[JANNETTYRACING]

Originally Posted by Chevy71

When you say it's done at 575whp what is done? Do you lose low side PSI or only high side? I am seeing a lot of people in the 600's with no fuel issues and no fuel update. There is so much conflicting information on here it's hard to really know what to trust. I want to learn from others and their experiences, but I may just have to see it myself on the dyno.

When I say done, anyone would be a fool to try and stretch that at sea level on an accurate dyno.

You only have 6 milliseconds to inject all your fuel during the cycle,

The size of the injectors determines how much fuel can be injected in 6 milliseconds.

The high pressure pump falls off hard.

Understand the high pressure pump is a positive displacement pump it will only pump it's own volume Period.

Yes you can increase the stroke of the pump via the cam lobe but you don't get 30% more fuel form a 30% lobe.

I mean this with all due respect but from reading all your posts it appears you trying to get blood out of a stone.

The fuel system is the most important part of your build that is where you spend your money before all the other bells and whistles.

I Hope this clears the air a bit.

Ted

[LesBaer]

I think he's not understanding that there are two things to worry about - octane and volume of fuel.

[SSFanboy]

The 575whp comments are scaring me. I recently had a CAM (w/32% lobe) and 90mm pulley upgrade on my Maggie. I'm getting about 568whp on a DynoJet with 8psi. The shop says I can go to an 85mm pulley and get an additional 20hp at 10psi. Without a fuel system upgrade, is that going to be pushing it and possibly causing a lean condition that could be disastrous for my LT1 engine? I'm at 450ft above seal level in North Texas. Should I hold off on the pulley upgrade?

[JANNETTYRACING]

Originally Posted by SSFanboy

The 575whp comments are scaring me. I recently had a CAM (w/32% lobe) and 90mm pulley upgrade on my Maggie. I'm getting about 568whp on a DynoJet with 8psi. The shop says I can go to an 85mm pulley and get an additional 20hp at 10psi. Without a fuel system upgrade, is that going to be pushing it and possibly causing a lean condition that could be disastrous for my LT1 engine? I'm at 450ft above seal level in North Texas. Should I hold off on the pulley upgrade?

Remember what you can get away with on the dyno will be more that you can get away with on the track.

Ted.

[Chevy71]

Originally Posted by LesBaer

I think he's not understanding that there are two things to worry about - octane and volume of fuel.

I do understand and have worked with this style fuel system for years. That's why my statements about the HPFP only boosting pressure from the volume it's given by the LPFP and why am I changing a HPFP but leaving the low side; keeps getting repeated. If pump gas octane was an issue, why would we have so many factory cars exceeding the HP this forum is listing as a limit to the power? I've seen countless hellcats run 680's on pump gas unaided just to name one. Octane isn't stopping that tsunami of a fuel system they run haha

[Chevy71]

Originally Posted by JANNETTYRACING

When I say done, anyone would be a fool to try and stretch that at sea level on an accurate dyno.

You only have 6 milliseconds to inject all your fuel during the cycle,

The size of the injectors determines how much fuel can be injected in 6 milliseconds.

The high pressure pump falls off hard.

Understand the high pressure pump is a positive displacement pump it will only pump it's own volume Period.

Yes you can increase the stroke of the pump via the cam lobe but you don't get 30% more fuel form a 30% lobe.

I mean this with all due respect but from reading all your posts it appears you trying to get blood out of a stone.

The fuel system is the most important part of your build that is where you spend your money before all the other bells and whistles.

I Hope this clears the air a bit.

Ted

Please don't take my questions as arguing, I'm just trying to clear this up in my mind.
I agree, the pump can only move the volume it's supplied by the low side, and that LT1 pump is a fixed 5.7mm pump that boost the psi of the fuel that's already there. The rate that pump moves fuel is a factor in how much fuel goes to the injectors per fueling cycle. Increasing that open rate with a fuel lobe on a cam will increase the fuel it moves, especially if the pumps piston cycle does not go full stroke from the factory, which we all know is very possible. The LT4 pump is .2 bigger.. it will move more and make more psi, but it won't take much to reach the max in that as well. I'm not trying to bleed a stone, it just doesn't match all the DI engines I have dyno'd for commercial abuse that run 90-105 percent load around the clock. I'm not saying one of the pumps or injectors in one car isn't weaker/stronger than the next or a car certainly can surpass your bench mark on HP, I just feel like each system needs tested to truly find the mark where changes are needed, and how big of a change is needed to correct it.

[JANNETTYRACING]

Originally Posted by Chevy71

I do understand and have worked with this style fuel system for years. That's why my statements about the HPFP only boosting pressure from the volume it's given by the LPFP and why am I changing a HPFP but leaving the low side; keeps getting repeated. If pump gas octane was an issue, why would we have so many factory cars exceeding the HP this forum is listing as a limit to the power? I've seen countless hellcats run 680's on pump gas unaided just to name one. Octane isn't stopping that tsunami of a fuel system they run haha

Each engine combination will have a different HP threshold on pump gas.

We make over 700 RWHP with ZL-1 on pump gas because of low compression.

[JANNETTYRACING]

Originally Posted by Chevy71

Please don't take my questions as arguing, I'm just trying to clear this up in my mind.
I agree, the pump can only move the volume it's supplied by the low side, and that LT1 pump is a fixed 5.7mm pump that boost the psi of the fuel that's already there. The rate that pump moves fuel is a factor in how much fuel goes to the injectors per fueling cycle. Increasing that open rate with a fuel lobe on a cam will increase the fuel it moves, especially if the pumps piston cycle does not go full stroke from the factory, which we all know is very possible. The LT4 pump is .2 bigger.. it will move more and make more psi, but it won't take much to reach the max in that as well. I'm not trying to bleed a stone, it just doesn't match all the DI engines I have dyno'd for commercial abuse that run 90-105 percent load around the clock. I'm not saying one of the pumps or injectors in one car isn't weaker/stronger than the next or a car certainly can surpass your bench mark on HP, I just feel like each system needs tested to truly find the mark where changes are needed, and how big of a change is needed to correct it.

I look at fuel system as the foundation on which the house is built.

I start with a solid foundation then build the house.

I see too many people building a Mansion on a stone wall.

Just trying to help.

Ted.

[Chevy71]

Originally Posted by JANNETTYRACING

I look at fuel system as the foundation on which the house is built.

I start with a solid foundation then build the house.

I see too many people building a Mansion on a stone wall.

Just trying to help.

Ted.

All appreciated as well. I agree the fuel system is very important.

[JANNETTYRACING]

Originally Posted by Chevy71

All appreciated as well. I agree the fuel system is very important.

Fuel supply is the foundation of all builds, without it your house will crumble.

[JANNETTYRACING]

Love this build, really good power on low boost.

[asthmamax11]

Ted
Can this car consistently make those #'s without a significant cool down ?

[JANNETTYRACING]

Originally Posted by asthmamax11

Ted
Can this car consistently make those #'s without a significant cool down ?

All runs on my dyno are fully warmed up ECT IAT and Oil temps.

Can you be more specific with your question?

In what setting?

[Drsagacity]

Ted, we have exchanged some messages and I love these threads. I appreciate all of the great info you are sharing.

So, upgrading the fuel system with LT4 components and add a cam. Why wouldn’t that also be the time to add drop in pistons/rods? I am shocked that when getting inside the motor more people wouldn’t spend the extra $1000 for drop in pistons. What am I missing?