My AFR readings may not be totally accurate, since I am using a narrow band "gauge", but... the readings sort of make sense. I am getting AFR readings of 16-20. I have a BNR stage 4 turbo, Racing Beat REV-TII exhaust, 720cc primaries and secondaries (Rtek v1.8), and a Walbro fuel pump. I don't want to run TOO lean. Would bigger injectors help out? Eventually I am getting an EMS... but for now, what would I be able to do?

 

that's not enough injector for high boost levels.

and how the hell do you know your AFR is 16-20? all a narrowband tells you under WOT is whether you are at stoich or not. it's almost useless for WOT tuning, although you can use it to tune driveability

 

When I let it idle and warm up... I am getting these readings.

 

imo i would say get the bigger injectors and also a ems or some sort of fuel controller . i wouldn't boost too much till you do that so you don't toast your motor.

 

get bigger injectors and a wideband. those narrow bands are pretty useless. go to a stanalone or a fuel computer when you can afford it but the larger injectors should richen up your mixture for now.

 

if you were running 16:1 under boost itd be blown by now.

 

There is limited precision in a narrowband. All you can really say for sure is whether you are at 14.7:1 or you are richer or leaner than that. So to say that you were 16-20 AFR really means little because you cannot quantify accurately with a narrowband. you also are not specifying under what conditions besides "once I warm up." You need to think about what kind of load the engine is under and what manifold pressure. It SHOULD be this lean under some conditions, especially some cruising and deceleration.

Does your gauge go red when you are boosting it?

 

Wait a sec here...You are looking at your AF ratios at idle and deciding they are too lean? That's now how to measure them...For one thing, the narrowband cools off too much to get a good measurement at idle. For another, the ECU is running the engine very lean to save fuel. And finally if you have the emissions system in tact the airpump is pumping air into the exhaust ports which will make the O2 reading go off-scale lean.

 

agreed. get a wideband and bigger injectors, at least for the secondaries for sure 720cc secondaries are ideal for the stock turbo's but you've got yourself a stage 4 BNR..... pump it up man!!!