Getting your Nistuned Z31 on the road (to the PRO tuner)

Alot of people have been acquiring Nistune lately, and ALOT of people don’t have a damn clue what they are doing with it. Alot of people will soon have blown up cars if they do not bring their car to a professional car tuner.

So you have a Z31 with pallnet rails, larger injectors, big turbo, nistune, and a monkey on your back to get it on the road, well, don’t forget you need an adjustable fuel pressure regulator too. The stock FPR runs at 37psi (ish) so no, your 90000cc injectors are not flowing at 90000cc’s with it, you need an adjustable regulator to bring up or lower the pressure so that your new injectors are flowing at their from the factory rate. DON’T cheap out on this, I don’t care, by the damn Fuelab or Aeromotive regulator.

It also helps to have a wideband o2 sensor installed. No really, install one now before you do anything else. This isn’t 1930 anymore, nobody is tuning by spark plug, install a wideband before you blow up your car like a dummy.

That being said, we can move on to the fun stuff, resizing your injectors in Nistune and getting the car running.

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Lower Intake Manifold Coolant Hose

The lower intake manifold has a coolant hose that usually deteriorates, leaks, or just falls apart when doing maintenance on the intake or coolant system. OEM hoses are available but made of the same crummy rubber that dry rots. Silicone is a superior product that will last a long time and withstand heat and automotive fluids.

This elbow will need to be trimmed in order to fit.


300zx Z31 Billet Throttle Body

My throttle body leaked a terrible amount, enough to notice the car running extremely rich under boost once the air started to leak out and the fuel mixture became incorrect.

The solution? A Hypertune SR20 billet throttle!

Hypertune of Australia produces an all billet throttle, 66mm ID, features sealed bearings, and is available in any anodized color.

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300zx Z31 Throttle Shaft Seals

The z31 throttle body cannot handle over 6psi of boost before leaking. What about the 240sx throttle? No, also not built for boost. The 280zx, the 80’s 300zx, the 240sx, the non-turbo 90’s 300zx. Factory non turbo car 1990’s and back had throttle bodies that were incapable of holding high levels of boost. This issue was fixed in Nissans from 1990 and up in factory turbo cars with the utilization of double lipped throttle shaft seals.

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Boost Leaks

One of the most important parts of building a turbo charged car is insuring that there are no boost leaks. Boost leaks are air leaks once the intake piping and manifold have been pressurized. Any air lost from these leaks will cause a rich condition on a mass airflow sensor car. In addition, because the turbocharger has to work harder to reach its peak boost level, it may overwork itself if the car has been tuned to utilize the entire efficient range of the turbo itself. IE: your turbo is capable of flowing up to 300hp, and you are utilizing all 300hp that the turbo can produce, a boost leak would cause the turbo to spool past its efficiency range in order to still produce the boost level it has been set for.

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Intake Manifold With Deletes

For those curious, this is a factory intake manifold with the emissions and idle controls deleted. PCV has been retained.

The IACV is used to control your engines idle speed so when you are utilizing accessories, the alternator is outputting enough current to keep up with electrical demand. It is useful for cars that use A/C alot or have larger than stock sound systems. Deleting it means idling the car from the throttle alone which requires you to adjust the throttle to be cracked open a hair, and calibrating the TPS (Throttle position sensor). A good idle for a car without an IACV is 1000rpm give or take (up to the user really)

The AAV helps with cold starts, it bypasses the throttle body and pulls air straight from the air intake arm and diverts it straight into the intake manifold. As the car warms up and coolant runs through the little metal elbow next to the AAV, it warms up a special bimetal plate inside, causing it to twist and close up the air hole.

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