Tony D

I had occasion to pull into a 1968 VW Type 3 Squareback in the JY the other day, and all sorts of memories came flooding back, not the least of which was a MAP sensor that was calibrated by a screw and a about the size of a Beer Can! What does this have to do with EMI/RF? When first working in the Auto Mechanic Trade, there was a terrible propensity for the Type3 Models to just shut off without any reason whatsoever. One such incident was immortalized in "The Idiots Manual" by John Muir, where the car would die every morning at the same corner, but never on the weekend, or any other time. Turns out a leaking Amana Radarange was in operation warming coffee, and that the leakage was enough to kill the early Type 3 Electronics! No AMP Connector on the ECU, a tab-sealed box with the EFI pigtail coming out of it. Steps to shield the box involved a big aluminum envelope with a ground tab on one end... Just to make the point that interference ONCE was a serious (if not intermittent) problem with electronics in mobile vehicles. Cadillac had one hell of a time when they decided to put a CB in the car as a STOCK option. Shielding on those cars was in the strangest places! Grounding and interference shielding IS a valid MS topic. When my initial tach issues were going on, I found that the AC powercord for the laptop had to be routed DIRECTLY out the passenger's window or interference would be picked up. Same goes for if I powered it from an Inverter powered off the Cigar Lighter. Wether we like to admit it or not, shielding is not the MS's strongpoint! Anything to advance that knowledge is a good thing. Wether it's against Nuke Blast or the Cop Zapper Guns, who cares? At this point I think if someone used a Zerostat within 20 feet of my car it would freak the ECU and cause problems...

OH WOW! I just clicked on the Aeromotive links and saw their advertizing is dead on in line with what I was trying to explain. See how they are giving N/A and Forced Induction HP ratings that are different for the SAME pump? Similarly they give different ratings for EFI versus Carburetted engine applications, and they give the flow chart for the pump to correlate flowrate against pressure... Now you know why! Just look at the flow curve from them and deterimne if it will meet your needs. That is a big pump. Funny thing is they recomend the 16302 "fuel pump controller" for long trips to keep fuel cooler. It's a fuel pump modulator that cuts voltage below a predetermined RPM. I guess those 81-83 Datsun Engineers were on to something back then by using the same strategy to "keep noise down at idle" in the GL models of the ZXT!

As for elevated pressures, mos JDM conversion of carbs used stock turbo EFI pumps. This goes to veritechs Q on the Aeromotive pumps... The FLOW the stock pump is capable of producing goes UP as pressure decreases. So a pump that can only accomodate 250HP at an EFI pressure of 55psi, may indeed be able to comfortably support 350-375hp at a carburetted pressure of 23-27psi fuel pressure (22psi+3psi for the carbs differential). I know this firsthand. Now the Aeromotive advertizing maybe misleading, it may not. While the pump gives a RATED FLOW of X GPH or X PPH in their advertizing, that is only ONE POINT on their flow curve. At 70psi, it may well produce enough flow to support an engine. Chances are VERY good though, that the flow rating is decreased considerably at 70 psi when compared to it's delivery at 45psi. The stock 280ZX Turbo EFI pump WILL produce 60psi. But PRESSUREdoes you absolutely NO GOOD whatsoever if no flow accompanies it---and that is about where the stock 280ZXT pump "deadheads" or in otherwords does not flow any more. Pressure versus Flow are inverse quantities, and as flow increases, pressure decreases. Also vice-versa. So just because they give you a rating of something at 45psi it doesn't mean it won't make 70psi, with flow. You need ot get the flow curve from the manufacturer. Some pumps don't have internal reliefs like the ZXT pump does (which is why it stops at 60psi and internally recirculates), so they can still flow, but they draw a buttload of amps. nothing is free. It all takes horsepower to flow a fluid through a tube. Hydraulics is hydraulics. Nothing changes the laws of physics. Hope that makes it clearer to someone...

