im just a tad worried about, my 80mph to 90mph overtaking power etc where i use a little boost for a long time... as my afr gauge is staying in the 14's i'm talking about when your cruising in the fast lane with a slight bit of boost..

what afr is expected at 0.5 bar 7psi? i'm getting 14.6
also 0.7, 0.8, 0.9 around the 14.5ish these are the readings that worry me.. not the big boost... i'm geting 14.7 ish at idle..

when i hit 1bar boost it goes 12's then at 2.0 bar plus its 11's

cheers

 

are these readings at light throttle?

also really depends whos chip it is and how its been written!

 

I personally tend to run a little richer than that on moderate boost, but its probably not going to harm it being in the 14s, id generally aim for 13s though, but im cautious with stuff like that.

 

how would you get it from a 14 to a 13 reading chip? increase fuel pressure?

cheers james

 

I was referring to on cars that I map mate, so I would simply increase the injector duration a little at that point.

Not so easy with an off the shelf chip though, you are into the realms of only being able to make global adjustments then of course, so to richen it here, would rich it everywhere.

I dont know what setup he has, so not sure if he can alter the map or not.

 

ive got a msd chip, shall i give the screw a slight twist to see if i can lower it a little? these readings are at light throttle.

cheers

 

I would speak to MSD, as they will know if that is normal operation for this chipset or not.

Stu may have found those AFRs you have there work really well on your spec of engine and hence there is no point you changing them, or he may have some good advice on how much to change them by.

 

what sort of afr would u want to see at 1.5 bar full throttle.

 

think the general rule is no higher then low 12's on full load at high rpm

 

id like to see 11.4 to 11 at 2.2 bar of boost may even be just in the 10s