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Join Date: Jun 2001
Location: Sweden
Posts: 5,771
Originally posted by Lukesportsman
Don't most guys using Bitz/MSII use Ford injectors? These would be high impedence rather than the low impedence peak and holds. From my experience (I race Fords) and my brother was the injector engineer at Honda in the 90's, the Bosche Ford style doesn't prefer 5-6 bar pressure. Most Ford injectors are designed to have a base of about 3 bar or 45psi to max flow pattern. This obviously is boost referenced so 3 bar going to 4 bar under boost.

Have your experiences shown different, Goran in respect to Ford style injectors? I brought this up because those converting with Porsche style injectors (Carrera) vs. those using Bitz or other have different requirements. From the test cell photos

Chrysler injectors flowed the most, appearing like a garden hose with miserable pattern. Honda was testing a lot of designs in the late 90's but I don't recall any Porsche injectors.
I don't quite understand what you are trying to say?

Most injectors need differential fuel pressure (across the injector) of 3 bar. That's where the spray pattern is optimal. This pressure is governed by FPR. Actual deadheading system pressure for particular pump is not critical as long as pressure is higher than 3 bar + boost and pump can deliver required mass flow at that pressure.

Remember, even if FPR raises system pressure to 4 bar at 1 bar of boost, injector itself will still see only 3 bar as it has 1 bar of boost "to fight against". Whole point of FPR is to obtain constant pressure across injector.

Further on, there are few injector manufacturers. Bosch, Siemens and Nippon-Denso are one of biggest.

There are two different types of injector coils: low impedance and high impedance. High impedance are cheaper to make, need less expensive EFI electronics annd are fitted in comercial vehicles.

Low impedance injectors require more expensive peak & hold circuitry which makes them open faster, and are usual type of injectors where you need good dynamics in pulse-width-ratio and where flow rating goes past 400cc.

There are also different types of nozzles. Like pintle-type, disc-type, multi-hole etc.

As far as I know, neither Porsche nor Ford makes their own injectors. It's all just a pick from AC Delco, Bosch or something elses shelf.

You can use any injector you like with MSII. Fully decked, it supports both low-Z and hi-Z injectors. Which one is up to user.
Thank you for your time,
Old 11-29-2006, 08:45 AM
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