The Subaru SVX World Network   SVX Network Forums
Live Chat!
SVX or Subaru Links
Old Lockers
Photo Post
How-To Documents
Message Archive
SVX Shop Search
IRC users:

Go Back   The Subaru SVX World Network > SVX Main Forums > Technical Q & A

Reply
 
Thread Tools Display Modes
  #121  
Old 10-13-2007, 07:00 PM
benebob's Avatar
benebob benebob is offline
Have a poncho I can borrow?
 
Join Date: May 2001
Location: Lancaster, PA
Posts: 6,561
Quote:
Originally Posted by SVXRide View Post
because someone actually did the calculations and they're trying to spread the hp/tq across a specific rpm band versus a single peak with equal length?
-Bill

Gotcha, and why does the most powerful beast per pound (the space shuttle) get by with no headers?
Reply With Quote
  #122  
Old 10-14-2007, 12:46 AM
jeffast jeffast is offline
I kill more trannies then god
 
Join Date: Apr 2006
Location: wyotech
Posts: 1,209
Quote:
Originally Posted by benebob View Post
Gotcha, and why does the most powerful beast per pound (the space shuttle) get by with no headers?
god i wish i had the power to kill people over the net,
you were wrong ben, dear god, just be a man and admit it.
__________________
1991 xt6 eg33?
1993 gc track car
Reply With Quote
  #123  
Old 10-14-2007, 08:47 AM
TomsSVX's Avatar
TomsSVX TomsSVX is offline
Maniac modifier
 
Join Date: Dec 2003
Location: Branchburg, New Jersey
Posts: 15,489
Registered SVX Classic SVX
Quote:
Originally Posted by benebob View Post
Then why would the most powerfully tuned per liter engines (motorcycles) have disproportiontely long mostly unequal headers.
Because they are air cooled. The length of the header has a thermal effect on the cylinder. the rear being the warmer needs to have a different length to cool as it has a lack of air flow unlike the front cylinder.

Tom
Reply With Quote
  #124  
Old 10-14-2007, 11:08 AM
benebob's Avatar
benebob benebob is offline
Have a poncho I can borrow?
 
Join Date: May 2001
Location: Lancaster, PA
Posts: 6,561
Quote:
Originally Posted by TomsSVX View Post
Because they are air cooled. The length of the header has a thermal effect on the cylinder. the rear being the warmer needs to have a different length to cool as it has a lack of air flow unlike the front cylinder.

Tom

10 years ago I'd agree with that but not that many are aircooled anymore even Harley farmed out engine design and manufacturing for Buell to Europe so as to get water cooled tech assistance. Of course V twins will naturally have this issue but inlines and do not but yet they tend to be unequal and long as possible.
Reply With Quote
  #125  
Old 10-14-2007, 11:13 AM
benebob's Avatar
benebob benebob is offline
Have a poncho I can borrow?
 
Join Date: May 2001
Location: Lancaster, PA
Posts: 6,561
Quote:
Originally Posted by jeffast View Post
god i wish i had the power to kill people over the net,
you were wrong ben, dear god, just be a man and admit it.

Wrong sure as Bill puts it for the special situations where someone is running a CVT at peak hp or is trying to get the highest peak hp but that isn't what most people are after. To each his own as you say but as one who lets SVXfiles do my exhaust research it was just an anomally we were discussing the other day.
Reply With Quote
  #126  
Old 10-14-2007, 12:55 PM
UPnorth362's Avatar
UPnorth362 UPnorth362 is offline
Registered User
 
Join Date: Apr 2007
Location: Miami Beach, FL
Posts: 185
Send a message via Yahoo to UPnorth362
Quote:
Originally Posted by benebob View Post
Then why would the most powerfully tuned per liter engines (motorcycles) have disproportiontely long mostly unequal headers.
First off, motorcycles are not the highest Hp per liter engines. I get 5Hp out of a 3.5 cc 4stroke motor. How about rotary engines, and F1 cars?

Second, its not hard to get hp out of an engine that spins 14000-16000rpm, with a low loss gear box.

Third, more hp is to be made with equal length headers on a sport bike. You will also notice that the fuel mixture on two of the cylinders is different than the other two to compensate for many of the variables on hi revving engines with unequal length headers. Plus, motorcycles dont fit into the same catigory as cars.

Look at formula 1 cars. Close to, if not more than 300hp pr liter, and the equal length headers on them are works of art.
__________________
IT'S 5:00 SOMEWHERE!!!

92 Liquid Silver SVX LS-L
Reply With Quote
  #127  
Old 10-14-2007, 02:14 PM
benebob's Avatar
benebob benebob is offline
Have a poncho I can borrow?
 
