Tony D
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Posts posted by Tony D
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"Not sure why people are mounting surge tank systems outside of the main fuel tank. "
Bolt on simplicity. No cutting of the tank, mounts easily enough wherever you have space. Easily serviced if you suspect there is a problem. Possibility to make a FAR more efficient scavenging system than if it's in the tank. You can make a better more efficient surge tank externally than possible internally. If they could have made a 42" tall IMSA surge tank internally they would have. Some stuff just works better externally.
One other thought, I have the ability to service my fuel pump standing up, over the fender of the vehicle in a vessel that I only have to drain out a couple of liters of fuel from at any given time---no tank draining of couipus gallons required. It also is easier to amke a proper 'in tank' adapter in an external surge tank, than reworking a tank to properly work with, say, a Z32 TT Pump.
If you want to drop the tank and cut it apart, more power to ya, but just bolting on a smaller vessel that has better functionality does seem like an easier course in most cases.
Besides, nobody can see my surge tank, I---like an idiot---mounted it on the factor holes for the EFI pump behind the axles on the outlet portion of the tank. It's hidden, on other conversions I mounted is for the "Car Show Experience"! LOL
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I was just tooling around some JDM websites, and rest assured the DRIFT-BOYS know about using surge tanks on their cars now! I found several very nice (and Expensive) JDM ready made surge tanks that were designed to house various OEM In-Tank pumps, in various capacities. My favorite was a smaller unit of 650CC capacity (when the pump is installed) that is fed off the main tank. That is a nice idea...
Anyway, Photos of which setup? The IMSA car... I may actually have them, I just converted about 9,000 exposures from my early Sony Digital Camera---and ran across some photos of the #75 Car with the rear coverings off.
The Low-Pressure Application of the EFI Pump was THE way it was done in Japan in the 80's. My $100 (12,000 yen) FPR was set up specifically to take EFI pressures and drop them to Carburetted range, along with the boost-pressure port to keep it 1:1 setpoint above boost. I ran my car for 17 years on a pump that I took out of a junkyard and that was probably 10 years old then. Actually the pump is STILL functional. I think in carburetted blow-through applications the stock EFI pump will probably last longer than most would want it to... LOL
The pump most definately was not hot during operation. For a while I was actually running the return into the feed line, and then bleeding off some more to the tank through the dinky 240 Fuel Return Line (what, 4mm? It's small!) and the pump didn't get hot then, either. I KNOW you can't do that on an EFI system as the pump gets hot QUICKLY with recirculation scenarios.
There are many Fuel Pressure Regulators (they are all bypass style) that return the fuel to the tank, and have a regulation setpoint between 1 and 10psi. With a spring change I can convert my old Carb unit from 3.5psi pressure to 3Bar! Clever those Japanese. And that FPR is the same age---I see they are STILL selling the same regulator to this day!
I don't think 'overspeeding' the pump is an issue operating it at lower pressures---the speed of a DC Motor is pretty much set via voltage---the MSD Boost-A-Pump jumps voltage to get the pump operating at a much higher speed to supply more flow with THAT I could see wear being an issue as you are increasing flow AND pressure. With the setup these Bosch Pumps have (and judging by the pitch of the motor) it really doesn't sound like it speeds up much at all...I think it just doesn't 'slow down as much' as when the fuel pressure loading is on it. I suspect Bosch gives those derated pressure curves because they design for free-flow delivery/speed and then just live with the amperage/flow loss at pressure. They are designed for the flow/pressure curve versus amperage. It's when you add more pressure, speed, AND flow requirements that I would say wear will happen because then you are edceeding the original design.
By operating it the way I did, it was on a 'derated curve' ---well within design limits. Remember if the flow is there to be used, flow will raise amperage just as much as a pressure demand will!
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Yes, that is the difference and why I refer to the 'characteristic curve', the pressure really doens't 'rise' much, but the 'shape of the egg' really gets altered, as does the relative position on the O-Scope relative to the X-Axis Baseline.
An N/A Pressure Curve (Trace) has most of the bottom below the axis while 'intaking', and a pronounced 'indent' under power.
A Highly Turbocharged Curve (Trace) is above the X-Axis due to the presence of pressure in the cylinder from the intake---it may barely touch the X-Axis during overlap/scavenging, but usually it will be above it, and the power stroke portion of the trace will be much less "indented" comparatively to an N/A Trace.
Yes, preigniton is compression ignition, but chances are it's inaudible and you will never notice it. The key is that it happens before you are igniting the mixture via the spark---(hence 'preignition'). Detonation happens after normal combustion has started, and is usually the result of secondary ignition sources working on terribly lean mixtures which burn WAAAAY faster than they should, and result in a real high pressure peak. You can see these on the scope as 'spikes' in the 'indented portion of the egg'.
