teknomage Posted June 23, 2009 Share Posted June 23, 2009 my rear end and 5th gear are stock 77Z 3.545 R200 and .0864 turning a set of 205 70R14 tires which gives me a top speed of about 113 at the governed 4600 rpm. At 60 mph I am turning 2442 rpm, the engines torque peak is at 2200. (FYI anywhere the torque peak is for your engine is typically wear you have the lowest brake specific fuel consumption, you should gear to be at your cruise speed right on top of your torque peak for best economy) Yesterday I took a road trip with the aneroid disconnected and achieved 50.34 mpg at a steady state 60mph with a climb over a mountain pass from 5000 to 6700' and a distance of 57 miles. It cost me $2.80 to go that 57 miles I have a 82 5 speed tranny I want to swap in with it's .0745 overdrive, and I am on the hunt for a good 3.364 R200 out of a 79 4 spd manual if anyone has one pleas PM me. If I get this combination it would move my best speed on the torque peak up from 54 mph to 66 mph When I upgrade my rims to some solid disc salt lake racer low profile style 17's I should be able to raise that best speed with a larger diameter tire. For now I am going to wear out the rubber I have. What is the fuel tank capacity in the 77Z? if it is still the 17.5 gallons I have a highway range of 880 miles!! I have checked out the Aero sub forum, and will continue to do so for notes to polish my grand touring sedan project... the bosh VE pump used on my 2 LD28's both have a rheostat on the throttle bell crank that can be used for logic, such as the manifold pressure to aneroid solenoid. This is an altitude compensating aneroid so how well it does at boost compensating is in question, but it is there and better than nothing. I am actually quite pleased with the performance without any compensation. With the turbo packing those cylinders with more air molecules. Again once I get a few more things done I will get us a dyno run, hopefully even a dyno diesel tune On my ride I want boost compensation selectable from the cockpit so I can be in boost making additional power and choose when to use more fuel, for yet more power. What I have determined with certainty is this. with manifold pressure communicated to the aneroid under normal highway conditions I get 37 mpg with it disconnected I get 50 mpg, weather or not it is connected I feel additional power from the turbo surge. the stock 280zx turbo on the LD28 is making boost above 20 mph even when out of the throttle at a light and even steady cruise state at 60 mph level steady cruise where I am barely depressing the throttle I am getting almost 2 psi of boost, simply due to the amount of air the unthrottled LD moves. I will be making a elbow to temporarily replace the turbo between the manifold and my exhaust while I rebuild my worn junkyard turbo (I am loosing oil out the shaft seal into my exhaust,, stinky). While this is done I will take a couple trips and note the mileage with this combination minus the turbo exhaust restriction. I would like to determine with certainty, weather the boost created by restricting the exhaust and capturing its normally wasted energy improves or reduces economy. I would also like to determine weather cooling the induction with an intercooler improves or reduces economy. At some point I want to go to a Holeset VGT turbo and link the VGT to the TPS in some fashion. thanks for the forum on the LD28's will be joining and parsing. I get real funny looks pulling up to the green handle in my z, about a third of the time the dude with his head cocked to the side comes walking over to ask what the hell did I do to my Z, and leaves thinking of building something similar. I have a 2nd LD28 on the engine stand to build up wild, I am contemplating swapping a complete cummins fuel delivery system and turbo onto it that is OBD2, and building it for big boost, I will do everyting I can for power without sacrificing my great economy and durability on this engine build. Tooday I am finishing my induction with a ram air filter intake centered in the air intake in the chin spoiler. Quote Link to comment Share on other sites More sharing options...
Daeron Posted June 23, 2009 Share Posted June 23, 2009 See, to ME the Ultimate Datsun Pickup would be a 4x4 83.5-86 720 King Cab with a turbocharged LD28 in it.... and that is what I have ALWAYS wanted this engine for. I know that turbodiesels in automobiles are becoming more popular as the weeks, months, and years go by, but to me it has always been a truck motor that got derailed into a Maxima somehow. If I could get me one of them there pick em up trucks, then I might just turn mysself into a mud-lovin redneck...... Quote Link to comment Share on other sites More sharing options...
