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.

[braapp]

Statesman no data with these which i don't understand as these are a very common injector, but are a supposedly matched set. Ive got the C/success dvd on the way i think its the dearest dvd i have bought by $300 dollars so hopefully it may have some info on the other tables or working out such.

[statesman]

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.

A lot of bosch injectors are rated at 3bar, so I'd suggest checking if your new injectors have been rated at 3bar or 4bar. If they are rated at 3bar, you'll have to convert it to 4bar to get the right flow rate.

[braapp]

Yeah converted them too 4bar then g/s as they are listed at 42lb @3bar this is the part number 0280155968 or aka green giants also used in some volvo turbo engines, there is some info for these on other tuning sites but if its right or not is a gamble.

[braapp]

definitely need too adjust some other tables I'm confident that pressure should be right but under medium load it hesitates, anyway to log data ( width pulse ) to work this out or does anyone have correct data for these.

[statesman]

Getting the correct data would be ideal, but if you can't get it then log your trims and if your trims are all rich or all lean then adjust your IFR table accordingly.

They're fairly big injectors... what mods have you done to your engine?

[braapp]

gday statesman mods as follows.

standard ci, mafless, 238 242 112 lsa camshaft, trickflow 215cc heads 11.7:1 comp, manley pushrods, linkbar morel lifters, dual 3'' 4 into 1 1 7/8,walbro 485 ( id like to go e85 but just trying to get it going on 98 for now)

All mechanical/ machining work is done by me i just need to workout the tuning side of things.

[braapp]

I re did the maths ( not sure what i did wrong ) and put in the new g/s and they work fine this is without touching any other tables.

[statesman]

Little mistakes are easy to make. Glad to hear that you've got it sorted out.

[joecar]

Cool :cheers:

[5.7ute]

Here is the data in GM units. Thanks must go to David Steck from DSX tuning for supplying the spreadsheet to convert from ford to GM units.
note: the 16volts & up data is incorrect due to the limits of the ford data.

[5.7ute]

Sorry guys, had the wrong SPA table data in that file. (Been a while since I opened a tune file) use this one.