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GTS25-T Tuning > Skyline GTS25-
T Tuning Part 2
R33
GTS25T
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 RB25 is no
exception with regular maintenance and a safe tune 270rwkw is easily
possible. Some people push the limits with 300rwkw+ but if you want
an engine that will last 270rwkw is a safer limit.
Turbo Selection
There are many good turbo options available but I recommend a turbo
that will bolt onto standard manifold this will save time and money
in the long run. Many people in Australia have had there standard Nissan
Skyline 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 230rwkw or up to 250rwkw with cams. Some people have used larger
exhaust housings from the R34 GTT or the old single turbo 300zx and
have achieved 270rwkw+.
HKS in Japan have a range of turbo's for the R33 that
come with all the parts needed to bolt on. Suitable Nissan Skyline kits
available from HKS at the moment include the HKS GT-RS known to make
280rwkw and the HKS PRO-S known to make around 300rwkw the GTRS is cheaper
and a little more responsive than the PRO-S. Another popular choice
since superseded by newer models was the 2535 which is similar to the
GT-RS.
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. You can either have your standard injectors high-flowed,
or buy after market ones from Nismo or Performance company's. I recommend
you use injectors that are a direct replacement and don’t require any
modifications s to fit. The JDM spec S15 Silvia injectors are also a
popular choice as they flow more and fit without modification.
Airflow
meter
To improve the tunability of the engine its a good idea to upgrade your
airflow meter 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 cheaper of the 2 but the Q45 will allow more airflow.
click for more information
ECU
If you have not done so already the ECU will need to be upgraded even
with a SAFC or similar the stock ECU will not do the job. As stated
before the Power FC is a popular option due to its price, ease of installation,
and use. There are plenty of other options that are superior to the
Power FC and allow many other tuning functions like launch control,
and the ability to use a map sensor instead of the airflow meter. But
the FC is still a popular and is proven to perform.
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.
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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