Backpressure - Page 2 - Harley Davidson Forums: Harley Davidson Motorcycle Forum
Harley-DavidsonForums.com is an independent enthusiast website owned and operated by VerticalScope Inc. Harley-DavidsonForums.com is not sponsored by or in any way affiliated with Harley-Davidson Inc.. The Harley Davidson names and logos are trademarks owned by Harley-Davidson Inc.

Go Back   Harley Davidson Forums: Harley Davidson Motorcycle Forum > Technical > Exhaust Systems

» Insurance
» Our Partners
»ATV Reviews
»Motorcycle Games
Reply
 
LinkBack Thread Tools Display Modes
Old 11-03-2012, 10:42 AM   #11 (permalink)
Senior Member
 
huskerbob's Avatar
 
Join Date: May 2012
Location: Fayetteville, NC
Posts: 273
Quote:
Originally Posted by webco2 View Post
I want it all. I want lowend torque and topend HP. So..what do I do??? Punt???
own two bikes..........one of each
huskerbob is offline   Reply With Quote
Old 11-03-2012, 10:49 AM   #12 (permalink)
Luke 22:36
 
Kainam's Avatar
 
Join Date: Oct 2006
Location: Kansas City
Posts: 15,903
Images: 149
Garage
Supercharger
__________________
'05 Carbed Night Train
111 rwhp, 112 rwtq
Best 1/4 ET 12.557s
Best 1/4 MPH 108.59
Kainam is online now   Reply With Quote
Old 11-03-2012, 06:19 PM   #13 (permalink)
evohogfarts
 
ltrhdevo's Avatar
 
Join Date: Jan 2010
Location: USA
Posts: 1,512
Images: 42
I'd trade my exhaust for stock any day for the right back pressure the motor was made for. I'm think'n it will last longer, an't got the $$$ to do any thing about it.
__________________
knuckle buster

LiveToRideHarleyDavidsonEvo

ltrhdevo is offline   Reply With Quote
Old 11-04-2012, 06:47 AM   #14 (permalink)
Senior Member
 
Hunt/fish 365's Avatar
 
Join Date: Oct 2012
Location: Turbotville, PA
Posts: 602
Quote:
Originally Posted by Kainam View Post
How come horsepower actually went up when adding more restriction in my Thunderheaders?

I would have to hazard a guess that your exhaust is too open. Everything needs to be tuned to work together at the same RPM's. If say a 1.75" pipe was ideal, and a 2" was added it wouldn't work as well. If the engine was tuned to run in the 2500-4500 rpm range, and the pipes in the 3500-5500 rpm range performance will suffer. Some of the scavaging effect was lost at lower rpm's. Nothing was gained at the higher rpm's as the engine didn't breath well enough to take advantage of the bigger pipes.

Just adding one thing such as bigger carb, cam, exhaust or what ever usually doesn't help anything. It all needs to work together.
Hunt/fish 365 is offline   Reply With Quote
Old 11-04-2012, 07:17 AM   #15 (permalink)
Luke 22:36
 
Kainam's Avatar
 
Join Date: Oct 2006
Location: Kansas City
Posts: 15,903
Images: 149
Garage
You mean a Thunderheader doesn't have enough backpressure?
__________________
'05 Carbed Night Train
111 rwhp, 112 rwtq
Best 1/4 ET 12.557s
Best 1/4 MPH 108.59
Kainam is online now   Reply With Quote
Old 11-04-2012, 07:56 AM   #16 (permalink)
Seņor Member
 
Chief Illiniwek's Avatar
 
Join Date: Feb 2011
Location: Illinois
Posts: 14,492
Images: 55
Quote:
Originally Posted by Kainam View Post
You mean a Thunderheader doesn't have enough backpressure?
__________________
2011 Road King Classic, Python slip-ons, Stage 1 SE a/c, Power Commander V

Chief Illiniwek is offline   Reply With Quote
Old 11-04-2012, 08:32 AM   #17 (permalink)
evohogfarts
 
ltrhdevo's Avatar
 
Join Date: Jan 2010
Location: USA
Posts: 1,512
Images: 42
With just a ev27 cam, S&S shorty/with thunderjet carb tuner ,dyna signle fire and "Python" thunder headers, it takes for ever to warm up, and you cant dog the bike at all. 3&4 gear are a pain, its where its needs the the back pressure the most, and cold start ups.
If you run it like down the strip when riding it runs great. The best way to ride it is to keep the rpm's up. Python thunder headers are tuned exhaust and a good street/drag every day use. Still wish there was $$ to put stock exhaust back on , even trade so some one else can make noise & play with horse power
__________________
knuckle buster

LiveToRideHarleyDavidsonEvo

ltrhdevo is offline   Reply With Quote
Old 11-04-2012, 08:47 AM   #18 (permalink)
Luke 22:36
 
Kainam's Avatar
 
Join Date: Oct 2006
Location: Kansas City
Posts: 15,903
Images: 149
Garage
Pythons and Thunderheaders are 2 different exhausts.
__________________
'05 Carbed Night Train
111 rwhp, 112 rwtq
Best 1/4 ET 12.557s
Best 1/4 MPH 108.59
Kainam is online now   Reply With Quote
Old 11-04-2012, 08:50 AM   #19 (permalink)
evohogfarts
 
ltrhdevo's Avatar
 
Join Date: Jan 2010
Location: USA
Posts: 1,512
Images: 42
Quote:
Originally Posted by Kainam View Post
Pythons and Thunderheaders are 2 different exhausts.
help fill me in with that, They came with the bike and its been a learning thing for me
thanks, Kainam
__________________
knuckle buster

LiveToRideHarleyDavidsonEvo

ltrhdevo is offline   Reply With Quote
Old 11-04-2012, 08:54 AM   #20 (permalink)
Luke 22:36
 
Kainam's Avatar
 
Join Date: Oct 2006
Location: Kansas City
Posts: 15,903
Images: 149
Garage
You have Thunderheaders:




These are Python's 2-1




D&D FatCats, and V&H 2-1 look similar to the Python.
__________________
'05 Carbed Night Train
111 rwhp, 112 rwtq
Best 1/4 ET 12.557s
Best 1/4 MPH 108.59
Kainam is online now   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


Powered by vBadvanced CMPS v3.2.2

All times are GMT -5. The time now is 12:11 PM.



Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
This site is in no way affiliated with Harley-Davidson
Motorcycle News, Videos and Reviews
Honda Grom Forum Harley Davidson Forum Honda 600RR Kawasaki Forum Yamaha R6 Forum Yamaha FZ-09 Forum
1199 Panigale Forum Roadglide Forum Honda CBR1000 Forum Vulcan Forum Yamaha R1 Forum Yamaha R3 Forum
Ducati Monster Forum Harley Forums Honda CBR250R Forum ZX10R Forum Star Raider Forum Yamaha Viking Forum
Suzuki GSXR Forum V-Rod Forums Honda Shadow Forum Kawasaki Motorcycle Forum Star Warrior Forum KTM Duke 390 Forum
SV650 Forum BMW S1000RR Forum Honda Fury Forum Kawasaki Versys Forum Drag Racing Forum Ducati 899 Panigale Forum
Suzuki V-Strom BMW K1600 Triumph Forum Victory Forums Sportbikes BMW NineT Forum
Volusia Forum BMW F800 Forum Triumph 675 Forum MV Agusta Forum HD Street Forum Suzuki GW250 Forum
Yamaha Motorcycles Victory Gunner Forum Honda Vultus Forum HD LiveWire Forum Ninja H2 Forum Ducati Scrambler Forum