Tony D

What is the control scheme on these compressors, sliding valve driven by PWM?

No, it does not. You are TOTALLY missing my description on what is happening. You show pressure but what you have in there is fuel which has changed state. That gasseous fuel does NOTHING to start the car when you crank it. It needs liquid fuel, not gasseous vapors. And those little millisecond pulses will not get those bubbles out. And those superheated injectors will do their thing to keep liquid fuel flashing to gas for a little while as well. See, in the dead-headed injector, fuel can not FLOW THROUGH THEM! So any gas trapped in there has to be displaced. Gas compresses but since it's at the same pressure as the regulated fuel, it doesn't go anywhere. The FINAL solution to the problem was side-feed injectors. You don't see the issue in cars with that style injector, because the fuel is ocntinually flowing THROUGH the injector OVER the body and cooling it, instead of simply being pushed in the back-end and being let shoot out the front! Your gauge shows pressure, but it's not FUEL thats' in there registering. It's boiling petrol with the FPR bleeding the displaced petrol out of the rail and back to the tank. Wrap the rail properly, isolate it properly from heat, and you will not have this issue. Priming pulse will take care of 99.999% of the starting problem. Just bypass your 's' terminal with a spring loaded switch so you can 'crank' the car for a couple seconds without the starter turning. 3 to 5 seconds usually does it. This is VERY simple to fix, and not that big a deal. You don't need to spray freon or R134 or whatever whiz-bang Hydrocarbon they are selling these days. You just need to circulate the fuel out of the rail and then live with a slight stumble on startup. I mean, how often does this really happen? Filling a tank of gas takes longer than the time period, so no issue there. Doing a splash-n-dash might exacerbate it. If it was 'vapor lock' it would happen when running. And in the S30 and S130's as long as the engine is idling, and fuel is flowing, there is no gasseous bubble formation. It's only after it stops and fuel cooling flow stops that the temp can rise above 200F and cause an issue.

Nobody makes variable displacment compressors for that small service in portable applications. They are far too expensive. Variable orifice works on change of state. It still relies on overcompression and accumulation/capacitance for fundamental operation. Only large stationary plants use variable displacement compressors to lower the electrical load required to compress the refrigerant to the required pressures and volumes to accomplish the BTU transfer required.

I would almost go back to the .63 and get back 1000rpms of powerband and see if the plugs do the same thing there. Usually boost threshold GT35 is around 3400? So now 4400??? With a cap of around 6500, that is sounding awfuly 'peaky' to me. You got nothing better to do Phil, put the .63 back on there with the new plugs and satiate all (my) curiosities. If it works, you just picked up 1000 rpms of hard pull. If it doesn't you're only out a couple hours of your life. That's one nights drinking...

Xnke, what you are missing in your assumptions is that a 'more efficient cooler' somehow will change the BTU's that need to be rejected. It won't. And the compression required (lower head pressure or not) will still be the same. It's why I said the work done is the same. I'm not going to get into polytropic head calculations, but you aren't changing anything, the cabin will still have X BTU's to remove, and the condenser will still have X BTU's to reject. If you have a bigger condenser, this doens't make that any different. You may be exchanging them quicker, but you still have to compress and cool again to remove it. You are confusing excess capacity with efficiency. You touched on the ONLY thing that would really make a difference: A Variable Displacement Compressor. In fact, operating a compressor at the lowest possible head pressure CONTINUOUSLY is the most effective and efficient way to operate this system. The FO system would work, with the evaporator core temperature controlling a varialbe unloading piston (or various other capacity control scheme on the compressor) to keep it loaded 100% and ONLY compressing what it NEEDS to compress to accomplish the BTU rejection/adsorption in the system. In this case the accumulator would act to dampen transients. This is how larger industrial systems with complex PLC control schemes work. FAR more space required than available in the engine bay! This is why I chose the Geo Metro Compressor---it would be operating near capacity all the time---it's the SMALLEST compressor that will accomplish the job. And THAT leads to EFFICIENCY. Making cores flow better, increasing their heat rejection only allows them to be SMALLER to do the same job. If you OVERSIZE THEM then you loose that efficiency as you now have unrequired system volume, blah blah blah... I just spent three days programming a system integrator that allows 3 500HP variable displacement compressors track a dynamic plant load---each compressor having approximately 35% turndown, and each compressor supposedly having a 50% total load capacity. System pressure was designed to be X kPa, and I successfully tuned the system to run a X-250kPa much to the System Engineer's Consternation. He too believed he needed large storage, but if the control system is good enough and can respond quickly there is no need for any overshoot, or undershoot, and reservior (accumulator) capacity just becomes a luxury. This setting saved this plan ungodly amounts of Kw. I do this stuff every day and have a pretty good handle on system dynamics. The exchangers don't change the BTU's in or rejected. And ultimately THAT determines comrpessor size. IMO, with the compressor you have you are solidly in 1970's technology by oversizing the compressor by a factor of about 3X. This is terribly inefficient. Exchanger modifications will allow you to exchange BTU's but the medium to exchange these BTUs must be compressed and expanded to do this function. You will overcompress, then depend on accumulator volume to dampen them. If you want EFFICIENCY, any engineer will tell you go with the SMALLEST possible compressor and ADD CAPTIVE VOLUME (capacitance). The COMPRESSOR is the key to the efficiency equation. Anything else is window dressing, it is at the change-of-state portion of the equation, and this is a zero-sum game. BTU's in and BTU's out. The energy used comes from compression to ENABLE change of state. You need to get efficiency out of the compressor.

