Diy Tuning

[El Andrew]

[Puffwagon]

There is a funny entry in the breakpoint calculation that you did but the rest looks pretty good. I didn't bust out the calculator though, I just kinda eyeballed it.

[DarrylC]

4 hours ago, El Andrew said:

 

El Andrew,

    Dont use those numbers, scale the factory injectors or I will send you a calibration for them that works. Those number have been on the net before and are no good for our 4 bar system even when scaled. They should be about 48lb high slope.

[galapogos01]

That data sheet is for 39psi / 270kpa. If there's an error in the sheet let us know and I'll make a new one.

[rollex]

Do you know what fuel/density they were originally tested with?

 

I think the problem with most data is it uses different density fuel and that the figures don't change linearly with pressure as I often hear that of people simply cant get data to match.

[turbotrana]

It is not a time effective solution to try and tune an injector without solid bench test data. You can get it in the ballpark to drive well and it is a good tuning exercise but it is more of an art than a science.

I did this exercise with the Old Nizpro drilled injectors years ago. Nizpro gave their data out to their tuners but the cars did not cold start properly, a  sign your numbers are out. I had some advice from a forum member that the injectors flowed alot less than advertised and to start off with a hi slope of 60lb/hr vs nispros 72lb/hr.  This was key to getting me sane as I was hovering around the Nizpro numbers scratching my head. Once you start understanding how breakpoint, min p/w, injector offset all affect fueling down low then you can start juggling and with a good air fuel ratio meter and with alot of headache you can achieve good drivability. I'd rather just pay to get some ID injectors with proper data. Tuning high power/load is easy, tuning for drivability on an unknown injector sorts the men from the boys and maybe something you should leave for down the track with more tuning experience.

Edited 16/08/18 08:34 AM by turbotrana

[El Andrew]

Thanks guys - that is all very interesting info.

@Puffwagon - Thanks for that.  I think that was just cell formatting which I've now fixed.  Thanks @DarrylC for the offer, however given the BA is dead I probably won't use those injectors now as probably not a decent enough jump over the factory FG injectors.

 

I'm a bit confused as although the supplied data is for 39 PSI, don't the multipliers then operate to scale for various fuel pressures?  I've done that using a graph as the relationships aren't linear.

 

When I grab injectors for the FG I might still give injector tuning a go as a learning exercise, but will make sure I've got access to good data to fall back on if I need it.

[Puffwagon]

It's all pretty easy to work out if you know what things are doing and why they are doing them.

 

The only thing you need to bench test and get 100% right is the dead times at various pressures which cant be done with guess work.

[arronm]

8 hours ago, turbotrana said:

It is not a time effective solution to try and tune an injector without solid bench test data. You can get it in the ballpark to drive well and it is a good tuning exercise but it is more of an art than a science.

I did this exercise with the Old Nizpro drilled injectors years ago. Nizpro gave their data out to their tuners but the cars did not cold start properly, a  sign your numbers are out. I had some advice from a forum member that the injectors flowed alot less than advertised and to start off with a hi slope of 60lb/hr vs nispros 72lb/hr.  This was key to getting me sane as I was hovering around the Nizpro numbers scratching my head. Once you start understanding how breakpoint, min p/w, injector offset all affect fueling down low then you can start juggling and with a good air fuel ratio meter and with alot of headache you can achieve good drivability. I'd rather just pay to get some ID injectors with proper data. Tuning high power/load is easy, tuning for drivability on an unknown injector sorts the men from the boys and maybe something you should leave for down the track with more tuning experience.

Nizpro drilled injector.

 

 

 

Best stock image I could find to show difference

 

Edited 16/08/18 05:12 PM by arronm

[rollex]

Good data saves you hours. If you put a dollar figure on your time it is a no brainer dollar wise to go for flow matched injectors with known to be workable data.