Can 50 lb/hr injector support 650hp flywheel?

[streetking408ys]

'13 Sierra Denali 1500 AWD 6.2 L9H w/Magnuson TVS1900 pump 93 octane

About to start the build on this truck. Just got the Magnuson and it came with 12613412 injectors (50 lb/hr @ 58psi). Does anyone have 1st hand experience with knowing whether these injectors will support up to about 650 flywheel horsepower? Looking to make 600-650 flywheel depending on how the truck runs with the combination, how much boost we make at X blower RPM along with what the IAT's end up wanting to do. I just want to make sure I'll have enough injector to cover a max of 650hp flywheel. As far as fuel pump I was told the stock flex fuel pump will cover 600-650 wheel hp on pump 93 so the factory pump should suffice. Any insight/experience would be appreciated. Thank you in advance.

[blindsquirrel]

750 at the crank but only if 1:1 referenced regulator, so that fuel pressure remains 58psi higher than whatever is in the manifold. 12613412's, referenced & 58psi, will do 650 at the tire. Just.

650 at the crank if returnless and boost doesn't go over 15psi. If it's returnless, then boost has the same effect as lowering the rail pressure by the same amount - 10psi boost makes the injector flow the same as if you only had 48psi rail, 15psi boost same as 43psi rail...

[Alvin]

That's going to be close.

The early magnacharger kits for 2010 6.2 F bodies came with LSA injectors (52) and they would be out of injector if you did anything to them like a intake/headers.

[JayRolla]

I would think about getting something larger. A stock LSA engine makes 556hp and my injectors were maxed with intake, headers, 3" pipes. So was probably around 500-520hp flywheel.

Watch that fuel pressure and IDC's. If the pressure drops drastically the IDC's will rise. Want to stay under 80% IDC ideally and definitely under 90% when boosted.

[blindsquirrel]

Yeahbut the factory-rated 638hp LS9 uses the exact same 12598646 injectors...

[Alvin]

Yeahbut the factory-rated 638hp LS9 uses the exact same 12598646 injectors...

CTS V and LS9 also raise fuel pressure under WOT.

[blindsquirrel]

And see my earlier post about limits with different base pressures/fuel system types.

[Alvin]

And see my earlier post about limits with different base pressures/fuel system types.

So rip everything out for a custom fuel system so you can get a boost referenced regulator that bleeds back after shut down and does a sloppy job at 1:1 or... just pick proper sized injectors for the application?

[JayRolla]

Yeahbut the factory-rated 638hp LS9 uses the exact same 12598646 injectors...

I was around 75% IDC if I remember correctly. But I did find a guy making 660whp on an LS9 with stock injectors hitting 96%. So, he probably be fine for that at the crank.

[blindsquirrel]

No don't rip everything out - get a quality regulator and not one of the shitty carb-regulator-with-a-fat-spring-in-it, put it down by the tank, add a single port in the tank or hat for a return line. Still has a single feed line up to the stock single-inlet rail, there's no need to circulate all the fuel up through the hot engine just to bring it back again unused.

Have you seen those bulkhead fittings that're like a rivnut? Drill hole, run a bolt through it to crimp in place, install o-ring fitting.

[blindsquirrel]

So what's the correct solution for Gen 3s and E40s where the injector tables just stop at 0 kPa VAC? Just let it slope down until it gets to 0 and then flatline, even though the flow rate keeps dropping as boost builds? I know flow rate is the least important spec and the Offset isn't a big deal with the kind of PWs you see with any significant load, but still.

[streetking408ys]

Thanks for the input guys. Screw it, I'm just going to throw a set of 1050x in there and I"ll never have to worry about injector and I know the idle/driveability will be good. Also we get near the upper edge of what the fuel pump can supply we will have duty cycle to throw at it in the event of some pressure loss.