Tony D

BAH-NAPS! If it's an L28 manifold, read the post by "Oz Connection" in this forum about 'small port heads' and the discussion about L28's with L20 EFI manifolds on them is covered pretty well. If the results are sounding like something you might like, then proceed. For a street car not running above 5500 the boost in low end torque is prodigious by the butt-dyno when you put the small runner manifold on, but it's all in by 5000-5500. You loose some top end compared to the stock L28 Manifold. Even the NAPS. If you do swap, and you have the two-barrel T/B, make sure you use the larger L28 unit on the L20 Manifold---it will fit, and the drivability will be a bit better than the dinky L20 Barrels. There is a considerable difference in primary and secondary bore sizes. In US Money, the L20 has a 'dime sized' primary barrel, while the L28 has a 'nickel' size. Roughly the difference between saddling up behind a newborn Ewe and her Mother, to put it in Kiwispeak! LOL Morocco dementia strikes again! I'm Baaaaaaaaa-d. Baaaaaaaaa-d I tell ya!

The OBD2 ECUs, ALL of them have a 'short term and long term fuel trim' feature that allows for self-adjustment of the ECU fueling over a FAR broader range than the old systems did. Make no mistake: This is NOT a substitute for a proper fuel mapping in the ECU. If you have a sensor failure, you will drive home on the map you have...NOT the fuel trimmed maps! What the fuel trim is intended to do is accomodate for various wear items and things that would alter the efficiency of the engine to an extent that would put it outside the 10% range of the original Bosch setup. GM has this on their ECU's as well. They all do it. Even aftermarket ECUs are now employing this technology to allow for a 'self tuning' situation where the map is sent with a basic startup map, and you just go out and drive the car over varying conditions...with you able to burn the map at the end of the run, and then repeat the procedure till you have a complete and accurate map without going and individually inputting cels and going back each time to change them manually. The aftermarked ECU's are getting increasingly spohisticated and CHEAP. The one I am referring to above was being sold retail for $1200, complete with Fuel Pump and the ability to run as a non-return line fueling system up to 500HP as they controlled pump speed through a PWM controller resident in the ECU working off a fuel pressure and temperature sensor in the single fuel feed line to the injectors.

I put mine (I only had two injector leads to hide) inside vacuum tubing. I did use Tefzel as well due to my concerns with the heat. If it can lay across the bleed air plenum of a GE F100 Engine in an F15C, I figure it's good enough for me. Aircraft Spruce has it available, shielded as well for those TPS and CAS triggers... It was a very big decision fos me to put the injector UNDER the barrel, instead of firing down the throat as with the stock SU air Cleaner there are PLENTY of hoses running in there that wouldn't be needed with EFI, and more than an easy job to run the injector wires to them. Most of the other sensors were hidden similarly inside the maze of vacuum tubes on a stock 74 SU setup. The injectors should be free-floating. They should be able to rotate. The fuel blocks should be at a fized distance to affect a seal, but not solidly clamp an injector. It should float slightly axially, bottoming before a seal is broken, and should easily rotate when everything is bolted down. A firm clamp will not only transmit a LOT of heat (o-ring being the only thing touching doesn't allow direct metal-to-metal transfer through conduction) it has a chance to distort the body when something grows through heat expansion. As far as 'pissing into the wind' do it sometime and tell me what happens to that stream, and you will get the idea and impetus behind that type of positioning. The heated discussion I got into involved a nondisclosure agreement I had with Cosworth Engineering in Lomita after some site visits to their shop and discussing their Counterflow Methanol Injection Scheme for CART engines. I couldn't at the time tell the person on the 'other end' of the discussion where I was getting my information, but my contention was it was 'common' and spelling out which machines of the past 3 decades employed it (since he was totally unfamiliar with any of them) was counterproductive (old technology doesn't count, what uses it today was what his retort was, I believe...). Rest assured, when the story hit major automotive press, I recalled the earlier discussion and called out his 'what modern engines employ counterflow injection' and pointed out the article. Nothing is more frustrating to me than knowing some high tech stuff, but being covered by a Non-Disclosure. I wasn't in there doing engine development work or anything. I was attending to their compressors and air system in the shop....but when the engineers on the floor realized I was asking cogent questions and understood what they were accomplishing (as well as 'gazaming' over up-close and personal revelations of very cool features of the engines, they offered to give me a full tour...after reminding me that I DID sign a Non-Disclosure as a condition of being admitted to the facility! Then they revealed all sorts of neat things. That ND expired earlier last year matter of fact. Jan/Feb 2008.) Curiously their revelation on injector orientation was not public till almost mid-late 2007! Which is surprising given the fact that as the photo shows, Lucas MFI and others used counterflow long before Cosworth employed it. Hell, they were counterflow injecting the methanol in FRONT of the turbo to aid in cooling. Hmmmm, what does that sound like? The in-head Barrel-Throttle is what got me!

