minho78

You need low impedance injectors. I think shape is selling a set of Siemens #55 which is enough for you setup.

Chris White

I'd be happy to tune it....after installing a TecGT....

buddd

how high of psi can i go with #55s? i plan on eventually way down the road upgrading my HG so i'd like to buy injectors once, are 55s fine to 20psi? if so i should be alright.

Chris White

You shouldn’t use low impedance injectors with the DME unless you add resistors.
If you go with the dropping resistors I would use the Siemens 72 lbs injectors.

buddd

one of you says high impedance the other says low.. what should i do? lol

lart951

buy a piggy back it's easy to tune with it, the mafterburner or either the power perfect they are no too expensive.

I used Siemens 55# injectors and had a similar set up as yours.

buddd

cant i just get a chip burned for my setup and be done with it? i plan on running the same psi and 93 octane every time i drive it

Chris White

Panic.

Low impedance injectors are usually better performers - they can open quicker than high impedance....if your system works with them.

Low impedance injectors are a ‘peak and hold’ injector – the initial opening current will reach 4 amps and then a lesser current (typically 1 amp) is needed to keep the injector open. The wave form is not a square wave signal.

High impedance injectors are a saturation injector – they are driven by a simple square wave – usually around 2 amps. Not as quick to open as a low impedance injector.

You can use a low impedance injector in a high impedance system by using resistors to minimize the current draw. High impedance control units systems are not built with injector drivers designed to put out the current needed to run low impedance injectors. – They will work for a while…but the injector driver may eventually die from overloading. You also won’t get the nice peak and hold signal so the low impedance injector will not perform as well.

All that being said – the 944 system is actually right in between the two! It’s a fairly uncommon mid impedance system. Some folks have run low impedance injectors without issue – I would still recommend using some resistors to better match the injector to the driver.

buddd

fair enough, which resistors should i use?

Chris White

72 lb seimens injectors with resistors.

Ian Carr

If by some miracle you can get a hold of Special Tool he lives over in bethel. He MIGHT be willing to help.

buddd

MAX 951 will burn a chip with my mod list, as long as I change my maf, so i'm just going LR stg 2 maf kit. anybody want to buy the autothority maf w/ intake tube and partial wiring harness with plug? PM me!

spyder348

what kind of turbo you running bud

buddd

Turbonetics T61 Ball Bearing Turbo (SFR Stage III Turbo, Oil and Water Cooled)

spyder348

nice. 72 lb. siemens injectors with 1 ohm 25 watt resistors(2 needed).