Go Back   EcoModder Forum > EcoModding > EcoModding Central
Register Now
 Register Now

Reply  Post New Thread
Submit Tools LinkBack Thread Tools
Old 04-27-2010, 02:51 AM   #1 (permalink)
EcoModding Lurker
Join Date: Apr 2010
Location: Dorset UK
Posts: 16
Thanks: 0
Thanked 1 Time in 1 Post
exhaust system mods, straight through?

Can I call on the collective wisdom for help. What difference does it make to throw away the makers exhaust system and fit a larger bore burgess type straight thru silencer. the initial pipe dia out of the turbo is 2,3/4in then it finally comes down to 1,3/4 at the tail pipe.
This would be into to my 97 , mazda RF turbo diesel intercooled vitara?
Theres no point in doing this if the difference is likely to be minmal.

Last edited by tasdrouille; 04-27-2010 at 07:30 AM..
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

Old 04-27-2010, 04:22 AM   #2 (permalink)
Join Date: Feb 2008
Location: maine
Posts: 758

oldscoob - '87 subaru wagon gl/dr
90 day: 47.06 mpg (US)
Thanks: 21
Thanked 18 Times in 14 Posts
not much point in it. diesels will send exhaust whistling before they never lose to it. most if not all exhaust mods benefit gasoline.

The only diesels I have seen benefit from opening are tractor trailers.. (4 foot long catalyst insanity).. if that is a problem on your little car, find a bigger honeycomb, and keep oem the rest.
  Reply With Quote
Old 04-27-2010, 03:14 PM   #3 (permalink)
Basjoos Wannabe
ShadeTreeMech's Avatar
Join Date: Apr 2009
Location: Arkansas
Posts: 870

The Van - '97 Mercury Villager gs
90 day: 19.8 mpg (US)

Lyle the Kindly Viking - '99 Volvo V70
90 day: 25.82 mpg (US)
Thanks: 174
Thanked 49 Times in 32 Posts
My experience has been that the OEm exhaust system tends to be overly restrictive. It takes a ceratin amount of power to push the exhaust through the system opening things up a bit can help, assuming you don't mash the pedal too much.

Assuming you have a bit of creativity you might try a bit of creating an active exhaust system which would open things up a bit whenever the accelerator is pressed. It's an idea I initially learned about watching Top Gear, go figure. But it would give you the OEM quietness, but then by using a butterfly valve you would allow the excess pressure to escape a secondary exhaust system.

If you don't mind pissing off the neighbours you may want to remove the offending part to see if there is much difference. I suspect it would allow your turbo a bit of a quicker spool up which would obviously be helpful. if it were me, considering how it becomes more restrictive downstream I'd lop it off in a heartbeat. Invest in a high quality silencer with a larger diameter and you should be good to go.

And glad to hear from someone from the big island. Hope you enjoy yourself here.
RIP Maxima 1997-2012

Originally Posted by jamesqf View Post
I think you missed the point I was trying to make, which is that it's not rational to do either speed or fuel economy mods for economic reasons. You do it as a form of recreation, for the fun and for the challenge.
  Reply With Quote
Old 04-28-2010, 11:50 AM   #4 (permalink)
Aero Wannabe
COcyclist's Avatar
Join Date: Dec 2007
Location: NW Colo
Posts: 738

TDi - '04 VW Golf
90 day: 53.2 mpg (US)
Thanks: 705
Thanked 218 Times in 169 Posts
I don't know about your particular Mazda diesel but I cut off the muffler on my VW diesel and replaced it with a straight pipe, with no real increase in noise. The cat-converter and the turbo quiets the exhaust noise nicely. It may make the turbo more efficient but I didn't see any significant gains in mpg or power. I think the upgraded exhaust may be more of an issue if you are boosting the power on your diesel than it is for high mpg at light engine loads. I deleted the muffler primarily to make more room for a belly pan install.
60 mpg hwy highest, 50+mpg lifetime
TDi=fast frugal fun

Originally Posted by freebeard View Post
The power needed to push an object through a fluid increases as the cube of the velocity. Mechanical friction increases as the square, so increasing speed requires progressively more power.
  Reply With Quote
Old 04-28-2010, 11:59 AM   #5 (permalink)
Master EcoModder
Phantom's Avatar
Join Date: Jan 2010
Location: Independence, KY
Posts: 603

Blue Meanie - '02 Volkswagon Golf TDI
90 day: 48.52 mpg (US)

Wife's car - '05 WV Passat TDI

Rudy - '94 Chevy C2500
Thanks: 89
Thanked 47 Times in 44 Posts
If you are not going to go for just for performance I would only open the system at the point it gets smaller than 2,3/4in.
I move at the speed of awesome.

