Forced Induction Custom FI Setup Questions

Ideal A/Fs

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Old Aug 29, 2006 | 10:34 PM
  #1  
baker_jeff's Avatar
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Default Ideal A/Fs

I'm a little curious because I'm hitting 12.5 A/F under boost.

Stock B16
Turbonetics T3

Whats my ideal A/F in and out of boost?

Anyone with a similar setup care to share?
Old Aug 29, 2006 | 11:12 PM
  #2  
NCHATCH's Avatar
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Default Re: Ideal A/Fs

12.5 is pretty good, although on a stock motor, depending on timing you may need to go a little lower. by keeping the air/fuel a tad lower on our motors, it helps cool a bit more and keep it alive a bit longer

although i have found that you cant just blanket tune every car to 12.0 and call it a day. my car seems to run so much better at 12.2 then 12.0

and as far as the haters out there who think there is a big loss in HP by going to 12.0 vice 12.5, there really isnt but a few ponies lost, very minimal. but the longevity of the motor is extended
Old Aug 29, 2006 | 11:12 PM
  #3  
Minor Threat's Avatar
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Default Re: Ideal A/Fs

I run 11.5-12 in boost, 15-16 light load, 13 between -10 and 0 vacuum.
Old Aug 29, 2006 | 11:15 PM
  #4  
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Default Re: Ideal A/Fs

Doesn't sound too bad to me...The way I kinda tuned mine is like this...

Cusing in vac. 15.5-14.5
Accel in vac. 12.5-13.5
up to 5 Lbs around 12.0-12.5
up to 12 lbs I just make sure I'm below 12.5 but not stupid like into the 10's waaay to much fuel will acually cost you at little bit of power (but it will keep you safe...)

I'd say a good range is 11.0 - 12.5 in boost. I'm hitting about 11.5-12.5
Old Aug 30, 2006 | 02:10 AM
  #5  
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Default Re: Ideal A/Fs

Originally Posted by Zeusfire69

up to 12 lbs I just make sure I'm below 12.5 but not stupid like into the 10's waaay to much fuel will acually cost you at little bit of power (but it will keep you safe...)

not necessarily. read this http://www.innovatemotorsports.com/resources/rich.php
Old Aug 30, 2006 | 04:48 PM
  #6  
Walter's Avatar
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Default Re: Ideal A/Fs

like said my book

A/F mixture and characteristics..

AFR Comment

6.0 Rich burn limit (fully warm engine)
9.0 Black smoke/low power
11.5 Approximate rich best torque at wide-open throttle
12.2 Safe best power at wide - open throttle
13.3 Approximate lean best torque
14.6 stoichiometric AFR (chemically ideal)
15.5 Lean cruise
16.5 Usual best economy
18.0 Carbureted learn burn limit
22+ EEC/EFI Lean burn limit.

now get your own conclusions!

Old Aug 30, 2006 | 05:05 PM
  #7  
Oscar's Avatar
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Default Re: Ideal A/Fs

what book is that from?
Old Aug 30, 2006 | 05:25 PM
  #8  
Walter's Avatar
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Default Re: Ideal A/Fs

mm why?
Old Aug 31, 2006 | 01:12 AM
  #9  
Zeusfire69's Avatar
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Default Re: Ideal A/Fs

Originally Posted by d112crzy
I'm not sure what exactly you're getting at here, this article just seems to confirm what I'm saying...? The way I'm understanding it, it is acually explaining the way the burn time in the cyl. can be affected by how rich or lean your mixture is. Thus, this is how your A/F affects knock as well as ignition timing....
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