I am looking over some stuff now regarding the new computer modeling and pressure tracing software that is out there, and the traces are WAY different than the equipment I used even 15-20 years ago! They aren't 'round CRT O-Scope Traces' anymore! LOL Anyway, this is also a good site that discusses Detonation and Preignition as well: http://www.contactmagazine.com/Issue54/EngineBasics.html
You can hear detonation happening, preignition--especially in stationary engines---is referred to many times as a 'silent killer'---you see the aftermath, and just scratch your head 'because we never heard anything'.
Here is a link to a paper that has some graphical traces of cylinder pressures, it's not the same thing you see on an O-Scope, but you can see the differences in curves somewhat---sorry it's a boring DD 60-Series, but it's a good engine... Page three has some nice graphs relating directly to different spark timing scenarios, and you can see what I was trying to explain above much easier.
http://me.engin.umich.edu/autolab/Publications/Adobe/P2004_05.PDF
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That honking Taurus fan pulls 30A+ when it kicks on!
JeffP was having similar problems relating to ECU power at idle because of all the electrical gadgets he has on his car as well, and he went to an external regulated alternator (some reworked GM unit from a late model car) that the company waranteed would give 90A delivery AT IDLE. This requires sufficient windings to cut magnetic fields--I think it was something like an 8" Stator housing---it's a big honker. It's not a matter of spinning it at a faster rpm, because that comes back to bite you when revving the engine up---what you want to look for is something like the Police Package Alternator---it's rated at something ridiculous like 140 or 200 Amps, but the key is what the thing puts out at idle speed---if you can get that information, I'm betting you are marginal for the actual load you have on the car when your accessories are running. Jeff monitored his and he was something like 50amps WITHOUT his fan running!!! (Electric Water Pump)
The better alternator reworking places can give you this kind of information. You may want to PM or E-Mail JeffP as he's done a lot of work in this area recently (making the alternator work at idle and live with a 7500 rpm redline). It may be on his webpage---don't know, haven't looked there in a while.
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That is very similar to what guys run on the dry lakes and Bonneville for "Altered" classes. Miles, do you have a functional splash pan from the radiator support to the K-Member?
With the effort you are expending, you may want to seriously consider segregating the airflow for your triples now that you have 'hood flex' under control. That 3" pipe should allow for plenty of cool air into the carbs, but they will make better use of it by sealing a flexible box against the hood, the inner fender well, and keeping all that cool air right at the mouths of the carbs.
That box you made is probably similar to what will happen with my 'Shark Car' when it gets reworked. The Aero Testing confirmed what I thought, it's good to see people making use of the results in a concrete way!
Your spoiler ducts go directly to your brakes, right? I can't remember looking under there at MSA...
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July 17th there was a Dovebid Auction wher a guy in Ceres had a whole slew of LD28 and LD28T's up for bid! I was travelling, and could not pre-submit bids so missed out. I wanted to bid on one LD28T, and a pair of the LD20's he had. The LD28's were apparently forklift or marine duty with REAR SUMPS so they would be a literal drop in for a Z-Car!
The LD20's were going to be for my son's 510 Wagon, and my 69 Coupe. Imagine a late ZX gearbox, with a 260Z R180 in a 69 510 Two-Door Coupe, cackling down the roadway...something like 2300rpms at 50mph, and in any case passing just about everybody by 3200rpms. I think that would have been one sweet setup. The LD20 was 54 HP, more than enough for a 510...and not much less than the Non-US models had with L13 and L14 petrol engines! Imagine the economy there!
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It's not as hard as it sounds. Setup a ground rail, and a hot rail. Connect all the grounds to the ground rail with a nice heavy ground to the battery and the same for the hot rail.
Cygnus you S.O.B.! Why didn't you say that last June!
I have to agree that wiring is usually the biggest bugaboo that causes heartache on the systems!
We are running a 'much more expensive' ECU on our Bonneville Car, and have had a niggling problem that we KNOW is electrically related. Last month, before the ElMirage Meet, we did just as Cygnus suggested, and ran a ground and power rail. I found them at Orvac Electronics in Fullerton and they were $15 each, and another $6 for a nice red and black plastic cover to keep anything from dropping on them. I WISH I had known these were available so readily and nearby my house, I would have utilized them on my setup for sure. They are a marine product (for boats) and let you connect everything to a common bus where you know you have easy access to them for troubleshooting and inspection.
I don't have them on the MS system, but I do have two more conversions in the making, and I'm thinking this is the way I will go.
For the hassle of the DIY aspect of the circuit board, I might suggest getting one preassembled---it takes the guesswork out of it should you be questioning your technique or the box. For the cost over kit prices (what now, about $250 off E-Bay?) that works out to be about $50 an hour in my case (took me 5 hours for assembly)--given that I eventually had some cold solder joints found later on, that may have contributed to issues I was having...the preassembly may be a good idea.
