Air/Fuel Ratio
07-13-06, 11:50 AM
#1
Air/Fuel Ratio
I just ordered the DEFI Air Fuel Ratio D-Gauge. As you can see, it does not represent the mixture in stoich, lean, rich with colors like almost all other a/f gauges...instead it represents the mixture in 10:1 12:1 etc....will you guys give me a detailed explination of the ideal ratio, max comfortable ratio, caution ratio, and extremely bad ratio...right now i just have a downpipe but i find myself boosting 11-12psi sometimes and I am using this to monitor my mixture as I add bolt-ons.
-Thankyou
http://i2.ebayimg.com/04/i/07/a9/ae/a7_1.JPG
-Thankyou
http://i2.ebayimg.com/04/i/07/a9/ae/a7_1.JPG
07-13-06, 12:20 PM
#2
Originally Posted by Monsterbox
As you can see, it does not represent the mixture in stoich, lean, rich with colors like almost all other a/f gauges..
The 'ideal' AF ratio depends and boost and rpm and is typically far richer on a rotary that would be typical on a piston engine.
Search for 'air fuel ratio' and you will find lots of threads, particularly in the PFC section of this board.
Also, with the stock ECU you should keep your boost at 10 psi. An AF gauge is not going to save your engine if you go lean on a cold night - it will just tell you what ratio you had when the engine blew.
Last edited by moconnor; 07-13-06 at 12:24 PM.
07-13-06, 12:50 PM
#4
I'm assuming you are running a wideband o2 sensor - if not the numbers that gauge are showing are meaningless.
You don't really need to monitor your AF ratio with mild mods and the stock ECU provided that you keep the boost at 10psi.
The stock ECU runs plenty rich for basic bolt-ons at 10 psi. Running higher boost is a bad idea on the stock ECU and a gauge is not going to warn you of instantaneous lean conditions.
You don't really need to monitor your AF ratio with mild mods and the stock ECU provided that you keep the boost at 10psi.
The stock ECU runs plenty rich for basic bolt-ons at 10 psi. Running higher boost is a bad idea on the stock ECU and a gauge is not going to warn you of instantaneous lean conditions.
07-13-06, 12:52 PM
#5
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The Defi D-gauge, or any gauge using the stock o2 sensor, should NEVER BE USED FOR WOT A/F RATIO MONITORING! NEVER! The stock o2 sensor is not accurate under load, whatsoever.
Secondly, the stock ecu is plenty rich with any bolt-ons at 10 psi or less. There is no reason to monitor A/F ratios. Your problem is slightly excessive boost, which can be fixed with a simple boost controller. You are approaching the problem the wrong way.
Secondly, the stock ecu is plenty rich with any bolt-ons at 10 psi or less. There is no reason to monitor A/F ratios. Your problem is slightly excessive boost, which can be fixed with a simple boost controller. You are approaching the problem the wrong way.
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