Tony D
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Posts posted by Tony D
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The issue isn't that the float bowl HAS to be pressurized slightly higher than the throat (it DOES need pressure at least equal to plenum pressure or at some point boost will push fuel up the gas feed line!) But if you pressurize the float bowl slightly higher than the plenum you can get by with MUCH smaller jets. Otherwise you will have to put Jets into the engine that will flow the horsepower potential of the engine. This way, the jet is flowing under pressure, and not under suction. Fuel level is raised in the emulsion tubes allowing for more fuel than air to be siphoned up the circuit for a richer mixture.
The Cartech System Jetting is radically different than the Jetting I ran when I had the HKS Plenum on the same engine. With the HKS Plenum, the jetting was near identical to the jetting used when it was an N/A setup. Actually, when I would pull the turbo system off, it was no big deal driving it around on the 'turbo jets'---I couldn't do that with the simple Non-Segregated Cartech Plenum---it was pig rich at the top end, and needed jets 3-5 sizes smaller. Something like 150's or 170's on Cartech, compared to nothing larger than 135's with the HKS setup. It's been a while since running them, and those numbers may be waaaay off almost 20 years since setup, and 15+ since running it that way, but it was something big like that.
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Rotary Valves in Big Busses. There is a company that converts diesels to run on CNG or LNG, and they use Rotary Valves. It's in the archives here or at ZC.C, they wouldn't return JeffP's inquiries...
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What you could try to do is have a 'leaky' bov to bleed boost...perhaps a bleeder orifice in the BOV line that closed with an RPM-Activated switch.
In other words, the BOV stays open, or partially open while it comes on-boost till about 2500 or 2900 rpms, when the bleed off solenoid closes, and the BOV positively seals, letting ALL boost go to the engine.
All you are looking to do is set up stable flow conditions. This may actually help with tuning the way the car comes on-boost. With a programmable output, this would not be so difficult, and with a needle type bleeder on the vent to the BOV, you could tailor the way it bleeds off. Obviously when the switch is activated, it's ON!
That may well be a simple solution, and allow you to boot it without issues.
I ran a .43 AR on my T3 so I would get 17psi at near 1700rpm. It was GREAT for AutoX, and really suprised people! I am sorry I ever sold that turbine off to put the .63 on the car...it was a different feel altogether. With the new EFI systems available now, the powerband was more like a Supercharged car, the only problem was it was totally out of air by 5500. Short-Shifting all the time. But it scooted like a much larger N/A engine.
All depends on what you want. I hit compressor surge on that setup at 21psi. BANG BANG BANG! Not a good sound. Minflow Turkey Gobbling is far more managable than that noise...That noise breaks things.
And yes, if you increase the low rpm flow of the engine, you will have the BEST of both worlds: Make power, and stop your surge issue!
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I can't recall, there was some well-off enthusiast who commissioned a replica engine to be built. This engine was some European DOHC design he thought 'the technical pinnacle of development' from the early 1900. Bugatti rings familiar, but I may be way off.
Anyway, his theory was that the limiting factor in the engine's output was not the engineering, but rather the materials available, and the supporting technology to manufacture them.
When his engine was built, compared to the original, the differences in power output was staggering. Something like a factor if six compared to the original output. Using modern metalurgy and machining techniques, the engine was capable of 8000+ rpms, and making something like 580HP whereas the original was spun to somewhere around 2500 or 3000 and made around 80HP... This build followed the original prints, there was no port redesign, just modern materials and precision tolerances.
I wish I could remember a name or something, it was a fascinating article. Oh, to be the one to have the money to do such experiments! LOL
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"Yes it will add lag but it will also add HP and get you out of the surge area. "
It doesn't add lag, it changes Boost Threshold. Lag is something different than Boost Threshold (the rpm point at which the engine will give full boost). This term gets so misused it's a 'Freeze Plug' situation with me, like that term is with Braap!
Once above Boost Threshold, "Lag" for any modern turbocharger is minimal, usually well less than half a second.
