... i was wondering what ratio i should tune for?... 12.0?... 11.6?... 12.5?...

also, what ratio should i tune for to pass smog?... 14.7 right?

i did a search but came up with conflicting information... thanks in advance for your help...

 

wow, i was about to make the same thread.

 

for all part throttle tuning, you want to aim for 14.7:1 for decent fuel economy and emissions, if you still have a cat. in boost you should tune for 12-13:1 depending on your setup.

more fuel is safer, but reduces mileage and increases smog.

 

SFP set me at 11.8-11.9 for the stock D16Y8 @ 10psi.

 

thats good and safe i'd definitely be that safe on a d16 @ 10psi.

 

how do you determine what each air fuel ratio means??the higher it is the leaner? or the lower the leaner?also how do you tell whats stoich?

 

higher is leaner... lower is richer... perfectly stoich is 14.7

for instance... at perfectly stoich mixture would be 14.7:1. With units this would read 14.7a:1f... for every 1 part of fuel there is 14.7 parts of air. see it now?

someone please correct me if im wrong.


anyone know what a/f you should tune to at wot and part throttle if you don't have a cat and are running 10 psi on an ls motor?


[Modified by tegasaurus, 10:17 PM 1/14/2003]

 

i've gone leaner than 14.7:1 for light loads. i've done some research on the matter and you get even better fuel economy and only slightly higher NOx emissions.

i am targeting 15:1 at light throttle. 14:1 at 0psi, 13:1 at 1psi and 12:1 at 2psi - 6psi and 11.5:1 at 6psi - 8psi...but i have no intercooler and I am very concerned abnout detonation....of which i have none right now.

i am also running a little more than 1degree of retard per psi of boost. very conservative for now.

 

Oh my god!

1 deg?

Most people who I have talked to who have had it set that high, would get nasty stumbling during 8-10psi.

Interesting.

 

really?

i used as much back in the JRSC days with no issues....set with a J&S ultra safeguard.

EGTs climb, but...redline still comes too quick for that to be an issue.

 

Retarding it that far wouldn't be an issue, unless you turn up the boost drastically. Otherwise if you slapped on an intercooler you'd be able to run closer to stock timing with the same results.

I never thought about setting fueling that way. URGH a JRSC. I bet your glad to get away from that. I hated mine. Don't know why, but the mucle car guy in me bought it.