question on air fuel ratios...

[cobra101]

My buddy has a 06 z06 and just got a dyno tune. his tuner said it is a very safe tune but his air-fuel is 12.2:1

I thought under 12:1 is safe (like 11.8 or so). Is 12.2 safe?

thanks for any info...

 

[01cobravortech]

You have boost, his motor doesn't. Therefore you need a 'richer' tune. That 12.2 appears to be somewhat rich, but if you were tuning the motor of a $70k car you better make sure you get it right. Being on the rich side takes care of that worry.

 

[cobra101]

ok. I thought it may be different non boosted. but then thought he also has 11 to 1 compression..so iwasnt sure.

yeah his tuner said the 12.2:1 was on the safe side.

he made 494 rwhp with just an air intake and tune. not too shabby (500 lbs lighter deboot)

 

[01cobravortech]

ok. I thought it may be different non boosted. but then thought he also has 11 to 1 compression..so iwasnt sure.

yeah his tuner said the 12.2:1 was on the safe side.

he made 494 rwhp with just an air intake and tune. not too shabby (500 lbs lighter deboot)

Yea his numbers are just crazy. Especially minus the 500lbs. And wait untilt he Supercharged Z06 comes out. That of course is going to be over $100k but it will be fun to see what it runs. And you don't have an 11:1 on your Cobra. I believe its 8:4 or 8:5

 

[hawaiiancobra]

my race tune is 12.5 from 2000rpm to 5000rpm the richens up to 12.2 to redline. my street tune is .5 richer across the board

 

[MikeW]

On a N/A car 13.1 is the sweet spot as a general rule of thumb. Sounds like the stock tune is pig rich like the 03/04 Cobra's were from the factory.

 

[98Snake03]

my race tune is 12.5 from 2000rpm to 5000rpm the richens up to 12.2 to redline. my street tune is .5 richer across the board

Through the pipe or through a bung?

Pipe reads .5 higher generally. It it's through a bung, you are on borrowed time IMO.

 

[HISSMAN]

my race tune is 12.5 from 2000rpm to 5000rpm the richens up to 12.2 to redline. my street tune is .5 richer across the board

Even with race fuel you do not want to run a 12.5:1 ratio. Add timing if you want power. What mods do you have?

-Jeff