Are there many VB921 success? (fixed)

hobieboy · Post by **hobieboy** » Fri Jul 21, 2006 7:51 am

I'm just about to fire my system up and have the usual cold feet...

There's lots of questions / issues I have read about folks using MSnS-Extra with VB921, but surely there are many of you out there using it successfully?
And I'm talking about using VB921 to drive the coils directly and not with EDIS/TFI/...

Is there a checklist / receipe from those with success so that I can verify against my set up prior to 1st try?

screamer69 · Post by **screamer69** » Fri Jul 21, 2006 8:22 am

ive been using mine for about 11 months now running single coil of the vb921 and apart from haveig the dwell set to hight to start with i carnt say ive had any problems with it the 1st engine done 2k nearly running this way and the new engines run just under 4k so i would call it successfull

just make sure u have evrthing set right and u should be ok once its running just check the vb921 and its its running hot turn down the dwell ( not like i did and leave it )

Post by **jsmcortina** » Fri Jul 21, 2006 8:43 am

I've been running 4 channels of VB921 on my V8 since last August.

James

GodSquadMandrake · Post by **GodSquadMandrake** » Fri Jul 21, 2006 9:24 am

No success here. Mine still doesn't work.

Keithg · Post by **Keithg** » Fri Jul 21, 2006 10:43 am

Not running it currently, but I had it working for a while with no problems. The only issue I had was I needed to go to resistor plugs to get the noise down low enough to keep it from resetting.

KeithG

Posted by email.

boost junkie · Post by **boost junkie** » Fri Jul 21, 2006 10:49 am

vb921 on v2.2 board. No problems here. Had to crank it up to 4.2ms dwell to get rid off higher boost stumbles but the VB's aren't event getting hot.

bens_cab · Post by **bens_cab** » Fri Jul 21, 2006 12:58 pm

im using 2 vb921s to run 4 coilpacks wasted spark it runs and idles but if i put load on it the car bucks and backfires pops and bangs but will idle ok so not sure if that a sucess or not

my running dwell is 3.0 to high or low ??

screamer69 · Post by **screamer69** » Fri Jul 21, 2006 1:01 pm

bens_cab wrote:im using 2 vb921s to run 4 coilpacks wasted spark it runs and idles but if i put load on it the car bucks and backfires pops and bangs but will idle ok so not sure if that a sucess or not my running dwell is 3.0 to high or low ??

i would have though u would need 4 vb921s to run 4 coilpacks ????

bens_cab · Post by **bens_cab** » Fri Jul 21, 2006 1:02 pm

sorry my bad 2 banks of 2 so bridged

Peter Florance · Post by **Peter Florance** » Fri Jul 21, 2006 5:19 pm

I've been running one since March 2006

No worrys but I did set the dwell with scope as recommended.

Peter Florance
Owner - First Fives.Org - The E12 Registry
1981 Euro BMW 528i w/3.5L & Megasquirt Fuel Injection
1981 US BMW 528i "Repo Car"
http://www.firstfives.org
mailto:peter@firstfives.org (peter@firstfives.org)
ssr# 284

----- Original Message -----
From: screamer69 (screamer69@ntlworld.com)
To: megasquirt-mss@msefi.com (megasquirt-mss@msefi.com)
Sent: Friday, July 21, 2006 11:22 AM
Subject: Are there many VB921 success?

ive been using mine for about 11 months now running single coil of the vb921 and apart from haveig the dwell set to hight to start with i carnt say ive had any problems with it the 1st engine done 2k nearly running this way and the new engines run just under 4k so i would call it successfull

just make sure u have evrthing set right and u should be ok once its running just check the vb921 and its its running hot turn down the dwell ( not like i did and leave it )

v3 board running extra 29k megatune 225 2.0 8v vauxhall turbo 205bhp-232ftlbs@13psi (part mapped due to f***ed fuel pump) shes going to 28psi soon

My Success story http://www.msefi.com/viewtopic.php?p=129576&sid=69a6a593bc430dcd75e0dcc9a18b1def#129576

-------------------- m2f --------------------

This post is at:
http://www.msefi.com/forums/viewtopic.php?p=131772#131772

-------------------- m2f --------------------

Posted by email.

Karl · Post by **Karl** » Sat Jul 29, 2006 2:00 pm

I don't want to say they don't work because many people have great luck with them. However, I have had the damnest time getting them to run.

First go around lasted a few months. Then I think I fried a coil pack. not sure since the MS fried too. I have two MS ver 3 boards one now keeps the fuel pump running all the time and the other won't turn the fuel pump on.(Something with the vb921 is causing a grounding problem and frying the MS board) Got it running now but the second vb921 gets really hot really quickly. I changed coil packs and dialed the dwell down and it still gets really hot.

We need a way to completly isolate the vb921s from the Ms. I read a post on how to do this but now I can't find it.

Im going back to the factory power transistor as soon as it comes in.