I will say this about the tuning: Once you see the tuning, and get out on the road you can 'shift arrow up' and 'shift arrow down' while driving at steady state and realize just how the lean-rich adjustment affects how the car drives, you will have the low speed portion of the map done before you know it! May be richer than ideal (they usually are when doing it seat-of-the-pants) but it's not a big deal. What I found was that the interface on the $400 MS is very similar to units costing...er...a LOT more, and I find myself cursing the expensive unit for not having features that ARE found on the MS!
I've toyed with several Standalones now, and really, once you have a grasp of how one works, you will quickly pick up how the otehr systems work.
If you go into it with the following set of questions, and you can answer them for each component in the system, you will find it goes much easier:
1) What is it? (Nomenclature, what is it called?)
2) What does it do? (Function, what does this component do, and how? Does it switch power, does it open and close, etc)
3) What controls it? (and How---is it an electrical signal, pneumatic, thermo-electric)
4) What does it control? (and How---varies a current, changes a pressure, etc)
5) Where is it? What does it look like? (Component Location/ID-not really a big thing in such a small system, but knowing where you have to look for something or where to find it may help when you have a 'helper' trying to diagnose what it's doing while your eyes are watching something else.)
This is stolen from some Air Force Field Training---"Troubleshooting Through System Knowledge" before that point, the instructors were pretty haphazard about telling you how circuits functioned, or how equipment worked. They did a lot of rote memorization and parroting of technical manuals, but one instructor came out with this approach and it really helped me devour technical details about systems. If you can answer those 5 questions, you will start to realize how much many "Experts" really only have superficial knowledge of a specific system!
This will go hand in hand with 'Five Whys'---the old Japanese Management Axiom of asking someone "Why" five times to any given answer. If they can't answer "Why" five times before changing a procedure, then maybe they haven't thought out the procedure or system that thoroughly. It makes you think far beyond a superficial problem-solving mode, and get past what may seem to be obvious reasons to underlying root causes that may affect more than one system in the vehicle (or whatever!)
Good Luck, I digressed!
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I'd say the Dual-Priced OBX Units are, as Gene Berg used to put it in his catalogs, "POTL"
Pick-of-the-Litter.
Gene Berg would buy large lots of components from vendors, then go through and inspect each one with his staff, using gauges and etc. When the lot was 'picked over' and those items that met his standard were culled for his stock and customers, he would sell off the lot to another place---usually a competitor like SCS or any of the other VW Houses present in SoCal/Orange County.
Some times, there would be two grades he would cull, POTL and Servicable. The POTL stuff was sold at a slightly higher price, and the Servicable would be his normal stock. Stuff that didn't meet those two grades was still sold off to competition.
Funny that SCS is out of business now going on 17 years or so...and Gene Berg is still there on Lime Street in Orange...several years no after his passing. Quality counts.
I'd suspect the OBX guy may be doing a 'check' or maybe replacing some components for the stuff. Then again, being e-bay I also wouldn't discount the fact that they are simply listing the same item at different pricing levels to see what fish they can drag in.
Ever see a refrigerator on the side of the road with 'free' on it? Sits there for months till Code Enforcement cites the owner.
That same refrigerator put out a week later with $50 on the sign and a rope tied loosely to a tree nearby will have two outcomes: Someone BUYS it, or someone STEALS it. Make something 'too cheap' and people will suspect it of being somehow defective, up the price, and then they buy...to complain how cheaply it was made later...but hey "for the price"! LOL
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What you have is a balancing act of getting the fuel to actually keep expanding as it burns sliiiightly faster than the rate at which the piston is advancing down the bore and giving it room to expand.
This is why racing fuels have different formulations---different engines have different mean piston speeds and dictate a different burn rate to keep the pressures up. This is why I'm not a proponent of AvGas, it is formulated to burn in large diameter cylinders with very low piston speeds. VP makes several different formulations for 'import' engines now realizing that the 105 for a Chevy V8 really won't produce the same peak power in an Import with pistons outrunning the flame front!
Indeed, with a Keniscope you can actually see these phenomenon happening, and it is neat to watch.
Want to watch something boring, watch the trace on a Diesel...Same every time...
But gasoline and gasseous fueled engines? They are all over the place! LOL
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(EFI pump as booster reply is at bottom)
I'm going to chime in on complex methods for preventing aeration:
There is only one thing that will work: Height. Period.
The IMSA #75 Twin Turbo 300ZX car had probably one of the most complex and sophisticated fueling systems in any Nissan Vehicle. It had six pre-pumps sucking from the fuel cel to TWO surge tanks, which then had two main pumps feeding the engine. This could support 1100HP, but during races and due to IMSA Rules imposing 26mm inlet rescrictor orifices on the turbos, it 'only' made 750HP.
The fuel cel pumps did suck air and send it on to the surge tanks---they had pickups and several points in the fuel cel and during low fuel conditions and hard cornering, it was inevitable that some of the booster pumps would pump air.
The answer they came up with, with millions of dollars of engineering experts and factory technical support was:
Make a Taller Surge Tank.
