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XDI High Pressure Fuel Pump upgrade
- Thread starter engineermike
- Start date
- Watchers 20
illtal
Well-Known Member
I think the DW1700 DI injectors are what he's referring to. I've Never even seen anyone with them. Nor have I seen a cam with more or different pump lobes on them.
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Mghoward74
Well-Known Member
Not DW, but XDI. They have a kit that comprises of a pump, DI injectors and a cam, which you will need to maximize the system. The DI injectors cost more than the pump, so the price goes up double. The cam is not expensive though. The cam is stock, but with the a different fuel lobe.
If anyone does attempt this, just know theres no need for port injectors and really no need to go E85. I was planning on getting the complete system, but I already have a Fore triple pump system. My injectors are big enough so no limitations are in that department.
By the time you pay for a complete DI system, you'll be a couple grand in over a Port system. On top of that, you'll have to open the engine up to install the injectors and cam. So unless you're' doing a short-block, there are those things to consider.
If anyone does attempt this, just know theres no need for port injectors and really no need to go E85. I was planning on getting the complete system, but I already have a Fore triple pump system. My injectors are big enough so no limitations are in that department.
By the time you pay for a complete DI system, you'll be a couple grand in over a Port system. On top of that, you'll have to open the engine up to install the injectors and cam. So unless you're' doing a short-block, there are those things to consider.
engineermike
Well-Known Member
- Thread starter
- #82
I wanted to update this thread with a few things I've learned over the last couple of months.
The bad: I noticed that I was losing control of an exhaust cam sometimes. After some logging I realized it was drifting retarded at high rpm and only doing it when the oil is hot, and it was only the #1 exhaust cam. This is the cam that drives the HPFP. I tried various tune fixes but even forcing the VCT solenoid to 0% (full advance) still didn't keep the cam from falling retarded. I tried replacing the VCT solenoid valve but a new one didn't solve the issue. I believe the higher drive torque required to turn the pump is overcoming the phaser's ability to keep the cam advanced. Eventually I started modifying the VCT solenoid valve and got it working reasonably well. It's not perfect, but the 5W40 oil has to get pretty hot for it to lose control now. I believe it would probably work with the stock solenoid on 5W50, as it would maintain viscosity to a higher temp. A 3rd option would be to lock the cam phaser on just that cam or perhaps both exhaust cams if you want to keep intake VCT. It's not ideal but the exhaust cam timing really isn't that influential on engine performance.
The good: I did some exhaust work and got the backpressure below 5 psi at the collector. I also did some more tuning changes to how the GDI system runs and how spark is controlled. The end result is that I'm now running the 3.5" pulley for about 14 psi boost and also hitting right at 20 deg timing. I was able to run 23+ deg timing on the 4" pulley (~10 psi). By the way, most pump gas forced induction tunes run the engine into knock, then retard timing, then run it into knock again. It will make more power that way, but I don't like the engine experiencing even brief knock every time I go WOT. So, I'm controlling timing by limiting knock advance such that it rarely ever gets any knock at all. I believe I can actually run more timing than I am now if I were to allow it to be controlled the way most do.
The ugly: Well I can't say for sure if the recent additional knock benefit was totally due to the GDI pump, the exhaust work, tuning, or even something like improved fuel quality post-Covid. I also have to warn anyone thinking about this that something should be done to make sure the exhuast cam 1 is under control. For most I would probably recommend just running 5W50 from Mobil1, but I haven't confirmed this will work.
The bad: I noticed that I was losing control of an exhaust cam sometimes. After some logging I realized it was drifting retarded at high rpm and only doing it when the oil is hot, and it was only the #1 exhaust cam. This is the cam that drives the HPFP. I tried various tune fixes but even forcing the VCT solenoid to 0% (full advance) still didn't keep the cam from falling retarded. I tried replacing the VCT solenoid valve but a new one didn't solve the issue. I believe the higher drive torque required to turn the pump is overcoming the phaser's ability to keep the cam advanced. Eventually I started modifying the VCT solenoid valve and got it working reasonably well. It's not perfect, but the 5W40 oil has to get pretty hot for it to lose control now. I believe it would probably work with the stock solenoid on 5W50, as it would maintain viscosity to a higher temp. A 3rd option would be to lock the cam phaser on just that cam or perhaps both exhaust cams if you want to keep intake VCT. It's not ideal but the exhaust cam timing really isn't that influential on engine performance.
