Nissan Skyline R32 GTS-T Tuning Guide

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Nissan Skyline R32 GTST
Under the hood (stock 115 to 125rwkw)
The R32 Nissan Skyline is equipted with the the Rev happy 157kw RB20DET engine featuring a twin cam 24 valve head, and a intercoolered turbo charger. The Turbo is a ball bearing item with a ceramic turbine wheel to aid responce. The RB20 lacks low end tourque compared the RB25 but acceleration in similar to newer skyline models as the car only weighs 1245kg.


Engine Tuning Stage 1

Exhaust (around 140rwkw)
The RB20DET is a sweet sounding engine but very quiet in standard form and as with most factory turbo cars the exhaust causes a huge restriction. A good free flowing exhaust will have the RB sounding great, turbo lag will be reduced, and power gained throughout the rev range. The new exhaust should start from the turbo with a dump pipe either a 3" open bell mouth or better still a split dump to separate the gases from the turbine and waste-gate. From here a high quality 3" high flow cat should be used, then 3" all the way to the back of the car with high flow mufflers.


Intake (140 to 150rwkw)
Now we have the exhaust side of the engine breathing the next step is to get more air into the engine. Either use a high performance air filter, or replace the air box with a POD style air filter. If you choose to go the POD filter route I recommend you fabricate some type of shield to keep hot air from the engine bay away from your intake. A cold air intake to the filter from the front of your Skyline will also give you a performance advantage. 5-10 rwkw is achievable with this mod.


Intercooler Upgrade (150 to 160rwkw)
The standard R32 intercooler is tiny and before a boost increase I recommend installing a better cooler if you don’t you risk detonation on warm days. The R34 GTT intercooler is a good cheap upgrade for the R32 and bolts onto the same position as the stock item but some modification is required but its an easy job for a aluminum welder. The GTT intercooler is rated up to about 200rwkw if you plan on going further than this power figure a GTR or aftermarket front mount will be required. Be aware that with these systems new pipe work will be required and you may notice a small decrease in throttle response. You may notice a small increase in power with this mod without increasing boost as airflow will increase and the air will be denser. But it’s the ability to run more boost that makes this mod a good one. If you don’t plan on increasing your power level to over 200rwkw I recommend the GTT intercooler as its cheep and you will notice no difference in throttle response.


Boost increase (160 to 170rwkw)
As mentioned before the turbo’s exhaust wheel is ceramic and they tend to fail if to much heat is generated. The amount of boost you can run with the stock turbo is debatable but I don’t recommend running more than 12psi. You have a few options when choosing to increase the boost either a manual boost controller, electronic boost controller, or a new waste-gate actuator.

A manual controller is very basic in its operation it bleeds off air causing the waste-gate actuator to open later. The amount of boost run depends on the amount of air bled form the system. It is critical to install an after market boost gauge before carrying out this modification as the stock gauge is not accurate enough and is measured in mmg not psi or bar. Manual boost controllers are cheep and easy to install but they do have there disadvantages some can cause boost spikes and boost creep I have also found boost tends to tail off high in the rev range.

Electronic boost controllers on the other hand use stepper motors and monitor boost about every 10th of a second because of this boost spikes and boost creep are kept to a minimum, and the desired boost level is held to redline. Electronic boost controllers are expensive and for this level of modification a manual controller will probably be good enough.

A 3rd option is to install a different waste-gate actuator HKS have a actuator with an adjustable arm to help set your desired boost level. I think this is a good option for this level of modification as boost spikes and boost creep are eliminated.

After this modification many people have problems with flat spots throughout the rev range this is due to the ECU seeing an increase in airflow and as a safety precaution it richens the air fuel mixtures. Many people find re-gaping the spark plugs from 1.1mm to 0.8mm fixes this problem but if it does not you need to consider the next upgrade.


ECU Edit (170 to 180+rwkw)
Many Performance shops are able to edit the standard ECU's settings this is good news If you are a R32 owner as you don’t have to be a new one. Timing, air fuel ratios and all other aspects of your stock ECU can be edited. In my opinion this is the best most cost effective option.

As mentioned before many people have problems with flat spots and rich air fuel ratios. Even if you don’t have these dreaded flat spots an aftermarket ECU will give good power gains and improve drivability. One popular option is the Apexi SAFC (Super air flow computer). The SAFC is a piggy back to the ECU and works by tricking the ECU into thinking your engine is getting more or less air than your engine actually is. Tuning should be done be a professional on a dyno this modification should fix those dreaded flat spots by leaning you air/fuel ratio's at different RPM points.

A better but more expensive option is the Apexi Power FC which replaces the standard ECU. Many people choose the Power FC as its less expensive than other aftermarket ECU's, and it plugs straight into you old loom so there is no need to cut any wires. All parameters of your car can be tuned with a Power FC but once again it should be dyno tuned by a professional. Please note the power FC cannot be used an automatic transmission.