510's below the L20B use a five hole flywheel and smaller diameter clutch (200mm) The L20B uses the same bolt pattern as all the six cylinder Z's and I put my old lightened L28 Flywheel on my son's wagon with an L20B. I haven't looked into it further than that. The numbers look about right for the way they did it in Japan.

Rather than restricting port size arbitrarily (That is, symmetrically), I'd say bring the bottom of the port UP with a filler like Devcon, this increases the shortside radius enhancing flow. The reduced port sizing will increase velocity, the larger radius on the short-side increases flow...add a very light bit of bowl work to really take advantage of the increased velocity...and I think you may be surprised by how much it picks up on the bottom end, with even a nice bump over stock on the top end. I don't think the smaller ports per se will 'restrict' or 'strangle' an otherwise 'stock' engine. There is porting that can be done to increase flow on the bottom end---it's just usually focused on the top end of the RPM range. Because it takes rpms to get it to the velocity it needs to be at to do the things it does... Pontiac is going under with 'wider is better' right? I always liked smaller holes, personally. They just look cleaner all around. Baaaaaaa!

Yes. I used the original 1973 Ticker Style Bendix Pump to suck out of the stock fuel line and fill my surge tank, with the 3/16" line being a 'high point bubble vent' for the surge tank, as well as having a branch that went to a 1/4" line on the tank (the return from the FPR was routed into the surge tank as well, hence needing the 1/4" line out as well). I never experienced starvation problems after setting it up like that using the stock 73 tank.

Ahhh, Lucal Slide Valve Injection... I got SO lambasted for making comments about the way that system injects fuel (take a close look at the injection orientation)... As for moving the injector position, they will have the exact same rotation possibilities as the stock setup did, it's more movement than you think. You could orient them all the same angle to front or rear, depending on 'harness drape' to give maximum visual effect with the loops of injection harness going to them... The only thing different I did on mine (other than mine leaked like a seive and sidelined my project---hint, don't simply think drilled finish is anywhere close enough! LOL) was I put the retention 'ears' for the screws up a little higher using a wider guide and the body of the screw to hold the cap straight instead of putting them at the bottom of the thing. This kept the injector from hitting the 'ears' the screws go through, further restricting movement.

I let the comment slide at the time, but now being in Morocco and near midnight the question begs (BRAAP be Praised): "What praytel, would they need freezeplugs in the balance tube for?" Casting Plugs... Core Plugs... But....freezeplugs Pete?

I still am trying to figure out where 'having to rebuild the engine often' comes from... Most stock turbos are in the power range he wants unintercooled and at 10psi of boost....and they run for 300-400K miles without needing an overhaul. I mean, for that HP level, a drop-in stock turbo will give you stock reliability and longevity. He wants better than 300K on the engine between overhauls???

I would personally put the HP pump and Surge Tank in the rear of the car, where the stock electric pump goes, but that's just me. With a pusher pump filling the sturge tank, the HP pump is always flooded with fuel so it doesn't 'have' to be a true 'pusher' pump. A surge tank external up front will require that pusher in the back. I had fuel starvation problems with mine until I did that. Something has to initially fill the surge tank before the main pump turns on.