There at one time was a device called the "Cagle" FPR, also Cartech sold the Italian Regulator used on the Maserati Bi-Turbo, and they both used spring referenced pressure to maintain fuel pressure differential over boost of 3-7psi. Key was you set the pressure at idle so that was your referenced starting point. 3-7psi at idle. This is how you keep pressure at idle vacuum. It also realizes that under drop-throttle spikes of 20+" Hg, you WILL effectively drop fuel pressure to ZERO, letting those floats seal positively against their seats and preventing that fuel bowl level spike. it's an art screwing with the carbs for boost. Anybody who says "carbs are easy" hasn't tried tuning them to the extent necessary for optimal preformance! Anyway, that is what I think you were missing, TZ. Many times with EFI, you will set fuel pressure to a known pressure at "0" manifold pressure, and the spring will compensate for the differential at all other pressures. (source of all noobs wonderingwhy they have 40psi static fuel pressure when the book says 36psi.... They are missing the differentiation between static fuel pressure and idling fuel pressure, even on EFI!) In a carburetted application, you have to have the fuel pressure set with the egnine running at idle to give proper fuel pressure at idle. You could, I suppose, fudge and set something like 7psi static, but the directions for the regulator said to set it at idle. Always follow the directions! In the "old days" there were all sorts of caveats you had to obey when checking fuel pressures (at idle, at 2000rpm...) and stuff like that (Timing at idle with vac advance removed and EGR port plugged....) BAH! EFI is better....

I used te stock ZX resistors as well, for the same reasons Z-Ya did. There is one year (81 believe, but it may be later, can't remember) where the resistor pack is actually a 6-Resistor unit, as opposed to a 4+2 configuration. This makes wiring a bit easier IMO because there is one wire feeding power to the resistors, so one connector does it all. On the 4+2 units, there are two connectors, though the power is eventually spliced together inside the ZX harness.

There is a NICE adapter from the lower radiator hose of a 240SX that slips into the raidator hose, and contains a switch for the cooling fan. Unscrew the switch, install your CLT, or the CLT for a GM, and no tricky on-car machining is required! I found this recently, and thought "Oh, that's a trick switch adapter" usually they are in the radiator tank, but having one in the radiator hose makes for a nice universal mounting for just about anything! I believe the car was a 91 if memory serves. Summit makes several adapters like this as well. Hope this helps with giving you another option.

Jeff has been back to the dyno since, but hasn't gotten a dyno printout since. Last "low-boost" outing had him making well over 300ft-lbs tq at 4500rpms, with engine going lean coming on and pulling hard at 6000. Fuel delivery with new cam setup is proving to be a problem. That was at 8psi... Once the injector latancy problems he is having is solved, and he can push the fuel to the engine, I'm thinking he will get a printout. But before he goes testing at 25+psi, he has to get the fuel to it at 8psi! His power delivery graph is quite a bit different than the one he has posted on the anglefire site. The new cam (more to his original specifications, than what someone decided to sell him in the dark...) has altered the way the car pulls dramatically. Much stronger at the top end. I think Jeff is getting old. I actually have heard him make comments like "this may be way too much power" or things along that line. What is the world coming to???? JeffP thinking he may have gone overboard in the quest for power: Say it isn't so!

VERY nice slip-jionts, Tim! I think that setup should work just fine. That is the way it should have been manufactured from SFP! That 321 is very resistant to cracking. The elongation of the manifold is the problem, radial expansion is what makes the slip-joint seal. The outer portion of the joint is considerably cooler than the inner portion, and with a slip fit to begin with, the expansion of the inner portion will make a nice gas-tight seal under load. Yep, I think that setup will work just fine! Looks VERY good! inconel..."unobtanium", priced to match! LOL

My suggestion would be to NOT reference the plenum pressure, but to reference manifold pressure. Why? When you drop-throttle, even with a blowoff valve, there is somewhat of a spike in plenum pressure, and this can sink the floats momentarily, causing a slightly elevated float bowl level, and a drop-throttle enrichment stumble. If you reference the manifold pressure, as soon as you drop throttle, or lift throttle, your fuel pressure drops precipitously. This allows for a sealing of the needle valve quickly, and a bit better fuel level control. now, if you want to really get into it, putting modulator rings in the plenum above your throttle plates will allow for a on-boost enrichment without using humongo jets giving a better idle and off-boost economy and drivability. For the effort of converting the DGV's to Turbo usage, buy a Megasquirt, and a stock turbo setup and go EFI. I ran a blow-through carb setups from 85-on in the Z, and as soon as Standalone EFI bacame economical, I converted gladly and NEVER looked back! I've run blowthroughs on VW's since the late 70's. EFI is better.

60E,Reservior, Mission, East End.

I would give a shot posting the specific question on the old Megasquirt Yahoo Groups Site. A different class of cat prowls there, and an obscure question like EMP shielding may get taken up in the discussion there...or not. But it doesn't get you banned from the "easy to use forum"....

