so i just came from getting tuned on the dyno, went pretty well, made 381 on pump and 22 pounds. afr tapered from 12.5 on spool up and held around 11.7-11.8 to readline. Then i immediatly get off the dyno and pull through the gears, and i see nothing but 10.8 through every gear. went back and took some fuel out, then i see about 11.1 through every gear. starting in 1st i see 12.0 when i looked down at readline, then as i shift it goes to 10.8 then goes up to 11.1, then shift 10.8 back to 11.1. but if i do a straight pull through third i get the same afr as when i was on the dyno? i did not log the street pulls, but i have always knocked during shifts, just a quick 1-2 count, doesnt hold through to next gear. is this normal, any input.

 

afr is different in different gears

 

AFR are always different on the dyno compared to the street. I assume this was based on your own WB and not just the Dyno WB? I have seen a variance of .5 AFR from a tail piper sniffer compared to an onboard WB with no cat even. You have a few factors to consider as well...airflow into the turbo is colder on the street, airflow to the IC is greater, oxygen density is higher, etc. There are a few things there to think about.

 

so will it be richer or leaner on the dyno?

using the same WB of course!

 

this was based on my aem uego on the dyno and off. so would this also mean that im not necessarily making 380 on the street, especially since the afr has gone that rich, and possibly lost power.

Either way, the car pulling reallly strong and really smooth. Just trying to get an understanding of tuning and how everything works.

 

It will read leaner on a dyno than it actually is. I saw a car that was at 12.0 on the dyno WB and 11.5-11.6 on the car. When we made some street pulls it went to 11.2 on the car.

 

Is this on a non-load bearing dyno? I see approx the same AFR on/off our mustang dyno.

I would bet that your lean spool is still on.

If you turn it off, AFR's get more consistent gear to gear and when you are rowing through the gears vs a straight pull in one gear.

 

from some quick reading, im getting that disabling lean spool helps to make tunig easier. if im already tuned, what benefits would i gain from disabling lean spool. if i disabled it, would it throw off my tune?

 

yes you will need to manually lean out your fuel map if you DISABLE lean spool.

likewise if you ENABLE is then ENSURE you RICHEN up your fuelmap before driving!

 

so then since im not the tuner, i would need a whole new tune to disable it. I will leave it where it is, i was just curious as to why the afr was soo much different from the dyno to the street. it concerns me because even though i made 381 on the dyno, i would think im really not making that power on the street since im only at 11.1-11.2, and judging by how my car usually is, it will be in the 10's going through the gears on average. doesnt seem right.

 

same WB yeah (ie not using the dyno's WB)

yes best to "retune" if you play with leanspool!