The surge tanks in this vehicle went from the bottom skid plate to literally the roof structure. They were close to 42" tall. The booster pumps fed at roughly 36" in from the bottom, through a deswirl tangential entry sort of arrangement. Fuel return was taken off similarly at the top. Fuel to the main pumps was taken down low right on the bottom of the tanks.
I think the chance of 'sucking air' with an open return line is extremely remote---on a racing vehicle pulling 2-3G's and having fueling requirements for top tier motorsports maybe more thought needs to go into it...but at our level, I'm strongly inclined to think we may be overthinking the issue a tad.
Like I said, I fed mine for years using the stock 240Z "ticker pump" a Bendix License pump that wouldn't supply the engine with enough fuel in Normally Aspirated form, much less making 350HP to the rear wheels! Sucking from that tank, was a stock Bosch EFI pump, which normally is out of poop by the time you try 250HP...but since I was running Carburetted Blow-Through the lower pressure of the system even at full boost only required 27psi of fuel pressure, and the stock Bosch EFI pump supplied that handily. Matter of fact, due to my jetting I was way rich---that system really overfed me for what I required. Never ever ran lean...
When that pump is operating at lower pressures, their flow capability is phenomenal... if you ahve 3psi in your surge tank, you really probably have too large a booster...really!
The big thing about the surge tank is to really provide a reservoir for when the unbaffled tank has a pickup uncovered. If you were straight EFI pumping---you loose fuel pressure and the engine burps.
If you have a surge tank, or even a swirl pot utilizing the return fuel to augment a 'bulge in the line' when you suck air from the tank it wil ONLY ever make it as far as your surge tank---the bubbles will IMMEDIATELY rise to the top and be carried out with the return line and overflow fuel.
If you run a hobbs pressure switch---or even watch a gauge of the pressure level of your surge tank, you will see it is 'dropping' boost pressure regularly if you are running a 240 tank, unbaffled, below 1/4 tank and turning corners at ANY kind of speed. But main fuel pressure will remain unaffected, as when that boost pump regains prime and starts pumping---even though your main pump is sucking down fuel, you still have return fuel coming in to keep the main primed.
On the issue of the EFI pump feeding the booster---that will work like you wouldn't believe---as long as you have an EFI tank, running the stock EFI pump will flow like crazy at 1-3psi, and more than adequately fill any surge tank for a larger pump. As long as you have the return line running into the surge tank as well, it should work superbly. Having a surge tank(s) is good insurance when running high-hp EFI setups simply from the fact you won't get that burp---which can cost you pistons! Where'd you dyno the car on Okinawa? Goya?
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That may well be, but target AFR's a wideband to the ECU would be the way to do that I suppose. Or Innovate's simulated switched output with your target set to 15, and tuned to 16's...
I know that you can really knock down emissions running at those parameters, though NOx goes through the roof due to temperatures in the combustion chamber. A little tweaking on the EGR through a GPO on the ECU, and you could tame combustion chamber temperatures and lean it out some bit further. Use the EGR coolers present on some diesels nowadays, and I suspect the EGR influence on lean-running would be even more positive. But since EGR is an 'emissions component' most people tend to simply remove it without giving much thought to what it actually does: Cool the combustion chamber. Ford was famous for really laying EGR to engines to keep detonation under control with super-lean mixes in early carburetted emissions control scenarios. For someone shooting for mileage, it actuall lets you lean out slightly more, and run similar advance...
Now we are crossing from the merely strange into the downright wierd: EGR as a performance enhancing device on a fuel mileage motor! LOL
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The best kill switch I ever saw was sold in the early 90's by a company called "Counterpoint" out of Sand Diego. They had a latching relay that interrupted whatever you liked: Fuel Pump, Ignition Power, Starter Enable...they recommended using two relays one for fuel one for cranking that way someone didn't kill your battery in the cold.
Anyway, the thing was a VERY compact box, and had some very simple counters on the circuitboard---but the KILLER part of the whole system was the actual switch: It was a touch-style membrane switch. You could stick it under uphoulstery, slip it in between the vinyl on the upper portion of your door skins on the S30, wherever! It had several features for safetey, like if the button was pressed when the key was on and engine running it would shut off the car after 45 seconds---this was a 'carjack escape' feature---you got out of the car, pressing the spot and the guy jumped in and took off...only to have the car die: away from you, and usually this would result in him bailing and running. If you forgot the switch, it would passively arm 30-45 seconds after the car was shut off automatically. No matter what, when you got in you had to touch that switch or the car just would not go!
It took pinpoint pressure to actuate the switch, and you got an audible signal that it activated. Just pushing with the palm of your hand would not to it, neither would the edge of your hand.
I installed one on my wife's Corvair, and it coufounded her when I said "you need a special touch with her..." and I squeezed the dashpad then turned the key and it started! "What did you do to my car?" LOL
Anyway, I haven't been able to find them since---I think they went out of business. I have ONE kit left, and have often thought about having the potting compound taken out of the box, and reverse engineering the device. It IMO was the best "Kill Switch" ever made.
