Zed Head
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Everything posted by Zed Head
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Darn it, Google must have showed me this video because YZFMax posted it in a different thread. It should be here anyway. Double odds of seeing it. Look at the float bowl action.
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An air pressure regulator has a similar function. But there's a vent, which an FPR doesn't have. https://www.instrumentationtoolbox.com/2017/03/how-air-pressure-regulator-works.html
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I don't have a good grasp on how a deadhead FPR works. Holley says it works by an adjustable restriction. Seems like the pressure would then vary with fuel pump volume, and fuel pump volume would vary with voltage, and voltage typically varies with RPM on a Z car. Doesn't seem like the deadhead system would be very consistent. I think it also puts more load on the pump, since the pump is pushing against a blockage that doesn't flow very much. https://www.holley.com/blog/post/how_to_choose_a_regulator_for_carbureted_vehicles/ Essentially, the deadhead style regulator uses a restriction in order to lower the fuel pressure by simply decreasing the fuel flow. This is accomplished with the use of a diaphragm and seat that restricts the fuel flow and uses a spring to provide pressure adjustability.
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At first brain wave it makes sense that you don't really need much pressure, from a static bowl perspective. Fill it up, the float rises and seals, you're done. But if you get in to the weeds you also have to consider how much fuel can pass through the float seat orifice at full throttle. Seems like low pressure might cause a fuel starvation problem at high load. You need pressure to push through that hole and keep that bowl full. That's why I like to dig in to what the factory engineers determine. They have engines to play with and tools to figure out the best numbers.
They just had a bunch of Euro 2020 games in England.
Austin, Texas. Delta is coming. Fascinating, from a scientific perspective.
Looks like they made some assumptions about what they were dealing with. Somebody misread the x-rays? https://www.latimes.com/california/story/2021-06-30/lapd-responds-to-explosion-at-scene-of-confiscation-of-illegal-fireworks Officers also found improvised explosive devices with simple fuses — about 40 the size of Coke cans and 200 smaller objects of similar construction — and conducted X-rays to determine their contents. Less than 10 pounds of the devices were transferred into a semitruck, which Moore said was rated, with its outer containment shell, to handle 18 pounds.
And 280Z. Back to H. Nissan really made the 260Z an odd odd bird...
240Z.
He said 260Z, not 240Z. Here's the GI from 1974. Oops.
Here's a part that continued through the R180 to the R200. Kind of suggests that October 1973 was when "something different" happened with the mustache bar for the 2+2. Maybe I should be looking at small bumper 2+2's also. Edit - actually I did when I looked through BAT. Only one guy showed the diff. https://bringatrailer.com/datsun/260z/?q=260z http://www.carpartsmanual.com/datsun/Z-1969-1978/axle/rear-suspension/28
Is it a 2+2? That was my key point.
https://jalopnik.com/fireworks-explosion-destroys-la-police-bomb-disposal-tr-1847210186
I found a big bumper 2+2 manual on BAT with an R200. It's been modded but a diff change isn't mentioned. Who knows. The other listings don't have any diff pictures. https://bringatrailer.com/listing/1974-datsun-260z-22-6/
I think that you'll be just setting dwell in the software with the coil and power transistor (another name for ignitor, more correct) that you're planning to use. There are probably recommended values to for the Denso PS coil. Your setup will be like the system used on the 280ZX turbo engines. Very common, used well up in to the 90's (my 95 Pathfinder had that system), probably still used today on some engines. The dwell settings do the job, the most basic one, that the ballast resistor was designed to do.
Seems like a good reference for people looking for aftermarket electric pumps. I haven't had a carbed Z but if I did I'd probably get rid of the restrictor and use an FPR on the return line set to 4.6 psi if I went electric. It's probably already been discussed a few hundred times. Just filling my brain for future possibilities...
Here's another source of info. Most of the dates are in mid-1974, but they don't give the first "From". Ends in August 1974, but no start shown. It is a manual transmission 2+2 though. Maybe there is a USA/Canada 260Z with an R200. That would be opposite of later trends though where they used the R180 for the 2+2's. Part 37 shows the one year 1975 pinion flange, then no changes. http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/differential-gear/r200
It came out in August of 1973. Probably some minor design change. Maybe for the big bumper 1974 models. http://www.carpartsmanual.com/datsun/Z-1969-1978/axle/rear-suspension/16
I don't want to overdo getting involved in your project. But I found another thing that shows a parameter that looks like it's in the Haltech tuning software. One of those things that could lead to problems if overlooked. The dwell setting. Depends on the module. Also, the word "module" could mean what they call an igniter. That would be the high speed relay that I mentioned above. Requires ECU control. That might be what your Denso coil has. This is from the RB30 page. All systems have similarities though. Good luck. https://support.haltech.com/portal/en/kb/articles/rb30-engine
Here's some Haltech stuff. Describes "Auto-Dwell", AKA current-limiting, and "ECU-Dwell", which is essentially using the module as high speed relay. The module keeps the heat/current out of the ECU. It's a fun topic, very energizing. https://support.haltech.com/portal/en/kb/articles/ignition-modules
Some ignition coils have their "dwell" controlled by the computer, like modern GM HEI coils which are almost zero ohms resistance. Other coils use independent modules that have current-limiting circuitry that maximizes "charge" then holds it. I did a Google and found an interesting article about coils and modules, below. There's a bunch out there. My basic point is that you should not even be considering keeping the ballast resistor for a modern ignition system. It is a relic, although a cool (as in neato, but also a pun) one, for keeping current flow controlled through a coil used for points. It only lasted three years after Nissan went electronic in 1974. 1978 did not use a ballast resistor. Each system is different. There should be details in the full installation manual about what you need for the coil; resistance, type of module, how to wire it, etc. My other post was pointing out that the system is designed for independent coils per cylinder. You only show one. Maybe the Haltech 750 can run one coil for six cylinders but it's not clear. That would be inthe manual also. https://www.consulab.com/files/ignitionHandoutV20181.pdf
I wonder how much pressure the original electric pumps for the carb'ed cars generated. The system started with the mechanical pump that relieves pressure at the pump itself through internal valving. They hit a pressure and just don't push anymore. What did Nissan specify for the pressure of the factory electric pump?
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