[Turbo Diesel Questions]

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.

[Turbo Diesel Questions]

I just got my 1977 280Z 2+2 on the road with its turbo intercooled ld28 diesel engine, power is more than sufficient, but at 800+ miles to a tank and the ability to go on road trips free using restaurant waste veggi oil, I am loving it. My bull mastiff is loving the extra space in the back with the seat folded down

 

you can take a look at my ongoing fuel log if you are interested in real world fuel mileage with this combination:

 

http://ecomodder.com/forum/em-fuel-log.php?vehicleid=2731

 

This link will take you to the ongoing spec for this car as I customize and hybridize it.

 

http://ecomodder.com/forum/emgarage.php?do=details&vehicleid=2731

 

I took thorough pics of the swap and can talk details to any one who needs just drop me a PM

 

to answer some of the questions in this post:

I am using the stock 280zxt turbo and manifold (get out your grinder to fit it) with a custom down pipe and 3" mandrell bent exhaust with two borla straight through glass packs (for a throghty but quite cruiz tone, I like to talk to my girl on the highway now and then). No angles greater than 60 degrees in the exhaust. I am seeing boost building just off idle with 1 psi by 30 mph, and 4.5 psi by 65 mph on an easy steady level cruise.

 

The LD28 is a unthrottled diesel so it takes all the air it can get and needs no pop off valve. Diesels are variable air fuel ratio engines so you just add as much fuel as needed for the power you want, any excess air is just a working fluid for high temperature gaseous pressure to exert force on the piston.

That said when I connect manifold pressure to the aneroid on fuel injection pump additional fuel is injected porportional to manifold pressure density. Power and accelleration are great and fuel mileage is in the high 30's

Disconnect this line so no additional fuel is injected under boost and the engine runs extra lean (no problem for a diesel) I still feel the turbo surge but the power is less and I get in the high 40's for miles per gallon.

 

I will be adding a selinoid to only allow manifold pressure to the aneroid at the press of a red button on my shifter, this button will run a few other things like a shot of steam on the turbo turbine to spool it .

 

As I bring this project all together I will get a dyno run for us to google at.

 

No modifications need to be made to the LD28 untill your boost levels approach 20 psi, I read one case history where the stock tired head gasket let go at 20 psi of boost. Just replace it with a better quality head gasket and head bolts if you blow it trying to go with max boost +++

 

I plan on using the condensation tank in the rear passenger quarter fender as a 2nd fuel tank in a dual tank svo system holding keroseen for easy starts, warmups, and shutdowns. Switching to the main tanks full of veggi oil for cruzing.

 

I might even add a parallel hybrid electric motor on the driveshaft for short runs to the store and back without firing up the engine, or for a little more scurry

 

One indespensiable guage you need to add to your cluster is an egt pyrometer on the number 5 exaust port and keep it under 1300 F and you have a Z capeable of a million miles!

 

diesel is a lubricant

gasoline is a solvent

how long is your engine going to last?

 

The LD28 for this project came out of my 81 nissan maxima manual that pulled the stock 77 Z 2+2 normally aispirated from fresno california up el cahone up black rock to the high plains desert in milfort utah at 5500 feet above sea level and averaged 38 mpg on the highway pulling a whole other car near its own weight.............

 

Enjoy, and please comment.

[How to rebuild your turbo]

So what is the normal lifespan of a rebuilt stock turbo?

 

Tell me more about this center section that was upgradeable to ball bearings?

Was it water cooled as well?

 

What are the merits, plus and minuses of going to a water cooled center section?

 

Thanks a bunch for the contact info, I will get a hold of those guys, and discuss my options.

 

As far as my Z goes it is not difficult to go with more turbo, it is Diesel, a LD28 based Z and the fuel injection pump has an aneroid that adjusts the fuel injection pulse proportional to the air pressure density in the intake manifold after my intercooler. Everything in the LD28 is burly to handle the detonation of compression ignition. I seem to recall having read a case history that the LD28 looses its head gasket at around 20 psi of boost, I have a long way to go to get to those levels, with the stock turbo and waste gate, and the unthrottled LD28 engine that gulps all the air I give it, I am seeing the engine start building boost just above idle, by 65MPH steady easy level cruiz about 3 psi, and at 85MPH steady easy level cruiz about 5psi of boost. I am not looking to go real wild, just reasonable performance, good mileage, and not feel altitude sickness in the mountain passes I regularly traverse.

[How to rebuild your turbo]

Well it looks like it is time to rebuild my stock turbo, I was wondering if any one out there had links to locations offering rebuild kits for our stock 280zx turbos.

 

Also what type of turbo is the stock 280zx turbo?

Is it a straight T3?

A T3/T4 hybrid?

Or something other special?

 

If I opt to just replace the turbo rather than rebuilding what turbo's will bolt right in without needing to modify manifold or exhaust?

a T3?

A T3/T4 hybrid?

 

What are the advantages of the T3/T4 hybrid?