Had stock home ported heads before now I have le3 heads. Before my a.f.r was 11.5-11.8 at w.o.t. now its at 12.8.

 

I forgot to add that it was tuned for everything before pretty well. I was afraid to spray it at 12.8 today and wanted to know if it should be fatter

 

You should know by now that you need to have it tuned.

 

I just wasn't sure how much of a difference it would make but now that it think about it the new heads are letting a ton more air in which I'm guessing is the reason its running leaner. I have a pretty rich tune from PCMforLess still lying around,I may see if that levels it out some.

 

It was running too rich before. You don't tune for nitrous by running too rich normally aspirated. You're probably closer to the correct A/F ratio now. Optimize the tune WITHOUT the nitrous, then tune for the nitrous with the nitrous system/jets.

The new heads reduced the pressure loss for any given flow. You are getting a denser charge in the cylinders, meaning you need more fuel. But if you are running an MAF tune, the MAF sensor should be picking up the extra mass air flow, and the PCM should be adding the extra fuel.

All that "theory" is no substitute for a hands-on tune,

 

Its a speed density tune. If it ever stops raining I'm going to spray it and see what it does. I'm gonna pick some 98 unleaded up and try that just for some added insurance,but there is alot of timing being pulled as it is because i still have to get the GM adapter for my Mallory hy fire VI

 

And there's your answer. When you do anything that affects the volumetric efficiency of the engine, you have to reprogram the VE tables.

 

The worst part about it all is I have all the software and hardware to tune it but i don't trust myself too make the changes. What is a good target for my a.f.r at say cruising@2400,half throttle,and wide open throttle? When i let completely off the gas it goes pretty lean honestly, used to go right out of sight now it stays around 14.9-15.1. When i first put it to the floorboard it drops to 11.9 then spikes up to 12.8-13.1. Cruising is around stoich

 

Well I finally found the culprit I believe. My wb02 sensor I believe is shot. Its reading lean at 13.5 and throwing black smoke out the back. Its all over the place but it seems rich honestly. I need too have it tuned on a dyno,I'm sick of mail order tunes never getting it right. But nice to know its not lean.

 

You could try calibrating it in free air.

 

It honestly makes sense though cuz i ruined two of my local Dino's wb02's last year from being so rich.

 

I'm confused...how is your wideband O2 sensor (assuming it's for a gauge) affecting how the car runs? You are using factory O2s for the PCM, right?

 

I'm saying its not right. What's affecting how the car runs are the new heads. The wb02 is spent making me think its running lean when it is actually rich. I've never seen the car sprayed from outside until my buddy video taped it today. Black smoke as soon as the nitrous was engaged. Black smoke at w.o.t. its obviously still rich but i was worried it was running lean because of the false reading the wb02 was giving. I also went up a size on the fuel jet just to make sure and it didn't change the gauge one bit.I think from sitting all winter,and from the car being rich before it probably just worebout the sensor.

 

Its also Rich naturally aspirated but not quite as bad. I'm gonna check the oil for fuel,the plugs look good. On the plus side, the car feels as powerful on motor now as it was on nitrous last year. I need to data log the car though so i can find out why my s.e.s light is on.I do know I have a couple of small exhaust leaks as well that may be messing with all 3 o2 sensors. Sorry if i was misleading Joe I was just assuming that the WB was fine and I'm pretty sure its junk lol.