Different subject altogether. Later cars used Oil Pressure to maintain the fuel pump, earlier cars used a set of contacts in the AFM. Does this car run at all?

#1 Compression stroke is easy to verify: remove the plugs, bump the starter with your finger over #1 spark plug hole, when it blows, you're starting compression stroke. Manually advance it to TDC and start from there. Your previous (most recent) photos show the position of #1 while #6 is on the compression stroke (180 out). Likely, distributor out 180, rotor should be the 'other way' at that point of cam rotation. Cam will 'Rabbit Ears' on #1 when in compression stroke, one valve will point up to the left of the car, the other up to the right. Finger test and you will never be wrong. Observe distributor rotation, and apply wires appropriately 153624 and it will be in the correct firing order, regardless of where the rotor points. Just start at #1, and minding rotation install wires accordingly.

You totally missed what I asked. Your reply gave what you thought the gauge was telling you. In reality, you have no clue whatsoever if that 'spike' is 160F or 230F. You need to verify the temperature with an independent gauge to determine if anything is wrong. The gauge in an S30 is as useless as teats on a boar hog. I wouldn't trust it as far as I can throw one! I have been driving in cars which were almost 'pegged' while an i'nfra-red scan showed 160F on the thermostat housing (and only slightly higher at the back of the head.) A Meat thermometer in the filler neck confirmed the I-R shots. Find out if you are truly 'spiking' or if you just have some dynamic in the response of the sender/gauge. My 260Z does this when I run the heater on COLD days. Yeah, it's 'overheating'...not! Time to time, not all the time. IR gun says 170 when it's 'spiked' and 160 when normal. Running the highway at 110F ambient, the same gauge spot is 210 (actual) should I cover 3/4 of the radiator with a plastic bag from the freeway updraft...

crap, I had like four roofs sitting out back, and could drop it on the way to LAX tomorrow... I snooze, I loose. So they sit. What else is new?

I dont think I was giving him a hard time, either. People thinking this have obviously never underwent peer review in college. That's not giving people a hard time, it's inquiring if they thought out their hypothesis and it's end result. On the face of it, the claim of 'taking less horsepower to drive the compressor' for instance... You have a set BTU load in, a set BTU load to reject, and you must compress X gas to X pressure to get the expansion required. He's using a large sanden compressor. Sure it's 'more efficient' than a york, but not much if any different than standard sandens from the 70's. The work needed to compress the gas and expand it will be the SAME based on BTU input. He's palaying with ideal gas laws, and compression physics. Using the same style compressor, 'efficiency' I'm laying money will be a wash. They don't sell lysholm screw compressors for AC service in Automotive Applications, nor do they sell Centrifugals, so the largest possible efficiency gains in the biggest power user (the compressor) are ruled out. Most people put sandens on their york AC systems long ago when the originals crapped a seal. That's when they converted to R134A as well. I know that's when I did it. The sanden is quieter, and makes more CFM than the york, but the york never needed an idle speed dashpot to keep the car from stalling at hot idle either... So yeah, it's more 'efficient' but that means it's pumping more. And in most cases the difference between a 1 cylinder, 2 cylinder, or 7 cylinder reciprocating compressor is the smoothness of delivery and less pulsation. That's about it. Drive horsepower remains the same as they are one-step compression machines, not multi-staged. That means similar efficiencies in compression. These are physical laws. You have to be pretty sneaky to get them to bend on a shoestring budget. It's coming down to semantics as usual. An 'airflow increase' may be a goal, but if the airflow is now 15 F hotter than a lower flow with a lower temperature....is there and improvement. There's no free ride... It will just take some time to confirm this. Buy a Kestrel and take good measurements. Static pressure stations underhood will help as well. Like I said, 'been there, done that, interested to see the result but suspect I already know it!'

