[towerfab]

I just added a cam and dsx port injection to my 2650 boosted set up. Dyno was just shy of 1000 rwhp. I stayed with the previously installed aux. pump and also have a JMS on the lt4 in tank pump. Is there anyone else that has this set up with their port injected set up? I'm considering changing the low side based on another shops recommendation. Thanks, T

[Joshinator99]

Fore Triple if you want to make big power.

Katech or DSX dual in tank if you want to road course the car.

[radz28]

Katech customer here:

Because I need the ability to control the fuel pump with the OEM tune and not have to disable codes or anything like that, I went with the Katech bucket (well - DSX didn't announce/release theirs at that time anyways). I, believe, Joshinator99 proved out the DW400 pump (which are what Katech uses) flow hardly more than the OEM LT4 pump, so there haven't been any codes or anything, which works in my situation. Katech uses 2- DW400 pumps (one standard and one jet/venturi), and running around 18-19-psi of boost (stock LT4 - no exhaust) I don't have to run the second pump much more than about 75% duty cycle to maintain 75-psi. That's through a stock fuel system (minus the fuel filter I had to add), and not cranking the voltage up on the primary fuel pump. That's on pump E85 (an indicated 75% in HPT SCANNER). I'm not making 1000, and they only advertise 900, so that's something to consider.

That's a lot of pre-qualifications to get through, but I couldn't think of a better way for you to compare, as our set-ups are different.

[Hammer-joe]

Originally Posted by towerfab

I just added a cam and dsx port injection to my 2650 boosted set up. Dyno was just shy of 1000 rwhp. I stayed with the previously installed aux. pump and also have a JMS on the lt4 in tank pump. Is there anyone else that has this set up with their port injected set up? I'm considering changing the low side based on another shops recommendation. Thanks, T

I have the DSX Atlas on my 18 Camaro. I'm running there aux pump I did update the pump to there GSL 396 pump. Stock in tank pump. I made 971 RWHP at 14 psi on e-85. I'm running a Procharger D1X

[KingLT1]

You can upgrade the pump in the Aux kit for a more headroom. Inline Hellcat pump.

[towerfab]

These are the obvious two choices I was originally thinking of but was hoping to avoid removing the aux pump set up. The guy that did the cam and port for me is running 1100 hp with the same low side so I thought I"d give it a try. Biggest difference is he's straight DI. not sure if the demands on the low side are different considering that.

[towerfab]

This is the kind of confirmation I was looking for. I too am running the larger dsx pump. I'm at 946 rwhp, 861 TQ at 15 psi running 75-80 % E. I'm having some issues with a few things, may be the tune but not sure yet. What kind of high side pressure do you see at low rpm, idle?

[towerfab]

someone mentioned there are a few pumps available at somethiing like 525 lph but that the amp draw might be an issue.

[Joshinator99]

Originally Posted by towerfab

This is the kind of confirmation I was looking for. I too am running the larger dsx pump. I'm at 946 rwhp, 861 TQ at 15 psi running 75-80 % E. I'm having some issues with a few things, may be the tune but not sure yet. What kind of high side pressure do you see at low rpm, idle?

High pressure (aka rail pressure) will vary greatly depending on load. It’ll be very “low” at idle (around 800 psi if memory serves) and will ramp up when under load. LT1 maxes out around 2175 PSI and LT4 systems typically max out around 2900 psi. Your DI system should be able to hold commanded pressure regardless of load. A low side not keeping up is the number one reason that the high pressure side drops out.

[towerfab]

Originally Posted by Joshinator99

High pressure (aka rail pressure) will vary greatly depending on load. It’ll be very “low” at idle (around 800 psi if memory serves) and will ramp up when under load. LT1 maxes out around 2175 PSI and LT4 systems typically max out around 2900 psi. Your DI system should be able to hold commanded pressure regardless of load. A low side not keeping up is the number one reason that the high pressure side drops out.

I definitely have some sort of serious issue with my rail pressure. 800 psi is
where it was at idle before the recent work, slightly higher with a very light load. I was running the 2650, lt4 low and high side with the dsx aux pump. After the cam and port installation I immediately noticed the rail pressure at idle fluctuating from 1100 to 2000 psi. I also noticed crazy fluctuations at a steady light to moderate load, say like 60-70 mph with no throttle fluctuation. I see the pressure at 1800 plus then suddenly drops to 1300, at which time I feel the car miss. I also notice the air fuel ratio go from 14-15 to over the top, 28+. While all this is happening I'm keeping an eye on the low side and it doesnt seem to be dropping, it stays pretty steady around 60 psi. I get p0300 among other 02 sensor codes. Seems like it takes about 10 to 15 minutes of driving before it starts acting up. I'm having some serious doubts about the installers skills. He thinks there is an electrical issue due to the fact that the car had a previous right front strike. My plan is to get it to another tech and tuner to hopefully figure it out.

