Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > Porsche Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Robbbyg's Avatar
 
Join Date: Aug 2008
Posts: 1,138
Garage
Equal length Pipes are wrong

How can they be efficent if the hot air is hitting at the same time??!
shouldnt they be lengthened/ made with the firing order of the engine in mind? for the Most efficent air delivery?

Well that's my view on it, anyone try it?
__________________
Wheels
Last row 1977 3.0 930 260hp built, still reassembling
Row 1998 996 MK1 3.4 296hp new daily driver
Old 05-08-2014, 10:23 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #1 (permalink)
Brando
 
quattrorunner's Avatar
 
Join Date: May 2006
Location: Las vegas
Posts: 5,924
Garage
It's not the same time if the engine has a fireing order.
__________________
Turbo powa!
1977 911s. it's cool
Old 05-08-2014, 10:40 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #2 (permalink)
Registered User
 
Maltese Falcon's Avatar
 
Join Date: Aug 2004
Location: Mulholland Dr. SoCal
Posts: 537
Everybody buy some u-bends, j-bends, and straight sections from Jegs or Summit.
Start putting together some various headers like;
equal length, pulse tuned length, 180 , tri-y, 6 into 1. Then build all of these one more time, but in step-tube sizes.
Then lets install and run on the dyno for comparisons of rwhp/Tq.
Keep in mind that forced induction engines push exhaust gasses around different from n/a engines, yet another variable in the design criteria.
Lots of work ahead of us !
Marty
__________________
Porsche builds the 21st century 9146
so easy...even a Cayman can do it !
Old 05-09-2014, 12:16 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Feb 2008
Location: Marietta GA
Posts: 2,549
Quote:
Originally Posted by Maltese Falcon View Post
Everybody buy some u-bends, j-bends, and straight sections from Jegs or Summit.
Start putting together some various headers like;
equal length, pulse tuned length, 180 , tri-y, 6 into 1. Then build all of these one more time, but in step-tube sizes.
Then lets install and run on the dyno for comparisons of rwhp/Tq.
Keep in mind that forced induction engines push exhaust gasses around different from n/a engines, yet another variable in the design criteria.
Lots of work ahead of us !
Marty
Can we use zip-ties and bungee cords to hold them together? I'm not confident in my welding skills.
__________________
1987 GP White 930
1977 Ford Bronco
Old 05-09-2014, 05:49 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #4 (permalink)
Registered User
 
Tilikum Turbo's Avatar
 
Join Date: May 2010
Location: Los Angeles
Posts: 1,004
Garage
Your lead-in to the question "are wrong" and then proposing a "view" is a disconnect in logic.
__________________
1983 911 3.3L Turbo(YES, I know the turbo badge is on the right...had to be different!)
1996 Toyota Corolla(der 'clapper')
Old 05-09-2014, 08:56 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)
Registered User
 
16Volt's Avatar
 
Join Date: Oct 2013
Location: Seattle, WA
Posts: 984
Quote:
Originally Posted by willtel View Post
Can we use zip-ties and bungee cords to hold them together? I'm not confident in my welding skills.
JB Weld.
__________________
- 86 Porsche 930 - Mr.Hyde
- 86 BMW 635CSi - Dr.Jeykell
- 2006 Infiniti M45 Sport
https://medium.com/@crashingdoor
Old 05-09-2014, 09:28 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #6 (permalink)
 
Registered User
 
T77911S's Avatar
 
Join Date: Oct 2006
Location: MYR S.C.
Posts: 10,990
Quote:
Originally Posted by Robbbyg View Post
How can they be efficent if the hot air is hitting at the same time??!
shouldnt they be lengthened/ made with the firing order of the engine in mind? for the Most efficent air delivery?

