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Re: BPW numbers



On a MAF system, if you UP the fuel pressure 7 - 10 %, and set the flow rate to a value 7 - 10% higher, the 305 injectors will have the best chance on a un-hotrodded 350 motor IMO.  you can add 20% more FP and mess up idle and cause BLM skewing, and the WOT will have more fuel, or you can leave the FP alone and idle will be great but WOT may have the injectors static and still have low o2 readings.  Either is a comprimise.  305 to 350 = bit more than 14% more air, need 14% more fuel and thats with no other intake mods. If you were using 12ms at WOT on the 305 you'll use the same injectors 14% longer in the 350 - closer to static (or over)
 
dont just change the BPW by 14%, (in a MAF) you'll do the opposite of what you are after. the injector base PW should be the actual setting for the injectors used - then you adjust it a bit for more FP.. which makes the injectors have a higher flow rate than they are "stamped". a better spray pattern too.  On a TPI (not TBI) each of the 8 are rated at 19#/hr for a 305 and 22#/hr for a 350. 19 * 1.14 = 21.66 amazingly... keeps the injectors below something like 80% of max duty cycle.
 
and you're "off road" so no problem with the feds.
 
Please anyone correct anything. I'm not a pro, I just play one on TV.
 
PS - my soon to be dropped-in 383 will start out with 350 injectors. (MAF too). 
----- Original Message -----
From: Programmer
Sent: Tuesday, February 22, 2000 4:46 PM
Subject: BPW numbers

Greetings guys,
 
Just wondering what BPW numbers would do when a guy changes a 305 to a 350. The 1988 TBI injectors are different, PROM BPW numbers are 148 for a 305 and 135 for a 350. This is based on flow in grams/sec...what would you have to set a 305 injector to, to work in a 350 properly -- or is the flow rate too low already ?
 
Lyndon.