[Nate...]

Does anyone know of any stock HPFP modifications besides this:
http://zzperformance.com/ats/camshaf...ance-cams.html

This ads like 27% stroke to the HPFP so I assume it would provide something like 27% more fuel ceiling across the whole RPM range. Assuming our stock pump maxes out at 7k rpm at like 375hp and the 27% stroke increase relates directly to the pumps flow rate, that means the stock fuel pump with the ZZP cam should be able to support 476 hp at 7k engine rpm.

Remembering that we have to keep the power level under the linear curve of the HPFP flow rate.

The 375hp stock ceiling is a complete guess that I am just using to practice this idea. If anyone knows the actual stock fuel volume curve please post.

[Jason@JacFab]

Excellent post! When I get a chance I will look at hptuners and see if there is anything useful in there.

One of my ideas if fuel becomes an issue is to see if an LGX hpfp will bolt on. The LGX pump is also used in the v8 engines, including the supercharged LT4. I was surprised that they would use the same pump on a 650hp supercharged engine as well as the v6.


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[Nate...]

Originally Posted by Jason@JacFab

Excellent post! When I get a chance I will look at hptuners and see if there is anything useful in there.

One of my ideas if fuel becomes an issue is to see if an LGX hpfp will bolt on. The LGX pump is also used in the v8 engines, including the supercharged LT4. I was surprised that they would use the same pump on a 650hp supercharged engine as well as the v6.


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That is surprising. It must be efficient at many different operating conditions and reasonably priced if that is the case.

I asked ZZP about this and here is our conversation:
Your Question: What is the increase in fuel available with this camshaft? The stroke is increased by like 27% but does that relate directly to the fuel available?
Answer: It effects the availability of fuel pressure more than fuel itself by the number earlier stated.

So I don't know how to interpret what that means. I don't understand the difference between fuel pressure and fuel availability by their definition. Pressure and volume should be directly related.

[Nate...]

So assuming E85 has 66.67% the power density of 93 Octane gasoline I added more HP limit calculations. Pure E85, 1:1 with gas, and 1/3 E85 with 2/3 gas. Very interesting to see.
All of this is assumption based.

[ChicagoTommy]

What about adding a higher output in tank pump, or an auxiliary pump? What about raising voltage to the in tank pump?

[Nate...]

Originally Posted by ChicagoTommy

What about adding a higher output in tank pump, or an auxiliary pump? What about raising voltage to the in tank pump?

We are talking about liquids. The graphs are showing a HP calculate by a flow rate of fuel (volume/time).

If the LPFP cannot support the +27% flow rate then that is absolutely a limiting factory, but that is not my understanding (it may be the case, I don't have data showing the LPFP flow rate). Increasing LPFP pressure will not increase the amount of volume that the HPFP can displace.

So as long as the LPFP is capable of supplying enough, having it supply more than enough will not help.

[ChicagoTommy]

Originally Posted by Nate...

We are talking about liquids. The graphs are showing a HP calculate by a flow rate of fuel (volume/time).

If the LPFP cannot support the +27% flow rate then that is absolutely a limiting factory, but that is not my understanding (it may be the case, I don't have data showing the LPFP flow rate). Increasing LPFP pressure will not increase the amount of volume that the HPFP can displace.

So as long as the LPFP is capable of supplying enough, having it supply more than enough will not help.

Interesting. I've seen a couple different platforms throw LPFP's at the system to try to gain headroom. Good to know it's not a viable solution.

[Nate...]

Originally Posted by ChicagoTommy

Interesting. I've seen a couple different platforms throw LPFP's at the system to try to gain headroom. Good to know it's not a viable solution.

Absolutely still possible. If the HPFP is capable of a higher flow rate (especially with +27%) than the LPFP then we will need to modify the LPFP to reach the full potential of these graphs.

[Jason@JacFab]

This is the case on the LFX. The in tank pump can not supply the fuel needed to the hpfp in high Hp boosted applications. All the big power guys swap the ZL1 in tank pump in.


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[Evil-Bee-NH]

Originally Posted by Jason@JacFab

This is the case on the LFX. The in tank pump can not supply the fuel needed to the hpfp in high Hp boosted applications. All the big power guys swap the ZL1 in tank pump in.


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Reminds me of another thread I alluded to that when wondering...

[Nate...]

Just found this:
http://www.xtreme-di.com/HPFP35/XDI-...25-2016_V7.pdf

"This GDI high pressure pump was developed to
replace common OEM high pressure pumps.
It delivers up to 35% more fuel flow when
mounted on the same CAM-Lobe.
Maximum Fuel Pressure is 180bar / 2600psi.
This is 20% more than most current
applications (150bar).
The design incorporates a flexible flange
geometry that allows for different clockings on
the engine. The low pressure inlet fitting
is screw-in to allow for easy adaptation
to OEM or application specific fuel lines."

[RobertAvitia]

I like where you guys are going with this.. very interesting

[Corner carver]

Originally Posted by Nate...

Just found this:
http://www.xtreme-di.com/HPFP35/XDI-...25-2016_V7.pdf

"This GDI high pressure pump was developed to
replace common OEM high pressure pumps.
It delivers up to 35% more fuel flow when
mounted on the same CAM-Lobe.
Maximum Fuel Pressure is 180bar / 2600psi.
This is 20% more than most current
applications (150bar).
The design incorporates a flexible flange
geometry that allows for different clockings on
the engine. The low pressure inlet fitting
is screw-in to allow for easy adaptation
to OEM or application specific fuel lines."

Nate for the win! What a badass find man!... Just need to add a capable in tank pump to keep pace and bingo! Big power fuel! You are my hero for finding this pump

[Nate...]

Originally Posted by oemtech

Same issue with the Hemi guys. Once you go boosted you will run out of pump. The 392 pump works well, Walboro is also a choice, Fore is another and custom ones from Arrington Performance is another. Hemi guys stay away from a boost a pump.

Those are recommendations for LPFP? What about the OEM one that JacFab talks about, the ZL1 pump.

Originally Posted by Corner carver

Nate for the win! What a badass find man!... Just need to add a capable in tank pump to keep pace and bingo! Big power fuel! You are my hero for finding this pump

I agree! I like this more than the cam change...Now I need to figure out the LPFP.