FricFrac

Derek have you been doing some R&D on the side you haven't been telling us about? Apparently "the fastest Datsun ever" has been found - possibly a Datsun Maxima so we know he must be running your head. Inquiring minds want to know..... http://www.kitsapsun.com/news/local/chase-from-belfair-ends-when-car-gives-out-2e728422-495c-530b-e053-0100007fc456-372817481.html

Its tough to do any sort of random and/or intermittent trouble shooting when you can't monitor/data log the system. A lot of intermittent issues are caused by thermal issues, bad connections/bad ground and electrolytic caps. We've seen all sorts of weird surging issues with the Z31 on the L28ET, etc. Not surprising since you can't modify a non NisTune Z31 ECU. I would put MicroSquirt on an ATV or an outboard engine - maybe even my VTec Honda lawn mower - not on my L28ET. If you were running an MS2 or MS3 at least you could data log some of this to get an idea of where the intermittent fault is coming from.....

Be careful Tony. I thought it was open source as well but it's just open to modifications and you are paying a licensing fee with each kit you buy. I was asking about running the MS firmware/software on another platform and got told

There are a lot of misconceptions with MegaSquirt and Xnke nailed them on the head. What I find happens is because MegaSquirt is such a good bang for the buck is that it draws not just the DIY crowd but the DIY cheap out, don't understand how the system works and lets put it together with duct tape and bailing wire. Then you get a mess which either gets abandoned and sold and/or ends up at a tuning shop to get sorted. The tuner may as well start from scratch rather than make the mess the previous owner through together work. Fortunately there are lots of smart guys and girls on this forum and a lot of support so getting an MS setup up and running has a fairly good success rate. Derek pointed out a couple of very important points with is MS build. First shielded wiring for the sensors and secondly a single ground point or as its more commonly know a star ground configuration. When we build custom harnesses for MegaSquirt and other stand alone ECUs these are critical design points we implement in our harnesses. Both of these are very important to eliminating noise BEFORE the MS unit has to take care of it. The MS3 has very good noise filtering algorithms but its just good design to eliminate the noise before it gets to the ECU. Jeff Linfert is a great guy and a wiz with the MegaSquirt - you are in good hands Darek We did a build for Charles Perry's race car - Jeff did the tuning.

There is no difference between an MS3X and the MS3Pro other than the significant extra expense for weather proof connectors. MS3X will let you run full seqential fuel and spark. Any MS can run the fuel pump, IAC, EFan. The 3X is a daughter card that you add to a regular MS3 to expand it's input/output capability. MS2 does not have the built in drivers for wasted spark for coils that don't have their own drivers built in. You need to add two additional BIP drivers to run wasted spark on coils that don't have their own drivers built in. You can, however, run wasted spark from an MS2 with COP/CNP if they have their own build in drivers. For the extra $100 to go from MS2 to MS3 the extra features and a more future proof system makes it worthwhile IMHO. For your build a regular MS3 and single coil is completely capable - spend the money on COP/CNP on a more efficient turbo system and you'll be farther ahead. Spend the extra $100 on the MS3 vs MS2 gives you more options down the road for upgrading by adding an MS3X daughter card, knock sensor board, etc.

Still busy building harnesses and complete turn key systems. Awesome feedback from our customers - thanks everyone . Let us take care of the electronics headache so you can concentrate on the build! www.mackaypowerproducts.com

Updates?

We do a lot of builds with the 240SX TPS with MegaSquirt and the L28ET. One thing to note is that after 25 years a lot of these sensors tend to be noisy. We have had limited sucess in cleaning them and have them continue to be reliable. I recommend to most of my customers to but new TPS to avoid grief from a noisy sensor.

Is there a reason you're going with an MS3Pro? Its a lot of extra money for some waterproof connectors....

Or base it off a performance plenum from a K20 head....

You realize that is gonna fall on deaf ears on this thread. Keep it coming

Get a turbo swap for less than $1000 typically and you'll make more stock power than the above with room to grow....

Location doesn't change the accuracy - it's the resolution of the encoder. The stock Nissan optical wheel has 360 slots on the outer track. It's actually too high of a resolution for a lot of stand alone ECUS. If you were going to put the encoder on the cam you wouldn't want to put it inside the valve cover. How to interface to the cam is the challenge. If the sensor could be mounted to the head itself rather than the valve cover it would make lining up the interface a lot more precise.

Re-read my post. I said you didn't need to run wasted spark with twin towers but that is the common configuration.... It's not about being able to figure out how to implement the sensor. This is the design phase of the head so now is the time to consider how to implement those items into the design.

Since its based off a Honda configuration why not set it up the same way the Honda Cam angle sensor is set up and use the Honda sensor?

