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[2LV8ETR]

Engine Tuning Stage 1

Exhaust:
The RB26DETT 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. Start with a cat back exhaust. Either get a local exhaust shop to make it or buy a after market one. Either way make sure it is at least 3 inches in diameter and has high flow mufflers. This is the cheapest option and will provide good results. For better results start the exhaust from the turbos. Dump pipes from the turbos can either be a 3" open bell mouth or better still, a split pipe designed to separate the gases from the turbine and wastegate. However if you choose split dump pipes make sure there is at least 40cm of separation before the split pipe rejoins the main pipe.

Intake:
Now we have the exhaust side 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 pod style air filters. 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 filters from the front of your Skyline will also give you a performance advantage.

Boost Increase:
Boost should not be increased above 1bar with the standard GT-R turbos because the ceramic exhaust wheels will fail if to much heat is produced. The N1 GT-R is equipped with larger turbos with steel wheels and in this case you can run 1.5bar, but efficiency runs out above this boost level. The good news is that GT-R's are equipped with a boost restrictor from the factory and once this is removed you can run 1bar of boost. To do this locate the yellow banded hose which is connected to the boost solenoid. There will be a lump where the yellow band is, remove this restrictor and you will have 1 bar of boost. Alternatives include a electronic or manual boost controller.

A manual controller is very basic in its operation it bleeds off air causing the wastegate actuator to open later. The amount of boost run depends on the amount of air bled from the system. It is critical to install an aftermarket boost gauge before carrying out this modification as the stock gauge is not accurate enough and is measured in mm/hg not psi or bar. Manual boost controllers are cheap and easy to install but they do have there disadvantages as 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.

Cam Gears:
At this stage the RB26DETT will benefit from a set new cam gears which are relatively cheap. The outright power will be increased but the main reason for installing cam gears is for a fatter torque and power curve. Upgraded cams can help reduce lag, improve mid range, and top end power. HKS, GReddy, and most other Japanese manufactures make cams which have proven to give good results.

ECU:
Nissan ECU's tend to run rich when extra air flow is introduced which hurts performance, but you have a few options to fix this problem. An aftermarket ECU will give good power gains and improve driveability. One popular option is the Apexi SAFC (Super Air Flow Converter). 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 it actually is. Tuning should be done be a professional on a dyno, and this modification will fix your air/fuel ratio but you cannot change other variables like timing etc with the SAFC.

A better but more expensive option is an aftermarket ECU such as the PowerFC or Wolf3D, which replaces the standard ECU. Many people choose the PowerFC as its less expensive than other aftermarket ECU's, and it plugs straight into your old loom so there is no need to cut any wires. All parameters of your car can be tuned with a PowerFC but once again it should be dyno tuned by a professional.

Another option is to get your standard ECU remapped and this is a good idea if your not planning future modifications. If you are however, the PowerFC is a better option as you will save money in tuning costs.

Clutch & Fuel Pump:
At this level of modification it’s unlikely that your clutch and/or fuel pump will need upgrading to handle the extra power. If you are launching the car hard (drag racing etc) the standard clutch will wear out quickly and need upgrading. Popular upgrades include the Exedy range of clutches. Many people choose to upgrade the flywheel at the same time with a lightened fly wheel which will improve acceleration.

Conclusion:
This completes stage 1 engine tuning for the RB26DETT. 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 run low 12 to high 11 second quarter mile passes.

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. RB engines are known for their strength and the RB26DETT is the strongest animal, and with regular maintenance and a safe tune 330+ awkw is possible.

Turbo Selection:
Many good turbo options are available for the Nissan Skyline GT-R. I recommend turbo’s that will bolt onto standard manifolds, this will save time and money in the long run. Popular models include:

HKS 2510 - Response close to stock with slight power increase.
HKS GT-SS - Responsive turbo with max power output of around 300 awkw.
Nissan N1, Garrett 2560R, HKS2530 -Are similar to each other, a good compromise between lag and max power, and 350+ awkw is possible.

Fuel System:
The GT-R fuel pump and injectors are good for levels up 265rwkw, any more than this and you are starting to push safe limits. Popular upgrades include pumps from Bosch, Walbro, and Tomei. There are many injector and fuel pump upgrades available for the GT-R, just remember to choose items which will support your power target and allow some room for future upgrades if need be.

Intercooler Upgrade:
The GT-R FMIC runs out of its efficiency range at power levels above 300awkw and needs to be upgraded. Many aftermarket bolt on kits are available for the GT-R these days. Be aware a small decrease in throttle response may be noticeable due to the larger core size.

Airflow Meters:
To improve the tuneability of the engine its a good idea to upgrade your airflow meters as this allows for finer tuning which will result in 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 the cheaper of the 2 but the Q45 will allow more airflow.

ECU:
If you have not done so already the ECU will need to be upgraded as even with an SAFC or similar the stock ECU will not do the job. As stated before the PowerFC is a popular option due to its price, ease of installation, and use. There are plenty of other options that are superior to the PowerFC and allow many other tuning functions like launch control, and the ability to use a MAP sensor instead of the AFM. But the PowerFC is still a popular and is proven to perform.

Head Gasket:
Running boost levels above 1.2bar 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 your tuner.

Clutch & 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. Exedy, Nismo, and HKS seem to be popular and reliable choices 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 too.

Cams Or Cam Gears:
At this stage the 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 poncams as they fit without modification and are proven to give good results.

Conclusion:
Use the above suggestions as a guide only.
If you use one, speak to your tuner for a more in-depth and accurate assessment. Every tuner has a different opinion and will do things differently.