My 2016Z has been modified with vv 2 cam , arh headers, ported heads springs, pro chg f1A, circle D stall,, ported throttle body, just installed a NX Express 150 shot. Now concerned about running out of fuel. Is this a legit concern? If so do I need another pump or maybe 2. What about injectors? What is meant by high and low side systems? Thanks in advance

 

Absolutely I would be worried about running out of fuel with those mods. Are you running on ethanol at all? Ethanol requires approximately 30% more by volume to equal the same power output as pump gas (93, etc). Even on pump gas you will still want a low side. What size fuel lobe is your cam? They run up to 34%'ish. That bumps up your high side (High-Pressure Fuel Pump = HPFP), which is responsible for taking your low side (in-tank pump) @55-60'ish base fuel pressure (which increases 1psi per 1lb of boost) and bumping it up to 2500-3000psi via a mechanical fuel pump which actuates off your camshaft fuel lobe (larger fuel lobe = more high side pressure). Your DI (direct injection) fuel injectors squirt fuel into your cylinder (literally), not your intake runner (as port injectors do), thus they require insanely high pressure to overcome the cylinder pressures. They also only operate within a 5-millisecond window due to the piston timing so you can only do so much with bumping up the DI system via HP Tuners (or tuning software). Most can do two things, get a larger cam lobe, you can buy 30% larger DI Injectors ($3000+), buy a larger bore HPFP ($$$$), and that still only gets you so far once again due to that 5-millisecond injector duration window. The only other two ways to go is spraying methanol (ALKY/SNOW kit, Alky recommended) OR the right way and the most complex way, unfortunately, is going PORT INJECTION. That adds 8 more port fuel injectors (like GM did with the ZR1) and using a CRFUELER (CrawfordRacing.com) Holley ECU you can control those 8 injectors by coming online when you start running out of factory DI fuel. That's what's so nice about port injection, it only comes online when you need it, keeping your DI system stock and driveability/idle quality nice and normal. There are other systems out there for port injection such as ProEFI (been there), and MegaSquirter, maybe some others.

But in your case, I would add a low side, to begin with. You can do a FORE in-tank drop in (double or triple depending on future goals), OR, as I did, do a custom low side which works by cutting a hole in your driver side tank and adding a billet flange pickup tube and a custom secondary fuel pump (MagnaFuel 750 in my case), with Aeromotive micron filter, and Aeromotive Regulator with custom -8an feed lines from the rear to the front, and -6an return (I would recommend the same return size as feed) line back to tank. You can see my custom build thread (search my name) and see pics of my custom setup. My Holley ECU kicks on my secondary fuel pump on boost/accel/rpm OR you can use a HOBBS Switch to complete a circuit @7psi, for example, to kick on the secondary fuel pump. You don't really want that running full time, no need for it. I needed to be this crazy for my build since I am running a Holley Port Injection setup with F1A-94. Port Injection requires more fuel, especially on ethanol. So you need dedicated lines from back to front. IF you are not on ethanol and sticking with a 150 shot you may get away with the MTI low side system which I believe ties into the rear fuel quick connect, thus using your factory fuel line up the side of the torque tube. That works for smaller upgrades but won't work for port injection. Especially if on ethanol.

 

Have you checked any logs? HP Tuners should show you a nice fuel pressure chart line overlayed on RPM, Boost, Time. That will show you if your low side fuel pressure is falling off. You will see a requested fuel pressure by the ECU, usually around 75-80psi, and your fuel pressure should try to meet that. If it's falling off up top then you absolutely know a low side is due. Don't drive it WOT for long like that you could be running very lean, which we all know is bad. These aren't cheap motors to rebuild.

 

Think I forgot to mention I am spraying methanol with dual nozzles. Will change the equation? Will yet need to install dual pumps?

 

who is tuning the car? yes for sure spraying meth will help but I'd think about going direct port so you don't hurt the blower and get better fuel distribution

 

You dont have a low side already, I'm surprised with those mods... Personally I'd address the lowside then go to port injection with fuel controller. Then fuel will not be an issue again.