The smaller ports enhance that low end, though. And I think that is what he was going for---if you were to bump the compression, optimize cam timing, and use a stepped manifold on a fairly stock head (basically the right combination of inexpensive stock parts) you could make an engine that was very thrifty when driven in the described manner, and probably make for a nice mill in front of an (eck) automatic transmission! Even with a stick, it would be a nice driver around town. Me? I'm just putting an LD28 in the damn thing with A/C and the Autobox for commuter duties... I like em stump pullers, or screamers. A Man of Extremes. I don't go for a lot of this middle-of-the-road stuff! LOL

Why are EFI and Triple Two Barrel Throttle Bodies mutually exclusive? Why not Triple EFI Throttle Bodies?

In Japan, for the streetlight racers I would slip the cam one tooth and give the cars back to the guys who would come back RAVING about how GREAT and POWERFUL the car was after the modification. They had no clue how to drive, they just wanted a car that hunkered down and went when they mashed the pedal at 2000rpms in fourth gear... Which is what the thread was about, and it's already mentioned clearly that the engine will be 'all in' by 5500rpms. Flat on it's face, just like those slipped-cam-jobs I did back in the 80's. Some people don't run at 7000rpm engine. Some people don't want/need it. Some people would prefer a lower rpm bias in the torque curve. And that seems to be what this thread was about, and the ways to go after that effect. More compression would help as well. Frankly, watching most people daily drive their Z's I'm of the opinion that I could swap a BMW Diesel or even a Golf TDI in there and nobody would be the wiser: shifting at 3000 because 'they don't want to strain the engine', shifting up at 4000 or 4500 when they are 'really going for it'... I've said it before, some people are diseased. Is it the low rpm or the high rpm set? I say both, and n'er will they reconcile.

Kinda like that, but in the end, all silvery and no waves or weldmark visible, apparently you have about as much patience with body work as I do...LOL

SSS Motors were not really known for grunt, either...

Just because someone is a "Z-Guy" doesn't at the same time preclued the fact he may be a total idiot. THe "Principle" I was referring to was his blatant lie about the parts being "RARE JDM"---that's a full crock of B.S. and I'll stand by it. Too bad I'm in Morocco now, I hate lying hucksters that use puffery to take in the ignorant. Apparently he finds nothing wrong with his description of the item. That's really sad. But anything to make a buck, huh? Whatever you got to do to move the iron. Since you gave him a 'heads up' and he's not changed the ad one iota, I guess that informed consent is not on his list of priorities to prospective clients. Welcome to e-bay.

Nissan, Too used the Goo. Techline Coatings may have something in a 'sample' they could send your way. They have offices in Murietta CA (Temecula) and Texas as I recall. They make rotor coatings that are semi-abradable for blower rotors. And they can be applied and cured fairly easily. That may work as well. But if you can get the same stuff the OEMs' use...

The L20ET injectors are the same injectors as L28E injectors...same terminal horsepower and torque figures. (Green Tops?) I swapped the injectors, L28 Long Block, and L20 P-Manifold into a 1977 Fairlady Z---the EFI components with the exception of the Manifold and Injectors remained unchanged. I fueld the L28 using the L20E AFM and L20E ECU that was resident in the vehicle without changing them in any way. This may be why it was so responsive down low as the L20E AFM would be like an L28 AFM with the flapper spring unwound---follow? Really sensitive to airflow changes, and goes to preprogrammed fueling well before the normal 3500 rpms in the big AFM'd cars. As long as the injectors are sized properly for the engine, the pulsewidths Nissan Used in Open Loop Systems (no O2 Sensor) are remarkably consistent. Let's not even go down that road. Doing it now it would be Megasquirted! As for runner measurements, nope, never did. The L20 Manifold was visibly smaller diameter than the N42 head Intake ports that were on the engine. Dinky is a good way to describe them.

I don't know about the small valve heads on an L28. I think some of the effect is from that step helping prevent reversion at the lower rpms with the stock cam (what there is of it anyway). The chamber design would help with compression, making the bottom end punchier as well. If the quench was set up properly it would be detonation resistant... hmmmmmm...