Lag is not the difference in time between flooring it, and when it reaches full boost and any point in the rpm range.
Like a car with a hot cam, you will not run it below it's camshaft operational limits---same goes for the turbo. You do not operate it below boost threshold.
As Clifton correctly stated, if you have set up a mismatched turbine / compressor situation where boost threshold occurs at a point below the rpm point where the engine can ingest the full flow of the compressor at the full pressure capable by the turbo (in essence going to the right on the map, towards the minimum flow surge line) then you have a problem.
In this instance, the ONLY option is to either match the parts correctly, OR open a bypass valve and bleed off the excess flow (moving the point of flow in the compressor map again back to the right, away form the surge line). You need a minimum flow number at any given pressure for a compressor cut. If you go below that flow at that pressure, you set up minimum flow surge, and that is all there is to it.
In stationary industrial compressors, this point is moved around by altering guide vanes on the inlet, or simply blowing off excess flow to the atmosphere to keep the minimum steady flow through the machine. These are constant speed machines, so the PID control loop for those flows is relatively simple... on a variable speed compressor with non-linear delivery the PID would get pretty complex for throttleing bypass off the engine at minimum flow at low speeds.
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"I was curious if there was any special prep work or machining, like rocker profiling or lightening, some nutty valvespring design, etc -that sort of thing. Something beyond what all the Datsun books originally written in the 70's detail for race engine prep. 20-30 years is an eternity in the racing world."
It is exactly that kind of thinking I am addressing when I make these kind of statements. In one sentence the disclaimer looking for widgets, but by the end of the sentence says that they are looking for just that!
Plainly stated, no, not much HAS changed in engine building except that the technology that has ALWAYS been in place at higher levels of the motorsports realm is slooooooooowly filtering downwards to the grassroots levels. Stuff that people take for granted when prepping an F1 engine in the 70's is roughly what top amatuer racers are doing to stay competitive now. The lag in technology form top tier series is decades...and usually because of costs involved.
The CNC machine has made porting something that is an appliance on SBC engines, but even then little details here and there on a port will still need some attention for that last umph...
There is not any shortcut to power, it lies in Three Basic Tenents:
1) Preparation.
2) Preparation.
3) Preparation.
It's hard work, painstakingly melticulous setup, measuring not once, twice but three or more times. Good measuring tools, competent setup and component selection...
The same stuff top tier guys have been doing for years. There's no shortcut. The books written in the 70's may seem dated, simply because they don't address this head or that. But when you actually read what they are saying, it's far less a 'building blocks on what parts to use' and more 'do it this way'...
Honsowetz works for Ed Pink Racing Engines now... Kind of tells you something outside of 'inside connections'.
Parts only do so much, Technique makes every engine better.
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Oh, for tuning, all is forgiven. I got mine with the proper retard to have 15psi at 1500 rpm... Melted the oil feed line brazed joints... it was not a good day! LOL
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Meh, the price went up since then, now it's like $1800! More specifics here:
http://www.aircraftspruce.com/catalog/inpages/ei-engineanalyzer3.php
I am truly the devil...
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Yep!
People think those Hondas are some K daily driver engine, when in reality they are full on F-1 Technology from the 60's or early 70's before they went Turbo. Those engines lasted qualifying and a race, maybe.
We will be into the L at the end of the season. Just to check. The L28 being twisted to 8700 went four seasons, and when it was pulled down the piston pins had walked to touch the cylinder bores. Everybody who saw it said the same thing: "Never Seen That Before!" Pressed in pins walking to the cylinder walls. Think the small end went egg-shaped from all that beating, allowing the pins to walk? Meeeeyeaaah!
I mean, Nissan Rods guys. Nissan Rods from two different L20B Trucks to be specific. Not Merchart 570 Gram Investment Cast Racing rods.... Nissan Rods...
It truly is amazing what the stock stuff will take if you simply make sure it's all right when it goes together.
