Gain extra benefits by becoming a Supporting Member Click here find out how!
Silver
Gold ***Platinum***
Carl1962 (2)briski1971 dfwwingnut CowboyTrukr (3)sz0k30 (6)
Suburbazine (2)Gunk(7)markl350 (6)roseyintxCutlass442 (10)Rager
Chevyfan60 (10)JohnE (12)cnbell (11)Todd M (11)savina64
LRH (3)61ohboy66conv55_FEVER george88gta (10)BillOrton39
68 Bel-AirNitroholic (10)
warpwr (8)Lynn63 (5)
Jim.Biron (7)
1956chevy (2)
BMF-1955
Classic Performance Products
Ciadella Interiors American Auto Wire Art Morrison.com
Hellwig Products Inc Performance Rod & Custom
Exile® Battery Keeper™ 6/12 volt charger w/ LED battery monitor
Impala Bob's Bob's Chevy Trucks Bob's Chevelle Parts Bob's Classic Chevy

  >> Switch to Mobile Version <<

Recent Hot Topics
Current Quote
"I've gotten my money's worth many times over. I don't know how people managed to get anything figured out on their old cars before the internet.
This site's the best!"
~ Supporting Member
Recent Topics
WIN / WIN

Use this to search for parts on Ebay
A portion of your purchase will come back to the site.
Username Post: tuned headers        (Topic#198904)
mouse55 
Member
Posts: 65

Reg: 11-16-06
09-15-08 07:16 AM - Post#1522631    

have any of you had tuned headers an replaced them with regular haeders an noticed any performance change.just wondering if they are worth the price difference.thanks

 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 15989
grumpyvette
Age: 66
Loc: FLORIDA USA
Reg: 03-16-01
09-15-08 07:29 AM - Post#1522643    
    In response to mouse55

SHORT answer, unless your running a very low restriction exhaust or no exhaust past the collectors theres unlikely to be a significant differance between true tunned headers and most commercially available street headers as the restriction tends to kill off the benefits, yes with open exhaust theres gains to be had, with a tunned header, but unless the compression,displacement, cam timing and intake design match, those gains the correctly designed header can produce are hard to see.
IN most cases when your running an exhaust system behind the header collectors the restrictiion to flow kills off some of the benefits, ANY significant BACK PRESSURE HURTS the effective scavaging, the header scavaging was supposed to provide. HEADERS are supposed to be designed to increase cylinder scavaging ,thus increasing the next cylinders volumetric fill efficiency, that boosts torque due to a larger percentage of the fuel/air mix being available to burn and produce cylinder pressure,thus producing power, but unless the cam timing and intake design are roughtly matched to that same rpm band they can,t effectively scavage the cylinders.
theres plenty of fluid dynamics math and research out there to show that the distances the exhaust travels between exhaust pulses and the diam. and length are easily calculated, and past that length the second previous pulse has little effect compared to the current and previous pulse energy and reflective wave
and lets not forget the cam timing displacement and intake port all effect the cylinder scavaging the headers can effectively provide also.
theres not much sence in paying a great deal more for a true tunned exhaust header unless your willing to match the other components to the combos intended rpm band and the cars gearing keeps you in that rpm band!

http://www.engr.colostate.edu/~allan/fluids/page7/...

http://www.rbracing-rsr.com/runnertorquecalc.html

http://victorylibrary.com/mopar/header-tech-c.htm

http://www.headerdesign.com/

http://www.pontiacracing.net/js_header_length1.htm

http://www.slowgt.com/Calc2.htm#Header
" " IF YOU CAN'T SMOKE THE TIRES FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK !"


Edited by grumpyvette on 09-15-08 07:46 AM. Reason for edit: No reason given.

 
Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

2892 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.142 seconds.   Total Queries: 13   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 07:41 AM
Top