Plain sight is a good camoflage, but 'no special point whatsoever' is even better!
I have used the Radio Rocker Switch using a latching relay for intitializing the kill function---after Counterpoint turned me on to latching relays that wont change state till energized, it changed the way I did the kill switch thing! Kind of like the Overdrive Switch in the Ford Trucks on the shift column...supplies the power momentarily for gating of a transistor to trigger the relay, or directly to the relay.
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Come to think of it, Aircraft Spruce in Corona also offers a nice aircraft cable swaging service. I used them to make my Corvair Clutch Cable when it broke---they can make just about any kind of cabling you want and properly swage all sorts of ends on to it and offer the service Mail Order!
If you get in a bind, that's always an option as well!
For some reason when he said 'Terrycable' this just popped back into my head.
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On another note, Graniger also sells 'Alternator Boxes' for compressors....if you take the pressure switching off the compressors themselves and put it remotely, with two compressors you can set up a 'lead-lag' setup.
Basically, below say 125psi, both compressors run on their respective starters or contactors. At 125, one compressor shuts off, and the other 'the lead' will pump up to final pressure 135, 150, 175 whatever. At that point, when it shuts off after reaching pressure...the alternator box will switch the compressors 'lead-lag' relationship, so that when the pressure switch calls for it to load again, the other compressor kicks on the supply demand.
If at any time the pressure drops below the lead cutout the second compressor will also kick back on, and maintain the pressure.
This setup really increases the life of recips, and keeps them cooler overall. This is one good reason to have compressors rated at least 10% above line pressure requirements (say 100psi line, 110psi for storage, and 120-125 for lead cutout).
There is a rule that you should only compress to the pressure you need, and nothing more---but this is for industrial rated units that can operate at 100% load all the time. The compressors being discussed here are not in that catagory. I'm talking a Quincy QRD style unit---that pump alone costs $5000! Some others come to mind, but when you get into that kind of money, the new lower-cost Atlas Copco GX screw units with integrated Oil Separator and Dryer start to make more sense. And now, finally after 20 years of people begging for them to do so, they FINALLY have a screw unit in the 2 to 7 HP range that is SINGLE PHASE.
If you want a compressor that will run 100% of the time, supply clean, oil separated air, and be quieter than most refrigerators, take a look at the Atlas Copco GX units (even though they are a competitor to the company I currently work for!) they really are Cadillac Compressors. (Maybe Stripped down to Buick or Olds configuration, but still a fine quality unit!)
I see right now one of these is on e-bay (15HP) selling for around $4K...
Brochure here:
http://www.benzcas.com/atlas-copco/pdfs/gx-2-22.pdf
E-Bay Auction Here:
Chances are good your local Atlas Copco Dealer will have one in stock close to that price...maybe maybe not... See what happens on the sale. If it was closer, I'd consider it... Nah, I'd get one as a 'take off' from a compressor retrofit. LOL
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yes IM aware that PVC pipe is not generally suggested for pressurized air....
Oh IM only too aware of the minimal risks, but Im also aware of the huge cost differance, I probably would never have tried it if a buddys shop had not used it without any problems for over 12 years now , and hes located less than 5 miles from here so he gets similar shop temps and pressures on the pipe,
PLEASE! Tell me that both you and your friend are using good old ND 30 compressor oil in your units, and DO NOT use Synthetic!
PAO or PAG based Synthetic Compressor Oils WILL attack any of the polycarbonate or polyvinylchloride plastics used in piping and separator bowls.
Ever wonder why the Polycarbonate Bowls have a metal cage around them? When synthetic oil gets onto the plastic it weakens it without much outward signs at all---and then catastrophically goes BOOM!
I personally have been in the area when a bowl has let go. Luckily nobody was around to get hit by the flying shards.
I have responded to customers with PVC systems at the request of Hartford Steam Boiler Company for insurance estimations of replacements after large runs (like you said, water...and oil...runs downhill) of piping in horizontal or near horizontal positions have catastrophically and without warning split or blown apart.
This is DIRECTLY caused by SYNTHETIC OILS. If you are running PVC or ANY kind of plastic piping DO NOT RUN SYNTHETIC OIL IN YOUR COMPRESSOR!!!
Also, make sure you have GOOOOOOD aerosol and condensate removing filters at the compressor.
If I have a customer that wants to save money by using plastic pipe, I will insist on copper or stainless steel piping from the compressor to the Wet Receiver, and from there to the Dryer into the Dry Receiver. From that point, most everything is knocked out, and IMO the risk is minimal. For a smaller system I'd run stainless or copper to the last stage of separation, and go plastic from there.
I have seen PVC droop from heat, balloon up from discharge heat, split, fracture, explode, and otherwise do some very nasty things dealing with compressed air. If you use it, try to separate out as much of the oil aerosols that you can as near the compressor as you can to minimize risk.
