z-ya

100MHz is fine. You will just need a current probe that can measure in the 0-10A range.

I'm an engineer at a scope company, so I have access to some pretty expensive equipment. Inexpensive current probes can be found on Ebay, but it not a measurement you will be making that often. You have to decide if you want to spend the money on a probe. Any scope will work at these frequencies. You just need to be sure that you calibrate the probe to the scope. Yes, I think 0.1ms resolution is fine for most applications. A high boost application with large injectors (bigger than 600cc/min) may need more resolution. You would also need to run injectors with a very fast opening time.

Yes I do. I'll try one over the next few days and post the results.

I would try 3 squirts, and then use the required fuel value to get the idle smooth. Are you doing fuel only? I can send you a map that should get you close. Send me you email address through PM.

Hear is what the injector current looks like when the PWM setting are correct: As you can see, the injector driver allows the injector to draw full current for a period of time (peak), and then limits (hold) the current (rippled looking part of waveform). The PWM time threshold is setting the amount time that the injector is allowed to draw full current to open quickly (peak). This should be set to a number slightly larger than your injector opening time to minimize overshoot, and injector overheating. The PWM Current Limit % is the hold current percentage. So the nomenclature in MT is backwards if you ask me. When you set it to 100%, it is really allowing 100% current, not limiting it by 100%. So this should be set so the hold current meets the injector specification. Most peak and hold injectors have a hold current between 0.75 and 1A. For all the injectors I tested, a number between 30 and 35% will work fine. For most applications, a injector opening time of 1ms should work fine. Keep the battery voltage correction at 0.2ms/V. Hear is the current waveform when the PWM time threshold is too short: You can see that the injector never fully opens, and the hold current never reaches 1A. Hear is what it looks like if the PWM time threshold is set too long: Notice that the injector opens, but the current spikes much higher than it needs too. This current spike or overshoot will cause the injector to heat up over time, and may cause intermittent heat related problems. Note that the hold current is also higher, but it eventually settles in on the proper hold current. Hear are some injector opening times for a couple injectors: 280ZXT 26lb = 1.21ms 450cc/min DSM = 0.973ms

The current limiting resistors are if you don't want to use the PWM feature. They protect the output drivers from sourcing too much current when the PWM current limit is set to 100% (I think is bug in the documentation because when it is set to 100%, there is no current limiting). For the stock low impedance 180cc/min injectors, you should set the PMW variables to: PWM Current limit = 35% PWM time Threshold = 1.5 ms What are you number of squirts set to? Try 3 squirts with simultaneous injector staging.

I've never been able to use alternating on an even fire 6 cylinder. My reasoning for this is the firing order: 1st and opposed (6) 2nd and opposed (5) 3rd and opposed (4) So with only two injector outputs, you can't fire the injectors like this. I've always run sequential with 2 or 3 squirts and a very smooth idle was the result. What injector drivers are firing what cylinders? I always drive three with one, and three with the other. OK, I just spent a bunch of time looking at the injector outputs, trigger input, and ignition output of MSn'Extra code on my scope, and it is not making a lot of sense. No matter if I run alternating or simultaneous, the injector outputs alternate. This is going to take more investigation. I'll let you know what I find out.

We have a club dyno day scheduled in June, and you are more than welcome to come. Keep informed on your progress and I'll reserve a spot for you.

When you get your harness built, you can test the whole thing on the bench. At that point you can see if the temp display in MT is correct. You are using the head sensor as the CLT input to MS? The head sensor is not submersed in coolant, right? I have never used the head sensor at the CLT input. It should work, but I don't for sure if the algorithms in MS that use CLT as an input will behave 100% correct all the time using the head temp.

You can't run alternating on a 6 cylinder with MS. You would need 3 injector outputs to do it. Wire three to one output, and three to the other. Like Tony said, if one fails, you can limp home on three cylinders. If they are high Z injectors, no series resistors are required, and you can turn PWM off. So set your MS for simultaneous, and start with 3 squirts. With 440cc/min injectors you may need to drop it down to 1 or 2, but start with 3.

I've learned a lot from reading your posts Ron, just thought I would return the favor That is basically what I am doing. An inductive current probe clamps on the wire like an inductive timing light clamps on a spark plug wire. The probe I used is a 1:1 probe, so for every amp of current, it outputs one volt. So the probe is really a current to voltage converter. Yes, I could have added a 1 Ohm resistor in series with the circuit, and then measured the voltage across it with a voltage probe. The problem is in adding a new component to the circuit. Any component added will have an effect on the circuit. The current probe has zero effect on the circuit, and therefore gives you the most accurate measurement.

I made all the measurements at 13V. Voltage compensation on the MS doesn't seem to make noticable difference in opening times. Measuring the dynamic current is the most accurate way (and easiest) to measure opening time. How else would you do it? Maybe some sort of fluid with a strobe light? The current tells the whole story. When the current starts to drop, the injector is open. The current increase after that is the DC resistance of the coil and series resistor combined.

