i learned something tonight

[E-Rue]

i learned something tonight.....

when i was doing VE tuning i didnt want to tach the truck WAY up into the 5000rpm areas, so i just tuned to 4000, and then kinda smoothed the curve out.

WRONG!!!!

i coudnt figure out why it was going lean up top, but only at high RPM.
after trying every possible change i could think of in the acceleration tables, it dawned on me that it was only lean at BIG rpm.

so.... i back tracked. i went out and started doing VE tuning again. but this time instead of going to the interstate and driving in 3rd gear, i put it in second gear and tached that bitch all the way up to 4000rpm, and held it there steadily increasing it over time. i realized when it was sputterin just a hair, at about 4500, that the WB was reading in the neighborhood of 16:1

so the lesson learned here? try and get as many boxes in the VE tables as humanly possible. you never know how different your truck is from someone elses utill you use a WB to read all the way up to the top, at steady cruise, and during acceleration.

i havnt finished tuning tonight yet, but im pretty sure this discovery is gonna solve all my up top lean issues. ill let ya know tomorrow.

e

 

[E-Rue]

should the F30 table taper off at the big end like most of the ones i see on stock trucks?

im having to make huge corrections in the fueling above 4400

on most of the .bin's im seeing, the fueling tapers off up there, but mine seems to need a LOT more fueling up top than mark larsons truck did.

i wonder if its the difference in our heads? then again he was runnin alky, and im not.

e

 

[JSM]

As rpm goes up efficiency goes down.

I have seen the fuel taper off also...well actually since other factors are involved, not sure fuel itself tapers, just the VE.

 

[Falco]

...then again he was runnin alky, and im not.

e

I might be wrong, but I guess that's the main difference. He is pulling out fuel to get advantage of the alky, you not...

Later,

 

[Buster]

E's using my chip from last year, really wasn't any fuel reduction for the alky in that chip. When I started tuning my new build this year I had to do a lot of work between 2800-4800 at cruise, got really lean in the higher RPMs, but above 4800 it only needed minor tweaking, and the VE defiantly goes down as RPMs goes up.

E, did you get RT yet? It really changes the whole tuning process, 15 minutes and your cruise fuels done, dig and I never really touched it before because we we're always working with WOT, which took a lot of time chip by chip

 

[Buster]

E,

BTW: if you want my VE tables, I'll send 'em to ya, there pretty much done for my truck, way different that what you had before. You might be able to use the whole chip, except you'll have to add in 20%-30% in F77.

 

[E-Rue]

i would love to see your latest chip. iv pretty much nailed the VE and im about half way done with the WOT stuff, but my idle stuff could be a touch better. i leaned it out a lot, but its still around 12:1

what kinda AFR did you end up deciding gave you the smoothest idle?

i might just try your chip out, and if i like the idle/tip in, put those entries into my chip. (dont want to start the tuning process over lol)

i had to make the same sort of changes your describing in the VE tables. it started getting lean around 2800, and got stoopid lean all the way up to 5000. (thats as far as i went) sometimes as bad as 17:1 it would spit and sputter. was crazy. i still need to finish up, and try out the WOT stuff again, but im pretty sure its gonna be a LOT closer to correct now. im shooting for a 12:1 ratio at WOT. truck seems to be ok with that.

e

 

[Buster]

i would love to see your latest chip. iv pretty much nailed the VE and im about half way done with the WOT stuff, but my idle stuff could be a touch better. i leaned it out a lot, but its still around 12:1

what kinda AFR did you end up deciding gave you the smoothest idle?

i might just try your chip out, and if i like the idle/tip in, put those entries into my chip. (dont want to start the tuning process over lol)

i had to make the same sort of changes your describing in the VE tables. it started getting lean around 2800, and got stoopid lean all the way up to 5000. (thats as far as i went) sometimes as bad as 17:1 it would spit and sputter. was crazy. i still need to finish up, and try out the WOT stuff again, but im pretty sure its gonna be a LOT closer to correct now. im shooting for a 12:1 ratio at WOT. truck seems to be ok with that.

e

At idle I'm running like 13.5-1. Send me your E-mail address and I'll send you the bin. As for wot I'm tuning for low 11-1's, It hasn't really effected performance a whole lot, and gives me some room for the alky to act up, you never know when one of the four alky nozzles is plugged up.