[Joshinator99]

Originally Posted by towerfab

I definitely have some sort of serious issue with my rail pressure. 800 psi is
where it was at idle before the recent work, slightly higher with a very light load. I was running the 2650, lt4 low and high side with the dsx aux pump. After the cam and port installation I immediately noticed the rail pressure at idle fluctuating from 1100 to 2000 psi. I also noticed crazy fluctuations at a steady light to moderate load, say like 60-70 mph with no throttle fluctuation. I see the pressure at 1800 plus then suddenly drops to 1300, at which time I feel the car miss. I also notice the air fuel ratio go from 14-15 to over the top, 28+. While all this is happening I'm keeping an eye on the low side and it doesnt seem to be dropping, it stays pretty steady around 60 psi. I get p0300 among other 02 sensor codes. Seems like it takes about 10 to 15 minutes of driving before it starts acting up. I'm having some serious doubts about the installers skills. He thinks there is an electrical issue due to the fact that the car had a previous right front strike. My plan is to get it to another tech and tuner to hopefully figure it out.

If your O2 sensor situation is wonky it will definitely throw the car off since it uses them to adjust the air to fuel mixture once they’re warmed up. Given that your car seems to run better cold and acts crazy after “10 to 15 minutes” of driving it leads me to believe you have oxygen sensor issues or exhaust leaks. I would fix those before chasing anything else.

[jlaudio11]

Originally Posted by towerfab

I definitely have some sort of serious issue with my rail pressure. 800 psi is
where it was at idle before the recent work, slightly higher with a very light load. I was running the 2650, lt4 low and high side with the dsx aux pump. After the cam and port installation I immediately noticed the rail pressure at idle fluctuating from 1100 to 2000 psi. I also noticed crazy fluctuations at a steady light to moderate load, say like 60-70 mph with no throttle fluctuation. I see the pressure at 1800 plus then suddenly drops to 1300, at which time I feel the car miss. I also notice the air fuel ratio go from 14-15 to over the top, 28+. While all this is happening I'm keeping an eye on the low side and it doesnt seem to be dropping, it stays pretty steady around 60 psi. I get p0300 among other 02 sensor codes. Seems like it takes about 10 to 15 minutes of driving before it starts acting up. I'm having some serious doubts about the installers skills. He thinks there is an electrical issue due to the fact that the car had a previous right front strike. My plan is to get it to another tech and tuner to hopefully figure it out.

How much did you look into the dsx port before adding it? There are issues with rail pressure dropping but supposedly not enough to cause the issue youre having. It has to do with the direct injection, injection window and start of injection. There are basically articles about it in the tech section on dsx's website and videos on their youtube.

[James Montigny]

Originally Posted by towerfab

This is the kind of confirmation I was looking for. I too am running the larger dsx pump. I'm at 946 rwhp, 861 TQ at 15 psi running 75-80 % E. I'm having some issues with a few things, may be the tune but not sure yet. What kind of high side pressure do you see at low rpm, idle?

The DSX low side was enough for me at 640, but it couldn't keep up at 850+

I ended up going with a dual in-tank from Aeromotive (similar to the Fore setup).
I would so something like that if your goals are to reach 946 (with out without meth)

[towerfab]

Originally Posted by Joshinator99

If your O2 sensor situation is wonky it will definitely throw the car off since it uses them to adjust the air to fuel mixture once they’re warmed up. Given that your car seems to run better cold and acts crazy after “10 to 15 minutes” of driving it leads me to believe you have oxygen sensor issues or exhaust leaks. I would fix those before chasing anything else.

I suspected something involving the 02 sensors. The 02 sensor codes were the first ones I noticed. They popped up driving the car home after picking it up from the shop. I changed both sensors (only 2, cats were deleted) and there was no change, codes kept coming back. I'm wondering if there is an electrical issue that could be messing with the 02 sensors. I double checked the wires to make sure they were not making contact with the headers.