Welcome to the North American Subaru Impreza Owners Club Friday November 21, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Engine Management & Tuning

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 03-12-2004, 09:37 AM   #1
savka
Scooby Specialist
 
Member#: 12737
Join Date: Nov 2001
Location: Bean-Town
Vehicle:
MY02 wagon 325/300
MBP

Default Can you explain tunning/spool relationship?

I have read on several posts that to no small part the spooling charecteristics of a turbo are dependent on engine managment tuning. Can someone please elucidate this stetement for me (and other I am sure).

My understanding was thet the quickness of the spool is determined by the differences in the compressor and exhaust wheel size/housings of a turbo. The exhaust side is in a sence a "motor" of the turbo and the compressor side is the "wheel" of the turbo. 'The motor spins the wheels'. So as long as the "wheels" are not too big the motor can rev up quickly. Similarly as long as the 'motor' is not too big the exhaust gases will spool it faster etc..

Will changing fuel/timing maps actually produce more gas to spin the turbine earlier?

What am I not understanding?
thanks
sav
* Registered users of the site do not see these ads.
savka is offline   Reply With Quote
Old 03-12-2004, 10:36 AM   #2
jblaine
Scooby Guru
 
Member#: 8512
Join Date: Jul 2001
Chapter/Region: South East
Location: St. Pete, FL
Vehicle:
2002 WRX chassis...
stage-infinity.com

Default

Turbos spool from energy.

Heat is a form of energy.

More heat, more energy.

Exhaust gases have heat.

Exhaust gas heat is tunable.
jblaine is offline   Reply With Quote
Old 03-12-2004, 10:39 AM   #3
Jon [in CT]
*** Banned ***
 
Member#: 2992
Join Date: Nov 2000
Chapter/Region: NESIC
Location: Connecticut, USA
Vehicle:
02 WRX Sedan
Silver

Default

The ratio of the pressure at the turbine inlet to the pressure at the turbine outlet determines how fast any particular constant pressure turbocharger will spool up. Raising the exhaust gas temperature (EGT) will increase that pressure ratio.

The A/F ratio which produces the highest EGT is the fuel's stoichiometric A/F ratio.

EGT rises as spark advance is retarded.

A misfire will send fuel into the exhaust which then burns in the exhaust pipe, raising EGT.
Jon [in CT] is offline   Reply With Quote
Old 03-12-2004, 02:21 PM   #4
savka
Scooby Specialist
 
Member#: 12737
Join Date: Nov 2001
Location: Bean-Town
Vehicle:
MY02 wagon 325/300
MBP

Default

Ahhhhhh....

Ok, that makes sence. Thank you both

So, a tuner's objective is to find that zone between lean A/F(high EGT's) and non-detonating conditions - correct?

Why does retarding timing increase EGT's? (unless of course its because since the spark is initiated later in the cycle which in turn leaves less time for the entire fuel mixture to combust, leading to some amount of this unburnt fuel exiting into the exhaust path where it continues to burn leading t highr EGT's - am I even close?)

sav

But this seems to say the opposite

From HOWSTUFFWORKS

"Other goals, like minimizing emissions, take priority when maximum power is not required. For instance, by retarding the spark timing (moving the spark closer to the top of the compression stroke), maximum cylinder pressures and temperatures can be reduced. Retarding the timing may also eliminate knocking.."

Last edited by savka; 03-12-2004 at 02:27 PM.
savka is offline   Reply With Quote
Old 03-12-2004, 02:23 PM   #5
cdvma
Scooby Specialist
 
Member#: 21980
Join Date: Jul 2002
Chapter/Region: NESIC
Location: Central MA
Vehicle:
2002 PSM WRX (Sold)
2009 BMW X5

Default

Right on spot.
cdvma is offline   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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Can you have a healthy relationship without good sex? Train Wreck Off-Topic 55 03-28-2006 02:43 AM
Autox gurus -- can you explain this? sdecker Motorsports 108 03-17-2004 06:24 PM
Motorcycle people - can you explain this? Kinsbane Off-Topic 5 10-18-2003 02:12 AM
Help! Can you explain these terms? silvercharged Newbies & FAQs 18 08-08-2002 09:38 AM
Can you explain Mandrel Bending? Lifino Newbies & FAQs 4 04-23-2001 06:39 PM


All times are GMT -4. The time now is 08:20 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.