Well that's my view on it, anyone try it?
i think i know what you are trying to say, so look at it this way.

if all the pipes are the same length, then the fact that no 2 cyclinders fire at the same time, there will be no chance of 2 exhaust gases trying to occupy the same space at the same time since each one travels the same distance. cut #1 long and #2 short, they could try to combine at the same time where the 2 pipes come together since #1 fires then 6 then #2.

far from expert here but i think it really comes down to equal back pressure and makeing each cyclinder produce the same power. also, if you have one cyclinder with a short pipe producing less back pressure, that could lean out that cylinder, or make you richen the others to compensate.
__________________
86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[__] RUNNING:[] NOT RUNNING:__2000 MER E320 WAGON [] WRECKED:[]RUNNING:
Old 05-09-2014, 10:56 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #7 (permalink)
Registered User
 
Join Date: Dec 2009
Posts: 256
Track, hi RPM, open exhaust: equals
Street: shortys
Old 05-09-2014, 11:54 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #8 (permalink)
Registered User
 
atcjorg's Avatar
 
Join Date: Jun 2012
Location: San Diego
Posts: 477
Garage
if he has a tool box somebody needs to weld it shut!!!!!!!!
__________________
81 sc 3.0 turbo wb coupe
Old 05-09-2014, 01:45 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #9 (permalink)
Registered User
 
Ken911's Avatar
 
Join Date: May 2005
Location: Loxahatchee, florida
Posts: 2,701
OK i know I'm going to get a lot of negative feedback here. But here goes. For a forced induction engine equal length headers are useless. The fact that there is a turbocharger in the line causes back pressure which negates any scavenging effect of having the pulses of each exhaust valve opening and closing being lined up. The best bet for a forced induction set of headers is the smallest volume ie shorties length possible to reduce turbo lag. Now there is an exception for the twin scroll versions since the sides have to be balanced to take advantage of it. I have talked to a few people who have actually tested this on a dyno and they confirmed what i was thinking. Equal length headers are designed for normally aspirated motors so that the exhaust pulses line up behind one another ans they flow into the collector. This results in a vacuum scavenging effect in the primaries and increased flow through the exhaust valves. Any way chose to believe it or not but if there really was anything to gain by equal length headers on a turbo motor all of the factory race teams would have used them. Instead they went with shorties on the 935's and also later turbo 3.6's etc.
__________________
88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 05-09-2014, 03:14 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #10 (permalink)
Registered User
 
copbait73's Avatar
 
Join Date: Nov 2003
Location: Chesterfield IN
Posts: 1,316
Garage
You may want to check out what ALL high performance turbo motors (F1, Indy, IMSA, etc.) do with their headers.
Old 05-09-2014, 04:51 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #11 (permalink)
Brando
 
quattrorunner's Avatar
 
Join Date: May 2006
Location: Las vegas
Posts: 5,924
Garage
Why are we talking about this?
__________________
Turbo powa!
1977 911s. it's cool
Old 05-09-2014, 05:02 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)
Banned
 
Join Date: Nov 2007
Location: Rockwall, Texas
Posts: 8,765
Quote:
Originally Posted by quattrorunner View Post
Why are we talking about this?
Probably because Robby wanted a diversion from trying to unfu@k that insane mess he made of his fuse/relay panel!
Old 05-09-2014, 05:09 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #13 (permalink)
Registered User
 
Join Date: Aug 2013
Posts: 1,206
That was pretty funny. God bless that fuse panel and props to guy who took it on. Just to clarify, "unf@ck" is German for "reorganize" right?
Old 05-09-2014, 05:42 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #14 (permalink)
Banned
 
Join Date: Nov 2007
Location: Rockwall, Texas
Posts: 8,765
Quote:
Originally Posted by OldSpool87 View Post
Just to clarify, "unf@ck" is German for "reorganize" right?
Nope, it's definitely "Texan" in origin! Or as Paul would say, originates from TexASS! But yes, you've got the translation spot on!