Clutch, Flywheel and Fuel Pump
At this level of modification the clutch may start to slip due to the extra power so it will need to be replaced with a heavy duty item. Many people choose to upgrade the flywheel at the same time this increases acceleration but you may loose a little torque.

The GTS-T is starting to age and the stock fuel pump may not even flow enough for standard power let alone your modified engine. I recommend that you upgrade it. Popular choices include the boche 040, or 044 these are probably your cheapest option, Nismo, Tomei and HKS also make aftermarket direct fit pumps.


Conclusion
This completes stage 1 engine tuning for the Nissan Skyline R32 GTST. Basically at this stage we are at the limits of the standard turbo and fuel systems but in terms of car modification this level of tuning is offers great value for money. Many people with these modifications with and a well sorted suspension and tyre packages have ran low 13 second quarter mile passes.

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Engine Tuning Stage 2
Stage 2 of tuning is where things start to get expensive as we need to upgrade many of the standard systems. Nissan Skyline RB engines are known for the strength the RB20 is no exception with regular maintenance and a safe tune 240rwkw is easily possible. Some people push the limits with 250rwkw+ but if you want an engine that will last 240rwkw is a safer limit.


Turbo Selection
There are many good turbo options available for the RB20 and for a street car I recommend a responsive turbo not a lag monster. A turbo that will bolt onto standard manifold will save time and money in the long run.

A popular and cheap turbo upgrade for the RB20DET is a standard turbo off the R33 GTS25T or the R34 GTT as they are a direct fit and 200+RWKW is possible. Boost should be limited to 14psi due to the ceramic wheel. Many people in Australia have had there standard turbo high-flowed by GCG turbo’s these turbos are popular because they use a ball bearing cartridge, and everything bolts back into place. Turbo response is said to be similar to stock and power figures average around 220rwkw or up to 235rwkw with cams.

Another popular Turbo upgrade for the RB20 is the HKS 2530 this turbo also bolts onto the standard manifold and can make arround 230rwkw with supporting mods.


Fuel system
If you haven’t done so already the fuel pump will need to be upgraded. Second hand GTR pumps are a popular option as are new pumps from bosch, walbro, and tomei. The GTR and Tomei pumps are a direct fit. You may also install a fuel pressure regulator to increase fuel pressure.

Standard injectors will also need to be upgraded at this stage. GTR injectors are a popular upgrade for the RB20 as they are cheap compared to new and are a direct fit. But if you are still using the stock ECU you will need a resistor pack as GTR injectors run on high impedance. Rx7 S5 460cc injectors are ALMOST a direct fit, they fit into the rail but are slightly shorter so the height or the rail needs to be cut down otherwise the injectors will leak...these are the same voltage (Low impedance) as stock and don't require resistor pack but keep in mind they only spray in a jet stream and not a spread as they are designed for a rotory engine.

When buying second hand injectors its a good idea to get them cleaned and flow tested, which normally costs $50 an injector. New injectors will cost you about twice as much as the options above; popular choices include Nismo and HKS. If you cannot afford new ones or don’t want to use second hand injectors it is possible to get you standard injectors high-flowed.


Airflow meter
The RB20DET air flow meter runs out of voltage after around 200rwkw's, most tuners will be able to tune the car past the limits of the AFM but it is a better idea to ugrade you AFM. This allows for finer tuning which will result in a smoother power delivery and make it easier for the tuner to produce a higher peak power output . Popular upgrade choices include the Z32 and the Q45. The Z32 is cheaper of the 2 but the Q45 will allow more airflow. An aftermarket ECU with Map sensors can be used insteed of an AFM but engines equipt with air-flow meters are more tunable. click for more information a about airflow meters


ECU tune
Your RB20 ECU can be tuned be many performance workshops you can either have this done or buy an aftermarket ECU like the Power FC.


Head Gasket
Running boost levels above 1.2 may require a new metal head gasket to lower compression and improve reliability. Opinions differ on this subject so I think its best to ask you tuner.


Clutch and flywheel
The stock clutch will certainly fail quickly at this power level the hardest part is finding a clutch that will handle the power yet not make your car a pig to drive. Exeedy seem to be popular and reliable choice and while you are upgrading your clutch a lightened flywheel is well worth considering. This will help the car rev quicker but the trade off is your car will loose momentum quicker to.


Cams or Cam gears
At this stage the Nissan skyline will benefit from a set new cams, cam gears, or both. The outright power will be increased but the main reason for installing cams is for a fatter torque and power curve. Upgraded cams can help reduce lag, improve mid and top end power. Popular choice is tomei pon cams as they fit without modification and are proven to give good results.