MS ver3 MSnS 2nd gen Eclipes 4g63t engine.

SeanS · Post by **SeanS** » Sat Jul 29, 2006 3:22 pm

... just chiming in.

I've done about 40k miles on my motorcycle using the stock coils. Luckily I have a scope and was able to determine the appropriate dwell times empirically.

also, my bike is my daily driver 24/7 365 days a year - I wouldn't ride it if I didn't trust it. I'm not sure of others problems, but in my direct experience igbt's are pretty much bulletproof (even when you try to destroy them).

For those who are having problems, I wish you better luck and send me some mail to see if i can help you out in any way.

superchargingmachine · Sat Jul 29, 2006 3:52 pm

In a different thread we touched on the subject of running the grounds for high current devices through the MS circuit board. In my case it was a TIP122(replaced 2N2222) for PWM idle but I think the same would be true for VB921's. Jsmcortina mentioned that he mounts his VB921's to the case and runs a separate ground that doesn't run through the board. I think this is a good idea. I'm not an electrical engineer but it just seems like running a lot of power thru the ground plane of the board is a bad idea.

milosch01 · Post by **milosch01** » Sat Jul 29, 2006 5:27 pm

For what it's worth, I have been running 3 for a few months now. No real problems, other than a shorting plug wire which I found today. Car was braking really fast on 5 cylinders, and of course running like crap. But apparently it didn't hurt anything because all 3 VB921s are still firing. I agree that running a separate ground is a good idea, and one of these days I may take the advice.

By the way, what is the method for tuning dwell by scope? I have not run across any such document so far.

thechuckster · Post by **thechuckster** » Sat Jul 29, 2006 5:38 pm

mine has been in test mode for about 3 months now.

I have 2 VB921s mounted in an external alloy case along with a VR interface (LM1815), Shift-light hardware and driver for thermofan relay.

I run the earth for the VB921s back out to the engine bay along with two leads to drive coils (am using one at the moment, but have wired up to use two).

The earth going back to the ECU does connect to the alloy case and any shielded wires (VR at the moment) connect the sheath to the earth when they connect to the case.

edit 1: I though this was similar to Jsmcortina's but i now stand corrected ;)

I end up with two looms from cabin to engine bay - the <ignition> and <everything> looms.

With shielded cable for low V stuff (TPS, O2) i'm not getting interference from the ignition.

edit 2: i know it's not wise to have the ignition earthing so at another place - but i didn't want any intereference from the ignition system near the VR interface.. overly-cautious perhaps?

Post by **jsmcortina** » Sun Jul 30, 2006 3:38 am

Hmm, my setup isn't exactly as described, but I wouldn't claim it is ideal or perfect either.
I made my own daughterboard for the VB921 that I mounted inside the same case. I ran the signal _and_ signal ground wires between daughtercard and V2.2 board, but also ran additional power grounds out to my single point grounding where all the Megasquirt and wideband grounds connect to the vehicle.

Running a different ground connected to a different part of the vehicle could easily cause a problem - any ground potential difference might stop the VB921 turning on, OR turn them on randomly.

On a V3.0 board I just built up for wasted spark V8 I mounted the additional three VB921 on the heatsink and used the board grounds. I ran more grounds off the DB37. This engine (Cadillac Northstar V8) has only had minutes running on the engine stand so no firm evidence whether this is good or bad.

James

Scummer · Post by **Scummer** » Sun Jul 30, 2006 5:53 am

I'm using VB921 to drive my coilpack from a Mitsu 3000GT. Probably around 10k miles on it without any issues sofar.

ptegler · Post by **ptegler** » Sun Jul 30, 2006 7:55 am

I too am running my VB921 right in the base of the triple coil wasted spark coil pak.

I ran seperate power and ground wires as well as the three ground wires up via a seperate sheilded harness
http://www.teglerizer.com/fi/megasquirt ... odule.html

ptegler

matt325is · Post by **matt325is** » Sun Jul 30, 2006 1:36 pm

I've been running 3 VB921s with 3 MSD 2post coils for my BMW 6cyl waste spark for a few weeks now. Uses the factory 60-2 wheel and vr sensor. Runs like a champ.

matt

hobieboy · Post by **hobieboy** » Thu Aug 10, 2006 11:33 am

My own update - wouldn't call it complete success yet but I finally was able to fire up the engine

This is for a 6 cylinder twin plugged waste spark set up using 6 VB921s to drive 6 coils.

One lesson I learnt in my case - the CPU doesn't have enough juice to drive 6 VB921s. I ended up using a line buffer before the VB921 and now all my coils seem to be charging (still needs to confirm my dwell with a scope).

Megasquirt Support Forum (MSEXTRA)

Are there many VB921 success? (fixed)

Are there many VB921 success? (fixed)

Are there many VB921 success?

probs ish

Re: probs ish

opps

Are there many VB921 success?

vb92 :(

no problems here

remotely mounted multiple VB921's