How much back pressure is "enough?"

faxxxy · 03-12-2009, 10:11 AM

Can you de-baffle and gut the goats belly and still have enough back pressure? Or is that going too far?

radco · 03-12-2009, 10:27 AM

Good ?,, I have a set that has only the silencer removed,, I left the baffle plates in, so I can have some back Pressure,,, I also have a Gutted BG. that I will try this year... Cannt wait to see what the Gear heads have to say.......Rich

faxxxy · 03-12-2009, 10:30 AM

I'm sure that most are going to say that you cannot do any of this by itsself..

If you reduce the back pressure, you must re-jet, and if you rejet, you must do a high flow intake.

That's my prediction, but I'm new at this, and I know I don't have to make every mistake myself, so i am excited to see what others have already tried.

blowndodge · 03-12-2009, 01:18 PM

The correct amount of backpressure is like a box of chocolates................ya never know what your going to get until you try it. ;)

radco · 03-12-2009, 01:46 PM

BUTT what is a sign of not enought Back Pressure ???? Too Much back pressure???? Thanks Rich

03-12-2009, 03:10 PM

Back Pressure is good. The more the better. Really folks, V-Twins thrive on back pressure and go flat without it.

**ringadingh** · 03-12-2009, 04:20 PM

They will run stronger with some back presure at the low end, however at top end too much pressure is restrictive. I run V&H pipes which are less restrictive over stock pipes and find that they do flow better.

oldbikers · 03-12-2009, 04:40 PM

I have the Vance & Hines with no goat belly and half of the baffle removed and it runs fine but if I remove all of the baffle it stumbles at lower speeds.

phenrichs · 03-12-2009, 04:46 PM

You will find that most drag bikes have a 2 into 1 exhaust primarily for the purpose of tuning back pressure. It can be a delicate balance on a carbed machine. FI machines are a bit easier thanks to computer controlled FI tuners.

Generally the concesus is if you do only the exhaust or intake you are ok. If you do both you will have to tweek the fuel system.

barrynfla · 03-16-2009, 02:04 PM

faxxxy, if you do the debaffle and gutting and feel that you're losing low-end power, you could try putting power cones, aka torque cones, aka anti-reversion cones in the pipes at the exhaust manifold. This will increase the back pressure and probably help. They're pretty cheap, too.

03-12-2009, 10:11 AM	#1
faxxxy Member Join Date: Mar 2009 Location: Bentonville, Home of Wal-Mart Posts: 142	How much back pressure is "enough?" Can you de-baffle and gut the goats belly and still have enough back pressure? Or is that going too far? Login or Register to Remove Ads
	0

03-12-2009, 10:27 AM	#2
radco Sr. Member Join Date: Oct 2007 Location: Dedham Maine Posts: 4,199	How much back pressure is "enough?" Good ?,, I have a set that has only the silencer removed,, I left the baffle plates in, so I can have some back Pressure,,, I also have a Gutted BG. that I will try this year... Cannt wait to see what the Gear heads have to say.......Rich __________________
	0

03-12-2009, 10:30 AM	#3
faxxxy Member Join Date: Mar 2009 Location: Bentonville, Home of Wal-Mart Posts: 142	How much back pressure is "enough?" I'm sure that most are going to say that you cannot do any of this by itsself.. If you reduce the back pressure, you must re-jet, and if you rejet, you must do a high flow intake. That's my prediction, but I'm new at this, and I know I don't have to make every mistake myself, so i am excited to see what others have already tried.
	0

03-12-2009, 01:18 PM	#4
blowndodge Sr. Contributor Join Date: Jul 2007 Location: Washington City, Utah Posts: 16,474	How much back pressure is "enough?" The correct amount of backpressure is like a box of chocolates................ya never know what your going to get until you try it. ;) __________________ I love my Victory Cross Country Tour 106. Smells like Victory! Ultra's are Limited There are two types of Harley riders. Those that trailer them and those that push them. The most Interesting Man in the World "Find the things in life you don't do well and don't do those things" Member # 0005
	0

03-12-2009, 01:46 PM	#5
radco Sr. Member Join Date: Oct 2007 Location: Dedham Maine Posts: 4,199	How much back pressure is "enough?" BUTT what is a sign of not enought Back Pressure ???? Too Much back pressure???? Thanks Rich __________________ Login or Register to Remove Ads
	0

03-12-2009, 03:10 PM	#6
Guest Posts: n/a	How much back pressure is "enough?" Back Pressure is good. The more the better. Really folks, V-Twins thrive on back pressure and go flat without it.
	0

03-12-2009, 04:20 PM	#7
ringadingh Join Date: Aug 2007 Location: Newmarket Ontario Canada Posts: 35,387	How much back pressure is "enough?" They will run stronger with some back presure at the low end, however at top end too much pressure is restrictive. I run V&H pipes which are less restrictive over stock pipes and find that they do flow better. __________________ 2002 Nomad aka Bountyhunter VBA #27 VROC #18951
	0

03-12-2009, 04:40 PM	#8
oldbikers Sr. Member Join Date: Apr 2008 Location: Sardis Mississippi Posts: 3,513	How much back pressure is "enough?" I have the Vance & Hines with no goat belly and half of the baffle removed and it runs fine but if I remove all of the baffle it stumbles at lower speeds. __________________ Jim Hardin Sardis MS Kawanow # 453 Proud PGR member
	0

03-12-2009, 04:46 PM	#9
phenrichs Sr. Member Join Date: Jun 2008 Location: Sioux Falls, SD Posts: 2,498	How much back pressure is "enough?" You will find that most drag bikes have a 2 into 1 exhaust primarily for the purpose of tuning back pressure. It can be a delicate balance on a carbed machine. FI machines are a bit easier thanks to computer controlled FI tuners. Generally the concesus is if you do only the exhaust or intake you are ok. If you do both you will have to tweek the fuel system.
	0

03-16-2009, 02:04 PM	#10
barrynfla Member Join Date: Feb 2009 Location: Tampa, FL Posts: 179	How much back pressure is "enough?" faxxxy, if you do the debaffle and gutting and feel that you're losing low-end power, you could try putting power cones, aka torque cones, aka anti-reversion cones in the pipes at the exhaust manifold. This will increase the back pressure and probably help. They're pretty cheap, too.
	0

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
seat "SOLD" and stock exhaust "SOLD"	papat	Parts & Accessories	2	11-11-2010 12:09 AM
Moved: How much back pressure is "enough?"	faxxxy	Vulcan Nomad/Vaquero/Voyager	0	03-12-2009 01:01 PM
When does "empty" mean "zip-nada-zilch"?	bobhamlin	Vulcan Nomad/Vaquero/Voyager	28	01-15-2009 03:18 PM
From back in the "Day"	Yellow Jacket	Off-Topic	2	12-10-2008 06:54 PM
Services for Charles "Chuck" "txcwdancer" Burt	msharrelson	In Memoriam	13	07-24-2008 09:24 PM