sharkbait11
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- Sep 18, 2009
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JESUS use the 36's for now. When you get a bigger blower throw them back on...its not that hard of a swap man lol.
JESUS use the 36's for now. When you get a bigger blower throw them back on...its not that hard of a swap man lol.
Also, some of the data is listed differently between Ford Racing's and HPT's (and SCT's), therefore I am going to give you an example of how to input the data...
I am working through your calculations. I believe that some of the units of measure are messed up. I think there is a discrepancy between pounds per minute, pounds per second, and pounds per pulse. However, I do not have it all worked out to a point were I am willing to post.
It would help me cross check my numbers (they do not agree with yours) if I under stood the relationship between pulse width and fuel mass. This is heavy stuff that is pushing the limits of my math skills. Again, I want to double-double check before posting.
I also found this on the Ford Racing site. Note the discussion about the small pulse width. Perhaps this does not apply in this situation as the reported condition is rich.
>>
PROPERLY SELECTING ELECTRONIC FUEL INJECTION COMPONENTS(continued...)
So, technically, the engine only needs a 19 lb/hr fuel injector to support 300 hp, but this will require that the injector is at nearly a 100% duty cycle in order to achieve this horsepower level. Duty cycle refers to how long the injector needs to be open (flowing fuel) in order to supply the required amount of fuel. If the injector needs a 100% duty cycle at a particular engine speed and load to inject enough fuel, that means it is open all the time. Under most conditions, fuel is injected when the intake valves are closed, which helps with fuel atomization and efficiency. If the injectors need to be on 100% of the time to supply enough fuel, this means that some fuel is being injected while the intake valves are open. Depending on the overlap of the cam in the engine, some of this unburned fuel can be blown right past the exhaust valve, or be poorly atomized, which makes for a less efficient combustion process. Perhaps more importantly, operating a fuel injector between roughly 85% and 99% duty cycle does not give the injector sufficient time to close before it is commanded to open again. This can cause extreme variability in the amount of fuel actually injected, which can sometimes result in a rich condition. Similar issues exist at the low end of the flow region at extremely low duty cycles, but this is highly dependent on the type and flow rate of each model of injector. In this case the injector does not have enough time to fully open before it is commanded to close again, which causes extreme variability that can result in a lean condition. For these reasons, we generally recommended selecting an injector with a flow rate sufficiently high that it will not be required to exceed an 85% duty cycle. So to figure out what size fuel injector will result in an 85% duty cycle, divide the original result by 0.85: 18.75 lb/hr/0.85 = 22 .1 lb/hr requirement.
Rickyll7
You asked for help to review the numbers. In order to cross check work, I needed to know the mass of fuel for a given pulse width and pressure. Instead responded with a lot of techno speak. While I can be accused of the same crime, your response provided no real information.
It is clear that you have a reasonable grasp of the techno's of the process. However, you did ask for help in cross checking your work (I assumed that you wanted PROOF of why your calculations did not work). Instead, a poke in the eye.
Not really wanted to start a flame thread, I am going to drop out and you work through this by yourself.:Teh-Win: While I speak only for myself, 80#'s are awful big to expect stock like performance.
I sent you my tune. Are there any values I'm leaving out? I loaded all the values from the ford data sheet, which is the same as the SCT value file for those injectors and I divided the crank fuel by 4 since the injector values didnt address those and the i divided the minimum pulse width by 2 so that the injectors will fire during cranking. How can I test an injector to see if it's stuck open?
Just wondering if you ever got this figured out? This info could really help me with what I am trying to do with my TT mustang. I am trying to tune 160 lb injectors on E85 and having a lot of trouble getting it to even Idle.
Before anyone says anything, yes I know it can be done as there are several guys that have done it.
Ricky- You mentioned that you divided the pulse width by 2 so the injectors will fire. I was told by James at RWTD on the HP Tuners board to never ever change the minimum pusle widths or the slopes except for scaling the slopes, breakpoint, and engine displacement but leaving min pw alone. I am now wondering if this value is too large and is preventing the car from firing? I can get it to run if I put it to the floor but it is at the minimum on the wideband with an AFR of 10. Very very frustrating.
On another note, I had the FRPP 80s before this but they were beyond maxed so I went to the 160s. My car is an 01 and I am tuning with SCT and it ran great. I just used the value file for the 80s from SCT, the BA2800 values, and a blown 2 valve with PI heads value file and it ran great.
Please let me know what you think.