PanzerAce Posted June 24, 2009 Share Posted June 24, 2009 So......methinks I need to start calling around to find a LD28 block Quote Link to comment Share on other sites More sharing options...
NavyCuda Posted June 25, 2009 Share Posted June 25, 2009 teknomage, You may want to reconsider a VGT turbo, as the IDI diesel is quite dirty and could seize the vanes. This was an issue encountered with the 6.0L powerstroke and it is direct injection. A ball bearing turbo would give you similar performance to the VGT, with less chance of failure. Personally I like the idea of turbocharging in series (compound), reason being it allows both turbos to operate in their efficiency range and they help to control egt, which is something that needs to be watched closely on a turbo IDI. I've got a nice air research t3 with a 2.5" V-band outlet housing, internal wastegate I'll probably use as the high pressure turbo, and size a holset from a cummins application for the low pressure turbo. Low Pressure turbo = big turbo high pressure turbo = small turbo Atmosphere > L.P compressor inlet > L.P compressor outlet > H.P. compressor inlet > H.P compressor outlet > Intercooler > Intake > Combustion chamber > Exhaust manifold > H.P Turbine/wastegate inlet > H.P. Turbine/wastegate outlet > L.P. Turbine/wastegate inlet > L.P. Turbine/wastegate outlet > Exhaust system Atmosphere I am still researching to understand the math of compounding, but if I find a suitable engine, then I will be able to experiment as well. Quote Link to comment Share on other sites More sharing options...
blaze73 Posted June 25, 2009 Share Posted June 25, 2009 FYI there is a difference between a VGT turbo and a VNT turbo. The 6.0 powerstroke as well as the VW diesels use a VNT unit from Garrett which some have had sticking problems with. I haven't heard that this has anything to do with IDI vs DI as many of the VW crowd have installed the VNT turbos on the older IDI engines and haven't had problems. The VGT turbos from Holset are in theory a more robust design as they use one big sliding collar to vary the AR ratio rather than a bunch of small moving vanes. There is however very little info on the VGT's as they have only been in commercial production on the '08 and up 6.7L Cummins. I have one of these turbos (HE351VE) and can tell you it is big....likely too big for an LD28. It is much bigger than the holset turbos that people frequently use on their L28ET's as the size is compensated for by the variable AR ratio. Another note about these turbos is that they are used as an exhaust brake in the 6.7L dodge trucks....on decel the vanes will slam shut creating enough back pressure to slow the truck....my buddies truck will make 7 or 8 psi of boost on decel with this thing activated! Quote Link to comment Share on other sites More sharing options...
woldson Posted June 25, 2009 Share Posted June 25, 2009 I believe you, and figure it's fine to do, however, is not excessive backpressure hard on an engine?? Quote Link to comment Share on other sites More sharing options...
Mack Posted June 25, 2009 Share Posted June 25, 2009 this has nothign to do with diesels, but I have an HE351VE and it is massive. Its going on my gas engine in my 280ZX if the head ever gets done. here is a good read on the HE351VE turbo as well as some alternate methods of control. lots of pics too! Quote Link to comment Share on other sites More sharing options...
