With the help and collective knowledge from many people in the 6.4 community KC Turbos has figured out a reliable way to run higher than 24,500psi of rail pressure. Why? It runs cleaner and adds more power. You can run less inj PW to make more power with lower egts. On our test truck with KC 59/75 compounds, 60% injectors, and twin pumps.
24.5k → 29k rail pressure
+64 HP
+91 TQ
Across MOST of the powerband
Let that sink in…
First off, if you are reading this you are an early adopter. People have wanted this for years, but it has not been tested for years. It is possible this can shorten the life of your injectors, hpfp, crack nozzles, etc. As of now we have found ZERO evidence of this. But only years of running high rail files will show true long term testing.
Ok… there are multiple ways to do this. And likely much to be improved upon. But this is what we found that works most reliably for us as a good baseline. As of now we have only figured it out in HP Tuners… but I am sure someone can work with SCT/EZ lynk to accomplish the same thing.
As of now you have to work with HP to have access to User defined parameters and use this XDF file. You have to pay for a access for user defined parameters through HP tuners. If you don't already know what that means then I recommend you reaching out to a tuner who does know how to use them. This is advanced level tuning.
Click the link to download. This is the XDF file for my 2010, you might need to make a different one depending on your year. We believe it should at least work for the 1 table you need. Rail pressure scaler
Once you have access to user defined parameters you can open up the downloaded XDF files which will give you access to a TON of extra tables related to the high pressure fuel system. You can use this to fix rail surge, make twin pumps work better, and adjust what is needed for the 29k rail mod.
Essentially we are doing something similar to spoofing the ICP sensor on 6.0 powerstroke to purposely read wrong and get around the 24.5k limit. You can choose to spoof this sensor in many different ways. Basically what you are doing is changing the way the PCM interprets the rail pressure sensor voltage so it thinks rail is lower than it really is. Don’t worry, this is very common in tuning and when done right will have zero effect on the rest of your tune.
We have had the best results of spoofing the sensor to 167mpa. This can be done in this table here and can only be accessed with an XDF file with user defined parameters.
Now your PCM will only see the spoofed readings. So when you are actually making 29000 psi the PCM is going to see 24,200 which is under that hard limiter.
|
Voltage |
Actual Pressure (200 MPa Sensor) |
Spoof Reading (167 MPa Scaling) |
|
0.5 V |
0 psi |
0 psi |
|
1.0 V |
3,625 psi |
3,025 psi |
|
1.5 V |
7,250 psi |
6,050 psi |
|
2.0 V |
10,875 psi |
9,075 psi |
|
2.5 V |
14,875 psi |
12,100 psi |
|
3.0 V |
18,125 psi |
15,125 psi |
|
3.5 V |
21,750 psi |
18,150 psi |
|
4.0 V |
25,375 psi |
21,175 psi |
|
4.5 V |
29,000 psi |
24,200 psi |
Keep in mind if you max out the rail sensor at 4.5v and spoofed 24,200psi (actual 29,000) you will lose control. What that means if you max out the sensor you might actually make 29,000 psi or 35,000+ and will have no way to know. Will that make more power???? on my truck it did. But you are more likely to have issues. So to be safe and retain control we have found commanding spoofed 164mpa to be far enough from the limit of the sensor that it does not max out. I am testing my truck commanding 166mpa letting it max out the sensor and make more power with zero issues, but its risky.
Here is what needs to be changed to make that work right.
Multiply ALL your current Rail Pressure maps by .82 (this will make it run just as it did before, but with the spoofed sensor voltage). Then max out the top of the table at 164mpa
Now you need to make sure to fix your Inj PW table. Multiply the rail pressure on the X axis by .82 and it will fix you inj PW to match what you had before.
That’s it! Now if you have enough pump you can command/hold right about 29,000psi of injection pressure and push your 6.4 harder than it ever has before. When monitoring rail pressure realize it will be reading 82% of what it is actually reading. Other than that we have not seen any issues affecting any other systems. But we would love to hear back from others as to what they learn on their trucks.
KC Turbos does not provide any 6.4 tuning, we are providing this information so tuners can use it for their customers and continue to push the industry forward. If you are looking for 6.4 tuning options, then you can reach out to
Venomous Calibrations on facebook
Donovan Adams on Facebook or Instagram
Yannick Tuning@manaliperformance.com