BTW, in one case, the pipes were in for 10 years before there was a problem. They had been using Synthetic for a year at that point, due to maintenance costs on the screw compressors they were using being greatly reduced using synthetic oils.
For a small recip, stick with standard ND 30 Compressor Oil, if you use Synthetic and plastic, there is a good chance something can happen. Been there, seen that!
On to Tank Size: The larger tank you have, the less horsepower you need. In theory if you have a lagre enough tank to handle you peak loads you can get by with one of those 12V tire compressors! Tank capacity is good for two reasons: Residence Time, and Recovery Time. Bigger tanks have more 'residence time' for the air, meaning it can sit there and cool---this means condensate forms in the TANK for the most part, and not in your lines. Residence time means debris in the airstream has time to settle out--by debris it can mean oil residues and oil aerosols as well. Small droplets fall as gravity work on them---smaller tanks have a flow through them and can carry this out into the lines---a good reason for putting a coalescer on right after the outlet valve on the tank.
Recovery time is the time it takes to come back up to pressure. Almost universally people who increase the tank size do not readjust their pressure switch accordingly. This is not just homeowners---this goes for people with 6, 500HP Dry Screw Units and several thousand gallons of storage capacity as well! What a larger reservoir does for you is of course increase storage. To take advantage of this, you should decrease the cut in/cut out differential on your compressors. Many times you can't do this with the switch that comes on most of the cheapie home units. I use relay controls and an Allen Bradley 745 Series switch from Grainger. It has both adjustable cut out and differential. Running two 300 gallon tanks, I run a 2 psi Differential on the compressor. Normally this would have the compressor running on and off with only an 80 gallon tank. But it takes 3 minutes for me to bring tank pressure up 2psi---about the same time it took the same compressor to bring it up from 90psi to 120 when on the 80 gallon tank alone.
What this does is keep your compressor operating at peak efficiency (full load) and decreases system pressure variations. It's a pain when the tank is at 90psi, and the nail gun is not sinking the 3"r's all the way in! With the compressor differential being set to 2 psi, it keeps pressure constant, and doesn't really result in the compressor running any longer that otherwise.
This is why you regulate down to system pressure, and then regulate down again at hose connecct at point of use. You will find your end-point pressure stays much more constant when you set it up this way, but it will take a $75 dollar switch retrofit, and maybe some relays. Grunmpyvette is correct, however you reach the pressure or flow rate is really irrelevant---you can run two or three units into a common receiver. But jsut remember that you store pressure at higher pressure, and regulate down at least twice to point of use.
Run your storage tank at whatever the compressor is rated at, your lines to the shop (regulated at the tank) at 100psi, and then the point of use with proper lines to final pressure: 30 to 90psi usually.
Also, making a 'ring' configuration will cut piping losses in half as any point in the system can be fed from two pipes---similar to his two into one setup.
Scrounge around Portland area, there are several large compressor manufacturers in your area (Rogers Machinery, Burton Compressor, I-R Air Center comes to mind) and see if they have some old tanks they took in on trade they are looking to unload or sell cheaply. Many times you can get a KILLER deal on a 7HP 3-Phase industrial unit that will last you for a lifetime, all your cost is in replacing the motor with a single phase motor. That is probably the largest size most homes can handle with the wiring available---that will be 7 to 14 Amps 220V. If you can scrounge the tanks, you can set up a really nice ssytem with plenty of storage and separation. Just remember to put ball valves at each tank inlet and outlet so you can shut them off individually, and hold pressure in between the times you use it. Makes it nice when you want to fill up a tire or two, or even blow off some stuff and you don't need to start the compressor....just open the valve do your thing and cork it back up for storage.
Air Stores Well!
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The Keisler TKO that JeffP used had a custom shifter that has a three-link shift rod bolted together with serration in it to lock the rod in whatever position you put it. As I recall it was originally configured to put the knob quite abit reward from where the pivot went into the gearbox...almost 4"!
I know he roconfigured it for the ZX as he didn't need that setback, but I would think any aftermarket shifter for the applicable T5 would make the shifter relocation a moot point. With the advantages of the adjustable stops on the shifter to keep from overcentering the shift rod/forks, as well as spring loaded shifting gates, for the money I don't know why wanybody would stick with the stock shifter. In for a pfenning, in for a pound!
Jeff's situation was similar to Tim's as well. At 450 verified to the rear wheels, I could watch the stock T5 shift knob move around quite a bit, and the noises the gearbox started making under load were not good! Keep in mind that there was an RX7 at Bonneville running turbos that was using a transmission with a stock mainshaft assembly, at speed...when the torque of the Rotary came full on (about 160-180mph) the countershaft assembly flexed enough that the Fifth and First Gears engaged simultaneously, locking the transmission (as well as the rear wheels). This caused the transmission to literally BLOW OUT under the car, lifting it into the air where it did a series of flat spins... (and this comes from a post event dissection).
