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Turbo Diesel Questions


Chewievette

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I'm quite keen on doing building a mild tuned ld28 for my daily. I guess first thing to do is get a good exhaust onto it.

 

Keen to try a turbo later on, would the injector pump from the rd28t be a good upgrade? (so wouldn't have to worry about modifying the standard one for boost). I guess power would be very similar, capacity is similar too so fuel should be pretty close.

 

Also, what is the LD28 head like? Would it be possible to put l28 valves into it so it flows better? (i assume they are bigger?)

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Also, what is the LD28 head like? Would it be possible to put l28 valves into it so it flows better? (i assume they are bigger?)

 

Cast iron, almost completely flat on the bottom. The combustion or "swirl" chamber is in the piston so they would have to be machined to clear larger valves too. Then you'd need to install new shrink fit cast iron valve inserts. I haven't seen measurements of the intake ports, but it might be a good idea to port the cast iron head to flow the potential of the much, much larger valves you installed as well.

 

The LD intake and exhaust valve diameters are 39 and 32mm respectively. By the looks of things the valves point straight up and down and are directly underneath the camshaft.

 

LD28 valves are 116.83-117.27mm long on the intake side and 117.03-117.47mm long on the exhaust side.

 

Closest length L28 valves are N42/N47 style, but they are still way too short at 114.9-115.2mm intake and 115.7-116.0mm exhaust.

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Fixed your Post.

 

Ahh yes, I stand corrected! Much appreciated.

 

I guess I'm going to have to look harder at the stupid VH swap... Have six of the damn things at work.

 

I was really hoping to blow a LD up to find out what it can take, or maybe it would take as much as I felt comfortable with... in which case it would be a pretty damn stout engine.

 

I'm hell bent on 30psi +, because it is the only way to use the turbos I have available to me and keep them efficent.

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  • 4 weeks later...

So I added a pyrometer in the turbo manifold on the #6 exhaust valve port. I am seeing the following EGT's idle 200-300F cruise 450-550F climb 750-950F these are well below the max for diesel egt of 1300F.

 

The biggest limitation I am seeing is under high speed full throttle, I have observed a coolant temperature spike. I think this is due to all the heat being dumped into the coolant around the pocket combustion chambers.

 

I hit the governor at 115 mph which I think is 4500 rpm or so.

 

The forced induction of the turbo has reduced smoking and soot in the exhaust, especially when climbing a hill in 5th. Which would indicate more complete combustion of the light oil.

 

I am averaging a solid 40 miles per gallon city/highway on 70-100% Vegitable Oil

 

To my dismay when Datsun came out with the raised trunk they reduced the fuel tank capacity from 17.5 to 15 gallons, that cost me about 120 miles of range. Longest trip on one tank so far 630 miles.

 

When I finally ran the tank dry, I dumped in a quart of rotella engine oil to get a couple more miles to the fuel pump. Smelled funny but ran well on engine oil :wink:

 

In 77 why the heck did they re-engineer the trunk like that?

My 76 fit a full size spare, has a 17.5 gallon tank, and more cargo space! Seems like they had it right the first time...

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I actually just added headlight covers last week, since I have logged my best fuel mileage yet 56 mpg at highway speeds, (...due to a 30+ mph tail wind :wink:...)

 

Underneath the bucket covers I also added H4 headlight lenses with HID bulbs and ballasts (I need to fix the wiring harness to light them off though, not getting enough voltage to trigger the ballasts)

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I actually just added headlight covers last week, since I have logged my best fuel mileage yet 56 mpg at highway speeds, (...due to a 30+ mph tail wind :wink:...)

 

Underneath the bucket covers I also added H4 headlight lenses with HID bulbs and ballasts (I need to fix the wiring harness to light them off though, not getting enough voltage to trigger the ballasts)

 

What kind of HID's? The ebay ballasts and kits can be very problematic, and the s30's seem to have weak headlight wiring to start off with.

 

Do you have a link to pictures of your LD install... I want to do one so bad, just the lack of engine availability makes it difficult.

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I will be adding relays into my wiring harness to get the proper voltage to the headlight harnesses, somthing every Z needs anyways. Then I will have my 3x brighter headlights with 1/2 the power draw, less power draw = less parasitic hp draw for accessories = better fuel mileage :wink:

 

I consider this Z my grand touring sedan, as to date the best mileage I have logged was 56 MPG! and I am averaging near 40 MPG, giving me over 600 miles on one tank. Not to mention in the summer my fuel is free!

 

Yea I am glad I finally broke down to afford a set of the headlight bucket lense covers, improved aerodynamics and improved look IMHO.

 

I do have extensive pictures of the swapp. I contacted hybridZ last night to request a new forum be created the "Diesel Z Forum" that we could populate with threads pertinent to what I have done and what others will be doing. I am a bit of a newbie here so if anyone knows how to get a "Diesel Z Forum" set up I have a log of private message discussions that this project started we would like to move into the forum to popluate it, as well as thier are some existing threads, namely the one I first posted in, that should be moved into this forum.

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I was dismayed at the fuel pump the other day to find out that the fuel tank capacity of a 1977 280z was reduced to just 15 gallons, makes me wish I would have stuffed everything into my 1976 280z with its 17.5 gallon tank, and a filler neck that would fit the larger diesel fuel pump nozzles. Currently I have to stand and hold the fuel pump nozzle against the antisiphone, unleaded restrictor in the fuel tank neck. I cannot just set and forget.

 

But the 77 had a better body and interior. I still do not comprehend why they had to reingineer everything in the 77 and raise the hatch deck, less cargo, fake spare, less fuel capacity..... The 76 has a nice low hatch deck for more cargo, a full size spare, and holds 2.5 additional gallons, which to me means an additional 100 miles of range.

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I agree with NavyCuda, I did substantial research before getting everyting together for this project, and I after much deliberation, I fell for the looks of the classic over technical superiority of the ZX. Besides the ZX 2+2 is just toooo ugly. If I went ZX I would get the 2 seater, but I need the 4 seater for:

cheaper insurance (part of the total cost of ownership)

taking kiddies to the movies

and more lounge space with the seat down for my mastiff :wink:

 

What about the difference in chasis weight what would a zx 2+2 weigh in at?

 

I like the classic for its:

instrument cluster

seats

body lines

lightness (my diesel z 2+2 comes in at 2700# empty)

Low crossectional area

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