i plan to run stock 550cc primaries and 1600cc secondaries. what injectors do i need to get? do i still need to get low imp since i have an s4, or will a normal bosch type injector work like sold on speedmachine performance or the RC ones?

 

I have s5 550 high impedence primaries. I use a KGparts 2ndary rail with bosch 1680 injectors, which are low impedence. I removed lower o-rings and pintle caps from the 1680s. I still have the air diffuser in and cut a piece of fuel hose to fit snug and act as lower seal. Search 2nd gen sections and you can find write ups on modifying 1600s and using stock fuel rail.

What haltech are you using? For our cars setup the E6K does not care about impedence, not sure about other haltechs.

 

e6k. i searched and didnt come up with muhc, if you know of any threads to point me to that would be nice...if not i will keep searching.

 

im finding stuff now....

 

marren and few others make firrect fit injectors that can be used in the stock rail

http://www.injector.com/fuelinjector...c6bf5b6ef63db8

the ones labeled as pro import injectors fit the stock rail and engine and use standard bosch plugs.

 

what about the ones that arent pro import? are they the ones people are modifying?

 

yes, the ones you buy from marren, I have a set have been modified by them. They fit very well.

 

The Pro Import/Japanese injectors are a Denso body that is a direct replacement. The other injectors are a Bosch body. They require the rails to be bored slightly and the pintle cap doesn't fit the diffuser exactly right. IMO there is no reason not to spend a little extra and buy an injector that fits so that you don't have to worry about them leaking air or fuel. All of the Marren injectors have the sqaure body Bosch style connector so they won't be a direct plug in for an S5 harness with the oval style connectors. For $5 more than what SMP gets for their Bosch injector that's not a direct fit you can get a Denso injector from Marren that pops right in.

You can run high or low impedance with the Haltech. Doesn't matter to it unless you're ganging together a lot of injectors and overloading the driver.