setting injector size

giddyup

giddyup

Active member
ok,since i haven t messed with the tweecer in a year or more....
someone remind of the formula that gives u the injector size and min pulsewidth for sd. :headscratch:




btw i m switchin to 50lbers
 
giddyup said:
ok,since i haven t messed with the tweecer in a year or more....
someone remind of the formula that gives u the injector size and min pulsewidth for sd. :headscratch:




btw i m switchin to 50lbers
Click to expand...

Divided 50 by 60 and then again by 60

Or you can divided the 50 by 3600.

Either way you will get the same answer :D
 
Last 50's I tuned, had the best injector scaler of .0125. This was used to get the best startup and fuel trims by monitoring KAMR. Yours could be similar based on which brand of injector you bought. Would recommend starting out on a min. injector pulsewidth of .000875
 
well,i finally got the injectors in.had a bit of a problem,i suppose to have 50lb injectors,but the truck is currently running on 0.0105495 inj scaler,and 0.000106812 inj min pulswidth.

it seems to be running ok,a/f are doing close to what my 19s did.but i get a poping on decel.and i haven t had to mess with the base fuel tables at all.is that normal?

anyway,with the injector thing,and it running on a 38lb scaler,i was concluding that they are 38lbers.i also changed the fuel crank pulswidth,like steve says to for 42s or bigger and had to put it back stock because it would start really lean,like 14.8 to 15.5 afrs.

any input is a great help.

rob
 
Your off about 1000% on you minimum injector pulsewidth scaler. It is probably surgin like a mofo. Try starting with a value of .000875. You really cant miss a decimal point and get away with it, be careful or you will join the broken motor club really fast.
 
beleive it or not it wasn t surging...lol i just noticed that steve.i had it set on that
.000875 and it would surge and get a lean pop on decel.i wen t to change it to .0011 and i guess my fat finger hit the button to many times.

does that scaler sound ok for 50lbers?
and do you happen to have jonnynumber5 aka keiths old tune? i m running his old blower setup and his injectors,along witha 8 lower and 3.47 upper. seeing 11 psi at 5500 in 3rd gear.
 
Send me your email addy and I'll send you his old tune, also make sure when you make changes you give it a few run cycles for its adaptive to start learning, you will be suprised on how well the computer can compensate
 
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