Benchracing for sure, as John stated, but there is a valid point: People, and new kids in general, look for some panacea bolt-on super special part that will give them this power. My response is always the same: Look at those ITS engines. There is power there, you just have to find it! If you start your quest for power by going after thesame things the ITS guys do, you will be LOADS ahead when you do start bolting things into the engine like a Cam, or bigger carburetion, etc.
Sweat the details first, and the power comes later. And when it does, it is far more reliable that something bolted onto a non-optimized lump.
I really should get an hourmeter to install on the engine, so we can see how long the thing has been at speed. The Bonneville Run is far more a nail-biting drive because you are wailing at redline (or near it) for literally miles... I can't wait to setup for THAT video!
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I used a 65mm Rotobroach, and in the past have used Blu-Mol hole Saws from Home Depot. With lots of cutting oil and a drill press, you go right through!
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Engine braking souldn't use any more fuel, and probably less...
Like stated, EFI has 'fuel cut' that basically shuts off the injection system when the idle contacts are closed and engine RPM is above X point, and it will not restart fueling until below 2500 rpms to keep from stallingthe engine.
On a carburetted car, the throttle closed puts the idle circuit in play, and even though you have a high vacuum, the idle jets on their best day can never flow as much fuel as you would lopaing on the mains with the throttles even BARELY cracked.
now, if you are engine braking and blipping the throttle you can set up a situation where in both carbs and EFI you are getting fuel from the main circuits in both instances, and then you defeat the purpose.... So if you are engine braking, do so on closed throttle and you will save fuel!
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Industrial Reciprocating Engines used for powerplants and usually fitted with a full array of diagnostic equipment (Kenicocks---you can trace cylinder pressures for BMEP Calculations during running!) have EGT probes in the following places (and in many cases these are dual thermocouples---two elements for one probe so if one fails you can switch to the secondary unit without shutdown).
Each Cylinder Exhaust Port, downstream of the exhaust valve, byone valve diameter.
Pre Turbine.
Post Turbine.
Each of these placements tells you different things, in the case of the individual cylinders, you can see delta T which is an indication of power balance between cylinders, and significantly exposes fuel mismanagement.
Pre Turbine -vs- Post Turbine reveals problems in the turbo itself, as well as possible problems in the exhaust manifold (such as a water jacket leak).
For anyone that is interested, I got JeffP hooked on the 6 cylinder EGT Analyzer for small aircraft sold through Aircraft Spruce. It is a full datalogging EGT box, with many different inputs, designed to monitor Small (er...471CID) aircraft engines in flight. It alarms on first up to temperature, highest temp, delta alarms, pre and post turbine temps... just a cool engine analyzer, and small enough for the dashboard.
If youwant to spend $1200 on such a gizmo! The kicker was for the small Cessnas, they offer it in 12VDC...
Onblard Datalogging for up to two hours, etc... Really cool piece, and a graphic display of all eight monitored temperatures...
I'm going off the deep end now, but that is where people stick EGTs, and kind of why. Each has a different usage.
IMO:
If you are only going to do ONE probe, I'd put it in the collector pre-turbine. In a cylinder port, without another to compare it to, the reading you get is totally useless on an enginewide analysis basis. Now if you add a second ... say in cylinders 2 & 4 for an SU poered car, you might be able to draw conclusions. But on a multi=port injected car, if you do one...you may as well do the other five or just stick to turbine inlet.
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Why not consider a compressor bypass valve? The proper design lets the thing build speed while the compressor is bypassed, closing as pressure in the manifold comes up... This bypass (or blowoff) keeps the minimum flow requirements of the turbine satisfied, while letting it accelerate to full boost building speed. This type of valve doesn't give the cool sound everybody became infatuated with since FnF came out a few years ago, and it's rather boring and quiet...but it lets you build boost quickly and keeps things flowing.
I doubt it's anyting to do with the boost controller itself. If indeed you are encountering Minimum-Flow Surge at 10psi, you can play with the controller to see if it doesn't do it at 9, or 8psi, and simply use a two stage that is operaed electronically by an rpm triggered switch.
