'86 300zx, need some help

I know we have at least one z car expert here.

There is an '86 300zx I'm gonna go check out. I don't know the condition or whether it is NA or turbo so I have some pre-checkout questions.

1: If it is a non turbo, can the turbo motor be swapped in easily? Meaning is the tranny the same, all the fitments, etc.... Or would I need an engine, tranny, engine bay mods, electrical, etc....

2: Assuming the turbo motor fits or the car is a turbo model, what can I reasonably expect to pay for a new turbo motor?

3: If I'm getting a new motor put in, is there any performance stuff I should get done while the motor is out?

4: What are the cheap base level bolt on mods to do for these cars? I want a reliable street car for now and will drive in the snow (with studs) occasionally.

Word to the wise..... Don't try to frankenstien a turbo motor into a NA car. You will spend far let money in the long run.

Non NA have NA ECUs. They don't have intercoolers. If you are in a state like California, you have some hoops to jump through to be smog compliant.

Save the cash and buy a turbo car to begin with.

Well, I'm not actively looking for one, so if this one is a NA I'll stay away.

good for you. Less headaches

Took a look at the car. It is NA, but damn its clean for its age. Owner wasn't there, I'm gonna check tomorrow. I might buy the thing anyway and use it as a daily driver, forget about performance stuff.

Heh heh. Well, for a G I can drive ti till it dies and save $$ for something else. I CAN resist temptation for a while.

Update: Drove it today, other than brakes (I'll just buy a brake upgrade) its a pretty solid car for its age. New timing belt, water pump, has the injector recall done, engine bay is clean and free of spray.

I also found on z31.com that the turbo swap isn't that problematic if you've got access to a well equipped shop (I do) and a turbo parts car. Same wiring harness, use the donor ECU, plumbing, one engine mount, divert water to the water cooled turbo, swap the cross member from the turbo car and oh yeah.... use the lower compression pistons from the donor. (Or forged aftermarket rods/pistons which would be smarter if you've got the motor apart anyway) Can be done pretty cheap if you're willing to work.

I'm undecided on that anyway, if I do it'll be next summer.

If you don't run big boost, you can run the N/A pistons.

Best trans was the 1988-89 turbo tranny.

Best injector scheme is the 1984-1986 top feed because they lend themselves to being replaced. They are also low impedance from 1984 to 1987 but the 88 and 89 turbo are high impedance.

I'm currently working on playing around with the values in different addresses of the prom to come up with a stock ecu that can support large low impedance injectors and still push a narrow enough pulse width to blow clean at idle.

Jim Wolf technology uses the later ECUs for the basis of their products because they are 16 bit while the earlier ones are different but I can't understand why they use saturated instead of peak and hold because peak and hold favor turbo cars and come in most every turbo car made.

1988 and later turbos had the best of everything you could get.......except it had the smaller T-25 turbo.

They had much bigger brakes and the SS version had the stiffest springs.

Search z31 and pore over the faqs before buying one.

One guy there made 530hp on 555cc injectors and just moved up to 880s so I'm not sure what he will end up with.

Ponyboy, I'm thinking a fun daily driver/decent street car. Probably won't be tracked until much later. So define big boost? I would like somewhere around 250 RWHP. Ok with the NA pistons? NA tranny ok as well?

As for the rest: I would probably go with tokico sport springs/shocks, front/rear swaybars, stock sized slotted rotors, later year calipers and lighter stock sized wheels.

Be a pretty fun car for super cheap.

I am currently doing the N/A conversion to turbo on two cars at the same time.

Takes time to collect up the parts unless you find a donor car and collecting the parts too quickly will make them expensive.

250rwhp isn't asking too much of the N/A pistons but you had better be intercooling and running premium.

You can probably get that running a stock turbo and the 9.0 to 1 pistons at around 11psi which means no ecu or injector upgrades to mess with..........just exhaust, intake, and smoothing everything that helps it breathe.

I'm shooting for that in my current 300zx though I missed out on that 550hp jwt ecu and injector combo on ebay last month which would have caused me to put together a new engine with forged pistons and the requesite head work.

  • shakes head at Slacker *

You are looking at a fairly old car. You are going to be dumping big money into it to fix the normal stuff that goes wrong. If you are going to buy the car because it's cheap, then that is fine.

Do the math. How much can you buy a turbo Z31 for vs. how much is it going to take you to make a non turbo into a turbo. You don't really know how bad the donor car is when you do the swap. You are swapping a devil that you know for a devil that you don't know.

As someone who fields calls like this on a weekly basis, I can tell you not to do it from experience.

Actually the guy has been flaking on selling it so maybe not. Especially since there are several turbo cars around for 2k.

Good call!