rb20det / rb25det vems issues

[Andy-c]

hi all im looking into fitting vems on a few skylines 2 r32 gtst's one for drift use only and one for fast road track use the other on an r33 gtst for fast road and track use also , i have been asking around for any known issue's with the vems unit on these engines and had a few people say there no good but when pressed thay cant tell me why or what the issues are
i have been advise to ask on here if there are any known issues and work arounds
and also to seek the advise of Rob on here

a little about me i have had small experiance building a megasquirt and would be looking to build the units myself mainly for eperiance and so i know where to go if any problems in the future and im quite handy with a spanner , not afraid of a challange if something isnt working right , im currently using an apexi power fc on a 200sx s14 and like the ability to tweek on the fly and belive the vems is a lot more useable in this respect hense why i am here

look forward to any help and advise any one is able to offer
cheers andy

[rob@vems.co.uk]

Well theres been a lot of shit slung at VEMS, and yet people forget that its been running the Time Attack S13s for about four years without a single issue.  People love bad mouthing things, yet have not one tangible thing they can point out as a fault.
If you look round on here you'll see that there are a lot of complaints about certain features, and a lot of successes - the key thing it that this is a DIY system, it has a load of solid features and stuff that is only on high-end ecus, but has plenty of niggles.
If you want a fit and forget system then its going to take work to get it going, if you want a system to experiment and fiddle around with, then VEMS aint such a bad choice.

[DI-Racing]

got an rb25det running on vems and installing one on a 2jztt and a 4age(if a certain naughty little leprechaun ever gets his shit together) also having good times with wide band kit on my s14a,,totally recommend the product,awesome quality and support,,

[Andy-c]

cheers guys
the only thing i can see is a sort of issue is the cas unit but i belive you have a work round for this
and have no time for people with complaints with no evidence or info on what they have tryed to do to fix it
the first to go under the knife will be the r32 rb20det (if i ever get my hands on it )

[mattias]

I just felt I had to add that the best work-around is to avoid using the stupid idea of having the primary trigger for the ECU at the cam. Why many Asian (mostly Japanese) manufacturers thought it wise to do so is probably because of cost or something like that.

There is a 24+1 trigger disc to put into the CAS and get a signal that many aftermarket ECUs can deal with.

[rob@vems.co.uk]

The reason that most Japanese cars from the 90s have CAS disks is because they designed their engines to have distributors, and changing the dizzy to a CAS is a hell of a lot cheaper than redesigning the bottom end to take a trigger wheel.

I had CAS converter disks photoetched for old and new types of CAS units, there are cars that have been running for years on these.

[mattias]

Rob: Any articles written about this? Many manufacturers kept or got rid of the distributor ignition and just made a trigger pattern on the  crank damper or flywheel with no major changes except a holder for a sensor, if that's more expensive I wouldn't know - I'm no mechanical engineer.

Fact is you have to be more careful with ignition timing when you have a cam belt or chain that affect your ignition timing, especially on an engine where the knock limit is close. Been there - done that.
Either way, the replacement CAS disc works - I've tuned a couple of Nissan 200SX S13s with them.

[rob@vems.co.uk]

No articles written, I've just seen examples of how certain engines went from distributor, to distributor with timing gear, to timing gear in a distributor housing with coil-packs.
The Toyota 4A-GE is a typical example of this.
And changing the pulley, adding a bracket, and a new wiring loom means changing the production line - will cost more than what I've seen where a single unit (distributor) is swapped out with a CAS they were putting the thing in the hole anyway.