The good: I did some exhaust work and got the backpressure below 5 psi at the collector. I also did some more tuning changes to how the GDI system runs and how spark is controlled. The end result is that I'm now running the 3.5" pulley for about 14 psi boost and also hitting right at 20 deg timing. I was able to run 23+ deg timing on the 4" pulley (~10 psi). By the way, most pump gas forced induction tunes run the engine into knock, then retard timing, then run it into knock again. It will make more power that way, but I don't like the engine experiencing even brief knock every time I go WOT. So, I'm controlling timing by limiting knock advance such that it rarely ever gets any knock at all. I believe I can actually run more timing than I am now if I were to allow it to be controlled the way most do.
The ugly: Well I can't say for sure if the recent additional knock benefit was totally due to the GDI pump, the exhaust work, tuning, or even something like improved fuel quality post-Covid. I also have to warn anyone thinking about this that something should be done to make sure the exhuast cam 1 is under control. For most I would probably recommend just running 5W50 from Mobil1, but I haven't confirmed this will work.
engineermike
Well-Known Member
- Thread starter
- #83
Not exactly XDI related, but definitely GDI related...one of my offline tuning counterparts (and forum member) made an impressive pass after optimizing the *stock* GDI system based on what I've learned tuning the XDI pump.
2019 GT, A10, Whipple at stock boost (3.875 pulley), 3.15 gear, stock weight plus spare tire and a full tank. The car has full exhaust (LTH) and no cats, but the drivetrain is otherwise stock. The kicker is that he was running Shell 93 straight from the pump with no octane booster. The car ran 10.53 at 139.1 mph at 2300' DA. IAT1 was over 100 deg and IAT2 started at 118 and ended at 124 deg, which I think shows the effectiveness of the Whipple intercooler.
In the tune, we completely restructured using 5 mapped points and a totally different spark and cam control strategy from Whipple. Shift points were 7500 rpm. We modified how the GDI pump and injector blend is controlled to get 100% of what the stock pump is capable of, which allowed it to run 18.5 deg timing. His prior pulls with Whipple GDI settings could only manage 14-15 deg timing and trapped 133. It did pick up "a knock" only on cylinders 1 and 5. I have found in multiple cars that 1 and 5 knock first on the Whipple setup. In my own car I run 2-2.5 deg less spark in 1 and 5 than the others, so I really think he has a little more power on the table once he commands individual cylinder spark corrections (and raises the boost).
2019 GT, A10, Whipple at stock boost (3.875 pulley), 3.15 gear, stock weight plus spare tire and a full tank. The car has full exhaust (LTH) and no cats, but the drivetrain is otherwise stock. The kicker is that he was running Shell 93 straight from the pump with no octane booster. The car ran 10.53 at 139.1 mph at 2300' DA. IAT1 was over 100 deg and IAT2 started at 118 and ended at 124 deg, which I think shows the effectiveness of the Whipple intercooler.
In the tune, we completely restructured using 5 mapped points and a totally different spark and cam control strategy from Whipple. Shift points were 7500 rpm. We modified how the GDI pump and injector blend is controlled to get 100% of what the stock pump is capable of, which allowed it to run 18.5 deg timing. His prior pulls with Whipple GDI settings could only manage 14-15 deg timing and trapped 133. It did pick up "a knock" only on cylinders 1 and 5. I have found in multiple cars that 1 and 5 knock first on the Whipple setup. In my own car I run 2-2.5 deg less spark in 1 and 5 than the others, so I really think he has a little more power on the table once he commands individual cylinder spark corrections (and raises the boost).
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