Daeron Posted June 26, 2009 Share Posted June 26, 2009 Low Pressure turbo = big turbo high pressure turbo = small turbo Atmosphere > L.P compressor inlet > L.P compressor outlet > H.P. compressor inlet > H.P compressor outlet > Intercooler > Intake > Combustion chamber > Exhaust manifold > H.P Turbine/wastegate inlet > H.P. Turbine/wastegate outlet > L.P. Turbine/wastegate inlet > L.P. Turbine/wastegate outlet > Exhaust system Atmosphere Great, simple description of something that *I* hadn't seen anthing on until recently, so I will post some pictures of this kind of setup.. (This is the exhaust side of the engine; the intake is over on the back side in both of these pics.) Compound turbocharging isn't using a little turbo at low boost and a big turbo at high boost, it is using one turbo to pressurize up to X psi, then shoots that into the other (H.P.^) turbo, which is the first one fed exhaust. The HP turbo takes that X PSI and charges it up to Y PSI, which is usually something ridiculous like 40 or 50 PSI. Ludicrous speed, GO!!! Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 26, 2009 Share Posted June 26, 2009 The LD28T is available in Europe, as well as through marine and industrial outlets. They were in Forklifts, etc. There is a dedicated "T" pump. I'm surprised at the .63 A/R housing performance on the turbo. The stock LD28T used a .43 A/R and comes on far harder than you are describing. The intercooling helps keep that EGT down with the leaner mixes quite a bit. Where / how did you port your N/A fuel pump to accept the pressure under boost? maybe a photo? Quote Link to comment Share on other sites More sharing options...
teknomage Posted June 26, 2009 Share Posted June 26, 2009 I have heard many say that "The LD28T is available in Europe, as well as through marine and industrial outlets. They were in Forklifts, etc." But in all my thorough research I have not turned up any such documentation, just heard everyone stating it. I do know the LD28 came out in a marine derivative but that is all I have ever seen documented. Never turbo charged and never in a forklift, I am not saying this is not true or possible I just have never turned up the empherical evidence of such. Please share if you have it, especially the specs of a factory turbo charged LD28 including the max boost, and any alterations that were made to the base engine to do such. which flows exhaust more easily a higher A/R like .065 or a smaller one like the .45? Not sure what all these turbo specs mean is there a clif notes guide online to understanding turbo specs? The N/A fuel pump has an aneroid (evacuated brass billows) as an altitude compensating emissions feature, I am not certian but I belive this mechanism is identical to if not the same as the aneroid used by bosch on thier turbocharged fuel pumps, only one has a hose barb and the other a filtered port to atmosphere. Either way thire function is the same sense pressure density and actuate a fuel delivery cam porportional to the elongation or de-elongation of the brass billows. More air pressure compresses and de-elongates the billows pulling the fuel delivery cam open, akin to driving your LD28 below sea level, say the marinarias trench below.... Quote Link to comment Share on other sites More sharing options...
NavyCuda Posted June 26, 2009 Share Posted June 26, 2009 I believe you, and figure it's fine to do, however, is not excessive backpressure hard on an engine?? Although I have no practical experience with compounding, I don't believe there would be excessive backpressure against the engine. I would figure there would be more, but it wouldn't be "doubled" or anything like that. Both turbos would be working in their respective efficiency ranges and the wastegates would keep everything in check, so I just don't see how the back pressure could actually get out of hand. It also seems compound turbocharging has a tendency to assist in dropping EGT's, so would definitely be a setup worth looking at for a high boost LD... I need to find a couple of cheap engines Quote Link to comment Share on other sites More sharing options...