Surge is simply a reaction to the compressors' ability to flow air at a give n pressure. If you exceed it, flow reverses, and you 'surge'. Either lower the pressure at that flow point, or increase the flow through a bypass to stabilize the unit. People may balk at blowing air overboard and 'wasting it' but if the engine can't digest the air, and the turbo needs to move it...you have no other option!
The last, most expensive option would be to increase the flow capability through the engine so the flow from the turbo is matched to the flow of the compressor at all points.
The last comment is that you are driving your car damn wrong! The engine should not be floored in the wrong gear. This is a typical American Driving Technique. If you want a Small Block Chevy---install one! Get the RPMS up for a proper roll on. You would NOT floor a Normally Aspirated high-performance L6 at 2000 and expect performance, you shouldn't be doing it on a turbo car, either! This is where turbos get the 'lag' misnomer, and all the black stories people tell....If you drove your turbo like you drove a N/A car, the stories of 'turbo lag' and 'non-linear power delivery' would not be an issue. You're lugging the car at tha point, and of course, it's going to protest!
Power comes on in L-Engines at 3000 / 3500+ rpms. Remember that, and drive accordingly.
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"I don't think you've mentioned what valvetrain tricks done to run those revs. "
No, I have not. Suprisingly little and less than most would think. This engine wsa assembled in a two car garage in Clairmont CA, same as the 2.8 run in the car in past seasons. People think they need super exotic this-or-that made of unobtanium...you don't. The best example I can site as to what the engine has is "Look at a competitve ITS L24 Build" JohnC made some comments about what it takes to get 208HP from an L24 that by rule and definition can't use anything not there in the same form that made 115HP....
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That looks to be a "Swagelock Thermocouple Connector"...which the lovely people at Swagelock charge a premium for, of course.
If you look at their dimensioned drawings, or even their catalogue you can see that the Thermocouple Probe Fitting is EXACTLY the same dimensionally as their Stainless Steel 3/16" (or whatever thermocouple probe size you use: 1/4", 3/8" etc...) TUBE fitting, except the hole goes straight through at tubing diameter, whereas the tubing fittings have a small 'step' and only the I.D. of the tubing is bored straight through. What I did was buy tubing fittings (Oranve Valve and Fitting, now Orange Fluid Systems I believe, in Anaheim---don't ask me why!) and then from the backside, with the nut and furreles removed, simply bored out the fittings from the backside with the appropriately sized drill! They don't always have the TC Fittings in stock, but Swagelock Dealers ALWAYS have tubing fittings you can modify. Just a thought if you want to save the difference in price between Tube Fittings and Thermocouple Fittings. If you really want to cheap out, you can buy Parker A-Lock, or Inperial Eastman Gyro-Lock which are patent infringements...excuse me, 'nearly the same thing' as the Swagelock fittings.
Me, I buy Swagelock---if it's good enough for the Space Shuttle, It's good enough fer Da Zed! LOL
Forgot to mention, I cut my hole and tapped it pre-turbine in the SPACER I made for the T3 hybrid so the compressor housing would clear the exhaust manifold. My manifold is still untouched, the spacer has two holes one for backpressure readings and one for the thermocouple.
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That brace may have some merit on Turbo Applications, I could see them benging enough HP on each cylinder (100+) to really start some twisting.
Then again, they usually aren't doing it at much over 7000rpms.
Hmmmmm, 8500rpm Turbo L-Engine....hmmmmmmmmmmmm...
As for Video, I just realized I have two in-car videos of the thing, and you can see the shiftlight to bang the next gear...it actuates at the aforementioned 93-9500rpms. I just need to edit down the file to the time we are actually making the run and not in the staging lanes and waiting for a tow in the return lanes at theend of the track.
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Supposedly L series have been up to 9000 RPMs in Japan (L20a crank?) but I couldn't imagine they would last long.
"Supposedly"? I'll take issue with the inference, since we spin ours to 9500 when dyno testing, and it's making peak power slightly over 8800rpm. Shift points in competition is between 9300 and 9500, depending on the gear.
