determine IFR and min pulse width with calibration data

[gokussx4]

The data I have is tested at 39.15. The part that is confusing to me is that the flow rate isn't listed on the data sheet for 39.15 psi, I have the low and high injector slope in lbs/s and the min pulsewidth. Also it includes multipliers for different psi. I understand how to arrive at a new fuel pressure with the formula of (sq root(target pressure / rated pressure)) * rated flow and if the 43.5 rated pressure is truely a 42lb flow rate then at 39.15 psi it would be 39.84 lb/hr.

So I noticed that when converting the high and low slope data provided to lbs/hr (high = 43 lb/hr , low = 46.06) it does not match what I calculated from the 43.5 psi and 42lb rate. I must be missing something here and would like to figure it out just because I am curious.

Big objective here is that I need to figure the correct number out so I can create my flow rate vs kpa table and also adjust the inj pw from the 39.15 psi test data to 58.

[DSteck]

It takes thorough understanding of how Ford and GM data relate along with the skill to do a conversion system in Excel. It's a bitch.

It sounds like you're planning to use injectors that Greg Banish already did the data conversion on. Just get his DVD, and you're done.

[gokussx4]

Thanks, does that DVD include flow rate vs kpa, offset vs. volts vs vac, short pulse tables and min default tables? From what I read his DVD is supposed to also teach you how to calculate this information. Is this true? Thanks

[DSteck]

It does not teach you how to calculate it. It does include the flow rate, offset, and short pulse information along with a minimum pulse width.

What injectors are you looking at using?

[gokussx4]

http://www.boschdealer.com/specsheets/0280155968cs.jpg

Its the bosch green giant. The part I don't understand is the multipliers the card gives. Looks like to me that the IFR calculator excel sheet would not be as accurate as the multipliers provided from this card. When I do the math it seems the excel sheet gives you a higher flow rate than using the provided multiplier. I read Greg's document on why flow rate is not a linear calculation as you increase pressure and it totally makes sense.

The only part I think I need atm is how to calculate the short pulse adder and limit from the low slope and breakpoint data. That would be extremely helpful.

I went to the tuning school to learn this exact type of information but unfortunately it did not provide it in the beginner or advanced course

[DSteck]

I could explain it, but it takes the capability to do power regression and polynomial regression in Excel to refit everything, and beyond that some algebra to convert the styles. I've made my own spreadsheet, and let me tell you... I have zero interest in trying to explain how it works. Lol. There's unfortunately no simple "this value means this" conversion.

[gokussx4]

I am not a statistics major by any means but I am a programmer by trade so I understand your reluctance in wanting to explain a highly involved set of equations. I didn't believe that there was an easy explanation but maybe at least a set of formulas and path to follow.

I just bought Greg's books on amazon (so damn cheap, why not). For purposes of clarity, if you don't mind, would you be able to use your excel sheet to tell me what you derived would be the short pulse addr for that injector? This way I can compare to my own findings and prove the math.

[DSteck]

I feel like I'd be stepping on Greg's toes if I did.

I'll tell you that at 1.0336ms, I get 0.053.

[gokussx4]

I understand, thank you for this though. That should help me understand if I calculated correctly.

[gokussx4]

Just wanted to update. The problem with ford data converting to gm format is that its missing one piece of data. You are provided 2 line slopes, a breakpoint (mass so half a point), and a minpw (would be time data but again half of a point). Without the breakpoint's pulsewidth or the min pulsewidth's fuel mass you cannot plot the slopes. Seems like if one had access to a flow bench you could get either of those missing pieces of data and then easily plot the points, find the difference between the high slopes column data on the short pulse adder table to the low slope equivalent mass. The difference between the pulsewidths is your adder! Its very simple.

I just can't believe that you can copyright data. Absurd! We come to forums to find data lol!

Anyway I am going to test this theory by taking my injectors to local flow bench to get one or both missing numbers. If it works out well I will post what I found for this injector (won't be copyright infringement because I got the data by paying for it through a flow bench I paid for). So, stay tuned

[DSteck]

You can calculate the breakpoint pulse width with the information provided.

[gokussx4]

Such a tease!!! lol

Hint? Maybe?

[gokussx4]

If Y fuel > Breakpoint fuel amount, then formula is:
Inj PW = (Breakpoint Fuel Amount / Low Slope) + [(Y - Breakpoint) / High Slope] + Inj Offset

If Y fuel < Breakpoint fuel amount, then formula is:
Inj PW = (Y / Low Slope) + Inj Offset

Something like this?

[gokussx4]

I tried that formula I listed and at a 15 volt offset I got a adder of .153 ms. I must not be doing this right, any hints?

[gokussx4]

DSteck could you check out my excel sheet here? I don't know if I got your value by accident or at least close to it. I ended up getting .055 at 1.0366ms.

[DSteck]

I don't have the hand written equations anymore since I already programmed the spread sheet. I'll have to look at the Excel file later, but to be honest, I have no interest in reviewing equations in a spread sheet.

[gokussx4]

Your the best DSteck! I think the only part I need to confirm is determining the breakpoint pulse width. I found somewhere on eectuning that to find the pulse width you take the breakpoint and divide by the low slope. If that is right then I am one step closer! Thanks again for helping me out.

[gokussx4]

Woot! I think I have it now.

For one I post up the wrong xlsx file because it had some data i was fooling around with at the low slope. So please ignore previous attachment.

Second I did some further reading on eectuning, see post by 85gt:
http://newserv.eectuning.org/forums/...18470&start=30

So I took his assumption and divided the breakpoint by the high slope. This revealed the .053 ms @ 1.0366 ms that DSteck kindly gave me to check my data against.

Next stop will be figuring out the offset vs volts vs kpa

Enjoy!

[kyphur]

subscribed...

[96LT4C4]

DSteck could you check out my excel sheet here? I don't know if I got your value by accident or at least close to it. I ended up getting .055 at 1.0366ms.

Did your spread sheet work? I am going through this right now. I have the Injector Offset vs. Battery Voltage figured out. Just wondering how you were coming along with this.