Adding turbo to non-turbo ZX motor?

[inline6]

Anyone have info with regard to turbocharging the 81-83 ZX normally aspirated motors vs. starting with the ZX turbo motor?

From what I can see, the norm. aspirated motor for the 81-83 is an F54 block which is stronger (same as turbo), but it has flat tops. The turbo on the other hand has dished pistons. Is that the only difference in the block? Obviously the turbo has a P90 or P90a cylinder head and the non-turbo has a P79.

Where am I going with all of this? With the modern capabilities of the electronic fuel injection systems we have today, can we bump up the compression ratio a bit by running the flat top ZX block and do "better" than the turbo ZX motor? How much of a bump in compression am a looking at with a P90 cylinder head on the flat top ZX block?

I am thinking about that combination with a medium to small sized turbo and a cam like they are running in the project car in sport Z.

Thanks.

[hls30.com]

I 'm not really sure what you are after by turning a non turbo into a turbo instead of using turbo pieces. the only improved technology you mention is EFI, If I was going to ad new technology to older pieces, and I am, I would want the best of the older pieces, and that would mean the pieces designed for use with a turbo. Bumping up the compression sounds good, but look at the history of turbocharged L series engines. I think you might find that more often than not the engines built with NA parts and subjected to turbo charging do not last nearly as long(Mileage-wise) as as those built with pieces engineered for turbo use.

I am guessing you are going to mate a current model EFI system to the L series engine. I have just finished the "collecting stage", and after I move across town, will be beginning the "put it all together stage".

I have the tools and the pieces, now to work on the time!

Will

[thefastestz]

There has to be a pricey kit for this as it has been posted many times.

If there was a kit for the early z maybe that could apply to the non-turbo ZX i am not sure.

Try a search and maybe you'll find some info.

[thefastestz]

here is one thread.

http://www.classiczcars.com/forums/showthread.php?s=&threadid=5939&highlight=turbo+kits

[inline6]

Looking at the How to Modify Your Nissan/Datsun OHC Engine, it does not appear to me that anything other than the pistons are different for 81-83 ZX turbo and non-turbo short blocks. The cranks and the rods share the same part number and so, must be identical.

The block appears to be the same as well according to this taken from Honsowetz book, "On the L28 Turbo block 11010-P9080, introduced in the 280ZX Turbo in December, 1980, and non-turbo L28s in July, 1981, slits were put in the Siamesed cores to provide a coolant passage between the cylinders."

On the question of strength of the pistons, hls30.com, you raise a good point. However, for what it is worth, both the turbo and the non-turbo motors use cast pistons from the factory, yes? Same crank, same rods means same pin height in the piston, right? Seems like a 10.9 cc dish is the only difference.

What I have in mind is just a little different than that which is commonly done, I think... Instead of getting a ZX turbo motor and adding a bigger throttle body, and bigger turbo, and adding SDS or similar programmable electronic fuel injection/ingnition system, why not start with the NA-- higher compression short block and do those same mods?

Fundamentally, what is the compression of a stock ZX NA short block with a P90 head in combination, and with the advances made in programmable fuel injection/ignition technology in the last 15 years, what CR can we safely run in a custom turbo motor setup these days?

Anybody? I'll start looking. I wonder what the latest turbo cars are coming with (CR) from the factory. I bet that is a good place to start. WRX, EVO? Audi's?

Garrett

[thefastestz]

You raise an interesting point. I'll have to do research too.

Since the L28et will probably be cheaper for me anyway i'm sure that is the way i'll be going.

[hls30.com]

I Agree with you, there are only a few differences, the head assembly, the oil pump, the pistons-I have never seen anything that said the NA version was cast-though I have never seen anything saying that they weren't.

The compression ratio was made to be lower to fight detonation, and true, modern engine management has more control than the rudimentary efi that came standard on 280z(x)s. Here in South Georgia the relative humidity and temperature during the summer mean that I need all of the help I can get to fight detonation. I also want to have some extra room to encroach on as I add modifications to the car.

Everyhting I have found (CR) for turbo is 7.4 to 8.9 also with dished pistons-but I have not looked in a while. I would look at current 6cyl applications for comparison.

I am doing something a little different to-though not with the non-turbo pieces.

Will

[inline6]

Ok. I should have titled this What compression ratio to run in a turbo? :classic:

Here is a compression ratio calculator:

http://www.turbofast.com.au/Tfcomp.html#readme

I put in the following for the stock ZX turbo:

Bore = 3.39 inches

Stroke = 3.11 inches

Deck Height = 0

Gasket Thickness .050 inches

Head Volume in cc's = 53.6 + 10.9 for the dished piston = 64.5

CR result = 7.4 to 1

Now take out the dish and you get 8.53 to 1. Interesting...

WRX compression ratio is 8.0 to 1...

Mitsubishi Evo is 8.8

Even the 1996 300 ZX was 8.5 to 1 :classic:

I'm thinking there is no reason to go with the 81-83 ZX turbo block.

Garrett

[Mr Camouflage]

Back in the 80's the thinking was that you had to have low compression with turbos.

Modern thinking is that the dont have to have such low compression that the 1980's engines had.

[hls30.com]

Interesting info-I will look into the piston particulars-somewhere there was a reason for using dished pistons-not just to change the CR-as I recall. There are enough suppliers that sell or can fab cast pistons that getting a set(assuming NA pistons are not cast) would not be too dificult. I will do some checking and get back with you.

[ZmeFly]

Thats not the problem, the problem lies in the pistons and rings on the NA block, thats why it is better to go with the turbo block.

No other reason.

Honestly though the time you would take to do and gather all that you need for the conversion you could easily have a complete turbo motor.

I dont see the point.

[280zx Fever]

F54 Turbo has differnt pistons dished.. and differnt oil pump.

I have a F54 with the P90 head... compression isnt overaly huge.. i think its because the engine is tired but it would be around 8.5 or something.. same as N42 top and bottom..