Ignition Rotor Mearsurements

[fj1289]

While I'm sitting here for a few more months before I get back, trying to get a head start on the next project.

Can someone make some measurements of the stock ignition rotor please?  Need the outside diameter and the inside diamter (hole the mounting bolt goes through.  Also, if you could post a pic of the ignition cover from the back side along with a ruler for a reference it would be greatly appreciated!

Thanks,
Chris W.

[FJ111200]

This is the best i can do, someone else probably could do better.
Diameter of 3CV rotor 72mm, then the point across the 2 small triggers is 80.07mm, then the large and small triggers is 80.30mm.
The inner mounting bolt hole diameter is 19.95mm.
Hope it is of some use to you.

[WestOzXJR]

Are you thinking after-market ignition and/or EFI Chris.

[fj1289]

Thanks FJ111200 - exactly what I was looking for.

Yes - doing EFI conversion.  Bought a bunch of parts off Marc Rittner a year or so ago when he was selling off all his FJ goodies to support his 200mph Aprilia project.  Also following his lead on using all Suzuki electrics and an aftermarket modified microsquirt ECU.

Overall plan: Busa wiring harness and switch gear and an Interface PNP Microsquirt for control.  Will run it batch fire for the fuel and wasted spark so I don't have to figure out a cam position sensor. 

I'm trying to decide on the crank trigger wheel right now.  Leaning towards one from trigger-wheels.com since the microsquirt will easily adapt to the 36-1 trigger wheel.  In the future I'd like to put a conversion together that would use the Busa ECU and utilize the ECU editors that are available now - that would probably be the most economical way to go, but will require a 24-1 trigger wheel and a cam position sensor. 

During some of my down time I'm trying to work through as many of the details of the instal that I can from 7664 miles away.  Hoping to get this up and going before the end of the year.  Initially it will go on a stock FJ1200, then once the bugs are worked out it I'll swap in the built 1314. 

With the aftermarket ECU, the cost goes up, but I'm pretty sure if you can work out the details to use a Busa ECU, you should be able to do this for less than a set of new FCRs. 

Chris W.

[WestOzXJR]

Well as you're no doubt aware resolving the crank trigger design is probably THE single most important matter and it's not easy to do from afar, so here's some food for thought...

I researched every ECU out there for over a year and resolving crank trigger design was the FIRST question I asked and it's surprising how few of the tech support people had a f**ken clue what they were talking about because most of what is made is to suit existing crank trigger/distributor set ups.

Eventually I settled on a US made Edge ECU which is easily programmed via a laptop/pc to read the STANDARD late XJR 24-2 rotor and pickup (which is commonly in use by many Yamaha engines - snowmobiles and the like) and thereby negates a resource consuming exercise to design/redesign what already exists.

Additionally, Yamaha has proven the durability of their mag/VR pickup over the long haul and as even Caterpillar will tell you, crank position triggers are not easy to make durable I guess because they suffer easily from vibration.

With this ECU you can program the relationship between the gap in the rotor teeth and TDC, thereby making it even easier because no need to index the position precisely as is the case with many other ECU's.



This setup is more than capable of doing ANYTHING you are ever likely to want it do including; off the shelf on-board data-logging including a/fuel ratio and exhaust temps if you want it plus boost control, nitrous and/or water switching, multiple PWM input/outputs, optional closed loop tuning, optional staged injection for eight injectors and depending on your horsepower expectation FOUR injectors may not be enough. For example, according to flow rate calculations with XJR injectors the standard Nippon Denso injectors are only good for 150hp (So i've gone to the standard four in the intake manifolds plus another four in the Suzuki GSXR1000 K1 41mm throttle bodies).

To get all the features of this ECU in a megasquirt you'll need to tow a trailer around to carry all the extra plug in boards.

If you want I can PM you Brian Lewis's details and a link to their website, Brian is awesome to deal with... Knowledgeable, patient and generous with his time.

And I declare that NO, I have no financial interest in the company.

If you want any info/knowledge I can share, PM me, be glad to assist you with whatever I can Chris.

[fj1289]

Thanks for the info!  I am definately interested in the trigger wheel and crank pickup.  A proven setup here could save a lot of headaches!  Especially intermittent mis-fire issues that can be caused if not 100% right. 

Also interested in the ECU, BUT since I've already purchased the PNP Microsquirt, will probably stay the course with it - but always open to new ideas and possible future projects!  I'm expecting the Busa TB's and injectors to handle the load of the 1314 with no issues.  But, this sounds like a great box to use if I go FI on the dragbike...

Looks like it's time to add some XJR ignition pieces to my RPM shopping list! 

[WestOzXJR]

Yes one of the good features of the Edge is you can bring up an oscilloscope screen showing and evaluating the quality of the crank trigger signal.

Because the quality of the signal IS the make or break of the end result and it's not always easy to get right and is often overlooked as the source of mis-fire issues.


My advice, for whatever it may or may not be worth, is carefully evaluate what the MICROsquirt is or is not capable of...

Ask yourself if you really want to invest all that time in learning a system only to find out down the track it can't do all you want and then need to change course mid learning curve.

IF you decide to go late XJR crank trigger and you can't find the bits you may want, PM me, I have several sets of crank trigger/base plate/rotor sets...

I'm not looking to sell 'em but if you luck out when the time comes I'd help you out and I know of other sources too, although mostly in the UK and Germany...

[Pat Conlon]

Chris, what are you going to use for a cam angle sensor? (necessary for sequential injection)
....or with just a crank signal,  are you planning on batch injection? (kinda like wasted spark... just with $$ fuel)

[fj1289]

Pat,

Definately batch fire for the injectors and wasted spark ignition.  Keep it as simple as possible at first.  Plus, I don't really see any drawbacks - same power curve batch vs sequential has been shown many times.  I think the biggest draw for sequential is an ability at low RPMs to reduce emissions.  After the RPM goes up past a certain point and the load is increasing too, the pulse width of the injector is going to span multiple cylinder events anyway.  So it may be "timed" with valve opening at idle or just off idle, but won't be for long.  I read one account where a guy was trying to find the "sweet spot" for injection timing on a Harley V-twin.  You'd think it would make a significant difference on an engine with few cylinders and an uneven firing order.  Never was able to measure any differences on the dyno.   

For future development, there may be a couple options for camshaft position sensors.  But the primary benefit would be to allow use of stock ECUs (especially ones that are already hacked - or could be) in order to keep down costs.  I have read about an EFI conversion on an oilcooled GSXR where they mounted the sensor on the valve cover and used the cam lobe for the signal.  Another option for a camshaft sensor could be machined to be press fit in the end of the camshaft in place of the plug.  May need to be pinned in place, but may be doable. 

Think I'm going to throw up a separate EFI topic and see where it goes