SwarthyOne

so, i recently bought a 1986 300zx. i didn't get a whole lot of documentation with the car, but the previous owner told me the car was originally n/a, but the engine is a turbo (actual turbo engine, not converted). the car also has a jim wolf ecu installed.

my issue is, i've never owned a vehicle with a turbo before. i've downloaded the owners manual and the haynes manuals, but (after a search of the z31 forums here and googling), i'm not sure if that's the most accurate information for an engine that has 90,000 on it.

the engine is as clean as a whistle, no leaks (save for the power steering), and looks to have been meticulously maintained. i would like to continue that. any help would be greatly appreciated, even if it's direction to another site with what you feel is good, accurate information about turbo care. thank you!

NismoPick

Welcome to ZDriver!

So are you asking which oil to use? Do you know what the prev owner was running? Or can you call / email him to find out? (usually a question you ask when buying a used car).

Synthetic oil is always the best choice on a turbo motor.

SwarthyOne

thanks for the welcome. i look forward to spending some time here!

i'm not necessarily looking for a brand recommendation, but a weight recommendation, which i realize i didn't really ask for now that i re-read my post. sorry about that. synthetic will be run exclusively. i will e-mail the previous owner and see what he recommends also. i'm also going to spend some time researching turbo engines so i DON'T spend a lot of time here asking questions i could find on my own. thanks for your reply.

rogerz

if the engine has 90 K on it you better think about timing belt renewal.
if she wanders the road like a drunk pig then -Replace outer tie rod ends, and ball joints. replace the bushings with poly (don't forget to lube them as directed unless you like squeaky things). New shocks. all those things will make you think you are driving a diffent car. doing them piece meal is a waste you won't see a great improvement until you do the complete job. Rear bushings nice too but more work and you won't notice as great an improvement. Rear shocks also because if the fronts are gone so are the rears. if car squats when you jump on the gas the rears are gone.

download the fsm from xenon website. most of what you need to know about the car is contained therein. z31 quirk is make sure your battery and cables are in class A shape the z31 will get a lot of strange behaviour with low voltage. there is other stuff but you can find most of it by reading thru the forums. check out zcar.com, hybridz and z31(if they get there site up and running again). zbum site is a good source.
personal opinion (cause I own one) is that the 86 z31 is the nicest looking of that lot altho the z32 is the sexiest.

rogerz

how much boost you running? over 10 psi is pushing things if you run it hard. might want to run midgrade fuel in it.

SwarthyOne

thanks for the reply, rogerz! to answer your questions, this car has been modded pretty heavily, but it really seems to have been a pro job all around. receipts for all the work and not much DIY. i really believe the owner was trying to achieve a goal rather than just throwing parts at the car.

i know for sure it has bilstein shocks and upgraded springs (pretty sure lowered at least an inch), the jwt ecu as mentioned above. 17-inch 40 series michelins, and a manual boost controller (which i'm currently reading up on as i have no idea wtf to do with it).

rogerz, i'm curious about your recommendation for midgrade fuel. what leads you to say that? and it does wander pretty badly at highway speeds, but i was thinking it was more from the stiff suspension than anything. i'll inquire about the tie-rod ends and joints. thanks!

rogerz

engine was originally designed for stock boost of probably 6-7 psi. increasing boost effectively ups the compression ratio. If you don't hear any engine noise (ie pinging) then you are all right otherwise going to a slightly higher octance will help. when we boosted my sons 85 going to mid grade stopped the pinging. boost controller does just what it says increases or decreases boost. Of course you need to have a working boost gage that you can read to know what your boost pressure is. you would be surprised at the number of people that upgrade springs and shocks without doing tie rod ends, ball joints and bushings. push a knife blade into one of the bushings to see how mushy it is or if it is poly. they don't wander the road with proper suspension maintenance.

SwarthyOne

tie-rod ends, bushings and bearings all replaced less than 5k ago. as stated, it's only at highway speeds that the wandering starts. freeway ruts seem to really jerk it around. tires are properly inflated and wearing evenly (may have had a camber adjustment as well). steering wheel is slightly off-center, but no vibration or pulling. i'm stumped on that one.

rogerz

ball joints? z's do tend to jump around when hitting ruts in the road. when I say wandering does it go where it wants to go and not where you want it to on a smooth even roadway. does it still have the stock safety (blowoff valve) on the plenum - right side forward (odd looking mushroom). if so plug it off with a 1" npt plug to be sure it isn't relieving pressure that you don't want it to. steering wheel can be anywhere what is important is that it has been aligned. a good shop will put the steering wheel at neutral. can't adjust camber on rear unless a mod has been made to the stock suspension. look at the rear and see if it looks lopsided. most z31 seem to lean left. another problem can be the steering gear bushings. if the ram moves in the bushings makes steering a bit odd because it is shifting left to right or vice versa depending on which way you are turning. what boost are you running? they are good sturdy cars but require some tlc. from what you say sounds like the guy did things right. fix the leaky steering ram (about $200 rebuilt plus some work). you need to drop the front crossmember on the turbo models to replace the ram. I found out. another thing to check is the universal joint in the steering column which attaches to the ram. if it is sticky causes weirdness. another lesson learned. if you replace the ram be sure to check that universal for ease of operation. if you have more questions try using private message beats back and forth in the forum

noboosts130

Wandering is usually associated with too much toe in/out on the front or rear. Have your alignment checked at a local shop that will do it for free. Were your tension rod bushings changed as well?

SwarthyOne

thank you guys so much for all of the information. between that and the info i'm getting from the previous owner, i should be able to narrow this down quickly. i'm letting it sit until the weekend when i get all of the fluids changed out and i'll probably run it to my friends and we'll dig into the suspension a little. i'm also having a couple other issues that are outside the scope of this post, so i'll be around!