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Nissan Skyline GTR Tuning
Under
the hood (stock 170 to 180 awkw)
The legendary RB26DETT lies under the hood of the R32, R33 and R34 GTR
in different forms but the tuning basics remain the same. The engine
is similar to that found in the rest of the nissan skyline range but
it’s a more hardcore race style engine built for Group A racing in Japan.
Featuring twin cams, 24 valves, solid lifters and a six-throttle inlet
manifold the nissan skyline was claimed to produce 206kw in reality
the actual power figure is much closer to 260kw. Induction is via twin
garret turbochargers with ceramic exhaust wheels and air is cooled by
a large front mount intercooler. This nissan skyline engine is said
to be strong enough to support 600hp with a standard bottom end.
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 your nissan skyline sounding great,
turbo lag will be reduced, and power gained throughout the rev range.
15+ awkw achievable
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 turbo's. Dump pipes from the turbo’s can either be a 3"
open bell mouth or better still a split pipe design 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 they spit
pipe rejoins the main pipe. another 10+ awkw achievable
Intake
Now we have the exhaust side of your nissan skyline 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 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. 5-10 awkw is achievable
Boost
increase
Boost should not be increased above 1 bar with the standard GTR turbo’s
because the ceramic exhaust wheels will fail if to much heat is produced.
The N1 GTR is equipped with larger turbo’s with steel wheels in this
case you can run 1.5 bar, efficiency runs out above this boost level.
The good news is that GTR's are equipped with a boost restrictor from
factory and once this is removed you can run 1 bar 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 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. 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 but
better still just remove the restrictor. 15+ awkw is possible
Cam
Gears
At this stage the Nissan skyline 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, GREADY most other Japanese manufactures make cams
and have proven to give good results. 10kw+ can be achieved
ECU
Nissan ECU's tend to run rich when extra air flow in introduced this
hurts performance you have a few options to fix this problem. 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 it actually is. Tuning should be done
be a professional on a dyno, this modification will fix your air/fuel
ratio but you cannot change other variables like timing ect with the
SAFC.
A better
but more expensive option is the Apexi Power FC which replaces the standard
ECU. Many people choose the Power FC as it’s 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.
Another
option is to get your standard ECU remapped this is a good idea if your
not planning future modifications. If you are however the Power FC is
a better option as you will save money in tuning costs. 20+ awkw
is achievable
Clutch
and Flywheel
At this level of modification it’s likely that the stock nissan skyline
clutch will need upgrading to handle the extra power. If you are launching
the car hard (drag racing ect) the standard clutch will wear out quickly
and need upgrading. Popular upgrades include the Exeedy range of clutches.
Many people choose to upgrade the flywheel at the same time a lightened
fly wheel will improve acceleration.
Conclusion
(up to 250 awkw with stage 1 modifcations)
This completes stage 1 engine tuning for the nissan skyline GTR. 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.
Continue to Engine
Tuning Stage 2
>
Please
use this as a guide only I recommend consulting a professonal before
carrying out any of these modifications. Nissanskyline.6te.net takes
no responsiblity for any problems you may encounter from following this
guide.
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