"K" values and "null time"

sr20's · 12-14-2006, 11:06 AM

hi

how does one work out the above values

K value : 79E6
null time : 3C

i know its in hex etc
but what i need to know is whats the size of the injectors
is there a way to work it out ?

thanks

sr20's · 12-19-2006, 12:45 AM

not having much luck with the K value

its either to rich on idle and not to rich when you drive
or fine on idle but to lean when you drive

is there no way to work these values out ?

any help welcome
thanks

Calum · 01-04-2007, 05:55 PM

Whats the maf and what size injectors do you think you have?

sr20's · 01-05-2007, 02:18 AM

maf is from z32 (vg30dett)
injectors are stock Ve (sr20ve)

Calum · 01-05-2007, 11:25 AM

You've got the null time correct, but the k is way off. Try F3E6. Have you got the VQ map changed over for the Z32 maf? E-mail me a copy of the bin your working with if you want.

sr20's · 01-08-2007, 01:50 AM

Quote:

Originally Posted by Calum

You've got the null time correct, but the k is way off. Try F3E6. Have you got the VQ map changed over for the Z32 maf? E-mail me a copy of the bin your working with if you want.

ill try the K thanks
will drop you a mail
how do you get the k value ?

Calum · 01-08-2007, 02:14 PM

Experience. If you've got a good k-value for a given maf/injector combo you can calculate the new k-value:

(old injector size)/(new injector size) * k = new_k

If your switching mafs you have to manually walk the k-value until you find the right value (assuming you've got the correct VQ map loaded of course). Also, changing injector size means your scales on the main fuel and timing maps should be changed, but with 330s its not too big a deal vs stock. Check the scaling on the stock VE maps for something more appropriate, but you can easily set these using map tracing to see where your really operating.

Catch all that?

sr20's · 01-09-2007, 12:52 AM

Quote:

Originally Posted by Calum

Experience. If you've got a good k-value for a given maf/injector combo you can calculate the new k-value:

(old injector size)/(new injector size) * k = new_k

If your switching mafs you have to manually walk the k-value until you find the right value (assuming you've got the correct VQ map loaded of course). Also, changing injector size means your scales on the main fuel and timing maps should be changed, but with 330s its not too big a deal vs stock. Check the scaling on the stock VE maps for something more appropriate, but you can easily set these using map tracing to see where your really operating.

Catch all that?

most of it thanks

one thing about the scales on the timing map you mentioned that should change
why play with the timing map scale ? understand one should play with the fuel scale etc

Calum · 01-09-2007, 11:34 AM

Both x-axis (fuel and timing) are dependent on the injector size (this is the load axis we're talking about here of course). The 'load' axis is in terms of injector pulsewidth needed to maintain 14.7:1 afr, so changing your injector size means you need to scale these values accordingly. Just eyeball your values, then map trace and verify its working correctly.

Check this out, this is a picture of a timing map straight out of the FSM. They've got the rpm axis on the bottom, and 'load' on the left. Note that the load is in terms of injection pulsewidth.

sr20's · 01-10-2007, 12:42 AM

thanks makes sense now