Join Date: May 2001
Location: Lancaster, PA
Posts: 6,561
Quote:
Originally Posted by UPnorth362 View Post
First off, motorcycles are not the highest Hp per liter engines. I get 5Hp out of a 3.5 cc 4stroke motor. How about rotary engines, and F1 cars?

Second, its not hard to get hp out of an engine that spins 14000-16000rpm, with a low loss gear box.

Third, more hp is to be made with equal length headers on a sport bike. You will also notice that the fuel mixture on two of the cylinders is different than the other two to compensate for many of the variables on hi revving engines with unequal length headers. Plus, motorcycles dont fit into the same catigory as cars.

Look at formula 1 cars. Close to, if not more than 300hp pr liter, and the equal length headers on them are works of art.
I was talking about production engines but you're totally right the rotary is a little better or at least neck and neck, now that I think about it.

I realize that there isn't as much mass being spun so driveline loss is minimized.

As for the 3rd, that's what I was asking. Looking at the bikes coming out these days and they tend to not be equal length headers. Your explaination seems to make sense and explains this anomally pretty good. It was just an observation that I wanted explored since more and more these days they aren't equal length.
Reply With Quote
  #128  
Old 10-17-2007, 01:28 PM
94SubieSVX's Avatar
94SubieSVX 94SubieSVX is offline
OOC for a while
 
Join Date: Jun 2007
Location: Hamilton, NJ
Posts: 1,552
Send a message via AIM to 94SubieSVX
Dropped the car off at the exhuast shop today and everything went dandy. Until they called me and said that what I was getting done was ILLEGAL!!?? Apparently in Jersey you need 3 Cats, of course I'm only getting 1 put in. Luckily I went with my boss who was best buds with the owner of the shop since they were kids. They did the exhuast anyway, and it's all finished now I just gotta wait for a ride so I can go pick it up I can't waittttttttt
__________________
bLAh
Reply With Quote
  #129  
Old 10-17-2007, 02:26 PM
SVXRide's Avatar
SVXRide SVXRide is offline
Official AutoX Part Breaker
Subaru Gold Contributor
 
Join Date: Aug 2002
Location: Midlothian, VA 23112
Posts: 8,138
Registered SVX
yeah, the federal/state govt. can put some serious hurt on an exhaust shop if they find out they're removing cats and not replacing them when they do exhaust systems...
-Bill
__________________
Retired NASA Rocket Scientist

Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023

Center Network Member #989

'92 Fully caged, 5 speed, waiting for its fully built EG33
'92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension
'92(?) Laguna, 6 spd and other stuff (still at OT's place)
My Locker
Reply With Quote
  #130  
Old 10-17-2007, 07:31 PM
94SubieSVX's Avatar
94SubieSVX 94SubieSVX is offline
OOC for a while
 
Join Date: Jun 2007
Location: Hamilton, NJ
Posts: 1,552
Send a message via AIM to 94SubieSVX
Eh fuggetabout the feds...anyway, the exhaust sounds f$&^(@ insane. I can't wait to show it off
__________________
bLAh
Reply With Quote
  #131  
Old 10-17-2007, 09:01 PM
Crazy_pilot's Avatar
Crazy_pilot Crazy_pilot is offline
Moar shifty!
Subaru Gold Contributor
 
Join Date: Nov 2006
Location: Toronto, Canada. Eh?
Posts: 4,560
Send a message via MSN to Crazy_pilot
Registered SVX
Pics!!!! Soundclip!!!!! Caps Lock!!!!!!!!
__________________
Chris

92 Ebony Mica LS-L "A Rolling Restoration": 223,250 KM - Sleeping
2007 STi 6MT, Stance GR+ coilovers, PWR Rad, JDM hood badge, svxfiles 6000K HIDs, JDM Clear Corners, $15/15 min mod, $20/20 min mod, Energy Swaybar Bushings, Hella Supertones horns, Gold STi BBS rims, Group A lightweight crank pulley, A/C system removed, Custom header-back exhaust, Hybrid carbon/metal rear sway bar, restored headlights with CCFL halos
2008 Subaru Legacy Spec B - Diamond Grey Metallic - Sold
2020 Ram 1500 Longhorn - Red Pearl

Reply With Quote
  #132  
Old 10-17-2007, 09:25 PM
94SubieSVX's Avatar
94SubieSVX 94SubieSVX is offline
OOC for a while
 
Join Date: Jun 2007
Location: Hamilton, NJ
Posts: 1,552
Send a message via AIM to 94SubieSVX
Overall, after about a month with the new exhaust, I'm still happy with it. I love the sound at any RPM, between 2-3k RPM it sounds the best though. And it's not too loud, or quiet. I love it
__________________
bLAh

Last edited by 94SubieSVX; 11-09-2007 at 04:02 PM.
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

Forum Jump


All times are GMT -6. The time now is 07:17 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
© 2001-2015 SVX World Network
(208)-906-1122