"It's not rocket surgery!" -MetroMPG
  Reply With Quote
Old 04-29-2010, 11:11 PM   #6 (permalink)
Join Date: Oct 2009
Location: Oklahoma City, OK
Posts: 528

ECONORAM - '07 Dodge RAM 1500 QC SLT flex-fuel
90 day: 18.16 mpg (US)

the Avenger - '08 Dodge Avenger SXT
90 day: 27.06 mpg (US)
Thanks: 385
Thanked 94 Times in 80 Posts
Send a message via Yahoo to ECONORAM
A tuned exhaust will help any ICE. I drove diesel VW Rabbits for years, and was likely the first to install a Techtonics Tuning exhaust system on it. It definitely helped in the performance arena, and it was no louder than stock.
Turbo engines can often get by without a muffler, as the turbo tends to muffle the exhaust note. This is a good comparison, but not all flavors are included. V6Z24 | How-To - Choosing a muffler I had personally wished they had tried Flowmaster's racing delta 40s, but oh well.
  Reply With Quote
Old 05-03-2010, 09:33 PM   #7 (permalink)
Master Novice
elhigh's Avatar
Join Date: Jan 2008
Location: SE USA - East Tennessee
Posts: 2,314

Josie - '87 Toyota Pickup
90 day: 40.02 mpg (US)

Felicia - '09 Toyota Prius Base
90 day: 49.62 mpg (US)
Thanks: 427
Thanked 616 Times in 450 Posts
There's a company here in the States that will install a remote turbo where the muffler used to go, says the turbo does a fine job of muffling the noise. I'd say a muffler on a turbocharged engine is just there because they're in the habit of installing mufflers on cars. Just 'cause they always used to do it, they're always going to do it.

Lead or follow. Either is fine.
  Reply With Quote
Old 05-06-2010, 07:32 PM   #8 (permalink)
Master EcoModder
Join Date: Feb 2010
Location: Elmira, NY
Posts: 1,782
Thanks: 319
Thanked 356 Times in 297 Posts
The whole idea is to get exhaust gas out of the cylinder efficiently and getting the acceptable range of performance. Gases cool as they leave the engine and converter so a progressively smaller diameter pipe can be used. Minimizing the bends allows optimum flow. The deal with sound control is to prevent pressure wave resonance with the unibody.
  Reply With Quote
Old 05-06-2010, 11:31 PM   #9 (permalink)
Master EcoModder
Join Date: Apr 2010
Location: belgium, wi
Posts: 262

Bus - '94 Ford School Bus huge

Stupid - '01 Chevy Blazer LS
90 day: 21.38 mpg (US)

hawk - '00 Honda Superhawk
Thanks: 2
Thanked 24 Times in 19 Posts
Get rid of restrictions. Duramax saw 1-3mpg improvement and power gain with .5inch increase in diameter and straight through design. The benefit on a turbo motor, diesel or gas, is that the pressure past the turbo is lower than stock. This larger difference between the two sides of the turbine cause a greater speed of rotation, which equals more boost, more power, and greater efficiency (look up boost pressure and compression efficiency graphs). I would suggest it.
  Reply With Quote
Old 05-07-2010, 09:18 AM   #10 (permalink)
Porno Music Producer
zhillz's Avatar
Join Date: May 2010
Location: Tampa
Posts: 47

lolwut - '98 Honda Civic EX
90 day: 47.5 mpg (US)
Thanks: 0
Thanked 0 Times in 0 Posts
On NA engines you need back pressure and the oem exhaust aren't usually too bad for an ecomodder. Since your car is turbo, you need all the breathing you can get. On my performance oriented turbo Acura Integra, i ran 3" exhaust straight back and saw a huge improvement when I got it retuned.

  Reply With Quote
Reply  Post New Thread

Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
New CVT transmission electric-assist with electric assist Ptero Fossil Fuel Free 2 09-23-2010 10:41 PM
exhaust system: resonator bgd73 General Efficiency Discussion 3 08-05-2009 09:46 AM
Exhaust system question saunders1313 Hypermiling / EcoDriver's Ed 23 03-01-2009 02:19 AM
2006 in review: mods vs. technique. And the winner is... MetroMPG Hypermiling / EcoDriver's Ed 16 12-10-2007 07:46 AM

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com