Jeff needed to add one other thing that will POOF the transistor: Improper grounding, or letting the ground 'float' while power is applied. "POOF!"

You have to get a snug fit with the dowel in the pilot bushing, and give a concerted WHACK with a healthy hammer to build sufficient hydraulic pressure. No pilot bushing will resist hydraulic shock, it will come out with a few whacks. Only time I had to cut one out was when a roller pilot took a dump and welded to the input shaft on the tranny. In that case, I had to cut the cage carrier out. Solid bushings respond nicely to tight fit and thick grease pretty well. If the grease is shooting out all over your hand, you have a poor fit, and a bushing that needs replacement. That is also where the 'wet toilet paper' previously mentioned comes into play.

What temperature in the thermostat housing corresponds to '3/4' on your gauge (everybody seems to have a different number). Verify the temperature, realize that cracking a thermostat (especially if you have your heater on in the morning) gives a RUSH of coolant through the back of the head and out the thermostat housing. You likely are seeing nothing more than the result of latent heat being taken out of the back of the head and the rest of the engine after the thermostat opens and REAL flow is established through the system. Up to that point, it's really only recirculating through 2 10mm bypass lines, and whatever you have hooked up going 'round' the back of the block! Thermostat opens and flow rate through the system skyrockets. Heat is removed in a rush. Sticking thermostat can do it as well, but you saw what changing a thermostat did...

I encourage xnke's experiment, I don't know where it got misinterpreted that I didn't like it, I just wanted to make sure we could get quantifiable results. As you gleaned from some of the writing, when I had a non-travel job I could do 'experiments'... One of which was fitting the larger parts of a complete Geo Metro HVAC system into an S30 under the premise that it was the most compact and efficient modern unit available which would have similar greenhouse cooling requirements and internal volumes. I couldn't instrument well enough for my satisfaction (not enough probes available to me after I left the analytical place I was working) to quantify if the result was worth it. I basically was driving a 240 with no dashboard and Geo Vents taped and angle-ironed aroudn the front of the dash. To my subjective appraisal of the change it seemed to get colder than an ARA/Frigiking, but by no means was it as cold as my 75 Fairlady Z with the JDM cooler in it. That got me thinking further.... and you know where that leads. It was a LOT of work, and to get the geo stuff, small as it was, into even a stock 240 or 280 dashboard (you CAN fit the evap into the stock place for the early S30--it WAS available with factory in-dash air in JDM!) for a more efficient blow-through setup...in the end what I found was even utilizing the stock components (be they 260/280 in-dash or ARA-FrigiKing under-dash) the KEY was a blower that gave sufficient air exchange. Almost above all else, THIS SINGLE POINT made the BIGGEST DIFFERENCE in cool down times, and the ability of a passenger or driver to 'feel cool'... IMO the 280 and 240 fans are not up to the circulation job. Marginal at best. The JDM cooler for the tropics had a considerably different flow system in it and I wish to hell I had photos of the setup as it looks a lot like the modern stuff. Like I said, I had to 'dial it down' to keep from freezing inside the car in 33C Tropical Humidity. It seemed to have a bigger fan, but likely it was just a 280Z style blower. I went through a lot of work, determined I was going to reinvent the wheel with the Geo System in the car, but really it felt no better than the ARA it replaced. I just didn't feel like I wanted to continue and hack up behind my dashboard on an early S30 dash to accomodate the geo parts, or adapt the geo evap to a configuration that would fit as a slip-in sort of conversion in a 240 setup. Really, the 240 in-dash setup was very similar to the 260/280 setups, the evap was in the exact same place. The vacuum diaphragms are unobtainium, so venting would have to be either manual wires or something you make on your own. The new electromagnetic heater control valve Vintage Air makes gives interesting possibilites with linear pots for actuation if you want to retain the stock 'lever look'... but it's a thankless task IMO. Like I said, my ARA keeps the interior of my car at 70 F going 110mph on a 103F day with 85% R/H and I don't think I can ask for much more than that. I guess you could get it to 65 and that would be an 'improvement' but how much work will someone have to do to get that 'improvement'? Is this the point of 'diminishing returns' at some point? That is where I got with the Geo Metro project. Hell, the back axle from that damn donor car is STILL in the back yard!

