Quote:
Originally Posted by Fenrir
I've done some searching and haven't come up with anything (apologies if it was mentioned somewhere else already, I did search for a good 20 minutes here and on google), so figured I'd start a new thread.
Has anyone been logging the PSI on the HPF system? I've been seeing some strange numbers, and want to compare against a different logging solution. I'm using a DashHawk with custom PIDs entered in. Fuel PSI is hitting 3k at WOT at times according to my logs, curious if anyone else has been paying attention/noticed similar results or if my logs are just bunk. Attached the logs if anyone cares to look. Nothing exciting, just a few 2nd/3rd gear rolling pulls.
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3,000psi sounds about right. The DI system has to inject fuel into the cylinder at full compression at the top of the stroke when cylinder pressures are at their highest. That's how a DI system works...this is why the Direct Injectors have metal hardline's unlike the flexible fuel hoses of the port injectors, it's also why the DI system has a separate mechanical fuel pump as the electrical fuel pump in the tank cannot pressurize the fuel to a high enough PSI for use in the DI system.
For reference, Diesel engines have used Direct Injection exclusively for years. Diesels have compression ratio's on average anywhere between 16:1 and 25:1 (vs. the 86's 12.5:1) and Diesel direct injection systems often operate at 25,000psi or more on the bigger commercial diesels.