How does this look for using 6 VB921s in wasted Spark?

All Megasquirt 1 support questions. See also the Documentation

Moderators: jsmcortina, muythaibxr

Post Reply
Jon k
Super MS/Extra'er
Posts: 1256
Joined: Fri Oct 14, 2005 10:28 am

How does this look for using 6 VB921s in wasted Spark?

Post by Jon k »

Ok so I am not sure I am doing this exactly right. Let me summarize my board first:

MS-1 V3 completely default, VR sensor setup, and no VB921 @ Q16... I omitted it originally.

Now what I have done is placed (6) 680 Ohm resistors on the topside of the proto area. Underneath, I have the leads from the resistors uniting at each top point (Top of R26, R27, and R29). Splicing the leads was the only way I could think of splitting the top points to go to two resistors. They are sturdy and clean (a lot cleaner than the macro photo shows, the photo shows a lot of dust, etc). Next, on the other end of the 680 ohm resistors, but also underneath, I have 6 wires, 3 pairs of color matched hookup wire. These will be going to 6 VB921s that I have mounted to a second heatsink directly under the original and on the underside.

Image

Image

I only have a couple questions:

1) The directions on the MSnS-E site say to use this diagram for the 2nd, 3rd, 4th coils on a V3...

Image

It shows a different diagram involving IGBTIN and IGBTOUT as well as IGN and what not, but that is for using the first coil I think... but since I don't have the original VB921 in Q16 location, and it appears that the diagram using IGBTIN/OUT/IGN is just jumpering the signal around, I think I can ignore that diagram? But I am not sure.

2) Where do I ground these guys to? I see the "GND" area in the Proto area but there are only 2 holes for ground and I need 6 ground points total for the VB921s... recommendation?

Thanks.


Edit:

Worked on it a little more... I mounted the VB921s on a second heatsink directly below original. I have them set up in pairs Spark A, B, C left to right. Does this look good so far? Also unsure of where to pull the ground for the VB921s still.

Image

Thoughts?
Post Reply