We should be going to the dyno next week if all goes well. Maybe I can video it and post something on YouTube as well....
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The insidiousness comes from doing it in PM's or via E-Mail. They know it would not be tolerated on the forum, and therefore do it on the sly. Many times they know people won't bring it up---because it's not on the forum and they think it's a private message. My thought: those who did it would be outraged that their private communications were made public and that they got any repercussions from them at all. They hide behind the cloak of implied privacy, and scream like banshees when the cloak is removed.
Cowards always do.
Hopefully Ernie will see fit to at least give Mike and the other mods the benefit of the doubt and let them in on who was sending what.
I mean, think about it: If they are doing it to him, who else are they targeting?
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Traditionally, the supercharger is bypassed at idle ONLY.
The reason being is the positive displacement, linear delivery of the supercharger will simply overheat the air when an insufficient amount of flow is going through it. Pete (ZYa) was experiencing this on drop-throttle I believe. Temperatures soaring even though there was 'no boost'---well taking -15psia and compressing it to -10 psia is a BIG compression ratio, and makes a LOT of heat. So you bypass it at idle or closed throttle just so the thing doesn't heat up the air excessivley.
In this case, on drop-throttle, the supercharger would bypass much like a BOV (which would be routed similarly...though it could be put on the SC Discharge to dump pressure as well...would have to work out those dynamics) and instantly close upon reapplication of the throttle---boost would resume instantly due to high input.
There will be tuning issues with having the BOV for the Turbo lag the bypass action of the S/C. You want the Turbo to push air to the S/C simply to keep it's pressure up and spooling. Only once the air stagnates do you want to dump excess Turbo Boost from the plenum to the S/C. Otherwise on reapplication of the throttle, the S/C will be spinning fast, and literally suck the turbo discharge to a vacuum while the turbo tries to catch up...
This may make for a better dump valve design in that you use your BOV on the portion of the plumbing between the S/C and the T/B, and just let the turbo stay spooled and use the S/C to keep sucking on it preventing surge. That would probably be the most effetive and troublefree way to do it.
Basically what I'm getting at is the S/C needs to bypass at idle for extended periods to prevent heat buildup, but has different on-boost tendencies that would require different venting then...
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Reminder: there was a time when every Ford and Volvo that went off the production line got 1/2 a tube of AlumaSeal placed in the radiator...
The ammount of reduction innuisance warranty calls was the justification for it. Sometimes it really doesn't take the 'hard way' to fix something that is borderline.
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just a thought, and to add my two cent's worth, the stock FI is a standalone system. just remove the wire harness out of the drivers side of the donar vehicle(75-78 280Z) along with all the components you have mentioned and make sure all connections are clean and tight. and you shouldent have much problems.
The funny thing is when I was working on Corvairs in the 70's and 80's THE conversion for drivability was to take and do EXACTLY that! if you get an issue of the Corsa Technical Articles, you will find DETAILED instructions on how to adapt the 'simple Datsun 280Z fuel injection' to your 140HP Corvair!
The system does not care what it's on, just as long as it's relatively the same displacement, it runs just fine. I converted several Corvairs to EFI for people running them in the winter just because they wanted the better fuel economy and cold starting abilities of the system. I always wanted to do a Turbo Conversion simply because of the T3's wastegate and inherent drivability... But standalones came out that were cheaper---and the effort was judged useless on such a moot point.
Though nowadays when someone says "standalone" they aren't really referring to the ability of the system to be independently removed form the vehicle, but rather to a system that is universal and easily programmed to adapt to any engine, regardless of size.
No matter which way you slice it, the Datsun EFI will only work in a limited range of engine operational sizes before serious tweaking is required.
One thing that was interesting was that Datsun was still supporting those cars then, so one of my customers took his Corvair (while on the road) to the Datsun Dealership in Saginaw Michigan one time to get something checked out... They said 'we don't service GM's here' but when they saw the engine, they about crapped! Apparently they took photos, and forwarded them to the Regional Office for Datsun and Nissan North America. I found that funny. And one of the technicians there took a little while figuring out where everything was, and did his EFI Checks according to Datsun Methodology---and replaced a sensor...away my customer went! There are people that throw up roadblocks because the information doesn't fit in the box, and there are some that realize that regardless of the packaging, the content is the same no matter what!