When you are making serious power, stock will not cut it. This area may cause some severe, instantaneous, catastrophic failures at a VERY innoportune moment. This Mazda had made COUNTLESS passes with this very transmission, and the torque it produced during those juuuuust wasn't quite enough to make that second gear engage. But on that day, with the right air density, that little bit of torque was produced, that thousandth or couple of thousandths of flew happened, and BOOM! Totally different situation than just one pass before!
This situation came up when I watched Jeff's stick moving around and heard that stock T5 Screaming. I think the stock internals are marginal at best at that power level.
Thing is, Mazda guys were welding Mazda Bellhousings onto Nissan Trannies to hold the power...
Be safe and don't press it till you know your tranny can handle it.
From my 73, I ran the N/A tranny and purposely limited HP to the rear to below/max 350. I figured I'd go with a T5 when I upgraded. Who knows what I will use now...that N/A was not really dragged but did see AutoX and hard Street Driving for close to 17 years and held up fine, though it started out in my car with only 8400KM on it---it was from a Totaled 84 Skyline L20ET that I got RIGHT when it came into the junkyard, and then sat in my spare room for almost 3 years till it was ready to go into the car! Using one with higher mileage may not hold up as well or as long. I have about 50,000 miles on the car with the trannny in it at that power level.
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I'll add this. The N/A BMEP of say an SG8 Superior is something like 48, where the SGT8 (turbocharged) running 21psi of boost is something like 148. It was a big rise. Of course specific fuel consumption went up, to compensate for doubling the horsepower, but you can see the EFFECTIVE PRESSURE of the engine rose by almost 3X compared to the N/A rating of the same engine.
There is a calculus formula for finding pressure inside that Keniscope Trace, and that is how BMEP is calculated. Raising that egg above the 'Zero Axis' starts to make some real power!
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What you are talking about is altering the BMEP (Brake Mean Effective Pressure) if you attach a Keniscope (osciliscope tracking a piezio transducer) to the combustion chamber (they make spark plugs for this) you can see a characteristic curve that looks somewhat like a 'flexible egg' that someone stuck their finger into on one side.
When you are N/A, the curve on the bottom of the 'egg' dips below zero on the x-axis, when you boost, the whole 'egg' moves up along the y-axis accordingly.
Boosting makes the egg 'less poked in' and makes for more effective average pressure on the head of the piston, which you said increases torque. The head gaskets, and the head studs will hold enormous pressures in that nice, steady rise to peak cylinder pressure (which is a ocmbination of the burn, burn rate, and piston position).
When you detonate, or run lean even, the burn rate is MUCH faster. Lean burning makes the flame front rise pressure much faster, and to make a poor analogy you get a 'water hammer effect' like when you shut of flowing water---the pressure in a lean burning cylinder rises so fast the strains induced on the joints and gaskets tend to start seeping. If you ever quickly turned on a large refinery pipeline, you see that gaskets that held during slow bleed valve pressurization sometimes weep when rapidly pressurized---this is what affects sealing integrity, and once the process starts it weakens the area so it's prone to do it again.
Detonation is plainly an explosion (not a burn)---technically the burn rate in an explosion is superfast. Tens of Thousands of feet per second, versus a few thosand feet per second (watch a long length of Detcord light off and you can actually see it go, highspeed phootography reveals a discernable flame front on the cord!). This superfast rise to pressure, as well as the much higher pressures produced (the burn rate determines the rate of pressure rise---for a combustion chambe that may be decreasing in size due to an upstroking piston that can make for exponential rise) simply overwhelms the gasket joint, and it fails catastrophically.
SB Fords were known to lift the heads off due to stud stretching. You can do that from a normal burn at enough BMEP (peak pressure specifically)...when that clamping force is affected, then you get blown head gaskets as well. But without the 'detonation signs' of broken piston rings and lands...or burned/holed pistons.
I haven't Keniscoped a Datsun L, but spent hundreds of hours on Lean-Burn Staionary Industrial Engines (Specifically the Cooper/Superior SGTA Series). What happens to the curve when you play with temperatures of incoming air, gas admission rates, even spark plug gap (for cylinder to cylinder comparison) is amazing.
