300ZX N/A to 300ZX Twin Turbo swap

There are some issues associated with doing this swap that most people are NOT aware of. Most people think you can just throw some turbos and exhaust manifolds on their factory non-turbo car and go beat mustangs, not true!

The 300ZX n/a has a 10:1 compression ratio where as the Turbo engine runs a 9:1 compression ratio.
Also, the factory 300ZXTT has dual front mounted intercoolers. The piping to these intercoolers run next to the radiator and the a/c condenser. Nissan achieves this by making the turbo radiator slightly more narrow. They also do the same thing to the a/c condenser. Therefore, both of these units have to be replaced with the ones from the turbo car. If you were to get all of these parts and put them on the N/A engine you still will end up blowing the engine because of the high compression in the N/A cylinders unless you run 6psi or less.
There are 2 options for the manual transmission. You can either keep the n/a 5-spd or switch it to the Turbo version. The difference is in the inside of the bell housing and the diameter of the output shaft. The turbo clutch is 10” in diameter as opposed to the 9 ½” disc on the N/A version. The factory N/A clutch will not hold up to the torque that the turbo engine puts out. When we do our swap you end up with a lot more horsepower and torque than factory. So, you really want to either run an upgraded n/a clutch or a turbo clutch. That being said, the turbo clutch will NOT fit in the non-turbo’s bell housing. A turbo manual transmission is needed. For most of our customers the addition of the Stage 3 n/a racing clutch is sufficient. It is rated at 550hp. Our stage 1 TT swap comes with a stage 3 n/a clutch.
If you are going to keep it an automatic car then you can keep the N/A auto trans but it isn’t built to be as strong as the 5-spd manual trans. Nissan’s earlier auto trans designs are known to have failures prematurely even when they aren’t boosted. The turbo torque converter is a 1800 stall rather than the 1500 stall of the N/A version. This is totally up to the individual. It is easier to keep the N/A trans and driveshaft. If you swap to the turbo auto trans then you have to replace the driveshaft as well.
The other issue that has to be contended with is the wiring harness and ECU. There are differences in the harness (ie, the boost control solenoids) that make the swap a challenge. If you swap the harnesses then you have to install the waste gate solenoids. What we do is forgo the harness swap and leave the N/A harness in the car. Then we install a boost controller to keep boost within check. Stock boost is 9psi and if that is all you want then you don’t even need a boost controller, but we usually set them at 14psi because we reprogram the ECU anyway. Then we pull your N/A ECU and remove the hard soldered eprom and install an eprom socket for replaceable chips. Then we put a turbo fuel/timing map on an eprom and install it in the ECU and then in the car. It is completely plug-and-play. Nothing else is needed. We can custom-make the eprom to fit your needs. (ie, 370cc to 1000cc injectors, single or dual intake, fed or Cal. Emissions, etc.)
The N/A mid-pipes bolt directly to the JDM turbo down-pipes so you don’t need to do anything there.
We almost always replace the factory Turbo recirculation valves with blow-off valves.
We reprogram the ECU and install a turbo fuel map.
Replace the N/A fuel pump with a Walbro 255 performance fuel pump.
So, after doing this job 100+ times and all different ways in the beginning this is what we do:
Stage 1
Import a low-mileage JDM (Japanese Domestic Market “from Japan” they usually have 30k-50k miles) 300ZX twin turbo complete engine.
-Remove your n/a engine.
-Remove n/a radiator and condenser
-Install intercoolers
-Install Twin Turbo engine (after compression and leak ---- down testing)
-Install performance clutch
-Install new air intake pipes to turbos
-Install new Twin Turbo Radiator
-Install new twin turbo a/c condenser
-Fabricate intercooler piping
-Install new Blow Off Valves
-Install boost control jets
-Remove ECU, reprogram, and reinstall
-Replace the stock fuel pump with a Walbro 255 performance fuel pump
-Install new performance air intake
-Start up new TT motor and test system.
* JDM VG30DETT engine
* Brand New TT Radiator
* Brand New TT a/c Condenser
* Brand New Blow Off Valves
* Brand New Polished charge pipes
* Brand New Fever Racing Aluminum TT conv. Pipes
* Brand New Silicon couplers
* Brand New air intake pipes
* Brand New high flow air filter
* Brand New Stage 3 clutch
* Brand New racing oil cooler
* Fever Racing ECU upgrade
* Used OEM SMIC’s
* professional installation
Total cost of swap$ 8494.89 On Sale $7399.99
Replacement of front bumper is suggested but not mandatory. You could also add a front mount intercooler also.
Replacement of front bumper cover is highly recommended. This allows sufficient cooling to the front intercoolers.
Nismo 555cc injectors*
Nismo 740cc injectors*
Twin high flow air intake*
Sport 550 turbos*
Sport 700 ball bearing turbos*
Aluminum flywheel
Koyo Aluminum radiator
Spec stage III performance clutch
Polished upper plenum*
Polished valvecovers*
Polished water pipes*
Greddy upgraded intercooler kit
Stillen upgraded intercooler kit
Single x-flow front mount intercooler kit*
ADM stainless downpipes and midpipes
Fever Racing cat back stainless exh system
Timing belt service**
Upgraded oil cooler
Turbo timer and harness*
NEW Nissan factory non-turbo EFI harness*
Custom wide mouth front bumper cover*
Custom Front mount intercooler
Stainless tubular manifolds
NGK Platinum #7 colder plugs
Greddy Electronic boost controller
AEM wide band gauge
Twin Turbo 5-spd trans
TT 5-spd flywheel -used
TT 5-spd aluminum flywheel
1-piece driveshaft (TT or n/a)
$207 each x 6
$207 each x 6
$50 each x 2
$50 each x 2
$120 each x 4
$495+paint (wings west urethane front cover)
$15 x 6
(*requires additional labor)
(**recommended at time of swap- price is for t-belt, water pump, and t-stat replace while engine is still on engine stand)
(***price includes dyno time, burning of custom ECU e-prom, and installation. It is on top of the ECU price with a standard base map for the Twin turbo swap.)
We also carry a wide variety of extras beyond this. These are just some of the popular items we sell when we do the swaps. We carry complete body kits, many different brands of electronics other than were listed here, as well as do complete in-house dyno services, cryogenics services, custom fabrication and paint and body work. Call us if you have questions or to set an appointment.



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