Er yeah, it's not 18-22psi, it's 18-22 inches Hg. I'll lay money on it. If you have a stock EFI Z with that low a vacuum, it's affecting the fuel delivery. Check valve adjustment... Mine is anywhere from 12 to 20" Hg depending on what cam I'm running. I want to say the stock L28ET in the 260 has something like 35kpa at idle. Good Luck.

Looks like Alan has this well in hand, I'm in late to the party again. Believe it or not, I bought an L20A complete factory service manual off e-bay for $5 plus shipping. They are out there, early manuals that combine the specs for L24/L20A. Like Alan says, there are several models, so know which application you have! Good Luck!

Get a big enough turbo, and it will be no restriction at all. Then just run N/A ITB's, and tell all the Honduh boyz you got "An N/A Turbo!" The ultimate Ricer Mod: A turbo so big, hung on a high compression N/A Engine, but totally non functional in any way shape or form other than asthetic! What direction is this board turning???? LOL

Ohhhhh, one right up the 60 from Hacienda Heights! Matter of fact, the guy I told about the BW T-5 on the car drove from Diamond Bar to get it that morning. He was closer than you, but not by muuuuch.... Muahahahahaha!

"The problem was the plugs were arcing out against the block, not firing inside the cylinders at all. Try running your motor in pitch black and rev it up, check around the plugs to make sure they arent arcing out." This is common on Stationary Lean-Burn Turbocharged Engines. This is a GREAT reason to install your plug boots with Dielectric Compound. Not only does it make the boots easy to get off, but it totally eliminates any air available to convert to O3 and give an easy arc-over path for errant high tension voltage.

The "Large Port" on the Weber T/B is for the PCV line in some applications. There are some throttle bodies that have the line hooked up at the T/B, and not in the intake rubber bellows lines. I actually scored one of these in a Junkyard, and when I started rooting around in the car, found the ORIGINAL T/B, in the weber big throat box, complete with installation instructions and blank waranty registration card for the Weber Big Throat!. Total cost: $30. SCORE!

I took a 77 EFI system off a complete original car out in ElPaso Texas. I know it had a round-port manifold on it, but can for the life of me not recall the head casting number. I don't even recall if there were port liners. There are some odd variations of N42 castings out there from overseas, not all "N42's" are the same as what we got here in the USA. They used N42's on Cedrics and Glorias for years after they were out of the production run for the USA. I have a 1977 N42 head from a Cedric in my 73. had only 44000KM on it when I got it, from the original owner with all maintenance documents available. But that head has the Rectangular Ports..... which gives me pause to also go "hmmmmmmmmmm..."

I concur, looks like one of the Cat Turbos. I wish I had a digital photo of some of the Turbos I have crawled over.... 48" and 54" inlets on Sulzer Inline Ship Engines (one for every three cylinders on the 12 cylinder unit I worked on in San Pedro). Think they were ABB Brand. Have overhauled Elliott ET-18 (18" Diameter Turbine Wheels) as well as the Cooper line of turbos in the 1800 to 3300HP range. But I got away form that "hot side stuff" and went into simple Turbocompressors for plain jane air compression and plant utilities....

Volkswagen was the first to mass market with Electronic FI. The 1968 Type 3 went from Dual Carbs to EFI. For everyone touting the EFI as "new and spectacular" you got to wonder what their historical perspective is.... Anyway, went back to the yard today with my son (snuck him in...underaged), and pulled a Hydraulic Liftered L28ET with 155.442 miles on it that hopped a curb and was impounded. Still had pressure in the fuel rail, fresh gas, and nice green antifreeze in it, as well as refrigerant under pressure in the A/C System. So I have a spare. Was so beat by the end of the day, didn't bother to pull the differential companion flange, nor the spare 81ZXT CAS unit sitting just three cars away. Or to pull the 81ZXT Block. Must be getting old.