If manila folders are good at 6500 rpms to seal grease in a centrifugal compressor coupling with an 8" O.D., I think it will handle some static sealing duties. A Coke Carton (Or Budweiser...the stuff with the metallic paint on it) works wonders as well. But manila folder is a standard gasketing material. Like you said, the stock stuff is a bit thinner (vellumoid) but unless you have access to it, you are kinda limited. Manila folders are a great gasket material! Everybody seems to be able to get them. The heavier brown ones are good for carb top gaskets, etc... To Paraphrase Dogbert: "Better Racing through theft of Office Supplies"!

That all depends on how much a windshield costs to replace... Without the front triangulation (and lacking a roll bar) hooking hard in a corner resulted in a cracked windshield for me... Didn't occur after the strut bar install, and with stickier tires and more rear grip to boot! The front really feels 'tied together' with them up there. One triangulated to the firewall is even a better feeling. It's hard to sell stock save on crispness of turn in, but push some torque and you can literally feel the front end twist around when you're on the power hard coming off a corner! (Kaaa-RAAACK! )

Is it the same in current models? I know someone who would rent a car and uh... Lets just say he nver bought tires for his wife's Lumina... Or a battery...

Absolutely, it will starve with a stock L24 and SU's given the right circumstances on the track. With EFI it's even more acute as any drop in fuel pressure registers immediately as an 'engine cut'---not what you want on the power exiting a turn! None of the stock S30 tanks are acceptable for serious competition. Even Nissan recommended a surge tank setup for triple mikuinis in their competition preparation manual for the Japan Market racing series. They even had a part number!

To jump in and be redundant, that sounds like a classic case of a plugged filter. Fine as long as there is no demand on the system, perfect pressure. But put some load on it, fuel pressure drops and as soon as you lift your foot it returns. Insufficient flow on the pumping end to keep up with the demand side (injectors)---usually a plugged filter. The question is, when you boost stone cold, are you saying this does NOT happen (you mention it only happens when hot?) During warmup, this filter issue should be even more pronounced as it's on the 'warmup loop' with slightly higher pulsewidths.

crap, I was supposed to call art back now that you mention it, he needs an R200 moustache bar and is willing to pay.... crapcrapcrapcrapcrap! Maybe I can drop it by on Tuesday, Marcus can wait! They ALWAYS seem busy when I stop by there. That is probably a good sign.

No, the larger the gap you run the smoother the car will idle. Your gap is NOT based on the PLUGS, it is based on your ignition systems capabilities. Small gaps were for points-style ignitions. When they went to HEI (transistor standard in 1975 on) then the gaps got bigger. A turbo car may run gaps as tight at 0.018" due to spark blow-out issues, but an NA should be in the 35-45thou range with a decent ignition system. If you still ran points, then 25-30 would likely be the biggest you could go and get reliable fire from them. My 73 240 with a pertronix setup and flame thrower coil runs 0.045" without any problem whatsoever. I have another with a crane xr700 and it's gapped similarly. Even my VW has large gaps, and it's got one of the first per-lux ignitors in it!

