Tuning new injectors

[braapp]

This may have been covered if so sorry but i have not found the answers I'm looking for.
I'm not shore which tables i have to modify to fit new bosch 42 lb giants, the car is a vy ls1 and has been tuned with the standard injectors which are the bosch 28.8's. Is it just a matter of changing the injector flow rate due to the same style injector
if so where?

Any help much appreciated.

[braapp]

Ive worked it out, again sorry if this has been covered before.

[joecar]

Table B4001... you have to scale the rated flow rate from 3-bar to 4-bar (implying you should measure rail pressure also).


Also, if you have the data, you should edit the other injector tables also.

[braapp]

Gday Joecar my table was in g/s so I've converted the lb/h @ 4 bar and increased by 26.99% as thats what the difference was between them and the originals i hope. Mate I'm not sure what you mean by the date of the other tables, I was hopping that everything else remained the same.

[statesman]

The fuel economy readings on your dashboard display will give incorrect values after you change injector size. You'll have to adjust {B3501} "Scaler for Fuel Economy Output" if you want it to display sane values.

[braapp]

Thanks for the feedback statesman how do you go about working that out?

[statesman]

I don't know if there's a formula for working it out. When you install the larger injector, just bump up the value in B3501 until your dash gives a sane reading.

When joecar said "if you have the date", I think he meant "if you have the data". When you change injectors, if you have the data, then you really should change those other injector tables. Small pulse and voltage correction will probably be a bit different with your new injectors. This data 'should' come with the injectors... but in a lot of cases, it doesn't.

[joecar]

Gday Joecar my table was in g/s so I've converted the lb/h @ 4 bar and increased by 26.99% as thats what the difference was between them and the originals i hope. Mate I'm not sure what you mean by the date of the other tables, I was hopping that everything else remained the same.

Typo: date should read data, sorry poor typing ability.

You could leave the table in g/s and scale to 4-bar by multiplying by sqrt(4/3)... is this what you did...?

The 42 lb/hr injectors do have somewhat different characteristics then the 28 lb/hr ones, so some of the other tables will be different.

[joecar]

I don't know if there's a formula for working it out. When you install the larger injector, just bump up the value in B3501 until your dash gives a sane reading.

When joecar said "if you have the date", I think he meant "if you have the data". When you change injectors, if you have the data, then you really should change those other injector tables. Small pulse and voltage correction will probably be a bit different with your new injectors. This data 'should' come with the injectors... but in a lot of cases, it doesn't.

+1

I typed poorly: date --> data

[braapp]

Haha know i get ya data I'm far from a good maths person give me spanners any day, all i did was workout 42lb @4bar worked out the percentage difference between the two than increase by that and left in g/s is that a ball park figure or way off. In a commodore tuning book somewhere i read they used 60lb seimens and just x2 with those and did not mention anything else on a turbo vx.