Last edited by Ronnie's.930; 05-09-2014 at 05:58 PM..
Old 05-09-2014, 05:52 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #15 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,582
Garage
I did a fair amount of header research when designing our equal length 930 headers. Conventional wisdom at the time was the shorter the better. Turned out that was only half the story. The full story was the shorter the equal length the better. What true equal length primaries and secondaries do for you in a turbo application is allow the engine to produce more torque off boost and then to produce more peak power on boost. This is in a street application mind you, racing is a whole different ballgame. I dyno tested every system I could get my hands on using the same engine. The equal length system is magic. The tuned sound alone was worth the effort. The key is for each pulse to reach the turbo in the same timing as the firing order, not a mish mash of odd fire pulses. Each pulse hits the turbine in a coordinated efficient beat.
Building short tube headers is easy and gives you a high percentage of gain over standard heat exchangers. I would not have gone to all the effort and expense to build a tuned system if it had no added benefit. This is not a new or unique idea.


__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 05-09-2014, 06:07 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)
Registered User
 
full quack's Avatar
 
Join Date: Apr 2007
Location: Seattle-ish
Posts: 1,171
Send a message via Yahoo to full quack
I'm with Brian, full quantitative science over conjecture.....remember math & science do not lie!

Mark
Old 05-09-2014, 07:10 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #17 (permalink)
Registered User
 
Robbbyg's Avatar
 
Join Date: Aug 2008
Posts: 1,138
Garage
Quote:
Originally Posted by Ronnie's.930 View Post
Probably because Robby wanted a diversion from trying to unfu@k that insane mess he made of his fuse/relay panel!

HAHAHA bugger ive been found out

Actually its not too bad ive actually inadvertently installed a 4 point floaing suspension system for my relay panel, its completely unaffected by bumps..


__________________
Wheels
Last row 1977 3.0 930 260hp built, still reassembling
Row 1998 996 MK1 3.4 296hp new daily driver
Old 05-09-2014, 09:06 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #18 (permalink)
Registered User
 
Robbbyg's Avatar
 
Join Date: Aug 2008
Posts: 1,138
Garage
[QUOTE=RarlyL8;8056849]I did a fair amount of header research when designing our equal length 930 headers. Conventional wisdom at the time was the shorter the better. Turned out that was only half the story. The full story was the shorter the equal length the better. What true equal length primaries and secondaries do for you in a turbo application is allow the engine to produce more torque off boost and then to produce more peak power on boost. This is in a street application mind you, racing is a whole different ballgame. I dyno tested every system I could get my hands on using the same engine. The equal length system is magic. The tuned sound alone was worth the effort. The key is for each pulse to reach the turbo in the same timing as the firing order, not a mish mash of odd fire pulses. Each pulse hits the turbine in a coordinated efficient beat.
Building short tube headers is easy and gives you a high percentage of gain over standard heat exchangers. I would not have gone to all the effort and expense to build a tuned system if it had no added benefit. This is not a new or unique idea.


I was waiting to hear for some live facts thankyou
But and im sure this has been argued, and i think we already have sort of..

Definitively between a NA and Turbo motor????

diameters of pipes?

I read Corky Bells Turbo book and there is a consensus that Bigger is not always better in turboed motors, ie one site promotes the fact that you can roll a tennis ball down their pipes as theyre so large,

So Equal length is good!

But Velocity?

If i went out and got large diameter headers put on my engine with my little 3ldz would i have slower time to max boost?


and small diameter headers, Faster time to Max Boost?
__________________
Wheels
Last row 1977 3.0 930 260hp built, still reassembling
Row 1998 996 MK1 3.4 296hp new daily driver
Old 05-09-2014, 09:15 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #19 (permalink)
Registered User
 
Robbbyg's Avatar
 
Join Date: Aug 2008
Posts: 1,138
Garage
Quote:
Originally Posted by OldSpool87 View Post
That was pretty funny. God bless that fuse panel and props to guy who took it on. Just to clarify, "unf@ck" is German for "reorganize" right?
yeah theyre all jealous of my inventiveness
__________________
Wheels
Last row 1977 3.0 930 260hp built, still reassembling
Row 1998 996 MK1 3.4 296hp new daily driver
Old 05-09-2014, 09:19 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #20 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 03:51 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.