With the availability of the large-bore (60mm+) SU's the 'need' for the flow a triple SU would give really is negated. Lots of complexity for minimal gain compared to a simple alternative, IMO.

Oooh, been looking for those! Oneset of 8 on the way to me now from Summitt Racing for only $129. Pricey, but not that much. I wanted the SS versions for a project I had in mind, but didn't know anybody made them. The other mounts on that page may come in handy for my SU project. May order one or two for that testing as well... Thanks for the link.

What's 0.125" divided by 6? Equivalent to about a 0.020" hole in each throttle plate. Assuming total circumfrential seal. Now, take the diametrical distance to find circumfrence and divide that legnth into 0.020" and you start seeing where Accurate Injection gets his data about less than 0.002" being too much on a 45mm bore! There is a BIG difference between breathing through ONE plate, and SIX! I cracked my dual SU plates less than the 0.003 mentioned to get my idle speed correct. I could have drilled a hole in the throttle plates, but since I didn't have any spares and didn't want to JB Weld any mistakes I defaulted to throttle position instead of a hole. I figures something on the order of 1/16" in each of the two plates would be more than enough with throttle angle being used to 'trim up' to the final idle speed during synch. But that's only two plates, not six!

Yeah, that's what I was getting at: the way it was explained to me the ECU will watch firing events in each bank, and look for the corresponding spikes in O2 in the exhaust. If it read 6 spikes when it is registered to only be reading three...then I'm betting it throws a code due to a disparity to it's RPM -vs- Sensed Input. The rpm input shows say 1000 rpms, and due to the pulses of the O2 sensor being exposed to all six pulses in the collector would be returning spikes corresponding to 2000 rpms (2X what is 'should' be seeing.) I'm sure it's just some BIN or HEX hacking like JeffP and Bernard have been doing....but if you change that, it's just one thing that's reading it. What else will have to be redone or tweaked to keep working? I know what you are saying HM, I had to go audit a distributor where there were 13 Element Failures in a year. All the same frame machine, all the same element. All failed by some idiot over-using RTV and having it exude out the oil injector nozzle that sprayed on the internal gears and bearings. Curiously, the failures corresponded to a former Direct Technician getting canned and going to work....guess where? We always called him 'RTV-Dan'... Birds don't change their spots. Another time, a distributor 'failed' 13 elements in short order, but on four different units. Each failed just inside the warranty period, but because they were tracked separately nobody ever picked it up but me... When I went in to Audit the Distributor, I found 5# of rust inside each of the machines intercoolers. The rust was passing through the second stage and failing them prematurely. Simple failure to follow the standard work procedures was directly to blame---their tech (same guy each time) was flat-rating the job and never doing the simple cleaning I did. When I quit there, they lost 2.2 Million in service work the first year. But I was the 'bad guy' for leaving and taking the work with me! Seems customers knew who did the work the right way...the FIRST time! Each of my subsequent 'replacements' has been a resounding bozo which the customers hated. Poor them. Too bad, huh?

Spline drive is for sure Turbo Application--either running a Megasquirt or the Turbo stuff will work with that dizzy. The Turbo distributors only gave a signal for the ECU to determine sparking interval, with the Ignitor on the coil determining dwell. It was not a direct input. The ECU was an intermediary tp delay the spark signal for the next cylinder in the firing order to enable a 'spark advance feature'. The L28E had a self-contained dizzy, with the E12-80 ignitor handling dwell and spark directly off the reluctor trigger inside the dizzy. The advance function was accomplished by altering the phase angle of the breaker plate using a vacuum cannsiter and advance weights which will move it relative to the fixed reluctor's trigger wheel on the center spindle. Different animals altogether! Good news is changing from on to another is easily accomplished in the L-Series. Aside from the drive spindle, all the 'other' L6 dizzies are interchangable...

Moving it towards the center of the car (at least equidistant between the wheels) helps handling compared to loading it up high where the battery formerly was... Or worse, out where the EVAP cannister would be on a 260 or 280Z.