Regal, The dip will occur when you drop the hammer at 1900 or you drop it at 3000 RPM but like you said it's not going to be an issue at high rpm because of how fast the cam is spinning at that point (more frequent pumping force). It's the rate of change in the cam timing at low RPM that causes this as the ECU has to deal with the sudden change in cam phasing when the lobes aren't spinning fast enough to prevent the pressure dip. It's normal for this car. I have proven this in my testing by turning off the cam advance.
The "wavy" fuel pressure data log is 12 hz which is same as the OFT and it's a known bad DI pump and had to be replaced. I posted this for people concerned with noise and this will tell you if you have normal noise or possible DI pump noise.
Quote:
Originally Posted by Sonolin
Yes, I understand. But Element Tuning & others have said there's a fuel pressure "wave" in unhealthy running cars. (I said fuel pump, but that's probably the D/I right?)
I'm just trying to figure out how to diagnose that issue for sure that Element Tuning was referring to above (with the wavy fuel pressure line).
EDIT: Fixed my post should make more sense. I was just trying to summarize the thread.
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Yes the "wavy" line is from a know bad DI pump car. This is why I'm showing it to people. The dip in the OFT logs and the 48hz log I provided are from a normally function DI pump.
So this is why you'll have one side of the fence saying there's no problem, the noise is normal and the other side of the fence saying, hey this sounds really bad it can't be normal. Log your DI and rule it one way or the other.
Overall we're loosing track here guys. LOL! The direct injection fuel pressure is not controlled by the variable cam timing, and it has nothing to do with oil pressure. The direct injection pump is controlled by the "Spill Valve" and in your EMS you can set the DI pump pressure target to whatever you want (at least in the Hydra) and then some fine tuning is required so when you set a target you actually hit it.
The variable cam sprockets from Subaru have always been spring loaded but it's not the valve springs that control your engine valves. Typically the waste oil from the cam sprocket is feed through oiling ports in the from of the camshaft and that oil is pushed through to lubricate the cam journals.
In terms of oil weight guys don't go crazy. If your NA and you don't race the car you could stick with a good 0-20w. Like someone mentioned any oil that is packed with moly or other additives will be better than your super emissions friendly 0-20w. If you are tracking the car we have seen 280F oil temps NA so you should step up the viscosity.
Turbo guys should really step up in viscosity if taking the car to the track. My car overall was quieter and everything with the thicker weight but keep in mind it was also a high end oil with a ton of "add pack."
I'll post and follow up with the "wavy" car and if I feel I need a 4 lobe driven DI pump I'll do it and either tell you it was a waste of money or I'll just keep a big ol secret.
