Triggering systems have always been a bit confusing to me, so my apologies if I've missed something obvious.

I'm currently running an MS3X on my Series 4 NA. Set up as per Aaron's guide, except using the stock harness by way of an adapter. Soon I will be installing a Series 5 13BT.

I am having some lost-sync issues with the stock VR setup, and though I have found a few ways to minimize the issue I think the best way to resolve it is just to move to a hall sensor trigger. Unfortunately the FFE kit does not allow for PS and AC, so it's not an option. There are modifications that make it work but they are quite involved.

I bought a small generic 36-1 wheel and threaded hall sensor, and my idea is to gut a stock CAS then mount the wheel inside. Then mount the hall sensor in the CAS body. I have multiple spare CAS to experiment with.

Now I know this will keep some issues from the stock CAS (gear lash being the main one), but it keeps things a lot neater and should be perfectly fine for reasonable power levels.

Anyways, it looks like I can just tell Tunerstudio this is a "cam" wheel and that should work for triggering. Will this setup still allow for full sequential injection? Is there anything else I've missed here?

Any input is appreciated. Thanks

 

^The modifications needed to run the FFE trigger kit on an FC and retain PS/AC are not as hard as you think. I did it on mine, here's the skinny on what you'll need to make it work:

1. Find a good machinist to mill some material off the backside of the PS/AC bracket. Basically what you'll be doing is mounting the FFE bracket over the studs first, and then the PS/AC bracket gets installed on top of that. With all studs/bolts installed on the PS/AC bracket, it should fit exactly like OEM with everything torqued down. Your machinist will mill just enough material off the back side of the PS/AC bracket where it fits over the FFE bracket; hardest part of the job is mocking up the install so you can accurately mark the backside of the PS/AC bracket and measure exactly how much material needs to be removed from it

2. To get the belts to line up, it's deceptively easy. You'll need to get a spare E-shaft pulley for the water pump/alternator. Then replace the OEM M6-1.0 bolts that mount that pulley with longer M6-1.0 studs & M6 nuts. The existing WP/ALT pulley goes over the studs like normal. What you need to do with the spare pulley is flip it over 180* and try to mount it - it won't fit as-is because the bolt holes are slightly offset. One of those 4 bolt holes will have to be elongated a little to make it fit. Then you'll need some M6 AL spacers to fit over the studs, IIRC, 3/16" thick spacers did the trick, and you mount the spare pulley over that (flipped 180*), and secure the stack with the M6 nuts. Since the pulley is a bit smaller than the OEM A/C & PS crank pulleys, it will under drive them a bit, but it made no difference in A/C or PS performance on mine.

Here's a picture of the end result:

 

That's actually not nearly as bad as I thought, so I will probably do that in the long-term. Unfortunately between the cost of the FFE kit and the cost of machine work, it might be awhile until I can do that. I appreciate all the info though, that's very helpful

In the meantime (at least while NA), I'm still going to try my CAS idea. I have plenty of spare CAS so it's not a big deal to modify one.

What I still don't understand though (and also applies to the FFE kit), is does the 36-1 wheel on its own allow for full sequential fuel? I read people saying that you need a crank & a cam wheel, but I'm not sure if the 36-1 doubles as both.

 

That really depends on whether or not your ECU can support it. I'm not familiar with the Megasquirt ECUs, but in my FC I'm running an AEM Infinity which supports full sequential fuel with the 36-1 FFE hall sensor kit. Basically the 1 missing tooth serves the purpose of a cam wheel/sensor - Oversimplified, the ECU senses the missing tooth every 360* of e-shaft rotation to synchronize the spark firing & fuel events. There will be an ECU specific procedure to set your base timing & offsets correctly so the ECU knows exactly where TDC on the front rotor is.

 

You can just knock off 2 opposing teeth on the CAS and turn it into a 12-1 wheel to get rid of the 2 tooth portion of the cas which makes the denso cas problematic.That will give you plenty of resolution.

That FFE 36-1 wheel is a nice piece but retarded money when you buy it in canadian dollars and add the now extorsion rate shipping they charge out of the states. Plus it doesn't work with a/c or stock p/s. Pete 89T2 has a great solution to make it work.

I made my own wheel set-up with a universal 36-1 wheel set-up and a cut-up and rewelded stock A/C pulley. It's time consuming but a couple of bucks for material and the hall sensor is under $40 USD plus the machining costs for the 36-1 wheel spacer/adaptor, AC /PS bracket. Don't ask me how it works ,as I haven't tried it. The wheel I'm not worried about but the AC pulley was a bit of a adaptation to a miscalculation so it should work but it's a flimsy thing to begin with and cutting / machining it left some runout between that and rewelding it.

 

You don't need a cam sensor to run sequential on a rotary since the cycle is 360 degrees as opposed to 720 deg. for a full cycle on a 4 banger.You may want a better resolution wheel such as a 36-1 if you cut the cas to make it a 12-1. Adding a hall sensor to the cas depends on the resolution of the sensor when you add the small teeth spacing of the wheel that would fit in the cas.it may work at the max revs you would see on a rotary plus the cas spins at half the crank speed.

 

Cutting it for a 12-1 sounds neat. The whole problem as you mention above is the two-tooth "cam" wheel. No matter what I do, I get sync loss on that wheel at high rpm. From some reason it likes a really large gap for the sensor (.04" at present, and the more gap I add the happier it is).

My plan was to add a 36-1 wheel (with the wide teeth for hall use) mounted directly onto the end of the shaft inside the CAS body, then use a hall sensor for pickup.

Since I am already going to sacrifice one CAS for this endeavour, which teeth would I knock off for the 12-1 setup on the existing VR pickup? The ones directly under the two cam teeth? And then to configure it in the MS3 I would call it a 12-1 wheel (even though it's a 24-2) and the timing would work out?

Sorry for all the beginner questions, and I appreciate all the help

EDIT: I see, the 12-1 vs. 24-2 thing is to make it work out since one rotation of the engine is 1/2 rotation of the CAS.

 

On the crank you would want the missing tooth to land somewhere around 45 deg. BTDC on a 2 rotor . Where the crankshaft speed is highest during start-up. Guess you can pull the cas cover and guesstimate it . Probably doesn't matter much since the cas is going slower by half. I've never done it but there were a number of posts here years ago. I'd give it a search for 12-1 wheel .

 

I was actually able to get a spare CAS modified for 12-1 last night, and after playing with the MS3 settings a bit and breaking out the timing light, it works great so far. I only had it idling and low load, but if it works at high rpm without sync loss I see no need to install the hall trigger kit.

I still have the parts coming (a generic wheel and sensor was pretty cheap), so I'll keep them on the shelf in case.

Thanks all for the help, I appreciate it

 

A side note, you would not be able to use a 36-1 wheel directly because the CAS rotates at half engine speed. You could trim another tooth out of it to turn it into an "18-1", or use a 60-2 wheel and trim two teeth out to turn it into a "30-2".