Gavin, I will test Hybridz donating members injectors for free as long as the demand doesn't go way up. I will also determine what the optimal PWM settings are for your injectors.

I was surprised to see that changing the series resistor did not have a large effect on opening time. The resistor should be selected so the hold current is around 1A. In PWM mode, which does not limit peak current (only hold current), the opening time is about the same. I will post later this week my measurements in PWM mode. Opening time tolerance for new injectors should be in the 5%-10% range, so 1.25ms is most likely OK.

I don't think high Z injectors are any more or less prone to a slow opening time. This problem is caused by any number of problems, including wear, and gunk. New injectors I've measured are all within 5% of each other.

Hear are some measurements I made on various injectors I have kicking around. All of them are low impedance. For these tests I used a Megasquirt v3.0 to fire the injectors in non-PWM mode. There is a 6.8 Ohm resistor in series with the injector. I used a inductive current probe to measure dynamic current using an oscilloscope. Hear is what a 280ZX turbo injector looks like: As the injector opens, the current increases at a fairly linear rate until it is completely open (the small blip indicated with the label). The current spike after the injector opens is the DC resistance of the injector (2.6 Ohm), plus the 6.8 Ohm series resistor across the 13v on the injectors. So Ohms law, I = V/R, the hold current is 1.38A. A little bit high as most injects want between 0.75 and 1.0A of hold current. To demonstrate what a "lazy" injectors does, look at the screen shot below: Both are identical used Bosch 36lb injectors, but you can see that the opening times are not the same. In fact there is about a 50% difference between the two. This is typical of used injectors. This can cause a problem on turbo cars that don't require a lot of fuel to idle, but need large injectors for full boost. The idle will be lumpy because this one lazy injector may not open all the way, when the rest do. This is apparent at small injector opening times. Sometimes a cold injector will not open quick enough but be fine once the engine warms up.

Is you required fuel value correct? Increase the required fuel number until you get it started. Then as it warms up, you will need to back it off. Let the tuning begin!

Can you give us more details (engine, ignition, fuel injector flow rate, etc.)?

Not sure what manifold is used on this BSR car, or what carbs they are, but hear is how the strut tower brace is run: This photo shows the cold air box detail:

More manifold pics:

I will have more photos when the smoothing is done. Those are the only two I took, and the manifolds are at the metal shop. I can document the procedure for doing this mod if you like. There is a lot of work involved hear. Not just cutting, machining, and welding. Smoothing the outside (just the top), re-drilling the TB flange, enlarging the TB flange to 50mm, and smoothing out the ports on the inside (the E88 ports are actually larger than the EFI intake ports). Then there is the throttle linkages. You are going to charge a lot of money to make up for your time. I think this setup will look great on a close to stock 240Z that wants EFI. You could modify the stock air cleaner to adapt to the TBs. When I get it done. I will post all the information. I'm thinking it will be done in a couple weeks. This project is part of my 71 buildup I'm embarling on: http://forums.hybridz.org/showthread.php?t=120074

Trimmed lip in rear, otherwise stock. 225-50ZR15s on 15x8 wheels with +0.5" offset: 245-45ZR16 on 16x8 wheels with +0.5" offset:

Running a cooler thermostat is not necessarily going to make it run cooler. If your cooling system does not have the heat dissipating ability to maintain a 160 degree temperature, then the thermostat will always stay open. Let's say your cooling system has enough capacity to keep your engine at 175 on a hot summer day. If you put a 160 thermostat in, it will never actually reach 160. The engine temperature will continuously vary. I would rather have it run at a consistent temperature. A 180 thermostat in this example would do that. I know we could have a huge debate about this but I have seen how running a hotter thermostat stopped an overheating problem a couple times. In the race car, on my first track session after putting the supercharger on, it overheated and eventually blew the head gasket. When it hit 240 deg, the gasket blew. I was running a 160 thermostat. Got the whole thing back together, and put a 195 in there. The next time at the track, it maintained a constant 195 degrees and did not overheat. The ambient temperatures on the two track days was about the same. No other changes were made (besides a new head gasket). The only explanation I have is that when the thermostat closes, it stops the flow, allowing the majority of the coolant to remain in the radiator longer. It has not overheated since, and has run track sessions in 50 to 95 degree ambient temps. I got the idea to up the thermostat temp from a life-long mechanic that I have a great deal of respect for. He had the same problem in his 429 powered Cobra replica (scratch built). It would overheat with a 180, but not with a 195. He has seen this behavior a bunch of times. I don't think everyone should run out an put 160 thermostats in their cars. If you are not having any problems, leave it alone.

Tony, GM TBI injectors?

Sent PM. You can build an ECU to operate in the ns (nanoseconds) if you want, but the injectors will never open. So it all depends how quickly, from a mechanical perspective, your injector can open. The electrical part is easy. ps (picoseconds) is the standard unit of measure for digital design today. There are 10,000 ps in a us (micro second). Again, it all depends on how fast your injector can open. Most injectors cannot open quicker than one ms (millisecond). Older injectors can get "lazy", making the opeing time even slower. I can measure opening time for any injector if you like.