Walbro And Injectors: Need Tips
03-25-2004, 08:33 PM
#1
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Walbro And Injectors: Need Tips Turbo is back on the car and I installed my In tank Walbro last night. I have a set of 50lb injectors sitting ready to be put in. I also have a wideband and an Elec FP Guage...
I would like to get the car tuned for idle and part throttle for now. Where should I start? Basically, if I am upgrading from stock injectors to 50lb injectors, where should I scale the IFR table to before starting the car for the first time?
If I start it with the stock program and new injectors I am assuming this would be a bad idea as it would be waaay to much fuel.
I would like to get the car tuned for idle and part throttle for now. Where should I start? Basically, if I am upgrading from stock injectors to 50lb injectors, where should I scale the IFR table to before starting the car for the first time?
If I start it with the stock program and new injectors I am assuming this would be a bad idea as it would be waaay to much fuel.
03-26-2004, 03:22 PM
#3
Moderator
Nobody probably wants to answer such a question, because there is no good answer for all cars.
So many variables might affect this, who can know?
But, I approach it a certain way (helped by John Skiba, RIP
).
Go here and read:
http://www.blackls1ta.com/LS1-Edit_Tuning.htm
It will have an Excel shreadsheet where you can enter:
- Advertized Inj flow Rate
- Test Pressure at advertised Flow Rate
- Fuel Pressure on the vehicle at WOT.
No one is saying this spreadsheet is precise... it is a nice starting point, and by varying the values, you can get the correct scaling for the different cells.
For instance, at the absolute lowest I'd be comfortable for fuel pressure, 53 PSI... (IF that fuel pressure were constant and A/F ratio is verified to be adequate, if your injector size were 26:
Enter New Injector Size Information Below:
Tested Injector Flow Rate (lbs/hr) 26
Injector Test Pressure (PSI) 43.5
New Fuel Pressure to be used (PSI) 53
you'd get stock values of:
For 50# injectors:
So many variables might affect this, who can know?
But, I approach it a certain way (helped by John Skiba, RIP
).Go here and read:
http://www.blackls1ta.com/LS1-Edit_Tuning.htm
It will have an Excel shreadsheet where you can enter:
- Advertized Inj flow Rate
- Test Pressure at advertised Flow Rate
- Fuel Pressure on the vehicle at WOT.
No one is saying this spreadsheet is precise... it is a nice starting point, and by varying the values, you can get the correct scaling for the different cells.
For instance, at the absolute lowest I'd be comfortable for fuel pressure, 53 PSI... (IF that fuel pressure were constant and A/F ratio is verified to be adequate, if your injector size were 26:
Enter New Injector Size Information Below:
Tested Injector Flow Rate (lbs/hr) 26
Injector Test Pressure (PSI) 43.5
New Fuel Pressure to be used (PSI) 53
you'd get stock values of:
Code:
0 5 10 15 20 25 30 3.62 3.64 3.66 3.69 3.71 3.73 3.75 35 40 45 50 55 60 65 3.77 3.80 3.81 3.84 3.86 3.88 3.90 70 75 80 3.92 3.95 3.96
Code:
0 5 10 15 20 25 30 6.95 6.99 7.03 7.09 7.13 7.17 7.20 35 40 45 50 55 60 65 7.24 7.30 7.32 7.38 7.42 7.45 7.49 70 75 80 7.53 7.59 7.61
Last edited by Black LS1 T/A; 03-26-2004 at 03:51 PM.
03-26-2004, 03:33 PM
#4
Moderator
Now... my point: to get my LTFT's zero'd without lying to my computer with artificial MAF values , I had to drop the IFR lower and lower. Right now it sits at:
for me.
I don't believe I'd have to drop it this low if I knew the Inj Offset values for my Siemens 55's (or had low impedence injectors that supposedly open and close MUCH quicker).
Proceed with caution... results may vary.
Many may disagree with my methodology, but it works for me. Hopefully this gives you the starting point you need.
Code:
0 5 10 15 20 25 30 6.29 6.32 6.36 6.41 6.45 6.48 6.52 35 40 45 50 55 60 65 6.55 6.60 6.62 6.67 6.71 6.74 6.78 70 75 80 6.81 6.86 6.88
I don't believe I'd have to drop it this low if I knew the Inj Offset values for my Siemens 55's (or had low impedence injectors that supposedly open and close MUCH quicker).
Proceed with caution... results may vary.
Many may disagree with my methodology, but it works for me. Hopefully this gives you the starting point you need.
