Turbo A/F Ratio before boost on SD tune?
10-14-2007, 11:40 AM
#1
TECH Apprentice
Thread Starter
iTrader: (5)
Join Date: Oct 2003
Location: Glendale,AZ
Posts: 382
Likes: 0
Received 0 Likes
on
0 Posts
Turbo A/F Ratio before boost on SD tune? Are you guys just having PE set to one disired ratio. A Nice flat line, say for example 11.5:1. basicly when ever its floored. Or should you set it to 13:1 like a N/A motor untill the MAP sees positive pressure(105kpa)? then drop to 11.5:1 till peak torque and lean out a little to 11.8:1 by peak HP. Then richen up, up top for safety. This is just a sumation of the info I think I've gathered, and what I'll be asking my tuner to do.
10-14-2007, 09:56 PM
#3
You can safely target a leaner AFR but one thing you want to think about is what is driving the turbo... That is 2 things, heat and mass flow rate. One good way of boosting mass flow rate in the exhaust is to send some extra fuel its way. The only problem is you can negatively hurt heat. What I'm saying is sometimes it can help to run richer before you make boost just to get the turbo spooled. There something else similar to this.. that is guys will talk about retarding the timing before boost to help build up some heat.
