History of MembersPage/PhatBob/UserGuide
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2015-10-07 06:48:22 . . . . catv-80-98-222-153.catv.broadband.hu [minor: Low-Z notes]
2014-04-24 10:19:26 . . . . catv-80-98-222-153.catv.broadband.hu [linked new, pdf version]
2014-04-24 10:18:51 . . . . catv-80-98-222-153.catv.broadband.hu [linked new, pdf version]
2014-02-20 01:22:20 . . . . catv-80-98-222-153.catv.broadband.hu [use VemsTune not MegaTune]
2012-04-11 20:36:46 . . . . HusseinHolland? [add photo of Tial WG]
2011-09-20 18:50:00 . . . . MembersPage/JasonRussell [Started VemsTune updates]
2010-07-01 06:42:57 . . . . MembersPage/PaulF [Replacing links to pictures from phattransmissions.com to vems.co.uk]
2010-07-12 09:41:15 . . . . MembersPage/MattiasSandgren [Built-in miniterminal exists in MegaTune]
See complete list (163 entries)


Changes by last author:

Added:

When planning, usually best to start from the

* [product options]

* and for settings see VemsTune and [VT help] as the primary source of info

Please use the newer version [from here]

----

OBSOLETE old version ...

Changed:
Navigate to the directory that you installed MegaTune into and double click on the megatune.exe application, and you will be presented with a window:
Download and start VemsTune, and see [vemstune tutorial videos and help].

This page has some "MegaTune" reference and screenshots. MegaTune is the old (very old) tuning application, superceeded by VemsTune a long time ago. You'll find similar (just better, nicer and more) dialogs in VemsTune. In short, forget megatune and always use VemsTune (which is newer, uptodate, better, nicer and more complete, supports easier firmware upgrade, warns for many suspicious - likely unintended - settings, and supports the CRC-protected communication, which is the only way to go).

Changed:
VEMS can control anything from 1 to 8 fuel injectors individually, although it's also possible to control upto 16 injectors grouped in twos, although you will need to bare in mind that the grouping of the injectors will change the impedence that VEMS controlls. Low Resistance/Impedence (LowZ) injectors need some additional attention which is explained in a later section titled Using LowZ injectors
VEMS can control anything from 1 to 8 fuel injectors individually, although it's also possible to control upto 16 injectors grouped in twos, although you will need to bare in mind that the grouping of the injectors will change the impedence that VEMS controls. Low Resistance/Impedence (LowZ) injectors need some additional attention which is explained in a later section titled Using LowZ injectors
Changed:
Fuel injectors broadly fall into two types, those with a low resistance when measured with a DVM 2-8Ohm called Low Impedence, and those with resistance readings above 12Ohm High Impedence.
Fuel injectors broadly fall into two types

* those with a low resistance when measured with a DVM 2-6 Ohm called Low Impedence (many LPG injectors are low impedance)

* and those with resistance readings above 7 Ohm High Impedence.

** the 5.6 .. 5.9 Ohm 1600 cc/min Bosch 0 280 150 846 / 0 280 150 842 (unavailable in 2015) are theoretically low-Z, but most installers used them as high-Z (100% duty, 25.5msec configured, without series resistors): at low duty the heat is insignificant, and at high duty the fuel flow providing sufficient cooling, no overheat failures reported

Changed:
Although it is possible to drive LowZ injectors using VEMS's advanced Pulse Width Modulation (PWM), further tests on a range of injectors have shown us that the optimum strategy is to use the inline resistors. The recommended resistor for 2ohm injectors is a 6.8ohm 50W resistor, when used with the Transient Suppression diode you will have very high resolution control even with high flow injectors (this has been tested on 1000cc Delphi injectors and has provided massive improvement at lower engine speeds)
To drive LowZ injectors using VEMS's advanced (and energy efficient) Pulse Width Modulation (PWM):

Flyback option: [LowZ active flyback 4ch (or 8ch)] recommended (required before PWM-ing is enabled).

* optionally as an upgrade (if it was forgotten at order-time or concept changed later):

** [active flyback addon], v3.8 has separate pads for convenient mounting.

Series "inline" resistors might also work: 4.7 Ohm (preferred) or 6.8 Ohm (50W in any case). Advantage: can be applied with ECU ordered without LowZ active flyback.