Bigger injectors

isn · Post by **isn** » Thu Oct 15, 2009 8:40 am

Hi, im quite new to this and have a question.

Im about to change from my stock injectors(242.4g/m(n-heptar)) to new injectors(334.5g/m(n-heptar)

Its for a Volvo 940 -95 LPT with ECU 962.

In the definition file a find a constant called "Injector constant" set to 128
And the conversion is:
Equation format X128
Argument 0
This items raw data

So, anyone got any mathematical formula for changing the constant from 128(0-255) to what i need?

Post by **robertisaar** » Thu Oct 15, 2009 2:08 pm

if its anything like GM ECMs, then since you increased injector size by about 38%, then you'll either need to increase 128 to 177 or decrease it to 93.

isn · Post by **isn** » Thu Oct 15, 2009 3:26 pm

robertisaar wrote:if its anything like GM ECMs, then since you increased injector size by about 38%, then you'll either need to increase 128 to 177 or decrease it to 93.

In tunerpro it says, "lowering the value adjusts for bigger injectors"

So i guess 93, how did you get that number?

Wanna share?

isn · Post by **isn** » Thu Oct 15, 2009 3:27 pm

Also if i change to those injectors plus a 3" AMM(air mass meter), does that affect it in any way? Or do i need some other modifications to achieve a good AFR?

Because according to my own logic(which probably is screwed up) says that 3" AMM and those injectors would add up, and i can still go for 128 constant value...

Please correct me if im wrong, and thanks for the quick reply!

Post by **robertisaar** » Thu Oct 15, 2009 3:46 pm

anything MAF related is something that i shouldn't be asked about.... i don't like them or know too much about them.

as for getting that number: i just took the existing injector size, and the new injectors size, and found that they were about 38% larger...

tip: change one thing at a time. don't change injectors and the MAF at the same time or else you'll run into a world of trouble... swap injectors, change the constant, datalog, get it running good, then swap the MAF (AMM, whatever it gets refered to on a Volvo.

isn · Post by **isn** » Thu Oct 15, 2009 5:09 pm

robertisaar wrote:anything MAF related is something that i shouldn't be asked about.... i don't like them or know too much about them.

as for getting that number: i just took the existing injector size, and the new injectors size, and found that they were about 38% larger...

tip: change one thing at a time. don't change injectors and the MAF at the same time or else you'll run into a world of trouble... swap injectors, change the constant, datalog, get it running good, then swap the MAF (AMM, whatever it gets refered to on a Volvo.

Okay! I send many thanks to you for helping me halfway in this concern!