by Michael Decipha Ponthieux
Last Updated: 1-13-2014

Click HERE for Injector Data

Injector Pressure (Adjustable Fuel Pressure Regulator)

the fuel pressure REGULATOR regulates the injection pressure to remain CONSTANT

when the manifold is under vac the fuel is being sucked out of the injector thus MORE fuel is sprayed

when the manifold is under pressure (boost) the fuel is being pushed back in the injector thus MORE pressure is needed to keep the injector spraying the same amount of fuel

here's an example
Manifold Pressure MAPFuel PressureINJ PWAmount of Fuel Injected
-18 in hg292.00.0063
0 (atmos)392.00.0063
18 PSI582.00.0063

as you can see in the example above , the fuel pressure is adjusted to REGULATE the injector pressure that way the injection pressure remains constant

exactly why they call it a REGULATOR

Why 80's?

I highly recommend the 80s because they are excellent injectors and have very accurate low pulsewidth control, the siemens deka high impedance injectors are a completely new design, up until about 8 years ago, all injectors shared the same basic design, if you cut open an injector from a 1988 mustang or a 1998 mustang the internals are basically identical which is 30 year old technology, it wasn't until a few years ago the modern high flow OEM grade injectors that are available today were released, these new injectors no longer have the terrible low pulsewidth control that large injectors are notorious for

I highly recommend the 80s because they have excellent low pulsewidth control, excellent atomization, and very linear flow characteristics, and when buying new injectors the price doesn't really fluctuate that much based on the injectors size.

these injectors usually sell for $45/each or $360 for a complete set of 8, i recommend to shop around, and be on the look out for fakes, as of lately there's been a bunch of knock off china made fakes hitting the market that are absolute garbage, only buy from a trusted vendor

most of the the vehicles I tune end up getting either a larger turbo, more nitrous or additional engine mods and thus have to get larger injectors to support it which then requires a re tune, however, most of these engines would not have to be re tuned if the larger injectors were in there from the get go, so it saves both of us the hassle lol

Thats why I always recommend 80s since there's no downfall and they aren't much more price wise than a different sized set. If you spend a little more and do it right the first time, that's one less thing you have to worry about later on down the road when you decide you want more, sooner or later you will want more, i can guarantee it

just so you know, you don't have to get the 80s if you don't want to, but that is what i recommend if you ask me, which ever size you decide to go with is fine, so long as you get injectors that will support your engines needs you won't have anything to worry about (until you decide you want more)

If you feel that these injectors are too large for a stable idle, rest assured as the Siemens Deka are the OEM injectors on the factory CobraJet vehicles.

Various Injector Offsets can be had from Injector-Rehab

For reference, the Injector Positive Ignition 12v+ Relay feed should always go to the right side of the connector where looking at the connector with the center indention down. Injector Connector

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