blaze73 Posted June 26, 2009 Share Posted June 26, 2009 The intercooling helps keep that EGT down with the leaner mixes quite a bit. FYI Diesels operate quite the opposite to spark ignition engines in regards to the air fuel ratio vs. EGT. A "lean" burn in a diesel is so far above the ~10 - 15:1 combustible range that a gas engine must operate under....all that extra air cools things down. Adding more fuel = adding more heat = higher EGT. My VW will run cooler at 20psi than at 15psi (even adding hotter air!), all fuel settings equal. The intercooling will help EGT significantly however. Cooler air in = cooler air out. My EGT's dropped ~200F with the addition of an intercooler. Regarding how the aneroid works, the basic post below is from vwdiesel.net....lots of good info on the bosch VE pumps there. The top of that "boost pin" is attached to a rubber diaphragm with a pressure port on the other side hence why all the aneroids look simply like a pressure pot on top of the pump. They are not all alike however...the 1.9TD (not TDI) came with a untapered pin therefor adding no extra fuel in relation to boost....there are many different tapers and many people grind their own taper for even more fuel. "A lot of questions get asked about the boost pin, I thought I'd add a basic guide and a piccy for those interested in grinding their pins The GTD boost pin looks like the picture below, The extra fuel is metered by a pin in the pump that rides on the tapered section (note the wear mark from a standard GTD application) As boost rises the boost pin is pushed down against a spring, the pin moves up the taper and more fuel is delivered The more material is removed from the boost pin the more fuel is delivered Also note that one edge has more taper than the other - by rotating the boost pin you can change the amount of extra fuel delivered. As standard this pin was fitted in the middle of it's range (evident by wear mark) Note that more boost will push the pin further, up until approx 12psi when it bottoms out." EDIT: Here is another pic of how it all works Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 26, 2009 Share Posted June 26, 2009 The HP turbo takes that X PSI and charges it up to Y PSI, which is usually something ridiculous like 40 or 50 PSI. That would be quite low for compound turbocharging. I watched single stage turbos on the test stand at Garrett running surge drills and thermal cycling 0psi-45psi-choke, stall, open flow -psi 45psi- choke, stall, open flow.... over an over and over... till it broke. Compounds are not required for 45 or 50 psi, a single wheel can accomplish a 3 and in some cases a 4:1 Comrpession Ratio. Now, running a 3:1 and a 2:1...now you're talking. It's more on the likes of 70 to 100 psi they are running on two stages. Quote Link to comment Share on other sites More sharing options...
Daeron Posted June 26, 2009 Share Posted June 26, 2009 That would be quite low for compound turbocharging. I watched single stage turbos on the test stand at Garrett running surge drills and thermal cycling 0psi-45psi-choke, stall, open flow -psi 45psi- choke, stall, open flow.... over an over and over... till it broke. Compounds are not required for 45 or 50 psi, a single wheel can accomplish a 3 and in some cases a 4:1 Comrpession Ratio. Now, running a 3:1 and a 2:1...now you're talking. It's more on the likes of 70 to 100 psi they are running on two stages. I was trying to avoid sticking my foot in my mouth in case the impressions I had gotten were wrong. My point was that this is something above and beyond parallel twin turbos, or non-linear, "one little up to one big" twin turbos. Its a serial connection between the two. Quote Link to comment Share on other sites More sharing options...
blue72 Posted June 27, 2009 Share Posted June 27, 2009 In all my thorough research I have not turned up any such documentation, just heard everyone stating it. I haven't found any definitive proof yet either. I have a few photos of the LD20T, but only one low res photo of a stock looking LD28T. According to the websites that mention turbo L series diesels there are LD28, LD28Td and LD28Ti versions of this motor. These are the rough specs I've found for the three: LD28 = 93 horsepower @ 4400 rpm, 148lbft torque @ 2000 rpm LD28Td = 118 horsepower @ 4400 rpm, 198lbft torque @ 2000 rpm LD28Tdi = 124 horsepower @ 4400 rpm, 210lbft torque @ 2000 rpm They're pretty much the same on all the sites they're listed on, but never any accompanying photos. Supposedly they came in some Laurels or possibly Patrols. It is entirely possible that those are just rumors or errors too. Could be that others have misidentified LD20T or RD28T motors. -EDIT- I've checked through some very thorough Japanese Laurel specific websites and no mention of LD28T there either. Patrols apparently came with RD28T's. -EDIT- Either way, I dig your conversion. What a coincidence that I happened to be driving my Z this afternoon, you drove by on the same road and I got to check it out in person. I didn't even realize this thread existed here before this evening. Quote Link to comment Share on other sites More sharing options...