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Ooooh, that IS a neat little gizmo.
I most definately have to talk JeffP into buying one of those for his car now!
Just so it can match the turnbuckle he has adjusting his alternator!
LOL
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If you recall one of the early Datsun Tuning books had an LD28 in a 280Z with a turbo on it, giving comparable gasoline engined performance.
It's doable. I know Keith Bailey's LD28 Powered 240 got 40+ mpg at 80+ mph average speed, and would do 112mph.
The RPM redline on the LD28 isn't as low as you would think, close to 5000 I think---good enough for 125mph with a late ZX Tranny and 3.70 gears (4750 rpm top end speed like my wife's 260)...
For the effort, as a daily commuter it might be an interseting project. What the hell 'because I could' has always been enough justification for me to do something automotive related.
Free T-Shirt and a Feed will get me to drive ridiculous distances and expend no ammount of effort for that meager reward! Skipped work and spent all day in the Bren Center for a T-Shirt, Cold Hot Dog, and a miniature dixie cup of warm Pepsi...
I may be disturbed...LOL
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lol.... you got me Tony..... I forgot I don't have to deal with that oil pump drive gear, as I didn't use the distributor when I had my L6 motor... (TEC2 on board )
Its been so long since I've had to deal with the removal of that gear, I plumb forgot about it.
No bag on you, dude, I'm seriously peeved that you can't lube it that way! Having the TEC in our Bonneville car driven off the Crank Trigger in the Dizzy (small wheel setup) instead of truly on the pulley, I never considered the thought we COULD have primed the engine like that before a startup. 14.75:1 CR would have liked some prelube...
I swapped in an LD28 Oil Pump Drive spindle when we did the conversion so ne need to support that upper end.
I digress, but it still peeves me that I can't lube it like my old Corvair or SBC!
I WISH it was that easy.
As for N2, I've used that for years, comes from charging similar accumulators in Military Aircraft. You can get a small bottle of N2 and 2-Stage Regulator (Like for welding) pretty cheap. Easily charges tires (which also run N2)---you will be amazed how many tires you can fill off a small container charged fully to 3500 and regulated down to 32psi! Also, the Accumulators on the turbocompressors I service now also spec out N2 for their equipment for the same corrosion concerns---untreated mild steel thinwalled pressure vessels like a pumps' water bladder. Rust through in about three years using utility air. Last 20+ years using N2.
Cheap insurance if nothing else. The aluminum accumulators on military equipment all use N2 for moisture prevention. Airplanes and race cars go hand in hand IMO. Goose/Gander comparo!
. I forgot I don't have to deal with that oil pump drive gear, as I didn't use the distributor when I had my L6 motor... (TEC2 on board 
)
superchareg mount for l6 finished !
in Turbo / Supercharger
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Actually, Intercooler is the proper term in either case.
On a Turbo blowing into a Supercharger, it's intercooling between three stages of compression (three compressors) one dynamic (the turbo) and two positive displacement (the S/C and the Engine).
On a Turbo blowing straight into the Engine it's the same thing, but the difference is a Dynamic Compressor blowing into a positive displacement compressor (reciprocating) in this case the engine.
People forget the pistons are acting as a rudimentary and basic Air Compressor, operating at a compression ratio of anywhere between 7:1 and whatever....
The Aftercooler is an interchangable term for cooling after compression...And intercooler is an after cooler--but generally aftercooler is only applied to the cooling done before the discharge of the compressor package to the air system. In other words after all compression is complete.
In any Internal Combustion Engine with forced induction, all external forms of compression before the engine are intercooled---as the Engine is the final stage of compression.
People forget that engines are compressors, and that the quest is to decrease 'pumping losses' to increase efficiencies....decreased pumping losses mean more HP down to the road.