DIS: aftermarket system

[LGAFF]

OK the tuning experts can let me know if this helps....Lingenfelter apparently knows how to set up a 16 injector systems:

http://www.ls1tech.com/forums/pcm-diagnostics-tuning/1441617-looking-advise-running-16-fuel-injectors.html


Some aftermarket engine management systems can control 16 injectors. We did a roughly 1500 hp 540 BBC engine using BigStuff3 EFI and had 8 primary and 8 secondary injectors (again in a custom fabricated manifold). In this application we also staggered the injector operation so that we were not using the secondary 8 injectors except at higher boost levels when the first 8 were near maximum duty cycle. The BigStuff3 software allows you to adjust how the two sets of injectors are controlled. In this application we also had the fuel rails separated so that if the customer wanted we could add a second fuel tank, pump and feed/return line and then the second set of injectors could be fed with race fuel. This would allow you to run low boost/standard octane on the primary injectors and then run high boost/race gas with the secondary injectors.

[LGAFF]

Hell he mentions the LT-5!!!

As an example of how nothing is ever new, the 1990-1995 ZR1 Corvettes (LT5 engine) have 16 injectors. The engine is a 4 valve DOHC engine with an intake manifold that has individual runners to each valve. Each injector feeds a valve/port. The secondary ports have a bypass valve in them. When the bypass is closed the secondary port is closed and the secondary injectors are not operating. When the secondary port opens the secondary injectors become operational. GM uses the same size injectors in both locations and then just halves the pulse width when the secondary injectors come one so that the effective fuel flow stays roughly the same (easy way to do it given the ECM processor power and IO they had available back then).

[XfireZ51]

Probably not cheap. But the issue is less the injectors and more the ignition module.

[LGAFF]

Wow $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$

[LGAFF]

Seems like he understands the basic GM setup?

[XfireZ51]

One of the other ways of increasing fueling capacity is through increasing fuel pressure. I believe the C6 ZR uses a similar strategy with 3 stages of FP changes. Using 16 injectors on our ZRs allows a controllable pulse width at idle while still having sufficient fuel
flow at 7000rpm. Prior to the ZR, I worked for several years on boosting power on my Xfire from stock 205 to modded 350chp. The stock injectors would go static trying to keep up w WOT fueling. Larger 80psi injectors would work ok for WOT but you couldn't control pulse width well enough for idle. The solution was a modified ECM code that implemented a variable Base Pulse Constant based on Vacuum. This required the use of an external fuel pressure regulator that varied pressure vs. vacuum. So my fuel pressure would vary from
10psi at idle to 20psi @ WOT. The ECM code accommodated the change in pressure constantly recalculating fuel flow. Pretty cool stuff.

[LGAFF]

Dropped a note on the LPE facebook page to see what they think