Hello everyone, i have a 96 Z28 im in the middle of building. 350 to 383 Stroker and im also beefing up the 4L60 trans. Im trying to figure out what type of injectors and external fuel pump i should use but im not sure what is a good flow rate or psi. If anyone could help me out it will be much appreciated.

 

What is your estimated goal for HP at the flywheel? Are you doing ported stock heads and cam? Will there be a “power adder” (S/C, turbo, nitrous)? Other mods? It’s flywheel HP and whether there is a power adder that determines required injector size and fuel pump capacity.

Why did you indicate an “external” pump? Generally you can handle significant HP simply by replacing the in-tank pump, and there are even dual in-tank pumps for huge HP.

And I'll move this to a “tech” forum. Not a lot of tech help in the “New Member Intro” forum.

 

im still figuring out how this site works bare with me

the machinist who did my block said it will be about 400hp at the flywheel and the stock heads are ported and i have an erson cam in it. Im not running nos or anything else just engine and trans. The only reson i wanted an external fuel pump is because it is a pain in the butt dropping that tank. And thank you for moving it to the right spot, im still trying to figure this site out

 

And i dont want to put the trap door mod in my trunk

 

If ease of access it the goal, you will save yourself about a million headaches by just making the trap door modification, versus running an external pump. For super easy installation and stock functionality, look at Racetronix.

 

I do NOT want the trap door mod my mind is set on that.

 

The trouble and cost you are adding to run an external pump is far and beyond cutting the trap door. You can use decent kits to make the job professional example.

In the end, pumps don't need to be changed often, so this is really a situation of cutting off your nose to spite your face. If you don't want to cut the door, just pull the tank half down (the filler neck is the issue), and replace the in tank pump. The trouble of doing an external pump is WAY more effort than either of the offered solution, with no benefits.

 

I can appreciate that you don't wanna do a trap door, but Drew is right on this--the cost/benefit element doesn't calc well for an external pump. All you're doing is avoiding some work and inviting more. It sounds like you've done--and will be doing--quite a bit as it is. Yankin' the tank is a picnic compared to all the engine work you're doing. It ain't the end of the world.

Did the trap door myself, and if I need to swap the pump or lsu, can do so in < an hour. This turned out to be mighty handy; the first pump I got was bad and hadda return it. There's nothing to indicate the door's even there.

But diff strokes and all that. Bottom line: you're better off either yankin' the tank or doing the trap door.

 

Depending on your exhaust, you could upgrade yourself and spend a ton of money... I found a good condition plastic tank in a 2000 V6 which is about 15 pounds lighter, and has an extra gallon capacity. I am now in process of installing a Squash performance dual Walbro 450 setup with a hotwire/hobs setup. Here is a break down in cost (which pains me to type out):

1. Plastic tank (self pull) - $75
2. K&N vent filter - $15
3. Lines and fittings for the vent - $25
4. Random wiring/connectors/loom - $50
5. Squash Performance Duel Pump with wiring - $995
6. Russel quick disconnect to AN fittings - $35
7. XRP 8AN feed and 6AN return lines/fittings - $500

I have a Speed Engineering dual exhaust. With the plastic tank, the filler neck disconnects, so I am able to pull the tank by taking off the tank heat shield, pan hard rod and brace, and the drive side exhaust (disconnects at the axel). I have not done the trap door either, but have been considering it with the right kit to cover the door.

 

Let's respect the stated preference of not wanting to cut the trap door. Move on.

At 400 HP at the flywheel, you could get by with 28 #/HR injectors (flow rated at 43.5 PSI, which is the stock pressure for the LT1 fuel pressure regulator). Personally, I would recommend running 32 #/HR injectors, to allow for future mods, the engine making more than 400 HP, etc. There is no downside to running injectors that are a bit larger than the minimum required. As long as the correct flow rate and offsets are programmed into the PCM they will work fine. The Bosch III injectors have been shown to work well with the LT1.

At 400 HP the stock pump might be OK. I'll have to check my calc spreadsheet.

If an upgrade is needed, drop the tank as you prefer. If you want to use an external pump, you definitely have to drop the tank and have a sump of sorts added and weld a -10AN connector to the low point. Location of the pump can be a challenge. And in a rear end collision fire hazard would be increased (shades of the Pinto). Not overwhelming, but totally unnecessary. The location of the stock pump is very good with respect to safety. Once the tank is down, replace the stock internal pump.

I run an internal pump (Bosch 205 LPH high pressure) that can support 500 HP. You don't need that. Then I also have an external pump with an internal baffle and a -10AN connection at the very bottom/rear of the tank. That pump only runs to supply additional fuel when the 300 HP nitrous system is armed. I would definitely opt for an upgraded in-tank pump with no power adder. And I don’t have a “trap door”.

 

Bosch III vs. stock Multec. Scroll down to “Bosch 24 vs Multec 24” video.

https://fuelinjectorconnection.com/pages/videos

 

Thank you everyone for the feed back i will be putting it to use. I hope everyone has a great day