Forced Induction Superchargers | Turbochargers | Intercoolers

Cruise AFR and timing

Thread Tools
 
Search this Thread
 
Old 06-21-2017, 11:55 AM
  #21  
TECH Regular
iTrader: (2)
 
dburt86's Avatar
 
Join Date: Jun 2015
Location: CT
Posts: 498
Likes: 0
Received 1 Like on 1 Post
Default

First thing that comes to my mind is your injector data. Make sure its right. Then injection angle.
Old 11-10-2017, 03:02 PM
  #22  
TECH Regular
Thread Starter
 
squarles67's Avatar
 
Join Date: Jun 2013
Location: Orange, Texas
Posts: 487
Likes: 0
Received 6 Likes on 5 Posts
Default

To come back and post a resolution to this, it turns out this was a symptom of another problem, clogged injectors. In my thread here https://ls1tech.com/forums/forced-in...-out-fuel.html is where I figured it out with some help.

Injectors had trash in the top of them from the build so I took them out and cleaned them. Car is running faster than ever now and I'm working to re-tune the fuel map. It's cruising just fine in the 14.7 range now and I'll likley lean it out some more with fine tuning.

Last edited by squarles67; 11-11-2017 at 04:38 PM.
Old 11-11-2017, 11:41 AM
  #23  
TECH Senior Member
iTrader: (7)
 
Project GatTagO's Avatar
 
Join Date: Mar 2003
Location: The City of Fountains
Posts: 10,090
Received 1,386 Likes on 875 Posts

Default

Thanks for posting a resolution!

Also, keep in mind that an ignition misfire will present itself as a lean condition and the Holley will add fuel. I realize this wasn't your problem, but I'm just throwing it out there in case someone is experiencing this...

Andrew
Old 11-11-2017, 03:37 PM
  #24  
Banned
iTrader: (1)
 
kingtal0n's Avatar
 
Join Date: Nov 2011
Location: florida
Posts: 2,261
Received 18 Likes on 18 Posts
Default

best way to dial in cruise a/f and timing is using cruise control,

set cruise at some speed Xmph (lets say 40mph)

log injector duty, engine vacuum, and speed (miles per hour which we said was 40)

Let it log long enough to generate a field of data, the lowest and highest points for both injector duty and engine vacuum (the road is not perfect)

Once you've collected enough data, adjust your a/f or timing slightly.
and re-log the same exact way at the same speed.

The best a/f and timing will result with lowest injector duty cycle, which you will need to combine with engine vacuum to determine overall injector flow rate (for referenced fuel pressure regulator systems which I always run).

and as a bonus, if you were logging EGT it should also go down as you dial in proper a/f and timing, even if you are removing fuel and engine is getting leaner.
Old 11-12-2017, 03:00 PM
  #25  
On The Tree
iTrader: (2)
 
Rudy72's Avatar
 
Join Date: Jan 2016
Location: Norcal
Posts: 178
Received 2 Likes on 2 Posts
Default

I keep finding that the newer square port cylinder head LS3 doesn't like much timing, having a max around 26*, has anyone else found this to be true as well, sounds strange that a head can affect timing events so much compared to other LS motors.... so far I'm still working on this
Old 11-16-2017, 09:23 PM
  #26  
TECH Senior Member
iTrader: (7)
 
Project GatTagO's Avatar
 
Join Date: Mar 2003
Location: The City of Fountains
Posts: 10,090
Received 1,386 Likes on 875 Posts

Default

Originally Posted by Rudy72
I keep finding that the newer square port cylinder head LS3 doesn't like much timing, having a max around 26*, has anyone else found this to be true as well, sounds strange that a head can affect timing events so much compared to other LS motors.... so far I'm still working on this
The more efficient the chamber design, the less timing you need or want. Twenty six sounds about right for a LS3 port head.
Old 11-18-2017, 11:57 AM
  #27  
TECH Senior Member
iTrader: (39)
 
LilJayV10's Avatar
 
Join Date: Apr 2007
Location: Evansville,IN
Posts: 9,300
Received 857 Likes on 610 Posts

Default

Originally Posted by Rudy72
I keep finding that the newer square port cylinder head LS3 doesn't like much timing, having a max around 26*, has anyone else found this to be true as well, sounds strange that a head can affect timing events so much compared to other LS motors.... so far I'm still working on this

Sounds about right. They don't like/need very much timing.



Quick Reply: Cruise AFR and timing



All times are GMT -5. The time now is 06:12 PM.