)  
Old 12-20-2006, 11:36 AM
chuckbrandt's Avatar
Club Cobra Member
Visit my Photo Gallery

 
Join Date: Jul 2001
Location: Kansas City, KS
Cobra Make, Engine: ERA # 665, 390 (to start with) Toploader
Posts: 652
Not Ranked     
Default

imagine2frolic - you are probably right. On my car and I assume the FIA as well, this muffler fit the narrow confines pretty well. Jake Roulstone did a nice undercar exhaust using 2 glass packs on each side. There are of course new muffler shapes coming out all the time, I should do some more research I'm sure.

Chuck
__________________
Build website at www.chuckbrandt.com
Reply With Quote
  #7 (permalink)  
Old 12-20-2006, 12:02 PM
imagine2frolic's Avatar
Senior Club Cobra Member
Visit my Photo Gallery

 
Join Date: Oct 2006
Location: Orange Park, FL.
Cobra Make, Engine: n/a
Posts: 1,596
Send a message via Yahoo to imagine2frolic
Not Ranked     
Default

Chuck, since this post I went out into the shop, and removed my stock muffler from my Caravan. Replacing it with a offset center Magnaflow muffler only 18 " long. The sound of the exhaust is almost NIL compared to before, and this is with a straight through muffler replacing a factory triple baffled muffler. Soon I will know the difference in the gas milage.

289, let me know what you want to see, and hear, and I can have a few ideas for you.....
Reply With Quote
  #8 (permalink)  
Old 10-17-2017, 09:30 PM
CC Member
Visit my Photo Gallery

 
Join Date: Oct 2015
Cobra Make, Engine:
Posts: 21
Not Ranked     
Default

I've been seeing a lot of comparisons between Flowmaster and Magnaflow. Which one's a bang for the buck?
Reply With Quote
  #9 (permalink)  
Old 10-18-2017, 07:54 AM
PeteF's Avatar
CC Member
Visit my Photo Gallery

 
Join Date: Apr 2008
Location: Glastonbury, Ct
Cobra Make, Engine: ERA2041
Posts: 237
Not Ranked     
Default

I have ERA's undercar exhaust, and have been thinking of adding resonators at the tail end to quiet it down a little. Chambered Classics makes 12 inch resonators that might just fit. Anyone tried this or have comments ? Thanks
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 02:27 PM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: CC Policy
Links monetized by VigLink