The cold start injector only functions when cranking, and an easy check as stated was 'just shut it off'---the STARTING will happen off the 'cold start enrichment' delivered through the regular injectors. All that cold start valve is used for is the initial firing off. When you crank, it's just spraying fuel into the manifold, not unlike some pit man spraying nitro down the stacks on a hilborn injected dragster. Really high-tech! An easy way to check it is to unplug it. That electrically isolates it. You can also use a small clamp or vice grips and clamp off the fuel line to it depriving it of fuel source. If you are still fouling out, my bet would be engine temperature sensor connection has fallen off or is loose, or dirty. That will make the engine run pig rich! In some cases wet-fouling the plugs! And of course, FPR... BTW you mention a 1973 240Z and that someone else did the conversion. Your symptoms are CLASSIC for using the stock return line for the fuel system. If this is the case---the fuel return is going to the stock 3/16" line---before you do ANYTHING ELSE move the line to the other side of the engine compartment, and connect your return to the 1/4" vapor recovery line. At the back of the car, connect this line to a vent in the top of the fuel tank. Then see what you get. This is a COMMON mistake when guys do the conversion. They think it is fine to use that dinky line, when in reality you need a minimum of 1/4". Yes, 1/16" makes that much of a difference! At idle it will run rich and stumble, but will run FINE on the road and under boost. But go back to idle or low speed low load operation and the thing just keeps loading up. If you got a fuel pressure gauge, check that first. But I can tell you for positive, if the return line is using the dinky stock return line in the 240, it's going to do exactly what yours is doing, and you need to use the line I said, or run another properly sized return line. For a quick check, a piece of FI hose from the bottom port on the regulator straight to the vapor line (without the check valve assembly, please!) on the left fenderwell will allow proper fpr operation with no restrictions whatsoever. Good Luck, post back with what you find!

For what you are dealing with, yes. Stuff dealing with the AFM, no. But for the AAR, they are all the same, it was a 'generic' harness.

Using superheat and various other measurements this can be done. Measuring cycle time under standard conditions (say before/after) and charting heat removal in the cabin is also a rough measure of efficency increase. I was involved at Parker-Hannifin in testing HVAC systems in Ford Vehicles and am suspect of most claims of 'improvement'---yes even of older stuff. Your comment of 30% larger R134 Condensers is about right, but the 'old' condenser was about 50% oversized to begin with which is what I was getting at, if you propose the new condenser returns this same margin using R134A---while technically an 'improvement' it still falls within the original parameter of a 50% margin. Excess margin which usually isn't used. I'm not saying I don't like it, I'm asking what the proof will be that you will end up with anything quantifiably 'better' as you claim. My contention has been that likely you will at BEST equal the original system performance. I've been down this road, remember I mentioned Geo Metro earlier? Look at the compressor on that baby. About the size of a Z's AIR pump. Matter of fact, it mounts nicely there.... Relative heat loading and greenhouse similar.... Powered by a 1.0 three cylinder so HVAC system must be superefficient.... Lot of work, got the same relative results as with the 'old tech'---it's where my statement that 'newer usually just means smaller with less margin and working harder all the time' Really, you want the best thing for your efficiency? Ditch that huge Sanden style compressor, go get one off a Geo Metro, and get an Accumulator/Dryer fabbed that is HUGE---say 12oz or 24 oz. This will give you sufficient liquid side reserve to let that little Metro compressor cycle on and off when under full head load in the cabin. Storage means less horsepower is required during transients. Otherwise, BTU's in and BTU's out won't change. Compare a York to a Sanden, yep more efficient. But if you already had an aftermarket with a Sanden... you're going to be hard pressed to show an 'efficiency increase'... 35 years of HVAC hasn't changed much. I've been doing it about that long now and the automotive stuff is really simple compared with the industrial stuff out there. It's FO system in most cases! You can change that... but is the added complexity and service hassles that may be encountered worth it? I'm just asking questions, send the maths along, it's interesting experiment but measurable differences will in the end (I'm betting) will be nil. (Airflow across the exchangers will increase...but BTUs are BTUs and that is what will impact your radiator as much as airflow!) I'm interested to watch, but you made a STATEMENT instead of an "I hope to" so whenever someone states 'this is better' I have to ask why they are saying that. RIght now there is no proof. It's a hypothesis, not something that can be stated factually. I look forward to the progress, but until then it's all conjecture. All the best calculations in the world make something look great until you put it on the test bench and get sorely disapointed. Lets at least get to that point before making statements that it's better. That is what I was getting at. Remember, I NEVER said I didn't like it. I just didn't like the statement that it was better without any proof of that fact.

IMO that setting is way too high. Ask KTM what he found out about thermal runaway at a stoplight after running on the freeway. If you use a 190 fan switch, you best be running a 20 or 24# radiator cap! I used a standard Hayes (there is another brand out there now with something identical) electric switch that puts a sensor in the radiator fins. Set to come on 10F above the car's temperature on a 110F day in Palm Springs when driving at 30mph in 5th gear. Worked great. I run a 160F thermostat, and have done so for decades.