NavyCuda Posted June 27, 2009 Share Posted June 27, 2009 I haven't found any definitive proof yet either. I have a few photos of the LD20T, but only one low res photo of a stock looking LD28T. According to the websites that mention turbo L series diesels there are LD28, LD28Td and LD28Ti versions of this motor. These are the rough specs I've found for the three: LD28 = 93 horsepower @ 4400 rpm, 148lbft torque @ 2000 rpm LD28Td = 118 horsepower @ 4400 rpm, 198lbft torque @ 2000 rpm LD28Tdi = 124 horsepower @ 4400 rpm, 210lbft torque @ 2000 rpm They're pretty much the same on all the sites they're listed on, but never any accompanying photos. Supposedly they came in some Laurels or possibly Patrols. It is entirely possible that those are just rumors or errors too. Could be that others have misidentified LD20T or RD28T motors. -EDIT- I've checked through some very thorough Japanese Laurel specific websites and no mention of LD28T there either. Patrols apparently came with RD28T's. -EDIT- Either way, I dig your conversion. What a coincidence that I happened to be driving my Z this afternoon, you drove by on the same road and I got to check it out in person. I didn't even realize this thread existed here before this evening. Those sound like the specs for the ®D28T & Ti... Quote Link to comment Share on other sites More sharing options...
teknomage Posted June 28, 2009 Share Posted June 28, 2009 the nice photo blue72 pulled up for us on the LD28T to my trained eye appears to be a marine LD28 (which would have 3 compression rings (slow)) as the intake assembly has no provision near the entrance for EGR. This is not a stock LD28T but a LD28 Turbocharged, The down pipe on the turbo is very stock 280zx ish as is the manifold, but the heat shields on the turbo are new to my view. Clearly the PCV vented directly into the pressurized intake is not a foo bar that a great engineer like datsun would make, so I would have to chock this up to being non stock. Quote Link to comment Share on other sites More sharing options...
Tony D Posted June 28, 2009 Share Posted June 28, 2009 I was trying to avoid sticking my foot in my mouth in case the impressions I had gotten were wrong. My point was that this is something above and beyond parallel twin turbos, or non-linear... Parallell Twin Turbos are pretty much gone as well. They have a two-compressor single turbine turbo now making 45psi for high horsepower / high airflow applications, that is over a year old now that I know of! Twin turbos are not required for the compressor flow with that stetup. It's taking the example of the old Eliott SSA (?) where there were three turbine stages (axial flow) on a single long shaft driven by a single driver. Great if you could get one running and leave it on...terrible once it shut down and that shaft started to sag, waiting for restart... Garrett also has compound units in one housing last time I walked through the R&D section. Large and small compound series plumbed turbochargers, with all the casings common and with a single exhaust manifold connection. Now the Caterpillar energy recovery turbine (the fluid coupled turbine in the exhaust flow linked to put waste energy from the exhaust back into the PTO drive of the engine...) I've read about and seen photos of, but not actually witnessed in operation... As to this: "See, to ME the Ultimate Datsun Pickup would be a 4x4 83.5-86 720 King Cab with a turbocharged LD28 in it.... and that is what I have ALWAYS wanted this engine for. " The Di 3.0 or 2.7 that was in that same model in 99/2000 and 2005 would work for me. I'd not want that anemic LD28 in there when even the 2.7 kicks it's butt hands-down, and the 3.0 is a dream! The new Common Rail Isuzu and Toyota small pickups with the 2.5 Turbodiesels are great to drive around. Very nice! Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted July 3, 2009 Share Posted July 3, 2009 Here's one of the first implementations of "turbo compound" in the wright 3350PRT (prt stands for power recovery turbine). This one is in the naval aviation museum and you can see the 3 power recovery turbines at the rear of the engine with the exhaust pipes (look like a genie bottle but with two outlets). They drive the crankshaft through a torque convertor type device (fluid clutch) and bevel gears. They add 600hp to the engine output. Strangely enough, they have this engine in front of an airplane that never used a power recovery turbines version in the skyraider of squadron VA25. My dad flew 6 missions in that airplane behind the engine. You guys might have seen him on dogfights in the story of the skyraider that shot down the mig 17 (jet fighter). Hijack off. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 3, 2009 Share Posted July 3, 2009 (Best Kelly McGillis) "So he's the one that shot down the MiG?" Quote Link to comment Share on other sites More sharing options...
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