The key is to get the peak pressure event to happen at the proper portion of the crank position. It's not simply making more pressure, it's making pressure when the crank is ready to make use of it! Spark timing comes into it bigtime, as well as fuel formulation. Slow burning fuels will limit the horsepower you can make (there was the 'high octane makes lower horsepower' argument, and this is why) but because you have such a range of spark timing adjustment you can usually compensate for the slower burn by running more advance. Faster burning fuels will tolerate less advance (lower octane), and the spark timing can be less for the same peak pressure---this is the point where you have to make the tradeoff between slower peak rise to pressure, versus a quicker rise. The less time the heat is in the chamber, the better, so a fast event is marginally better than a slower, prolonged event. I would not say you want to detonate --defined as uncontrolled fast burn. You want the 'fastest burn' that you can reliably control without it going to an uncontrolled state. This is where preignition comes into the game. Preignition is different than detonation...you can melt the ceramic inuslatiors on the plugs, burn the groundstraps off them...all sorts of nasty stuff. You don't hear it, it's like detonation but much more insidious and damaging---you can see it in the keniscope trace as a 'big hump' on the oeak pressure. Instead of the rapid detonation spike you can see, it's maybe 3/4 as high as detonation, but then 'humps at top' and is rounded. Basically all the effects of detonation, without the outward signs of a blown headgasket. Things just melt and break apart silently. This is the realm between controlled burn and outright detonation. Engines can run like that for quite a while damaging things without any outward signs. Leanburn stationary engines are suscptible to this---they run 22:1 AFR's and have precombustion chambers at 14.7:1 with 'flame holes' to keep the lean burn chamber ignitied. This probably illustrates the difference in burn times as you can literally ignite in the precom chamber with Stochiometric, and literally light off and relight several times during the pressur cycle a lean burn cylinder that burns so fast it can burn and go out and relight up to three or four times before the pressure peak target is reached.
Man, I'm going all over the place on this, is it making any sense---there is so much to discuss it's not funny!
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Oh come on!
Nobody will google it and post it...
Do I have to do it to redeem my status?
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You say "my project" as if you have just one.
Guilty.....
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CHT and CLT is interchangable. They both have the same response curve.
I have a CHT as CLT on my Megasquirt. Like you can interchange the 82/83 CAS as a plug in replacement for an 81CAS unit, you can swap in the CHT sensor and plug the CLT sensor pigtail in it and it will work just fine.
Only the US Cars used Cylinder Head Temp, everywhere else used the Thermostat-Housing Located Sensor.
They both send the same sort of signal, and their response curves are identical, so from the ECU's point of view, either input will work.
In the bad old days, you would rig Hobbs Pressure Switches with resistors on them wired into the circuit to progressively move the thermostatic reading to the ECU "colder" maps---ultimately if you look to the FSM you will see that something like X ohms = -50F, and that's about all the enrichment you can get that way. Good enough for some decent boost as long as the pump doesn't deadhead....
Just have to have been around when we did this crap al the time to rememer it---it's nothing new! For sure I'm no electric genius, either! LOL
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Ad in Rotterdam has been fitting BMW third members to the vehicles he has been outfitting for competition in Rally Events. I will be in his shop in October with a new digital camera and hopefully can document his conversion for posterity.
This is the website for his shop:
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For initial setup, I have used the vapor line on the left frame rail for the return...it's 8mm I believe, same as the stock fuel feed. It may be minutely smaller. I just make a 'Highpoint Loop' with the old vapor line up by the vapor recovery tank, and then vent it out the rear of the vehicle in the area of the right rear tire, like the factory did on some Non-US models (they had a good old 'dump tube' in the filler neck!) My return goes from surge tank, to the 1/4" fitting at the top, right, rearmost highpoint fitting (vent) on the tank.
I picked up -6 .035" wall Stainless Steel tubing at the local Swagelock Distributor. Since I have their bitchen' bender, duplicating a factory hardline while it's out of the car is a snap...well, not really a snap---it's really a pain in the butt, but I can (have) do (done) it!
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This is why I have mirrors on the top of my sneakers!
To check out rusty rocker panels on Z's at shows without getting all grimy...
It runs! But...
in MegaSquirt
Posted
If you are seeing a jumping TPS, then it may be picking up some flyback form the igniton wires triggering the accel circuit.
My TPS is run using shielded wire.
You may have a loose connection giving an intermittent connection doing similar symptoms.
Now I'll look at the datalog and see if I made a fool of myself...
I can see a correlation of a 1% change of Throttle Position Affecting a 5% accel or decel enrichment situation. It may be that your trigger parameters for getting those enrichments are simply too senstive. There is a parameter you can set to totally disable enrichments on accel---I tuned mine without enrichments enables by changing those parameters, then renabled them after tuning was done and trimmed for 'quick' throttle response. If those parameters are set to sensitive, even noise form a normal dirty TPS pot will cause them to trigger-which looks like is what is happening in your case. That TP line can't move a BIT without triggering the Accel or Decel parameters. I'd null them out a bit and retry. My Accel doesn't come on unless I really mash the throttle with some authority. Not necessarily to the floor, but stabbing it quickly will enrichen the mix, where a roll-on (like to pass when there is plenty of room) will not trigger it. Then it stays on for the decay time set---several igniton cycles as I recall, can't remember what it is and the program isn't being found right now on this laptop,( I know it has to be in here somewhere) so I can't tell you where mine's set. i'm sure others will f eed back on this subject with their settings.
Valves with clearance are going to noiser. Noisy valves are loose valves. Loose valves are happy valves as they have residence time on the seat and can cool off. Quiet valves are tight valves, and tight valves are hot valves....