You are correct in saying that it's not 50% of the energy wasted on the exhaust stroke but a few percent is also incorrect. I'm sure we could do the math based on the pressure in the combustion chamber and figure the differences in potential required to jump the gap. This is a simple series cicuit. The current through the circuit will be the same. The voltage dropped across the gaps will be different but it still takes over 10kV to jump the gap on the wasted spark. This is absolutely more than a few percent wasted. Twin tower coils are typically higher output to compensate partially for this. I agree with regards to dwell time being a major advantage of a sequential system at higher RPM.

Yes NewZed and Bradyzq I suppose I wasn't specific enough with my statement. By removing the mechanical slop from a setup such as the distributor by directly interfacing to a cam/crank you can get a more precise measurement.As you can imagine under acceleration to and from deceleration you will move through the range of "slop" giving you potentially degrees of error. A COP/CNP gives a hotter spark GENERALLY speaking. There are thousands of different coils and wiring and combinations thereof so I'm speaking in generalities here. A wasted spark with a typical EDIS setup uses a dual tower coil pack which means your spark has to jump across TWO spark plug gaps. You are unnecessarily wasting half your energy across a second plug. The EDIS system was a technological step from a distributor to a distributorless ignition system as it is a less complicated system and was easier to implement when it was first conceived. You can run COP/CNP in a wasted spark configuration and avoid the energy lost in a twin tower configuration but remember you are doubling the duty cycle of your coil packs. GM uses a lump on the cam and a hall effect sensor. That would require having a lump added to the cam which I suppose is an option. You can use any sensor method you like. In all the military equipment I've worked on the most precise is to use a syncro. The next most common (and becoming more common) is an optical encoder. I've never seen a variable reluctance setup on any rotation sensor used on military equipment. Remember that a variable reluctance setup is sensitive to both the angle and gap of the sensor. It also produces an ugly analog signal that needs to be reconditioned into a digital signal. An optical encoder produces a digital signal without requiring reconditioning. The 1981 1/2 280ZXT used a variable reluctance setup (CAS) for Nissan's first ever turbo engine. That to the best of my knowledge was the end of the CAS for Nissan. They went to an optical encoder in 1982 and have been using optical encoders since then. Measuring from the cam is most precise way to measure cam timing otherwise you will be measuring the gear and chain lash at the very least from the cam to the front of the crank. That is why modern EFI systems use both a crank and a cam sensor to measure how much out of phase the crank and cam are in reference to each other. For most of us L28ET guys the precision of the optical dizzy is good enough but this modern head will be used to a much higher performance level than our typical L28ET build. I think some builders will be concerned with that precision.

Go Andy Go! I wanna see this beast driving around

Running the L28ET optical dizzy has always been a solution but most people runing sequential fuel and/or spark are going to want to clean up that huge lump hanging off the side of the block. Having the cam cores drilled and tapped to mount is definately a bonus. If we could settle on a cam sensor that is commonly found and readily avaliable would be a major bonus. I know you will be running a distributor for R&D purposes but I can't imagine spending $10k + putting a modern EFI head that will run under high compression or boosted applications and not running sequential spark. Sequential spark is more precise in timing and provides a hotter spark required with higher pressure combustion.

You need cam angle to get all the info with regards to timing for a stand alone EFI. Crank info isn't enough for full sequential fuel and/or spark.

An optical wheel is one of the best options for an RPM sensor. It absolutely should be considered in the design. Just because an antiquated EDIS system works doesn't mean it's the best option. An optical sensor off the cam will give the most flexibility and options for stand alone EFI systems. Even a variable reluctance setup with cam info would work of course.

Have you thought of running a stand alone EFI system? It sounds like a bit of a hack job and if you are going to be putting the time, effort and money into getting this mess sorted out its probably wise to upgrade to a modern EFI system and all new wiring harness, etc. It also sounds like you may have upgraded injectors which the stock ECU can't compensate for. Another reason to go with a stand alone programmable ECU. If you are looking to do any performance upgrades a stand alone EFI ECU is the ground work for any of those upgrades. The oil pump spindle and distributor are different on the 1982-83 L28ET. They have a splined end where the spindle and the dizzy meet. That's what you will need to run both the stock ECU or a stand alone EFI. The 1981 only has a CAS and trigger wheel but it's not as desireable of a setup since it uses variable reluctance and is more difficult to configure or modify. We do a lot of these builds at www.mackaypowerproducts.com right up to complete turn key systems for the L28ET, etc. If you have any questions we are more than happy to help out even if you want to do it all yourself.

These are designed and made in Canada....

It looks like Andy is working on a cover for the 1982-83 stock L28ET dizzy over here.

Looking forward to the dizzy cap. Will these be for sale? I have a few clients with full sequential spark that would probably be interested in this configuration.