Brent,
can you explain the reasoning for having the vacuum gauge going anti-clockwise (towards low numbers) for high vac?
Looking at the stock 'safe' map I see that the load (vacuum) bins reduce at high vacuum (low throttle) I thought that a standard distributor system using a vac. capsule would apply some advance there?
How would the wheel sensor offset function be adjusted if required?
Got V4 unit on car and working BTW! just need to understand what figures I need to plug in to get rolling OK
john
vacuum gauge
Moderators: JeffC, rdoherty, stieg, brentp
Hi John,
The gauge reads in absolute pressure. Higher pressure, the more the needle moves clockwise.
Since the unit can read boost from forced induction applications, the gauge needle moves backwards for vacuum, and forward for boost. Much like the real boost gauges you might see.
In Normally Aspirated mode the gauge is simply scaled from 103-0 KPa.
Are there any real-world gauges that move clockwise for more vacuum? Emulating what people would expect to see would be good- obviously reduces surprises and requires less 'explaining'.
Thank you for the feedback!
The gauge reads in absolute pressure. Higher pressure, the more the needle moves clockwise.
Since the unit can read boost from forced induction applications, the gauge needle moves backwards for vacuum, and forward for boost. Much like the real boost gauges you might see.
In Normally Aspirated mode the gauge is simply scaled from 103-0 KPa.
Are there any real-world gauges that move clockwise for more vacuum? Emulating what people would expect to see would be good- obviously reduces surprises and requires less 'explaining'.
Thank you for the feedback!
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Thanks Brent,
I had not seen an actual vac gauge before!. However the V4 gauge goes anticlockwise and the figures DECREASE (from 102 to zero), rather than increase (0 to 30 Hg) as per your examples.....although I notice they are both in Hg!! (see my previous old post
)
can you explain 'How would the wheel sensor offset function be adjusted if required?' (I mean your trigger offset....I understand the principle, just curious to know how one would know, or in which direction to make the adjustment)
john
I had not seen an actual vac gauge before!. However the V4 gauge goes anticlockwise and the figures DECREASE (from 102 to zero), rather than increase (0 to 30 Hg) as per your examples.....although I notice they are both in Hg!! (see my previous old post
) can you explain 'How would the wheel sensor offset function be adjusted if required?' (I mean your trigger offset....I understand the principle, just curious to know how one would know, or in which direction to make the adjustment)
john
The trigger offset is to adjust for slight sensor<->trigger wheel mis-alignments. Positive number, more static ignition advance, negative; less advance.
Also see: http://www.autosportlabs.net/MJLJ_V4_Op ... ger_Offset
The gauge in the software shows absolute pressure, in KPa, so it's an inverted concept from inches of Mercury. Smaller number, less pressure (higher vacuum). So if the physical gauge shown here were in Metric KPa, the values would decrease in an anti-clockwise manner as well.
Also see: http://www.autosportlabs.net/MJLJ_V4_Op ... ger_Offset
The gauge in the software shows absolute pressure, in KPa, so it's an inverted concept from inches of Mercury. Smaller number, less pressure (higher vacuum). So if the physical gauge shown here were in Metric KPa, the values would decrease in an anti-clockwise manner as well.
Offset
If I run the EDIS-6 without the megajolt should that give me exactly one tooth BTDC with a strobe (10 degrees) Limp-Home mode to enable me to check timing is accurate or in need of offset function?brentp wrote:The trigger offset is to adjust for slight sensor<->trigger wheel mis-alignments. Positive number, more static ignition advance, negative; less advance.
Also see: http://www.autosportlabs.net/MJLJ_V4_Op ... ger_Offset
john
For your initial calibration, just check for the 'limp home' 10 degrees of advance. If you're at 10 degrees, then you're spot on for when the MJLJ is controlling the advance: leave offset at zero.
As an example: if you observe 11 degrees, then you would put in -1 for the trigger offset; correspondingly if you measure 9 degrees then you would enter +1 as the trigger offset.
As an example: if you observe 11 degrees, then you would put in -1 for the trigger offset; correspondingly if you measure 9 degrees then you would enter +1 as the trigger offset.