[NOLA_1906]

Originally Posted by that1seven

ok finally home, a hole day in the rain, running power to a/c unit,gas line, craned a new a/c roof top i'm done home .. out of the rain

way we dyno'd was
we tried 2nd gear first.. wot.. than 3rd.. than 4th than 5th..
than we tried getting the speed up to 60mph than it would downshift automaticly into 3rd and yes i'm doing all my runs at wot
than we tried it at 65mph
we didn't run the truck very hot. took plenty of breaks, ambient temp was 65degree's
the dyno shop i was at isn't a noob, hes been the only one for the longest time here where i am.. untill just recent someone opened up a mustang dyno...
but
either way, being on a dyno having a wideband in the exhaust reading wuts coming out was 15.1afr..
I dont' understand how u guys can say the ecu/unichip still correcting the problem when the wideband reads 15.1 coming out of the exhaust
thundera is on the money where i was hoping the afr would have been 13-14.1

I spoke with Unichip a few minutes ago and they explained the three states that the Tundra uses. In the condition necessary to get a decent dyno run w/o downshifting, throttle is opened gradually until it reaches a point where it won't downshift. In this condition AfR is 12:5. Unichip corrects two points or so in open loop which puts it at 15:1. Unichip stated that this condition will only be seen on the dyno and in first and second gear under certain conditions just at V8hunter witnessed. The two conditions we will see most in open loop is hard acceleration with a downshift and slow acceleration with sustained load such as towing. In both these cases, the AFR's will be perfect. The thing we have to get past is that just because our AFR's are over stoich, doesn't mean the engine is about to blow. Stoich is established by the EPA for clean cats. AFRs of over 16:1 is common in Europe and perfectly safe. These aren't turbocharged vehicles guys. I can't explain everything Jack told me, but I'm sure with 30 years of experience, he knows more than anyone on this board about tuning. They are familiar with what That1Seven and V8 hunter experienced and they are confident that it is normal. They saw it on their dyno. On the street, your AFR's will be perfectly adjusted for all conditions. You guys can choose to be Chicken Littles and cry the sky is falling, or you can re-read Unichip's post and try to understand what is happening. Also, this condition will never be seen while towing a boat becasue the tundra will sense a sustained load which will richen the AFR's. Quite honestly guys, everything the Tundra is doing is beyond most of our understanding because we haven't studied it as long and as in depth as Unichip has. I choose to trust them over a screwed up dyno result.