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Who'd be interested if we made a L28ET trigger wheel?


Matt Cramer

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Got mine yesterday and installed it this afternoon. Took just a few minutes to get it installed. Took a little while longer to get it started since I didn't put the center dist wire back.

It is critical to turn off and back on MS3 between changing trigger settings. When it did start, it was advanced 50 deg. After a couple of tries I settled in on a tooth angle of 355.4 - not too far from the initial setting of 345.

 

More impressions will be included in my build thread: My MS3 Build

Edited by Sam280Z
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Arrived and installed in the new distributor. Cut the original round connector off

and waiting on a weatherpack kit to replace it.

 

Matt- The write up instructions are great, but what about a microsquirt? Would

a pull-up be required on the OPTOIN? Would it be better to use VR1 and VR2

with a pull-up on each input

 

It depends on the MicroSquirt variant. V1.0 and 2.0s would use OptoIn and VR2; V3.0s are the only ones that can use VR1 input (but they can use the opto input instead). Pull ups are required. I'll see if I can get MicroSquirt and DIYPNP instructions added.

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On my VG30E 280Z. I ended up with 300 trigger angle or tooth offset or whatever it is called now. I'm pretty sure I installed it "upright" according to the link you posted, Matt.

 

Tried the 345 and I was running 50+ degrees of timing at idle (waaay passed the marks on the crank pulley). It didn't like it. Tried a wild guess of 300 and voila! it was spot on. I should play the lottery.

 

Also, the VG30E CAS mount (and OE wheel) has two dowl/tabs that poke through the wheel. I took off that tab thing and ground down the one for which there wasn't a hole. Installed fine after that. I have to admit I'm a little OCD in some respects and having that gigantic tooth offset makes it hard for me to sleep. Why couldn't one of the #1 teeth be at TDC?

 

And I was just joking about the sticker. Thanks.

 

My timing values are a LOT more stable now.

Edited by BLOZ UP
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Also, the VG30E CAS mount (and OE wheel) has two dowl/tabs that poke through the wheel. I took off that tab thing and ground down the one for which there wasn't a hole. Installed fine after that. I have to admit I'm a little OCD in some respects and having that gigantic tooth offset makes it hard for me to sleep. Why couldn't one of the #1 teeth be at TDC?

 

The way the MegaSquirt wheel decoder works, that actually would not be as good. Having the #1 tooth at TDC would mean the missing tooth is in the 30 degrees BTDC area, which is close to the spark advance the engine will often be running. Having a real tooth shortly before the spark advance insures maximum accuracy. So by putting the missing tooth right after the 30 degree tooth (and in many installations, right after TDC) puts the missing tooth in a spot where it won't diminish accuracy where you need it.

 

I'll admit the missing tooth location was somewhat of an accident - but it turns out to work really well.

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Please could someone explain to me how this discs allows you to run fully sequential injection. In the past I've read on Hybridz that as well as a crank sensor you require a cam sensor to run fully sequential injection.

 

If I've missed the explanation in these pages then I apologise.

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Please could someone explain to me how this discs allows you to run fully sequential injection. In the past I've read on Hybridz that as well as a crank sensor you require a cam sensor to run fully sequential injection.

 

If I've missed the explanation in these pages then I apologise.

 

The 82-83 turbo dizzy has two leds inside that can read two trigger disc angles. You can use the 12-1 signal as a crank signal and the single tooth as a cam reference signal. Depending on the engine size, processor, and code you can run sequential spark/fuel. You can run 4 cylinder sequential with ms2/extra, wasted spark with ms2 extra or probably even full cop but I dont know if you can run both, that would be alot of outputs for an ms2 daughtercard, you can run full sequential fuel with ms3x for sure as well as full cop with extrnal ignitors.

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The wheel is a 12-1, but twice over to "fool" megasquirt into thinking that it's a crank wheel (since the CAS rotates at half the crank speed). It's really a 24-2 wheel. Then there is the second slot on the wheel for the "cam" signal, which is just that. It's really a good idea since the CAS has the two sensors in it, I'm surprised no one thought of it earlier.

Edited by BLOZ UP
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BLOZ, do you just "intercept" the stock wiring output from the distibutor and run it to one of the input pins on the MS connector plug?

 

Yes, but now with the new trigger wheel you have two dizzy outputs to "intercept." One for cam input and the other fro crank input.

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Yes, but now with the new trigger wheel you have two dizzy outputs to "intercept." One for cam input and the other fro crank input.

 

Right now I just have it using the 24-2 (or 24-1-1 or whatever) wheel--the main one. I haven't hooked up the "cam" part yet, the second trigger. I already had it running on the OE wheel, so I just swapped it, changed the settings and "vroom".

 

It's a 5v square wave signal that needs to be pulled up to 12v for MS.

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Matt,

I've been playing with the injection timing table and can get no discernible effect regardless of how I change the values. I started with 393 which is 10deg before the intake opens. I can go as low as 100 and as high as 500 with no change in AFR, MAP, or RPM. I have the injectors wired correctly (cyl1->A, cyl2->E, cyl3->C, cyl4->F, cyl5->B, cyl6->D)

 

I was wondering if there was a way to check if the timing is actually firing the #1 cylinder at the right time.

The stock trigger wheel required an offset of 63.4deg.

When I installed the DIY trigger wheel, I set the offset to zero.

 

Thanks,

Sam

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Matt,

I've been playing with the injection timing table and can get no discernible effect regardless of how I change the values. I started with 393 which is 10deg before the intake opens. I can go as low as 100 and as high as 500 with no change in AFR, MAP, or RPM. I have the injectors wired correctly (cyl1->A, cyl2->E, cyl3->C, cyl4->F, cyl5->B, cyl6->D)

 

I was wondering if there was a way to check if the timing is actually firing the #1 cylinder at the right time.

The stock trigger wheel required an offset of 63.4deg.

When I installed the DIY trigger wheel, I set the offset to zero.

 

Thanks,

Sam

 

If you are using coil on plug, it would be pretty easy. :) It may be possible to put a timing light on an injector wire if not. Haven't tried it myself - with the hardware we have, I would probably use an oscilloscope with a pick-up on the #1 cylinder plug wire and backprobe the #1 injector.

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Here's a Z31 wheel next to a new wheel and the problem I had. There's an extra hole on the Z31 distributor assembly.

 

post-1233-090686700 1327011547_thumb.jpg

 

The retainer in the middle and below the wheels in that picture has 2 prongs on it. Just grinding off correct one worked for me.

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Is this a hideously bad idea, or reasonable to build the pull-ups

into the weatherpack connector?

 

post-3640-009770000 1327111242_thumb.jpg

 

I arranged the connector-

Ground Crank/Primary (1/4W-1KOhm) 12V+ (1/4W-1KOhm) Cam/Secondary

 

I put it on the distributor side of the connector only due to not having the rest of the harness

ready to work on yet, and I did not want to wait until the installation started to decide where

to put the pull-up resistors.

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