How do you do a 300ZX twin turbo swap?

Answer 1

I have written this down to the best of my knowledge. I have thrown several recommendations with reasons. I will try to be as detailed as possible. The way I recommend to go about everything is using a JDM Front Clip. Z1 Motorsport sells these front clips for the 300ZX. I also recommend Z1 as being the place to get all your parts from. They just know what they are doing on this car, plus they are the cheapest place. Z1 Motorsport or Concept Z Performance. Really what is required to do an NA > TT conversion using a "JDM Front Clip" is taking out your Engine, transmision, NA intake piping, raditator, and exhaust off. Also you will be using the JDM ECU that comes with the front clip.

-Install the new TT intake piping first with the motor out.

-Install the oil cooler in front of the A/C & Emergency fan.

-Install the stock boost control solenoid next to the Fusible Link Box next to the Battery. This solenoid is what is connected witrh rubber hose to your internal wastegates on the turbos to keep a steady 9.5 psi stock boost on the turbochargers. If you would like to install an electric boost controller, this would be the perfect time to so do. I prefer the Greddy profec B spec II on the 300ZX because the unit fits perfectly on the center consel in the spot where the clock goes. Its the same fitment.

The new JDM Engine comes with everything required such as waterpump, oil pump, intake plenum

Prep the engine...by getting new O2 Sensors on the down pipes, remove and eliminate the EGR system (Z1 has a kit for that for like $15), and install a new Dedonation (Knock) Sensor if possible (Nissan brand ONLY)(if this ever goes bad after you have installed engine in, you are f**ked due to the location of this sensor (back of the engine under the lower intake plenum and connected to the engine block. Then move over your NA Intake Balance Tube (this is that black metal tube that sits on top of the Upper Itake Plenum with like 4 rubber hose that attach to it) over to the JDM TT engine in the same location. Reason for doing this is because the JDM Intake Balance tube is made differently to accomodate the Right Hand Steering, unless your plan on doing the right hand steering along with the TT Swap. This would be the perfect time upgrade on turbos or send your turbos our to get them bored out and fitted with larger wheels (basically making it a bigger turbo only in a small shell). Also you should always upgrade your injectors for 555cc or largers so you can boost up on your turbos and not be limited by the stock 370cc injectors that only allow you to boost up to 17 psi.

And one last recommendation is to replace the wire harness with a new one because by now all the original 300ZX wire harnesses are looking really bad and need replacing. I am talking about the EFI Wire harness. Do this while the engine is out because once it goes it, you cant change it anymore. Even though you have a twin turbo engine in the car, you still need to get a Non turbo wire harness. This is because you wont have the HICAS System.

Next, its time to drop in the new TT engine in and make a few modifications to it.

The JDM engine fits perfectly into the engine bay as the NA. When doing an NA to TT conversion you will not be moving over the Hicas Rear Steering system. This is one thing that you dont transfer over. You will be keeping your NA Powersteering system along with the NA powersteering Belt hooked on the driving belts system.

Next hook up all the wiring connectors in its proper spot and hook up the fuel system hoses (i recommend just replacing them all anyways, they're really cheap). Then install the radiator and then finish it with the TT intake pipes and all the air vacuum hose.

One thing I forgot to mention is the intercoolers, but with the new TT pipes, you would have seen that anyways, they are conncected to the intake pipes.

Next will be the transmission but, I always suggest that you replace the Rear Main Seal everytime the transmission is off (like $10).

Next install the JDM Transmission onto the engine without missing any screws on the Bell Housing. Then connect the Starter on the transmission. I am making it sound easy, but it is a bit of work for 2 people.

Next connect the Drive shaft onto the transmission. You could use the NA Drive Shaft, but I highly recomment that you take the stock 2 piece drive shaft and take it to some place where they specifically make driveshafts and have them make you a one piece drive shaft. The NA differencial has 4 Bolt that hooks up to the NA Drive shaft and the TT differencial has 6 bolts that the drive shaft would hook up to. So you will be keeping your NA Driveshaft with 4 bolts.

A stock 2 piece drive shaft will break easily on the center U-joint on the driveshaft over and over again. This is why I suggest a one piece drive shaft, plus I think you are supposed to gain a bit of power out of it, I am not too convinced about it though.

Hook up the Exhaust. The JDM Downpipes allow you to hook up the NA Testpipes on to it. The US TT Downpipes would normally not let you do that. SO you can keep whatever exhaust system you have the only thing you are getting rid of is the headers.

Next get yourself a Walbro 255 LPH Fuel Pump and install it in your gas tank. To access this you just have to take off the little carpet section between the 2 rear quarter windows. With more boosting you will be doing, you will require more fuel delivery or rick blowing your engine. If you can get a Stock TT fuel pump that would be best for it will support up to 700 HP where the Walbro 255 will support around 450 to 500 HP max, still would be enough for a stock set up.

Next fill up on some oil, I suggest conventional oil like 10w-30 or some cheap o'rielly oil or something, just to run the car for like 2 or 3 days to get the parts running and lubricated. After just 2 or 3 days change it to the better oil you will be driving with. My suggestions for the 300ZX is always full synthetic 0W-30 by Mobile1. If money is no object, use either Greddy Oil or Eneos Oil 0W-50 full synthetic.

Fill up on all other fluids while your at it.

Next Connect your JDM ECU and connect your battery.

And with that you should be set and ready for a start up. As long as all the clamps have been tighten up well and everything has been connected to the right connectors you should have an easy start up. It may take a while for the fuel to flow through the longtime unused lines and stuff, but it should work fine.

Good Lucks For more info or details please feel free to e-mail me at Dream300ZX@gmail.com