Injector Scaling - Low Slope Maximum Limit

[silver_cobra_01]

First of all, thank you everyone who took the time to help me with my last thread about base pressure adjustments. I appreciate it. This time around, I have a question about fuel injector scaling since I am changing from Siemens Deka 80 Lb injectors (I think they may be faulty) to FIC 1000CC injectors. I haven't received them yet, but I went to enter the SCT data that they provide online into my tune while I wait. Issue is that the low slope limit (~0.0400) is larger than the maximum allowed value in SCT (0.0300).

Don LaSota's book mentions rescaling for MAF limits by changing Hi Slope, Low Slope, Breakpoint, Engine Displacement, MAFTF, and optionally Manifold Volume. Seems like this would also be an adequate work around for Injector scaling. Will this work? Or are more or less changes necessary?

Thanks for the help.

 

[03cobra#2]

Hi! Been awhile since I've played around with the injector data but I have the same injectors. I would start by inputting all the values then start and run the car with about a 40psi base pressure. I would then start scaling as you need. If you start to run out of injector then increase base pressure / scale. If you start to hit a maf limit then rescale.

I know some people have used data for injector dynamics id1000 injectors as they are pretty much the same thing. You could try that.

I had Don set up my base tune using the data and setting the multipliers to 1, and when I took my car to the dyno my tuner used id1000 data. The car ran well both ways. Hope this helps.

 

[silver_cobra_01]

I would start by inputting all the values then start and run the car with about a 40psi base pressure.

That was my plan but I can't because of a hard limit on the maximum value for the low slope. Max value I can enter in SCT is 0.030 and the FIC data for 39PSI has a lo slope of 0.03936

Interesting that you said your car ran well both ways. Thanks for the response.

I'll see if I can email Don. If anyone else has info how to rescale and avoid the 0.0300 limit please feel free to chime in.

 

[03cobra#2]

That was my plan but I can't because of a hard limit on the maximum value for the low slope. Max value I can enter in SCT is 0.030 and the FIC data for 39PSI has a lo slope of 0.03936

Interesting that you said your car ran well both ways. Thanks for the response.

I'll see if I can email Don. If anyone else has info how to rescale and avoid the 0.0300 limit please feel free to chime in.

No problem. Now that I think of it you may have to scale some right off the bat to get the values to work. I would still start with a 40psi base. Email Don and he'll set you straight. Good luck this is the fun part!

 

[badcobra]

What MAF are you using? When I tuned my own car via SCT, I used an Excel file called Tuning Workbook Pro. It scales everything for you to plug into the tune. Steve Boing was the person who developed it, works amazing and takes all this guesswork out. I have attached it. Read through the instructions and see if you can figure it out.

 

[silver_cobra_01]

No problem. Now that I think of it you may have to scale some right off the bat to get the values to work. I would still start with a 40psi base. Email Don and he'll set you straight. Good luck this is the fun part!

Thank you. I will be starting at factory base pressure to keep it simple for now.

 

[03cobra#2]

What MAF are you using? When I tuned my own car via SCT, I used an Excel file called Tuning Workbook Pro. It scales everything for you to plug into the tune. Steve Boing was the person who developed it, works amazing and takes all this guesswork out. I have attached it. Read through the instructions and see if you can figure it out.

This is good info.

 

[silver_cobra_01]

What MAF are you using? When I tuned my own car via SCT, I used an Excel file called Tuning Workbook Pro. It scales everything for you to plug into the tune. Steve Boing was the person who developed it, works amazing and takes all this guesswork out. I have attached it. Read through the instructions and see if you can figure it out.

I am using an HPX-E. The instructions seemed to have answered my question and is similar to what is in Don's book. Thank you for the response, and btw, your cobra is amazing. Was reading some of your thread last night.

 

[badcobra]

I am using an HPX-E. The instructions seemed to have answered my question and is similar to what is in Don's book. Thank you for the response, and btw, your cobra is amazing. Was reading some of your thread last night.

Thank you! The HPX-E requires scaling an additional 30%. I don't believe that MAF is in the workbook file so you'll have to take the HPX numbers and scale them to the HPX-E in the sheet and it will spit out all the numbers to enter into the tune. My memory of using this is gets the transfer curve really close right out of the gate and then I always just forced open loop and tuned from there.

 

[silver_cobra_01]

Thank you! The HPX-E requires scaling an additional 30%. I don't believe that MAF is in the workbook file so you'll have to take the HPX numbers and scale them to the HPX-E in the sheet and it will spit out all the numbers to enter into the tune. My memory of using this is gets the transfer curve really close right out of the gate and then I always just forced open loop and tuned from there.

Right the e wasn’t in the workbook. Neither were the FIC1000 injectors but there was an option to input custom injector data. I used the hpx-e excel sheet from PMAS to find the values for the tube size I’m using and just plugged those into the tuning workbook and it seemed to have worked well. Made all the necessary scaling adjustments. I’m hoping to try the tune I’ve created off that in the next couple of days.

 

[badcobra]

Right the e wasn’t in the workbook. Neither were the FIC1000 injectors but there was an option to input custom injector data. I used the hpx-e excel sheet from PMAS to find the values for the tube size I’m using and just plugged those into the tuning workbook and it seemed to have worked well. Made all the necessary scaling adjustments. I’m hoping to try the tune I’ve created off that in the next couple of days.

FIC 1000 and ID1000 should be the identical values, but sounds like you already got it handled. Good luck