slowscott

iTrader: (8)

What should the stock afr be? I ask because both my car and my friends cobra show a wot afr around 14.x:1 with the stock tune and just intake/exhaust. I had mine tuned after headers to a "safe" 13.0:1. I figured my headers threw off the tune or it was changed with a hypertech by a previous owner. But my friend's cobra only has an intake and loudmouth and he knows the tune is stock. Both cars reading a 14 makes me wonder if they are supposed to be that way.

thanks

brad8266

iTrader: (23)

The stock "commanded" on the LS1 is like 11.6:1 , although you wont get that because the VE and MAF tables come too low stock, so you will actually run leaner than what is commanded.

I dont know what the Cobra commands on a stock PCM.

slow

iTrader: (7)

What year cobra does your friend have.

Without taking COT into consideration a 2003-4 cobra commands a 12.0 (0.82031 lambda) from 3500 rpms and above.

A NA cobra might command a little leaner, but it is richer than a 12.8 airfuel.

Ryan

slowscott

iTrader: (8)

So what will it actually read when hooked to a wideband? Or are you saying it will vary too much from car to car?

slow

iTrader: (7)

That is the value teh pcm is going to command, provided your airflow data is correct, (MAF, or VE depending on your tune) it will determine what kind of actual airfuel is delivered, but it should be very close.

If your seeing 14.x when the car is commaning 11.x then you need to tune the vehicle.

Ryan

slowscott

iTrader: (8)

its a 96 so yea na

slowscott

iTrader: (8)

Well I guess its good I got mine tuned haha. What would cause a cars tune to be so far off? Would an intake and loudmouth do that?

brad8266

iTrader: (23)

No they come from the factory all jacked up. The variances in every engine built can be different. They could have doine a better job though.

brad8266

iTrader: (23)

A stock car will usually measure lean on a wideband, even though the PCM commands 11.6

Armageddon

iTrader: (41)

An N/A car in the 13's is fine. Check his plugs and make sure they're not ashy. I wouldn't worry too much about it but there's a possibility he's borderline to some detonation. 14.0 is iffy, but you shouldn't ever see near stoich under heavy load. Air fuel isn't a predetermined #. AFR should be whatever the individual car runs safely/strongest at IMO.

slowscott

iTrader: (8)

Well it turns out he was being retarted and reading me his ratio at idle Idk what was up with mine. Tuner was probably right about the hypercrap

brad8266

iTrader: (23)

I dont think a Hypertech can change your fueling tables, all it can really do is change timing.