SR20DET
S13
Power
151kw (100 to 110rwkw)
The SR20DET is a highly tunable turbo engine, like most Nissan engines
it is known for its strength and ease to extract power from. An all
alloy block, alloy heads, twin cams, 16 valves, and a intercooled t25g
turbo mean that this engine had technology ahead of its time. With a
few simple modifications 160rwkw (220kw at the flywheel) is achievable
as the Silvia weighs well under 1300kg it is transformed into a very
potent street car.
Engine
Tuning Stage 1
Exhaust (around 120rwkw)
As with most factory turbo cars the exhaust causes a huge restriction.
A good free flowing exhaust will have your SR20DET performing much better,
turbo lag will be reduced, and power gained throughout the rev range.
The new exhaust should start from the turbo with a dump/front pipe,
either a 3" open bell mouth or better still a split dump to separate
the gases from the turbine and waste-gate can be used. From here use
a high quality 3" high flow cat, then a 3" system all the
way to the back of the car with high flow mufflers.
10-20rwkw is achievable with this mod
Intake (around
125rwkw)
Now we have the exhaust side of the SR20DET breathing the next step
is to get more air into the engine. Either use a high performance air
filter in the stock airbox, 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 car will also give you a performance advantage.
5-10rwkw is achievable with this mod
Intercooler
Upgrade (130 to 140rwkw)
The standard SR20DET intercooler is tiny and before a boost increase
I recommend installing a better one, if you don’t you risk detonation
on warm days. Second hand intercoolers can be used from cars such as
the toyota supra, nissan skyline or mazda rx7. New piping will be needed,
how much piping depends on which intercooler you decide upon.
The price of Hybrid
and Hybrid copy intercooler kits has dropped dramatically over the past
few years and many people have had good results with these. I think
this is a good option as all the piping and clamps come with the kit
so there is less hasle when it comes to fitting. Aftermarket japanese
intercooler kits perform a little better but they are more expensive,
if you dont plan on a radical turbo upgrade the hybrid kit will be fine.
The last option you have is to go for a custom made intercooler, if
money is not an issue this is the best option.
With most intercooler
upgrades you will end up with extra piping and a larger intercooler
core, as a result you may notice a small decrease in throttle response.
A small increase in power may be noticable 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.
5-10rwkw is achievable with this mod
Boost increase
(140 to 150rwkw)
Before increasing boost its a good idea to install colder spark plugs.
The exhaust wheel is ceramic on the T25G turbo 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
or 14psi for short periods. You have a few options when choosing to
increase the boost the first option is what many enthusiasts call the
free boost mod. This is a very simple mod, basically one of the factory
boost lines have a resrictor in place, replacing this line will result
in an increase in boost from around 7psi to 10psi. Full details can
be found here
on the nissan silvia forum. Be aware that some people have had problems
with boost spikes after completing this mod
* This small upgrade can be done with the stock intercooler in place
but be careful on warm days.
If you want a little extra boost you will need to install either a manual
boost controller, electronic boost controller, or a new wastegate actuator,
the differnces are explained bellow.
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. 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 in conjunction with the free boost mod will probably
be good enough.
A 3rd option is
to install a different waste-gate actuator, I have not looked into this
option for a silvia but I know for a fact that HKS make after market
ones for Skylines and would not be surprised if there is one availible
for the silvia. The Skyline HKS actuator has an adjustable arm to help
set your desired boost level. I think this would be a good option for
this level of modification as boost spikes and boost creep are eliminated.
After this modification
your car will probably be running very rich this is typical of nissan
ECU's basically once the ECU sees extra airflow it richens the mixtures
up for safty. This hearts power and may result in flat spots throughout
the rev range, many people find re-gaping the spark plugs to a smaller
gap can reduce or fix this problem.
10-15rwkw is achievable with this mod
ECU Upgrade
or piggyback (150 to 160rwkw)
An aftermarket ECU has the potential to 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 standard 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 trim your air fuel ratios at different RPM points, which will result
in a smoother power delivery and improved power throughout the rev range.
If you planning
to modify your car further at a later date a better but more expensive
option is the Apexi Power FC which replaces the standard ECU. All parameters
of your car can be tuned with a Power FC but once again it should be
dyno tuned by a professional. Other options are available but the Power
FC if familiar to many tuners, is easy to install as it plugs directly
into your wiring loom, and has been proven itself many times over.
* Please note the power FC cannot be used an automatic transmission.
10-15rwkw
is achievable with this mod
Fuel System
The sr20det is equipped with 370cc injectors, you are really
starting to test the limits of both the injectors and the fuel pump
at levels above 170-80rwkw. These cars are starting to age and even
in standard form the fuel pump may not be flowing well enough so for
peace of mind its probably a good idea to upgrade the stocker. Popular
choices include the bosche 040, or 044 these are probably your cheapest
new option, Nismo, Tomei and HKS also make aftermarket direct fit pumps.
A second hand S15 or Skyline GTR pump can also be used but I would suggest
buying a new pump.
To get
a little extra out of your standard injectors can buy a fuel pressure
regulator to increase the fuel pressure. This may get you out
of trouble and save you the expense of upgrading your injectors
but upgraded injectors would be a better option. The maroon top
S15 Silvia injectors are a popular upgrade and they flow to levels
up to 200rwkw. HKS 555cc injectors are also a popular upgrade
and flow enough for levels up to 250rwkw. |
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Clutch
and Flywheel
At this level of modification the clutch may start to slip due to the
extra power if 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.
Conclusion
This completes stage 1 engine tuning for the SR20DET S13. 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 a well sorted
suspension and tyre packages have run low 13 second quarter mile passes.
Continue to Engine Tuning Stage 2 (comming soon)
Please
use this as a guide only I recommend consulting a professonal before
carrying out any of these modifications. Nissansilvia.biz takes no responsiblity
for any problems you may encounter from following this guide.
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