550cc injectors is not a new topic but most of the posts related to this size injector are a couple years old so I thought it would be good to revisit the subject becuase of the new engine management systems available.

I made the mistake of installing 550 cc injectors with the following setup:

550 CC Injectors
Xtreme Boost Ported head
Wiseco 8:8:1 pistons with .020 overbore
Cosmetic turbo head gasket
Eagle H-beam connecting Rods
Crane #14 cams
Aem adjustable cams gears
OBX intake manifold ported
OBX Fuel Rail
AFX Underdrive Pulley
55 mm throttle body
Mopar timing tensioning bearings
Mopar hydraulic tensioner
Mopar water pump
Melling Oil pump
Fluidyne Radiator (not installed yet, waiting on fan)
ARP Head stud kit
SSI Valves

Clevite 77 Engine Bearings
Corteco engine gaskets



Turbo

Hahn Race Craft Super 16g
Hahn Race Craft front mount intercooler
Hahn Race Craft mandrel bent pipes
Blitz blow out valve

Exhaust

Hahn Race Craft downpipe
HKS Catback

Transmission
5 Speed conversion

Misc

Greddy Turbo Timer
Greddy oil pressure guage
Greddy Boost Guage

I am curently using a SAFC to tune and as you can imagine I am running way too rich.


Some of the posts in this forum make it seem like 550cc injectors are the max possible if I use a AEM or MS computer. Is this possible or do I need to pull my engine again and replace the injectors? I used an OBX intake manifold and taking just the manifold off is not an option. If I do get an AEM or MS computer is the turbo still too small for this size injector?

I'm using the Super 16G, the MegaSquirt, and some Accel 440's, and I've been running 18 psi on the injectors. My duty cycles are pretty much maxed out (85-90%)at 18 psi, so take that into consideration of how much boost you want to run with that turbo. A set of 550's would get you really close to the maximum output of the S16G...roughly in the 25-27 psi range. There have been people running much larger than 550's with the Megasquirt, so dont worry about that. I've tuned a 1G AWD Talon with the MS, and he runs 550's, and tuning is not deminished at all with those size injectors. Idles and cruises perfectly. Once your idle/cruise injector pulsewidths get into the 1.7ms range or below, then tuning idle/cruise gets to be more problematic. YOu would have to run roughly 650cc+ injector sizes to get that low.

I have 550cc injectors with a MS and a 50 trim t3/t4. at 5500k+ i am def maxed out at 95% duty running 15psi.

Dougie runs 780cc injectors and has no problems at all with idle ect.

Thanks for the help.

I guess I am in the market for a MS system then.