I had an old Rupp 600 Nitro Drag Racing Sled. There were several stickers on the cowl: "Carburettors Equipped For Methanol, Change Diaphragms After Every Racing Day" It is VERY corrosive, more than a stainless filter, you would be well advised to run stainless on all your fuel lines, run a methanol resistant slushed tank, and consider a Glasfibre Reinforced Nylon 66 Fuel Rail (which helps with heat, but that's beside the pint) for your injectors. Keep in mind that the AFR is around 7:1 as stated above, roughly twice the normal stoch for gasoline. That means injectors that are BIG. Twice what you normally would run for the same gasoline engine. And the injectors will have to be methanol compatible as well. For the effort, you may as well run CNG using salvaged components. Octane of 120+, the ability to carry at least 5 gallons equivalent onboard a Z-Car, and a cost around $2 a gallon, unless you get a home fueling unit (about $2K) and then your fuel costs are around .40 cents a gallon.... You will need some big injectors for that as you are injecting gasseous fuel instead of liquid, but IMO the conversion is probably slightly more practical if you have a CNG station nearby (mine is 2.5 miles from my house, on the way to the nearest 1/8 mile strip! So yeah, that's why I was thinking about it so much!) Methanol is nasty, corrosive stuff. Stainless and Plastic Fuel system components. But it will be a hoot. Ignition at colder temps shouldn't be as much an issue with EFI as carbs. My ethanol experiment wouldn't start (carburetted) at colder temps (needed a preheater), but EFI would change all that...

Well, while the 260ZT sits in the backyard languishing, with me too disgusted/preoccupied to work on it, I scored big on VW EFI parts today at the Junkyard. Which should get my 66 VW Bus (or the 62) running on fuel-only MS. Got me the OEM Air Temperature Sensor, Head Temperature Sensor, and Injector hardware (less the Dual Port Endpieces) What I was really happy about was the old style VW Distributor. I go Perlux Across the board on the VW's, and this will happen with that one as well, but the old 68-75 Type III have a secondary set of contacts that sent a breaker signal to the ECU for injector sequencing. Hopefully it will have no inductive problems. These old VW ECUS were buggier than Beta Megasquirt! LOL Man, working around that engine bay reminded me how far Electronics have come! The MAP sensor on the three vehicles I was raping was about the diameter of a Beer Can, and 4" long! And OH! the "Calibration for Altitude Routine" Turning the key on and off and back on again while coasting seemed to be a pain till I saw that thing in there and remembered the "old procedure"! And now I hear there's a dual MAP sensor board... LOL First things first, gotta get ONE of the two projects going...sooner or later. These were about the last of the bits I needed for the conversion. I'll probably use the Nissan stuff for the rest of the conversion on the VW. I'll check the head temperature sensor against a Nissan CHT. It's taken me since I logged on Megasquirt Yahoo Forums till now to FIND a complete VW EFI engine that had these components STILL ATTACHED. Now to compare the curves and substitute adequate, available spares! Not Z-Related, but I did pick up an Alternator from Jeff Priddy to put into the car to see if that one does any better in the "noise" area. Grasping at straws when I have the time...

That seems to be the consensus between most theorists. But as we all know sometimes anomalies exist in actual practice that don't fit the textbook guidelines. I have seen the gauge loop and setup he used (think Bernard has as well) and at least I can attest to the numbers he posted. Same gauge used on both intake and exhaust with zero loss fittings. So even if the "pressure" was wrong, the delta reading was indistinguishable. My only lament was that I didn't have access to my old master gauge set and deadweight calibrator to set a gauge up with a better resolution (1/10 lb, instead of just 1 lb resolution). I have since bought some peizo transducers for my Fluke (for work) and the enxttime we get frisky we will use those to check the pressure, electronically with a two-digit resolution to the right of the decimal. I think the differential on his old setup would be in the inches of mercury, or inches of water. I am pretty sure there is SOME restriction, just not sure how much of a differential. Less than 1# for sure! People don't want to believe his .63 was working like that, but it was... We haven't tested it with the GT series unit yet.

There are plenty of British Car Sites that will offer the same services, but why go cross-manufacturer when ZThreapy knows our setups and what works? Why the resistance to ZT?

This is most definately not the case! On an undersized turbine perhaps. But for a perfect example I refer you to JeffP's last setup where his exhaust gast pressure was 23psi at the turbine inlet when his intake manifold was at 23psi! This turbo came on violently at 3000rpms to full boost, not one of the laggy an controlable progressive gradual increasers with a 4500 boost threshold. Everyone said his turbine was "too small" and "restrictive" but actual testing on his engine proved the theorists wrong in that case. I would argue his setup at that point was ideal for what it was, even though he has gone to a larger A/R turbine now, with a more progressive boost building. I guess having a 450hp differential in about 500 rpm can be a bit of a control problem in a corner! Usually exhaust pressure is "higher" than intake pressure. On racing engines like F1 (as mentioned earlier) they could have far more intake than exhaust pressure, but then again the engine was optimized to have a VE under boost and was optimized as such. The VE of the engine without boost (like an RB26) is shot to hell when they aren't running turbo bost through their optimized ports and inlets.