Haynes Forums  

Go Back   Haynes Forums > Haynes Roadster Forums > Engine/transmission
FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
  #1  
Old 19th February 2010, 02:11 PM
DaddyA's Avatar
DaddyA DaddyA is offline
Senior Member
 
Join Date: Jan 2009
Location: Saltash, Cornwall
Posts: 263
Default Exhaust???

Hi,

while we are all waiting for a certain somebodies test results, just thought I'd throw a question out there.

Does the exhaust have to be made from round tube???

I was thinking (probably shouldn't), to keep the side of the roadster clean looking and with a close proximity to the ground - could you not make the exhaust (main system) from rectangular tube?

Obviously the silencer would be an issue, but rear engine cars seem to manage. Repositioning of the fuel tank might have to done to get the silencer where the fuel tank would normally be.

Twin exhausts out the back - whats your thoughts??
__________________
Cheers

Daz...

http://s641.photobucket.com/albums/uu133/tashlotty/
Reply With Quote
  #2  
Old 19th February 2010, 02:26 PM
gingea1pom's Avatar
gingea1pom gingea1pom is offline
Senior Member
 
Join Date: Sep 2009
Location: wiltshire
Posts: 826
Default

I have often thought about having the exhaust exiting out the rear but there just isn’t enough room.

But now you mention rectangular tube under the car.

My initial thought, without thinking to hard about it (trying to play the wii) have a 30mm by 300mm box section.

But like you say a silencer could be problematic.

I might need to sleep on it. I have my best ideas when I am a sleep.

Cheers Ginge
__________________
Sent from my iPad, from who knows where in the world

I was building but I am not now!


Build Pictures


Build Thread
Reply With Quote
  #3  
Old 19th February 2010, 02:31 PM
spud69's Avatar
spud69 spud69 is offline
Senior Member
 
Join Date: Jul 2008
Location: Hartlepool
Posts: 1,678
Default

Quote:
Originally Posted by gingea1pom View Post

I might need to sleep on it. I have my best ideas when I am a sleep.

Cheers Ginge
Sorry Ginge, but we don't want to know about your thoughts when you're asleep......
__________________
Haynes Roadster / Saturn GRP Bodywork. Now available direct through http://www.gillhamonline.co.uk/ or contact me direct on andrew.hugill@ntlworld.com

Regards..........AndyH
Reply With Quote
  #4  
Old 19th February 2010, 02:56 PM
davidimurray's Avatar
davidimurray davidimurray is offline
Senior Member
 
Join Date: Jan 2009
Location: Near Cardiff
Posts: 742
Default

No reason why you couldn't ..... but firstly I expect the flow characterstics would not be that good. It could also be quite difficult to manufacture, bends etc. If your looking to save space, then the critical parameter will be the cross sectional area. As the flowrate of the gas will be the same up both exhausts, the cross sectional area will dictate the gas velocity which is the key performance parameter. If you take a 35mm diameter pipe has a CSA of 962mm2, then you need a 31mmx31mm square to match that CSA.
Reply With Quote
  #5  
Old 19th February 2010, 03:04 PM
HandyAndy's Avatar
HandyAndy HandyAndy is offline
Senior Member
 
Join Date: Jan 2009
Location: cleveland
Posts: 3,917
Default

I do like the idea of twin pipes at the rear but with the car only 5 inches from the bottom chassis rail to the tarmac i,m not sure how it could be done,

sleeping policemen would be a pain to get over i imagine.

cheers
andy
__________________
Flat Pack Chassis Kits for sale, contact me at andyroadster@yahoo.co.uk
Reply With Quote
  #6  
Old 19th February 2010, 03:08 PM
gingea1pom's Avatar
gingea1pom gingea1pom is offline
Senior Member
 
Join Date: Sep 2009
Location: wiltshire
Posts: 826
Default

Excellent,

Working on that theory if my exhaust is 1mm x 962mm, I maintain the correct CSA, Hardly any decreas in ground clearance.

Does anyone know where I can get some 1mm x 962mm box section and a silencer to mach.

Cheers Ginge
__________________
Sent from my iPad, from who knows where in the world

I was building but I am not now!


Build Pictures


Build Thread
Reply With Quote
  #7  
Old 19th February 2010, 03:26 PM
twinturbo's Avatar
twinturbo twinturbo is offline
Super Moderator
 
Join Date: Jul 2008
Location: Carlisle
Posts: 4,389
Default

I had the same thought of twin rectangular section.. As I have a V6..

TT
__________________
You only get a woosh with a dump valve

Build Thread


Man Cave Mantiques



Cecil Street Auto Repairs Garage Carlisle




Build Cost £4181.65 - Last - Wheel Cylinders
Reply With Quote
  #8  
Old 19th February 2010, 04:27 PM
alga's Avatar
alga alga is offline
Senior Member
 
Join Date: Feb 2009
Location: Vilnius, Lithuania
Posts: 1,249
Default

Quote:
Originally Posted by gingea1pom View Post
Working on that theory if my exhaust is 1mm x 962mm, I maintain the correct CSA, Hardly any decreas in ground clearance.
I'm guessing the 17.5x increase in exhaust system surface area will have some effect on gas flow.
__________________
Albert
Haynes Roadster FAQ | Haynes Builder Locations
Gallery, build thread in Lithuanian / via Google Translate.
Reply With Quote
  #9  
Old 19th February 2010, 04:35 PM
gingea1pom's Avatar
gingea1pom gingea1pom is offline
Senior Member
 
Join Date: Sep 2009
Location: wiltshire
Posts: 826
Default

On a plus side would the increase in surface are not reduce temperature?
__________________
Sent from my iPad, from who knows where in the world

I was building but I am not now!


Build Pictures


Build Thread
Reply With Quote
  #10  
Old 19th February 2010, 04:58 PM
twinturbo's Avatar
twinturbo twinturbo is offline
Super Moderator
 
Join Date: Jul 2008
Location: Carlisle
Posts: 4,389
Default

How big a silencer is needed on a normal 2.0 4 pot car?

I will need 2 smaller ones, one on either side.

TT
__________________
You only get a woosh with a dump valve

Build Thread


Man Cave Mantiques



Cecil Street Auto Repairs Garage Carlisle




Build Cost £4181.65 - Last - Wheel Cylinders
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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 04:57 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.