Skyline Tips

What do you do when the performance bug starts to itch?

After reading an article "Heavy Breather", I got inspired to have a look at what was involved with my HR32. It turned out to be quite easy once I had located where everything was.

Picture taken with the front spoiler removed, looking in from the left-hand side. (1) Inlet box under the headlight, note the two 40mm inlets revealed after unblanking. (2) Intercooler pipe

The stock inlet to the air box, is located under the left-hand headlight with an opening at the radiator side of the headlight...not the biggest inlet, or the best place for one. Not wanting to cut a hole in the bodywork I decided to have a look at cutting another inlet into the bottom of the plastic inlet assembly. I made an interesting discovery - it already had been done, but was blanked off...Here follows the instructions:

(1) Remove the left headlight, and remove the inlet assembly from underneath. At this point you can decide to continue on with modification to the plastic inlet assembly, or to just leave it off.

After some feedback from a reader, here are the detailed instructions on how to remove the headlight...

There are two bolts behind the indicator (remove the screw in the top of the indicator and pull gently towards the front of the car, indicator assembly should come out). There are another two nuts on the engine side of the headlight - you will need a universal socket drive to get at these as they are obscured by the air-con lines and the carbon canister. There are actually four nuts in a vertical row, it is only the top and bottom ones you need to remove. I can't stress how difficult it is to remove these without a universal socket drive, also handy to have a long magnetic wand to pick up anything you drop. You will also need to loosen the three expanding pins that hold the front spoiler in front of the radiator. The headlight will come out with a bit of gentle pulling. Be careful when unplugging the connection for the driving light - the connection on the bulb is easy to break, and the bulb hard to locate in a shop.

Detail of a universal socket drive - an essential tool

(2) Remove the rivets holding the rubber and foam on the bottom of the plastic assembly.

(3) Peel back the rubber and foam, under that will be a metal pressing with two openings. Remove the two rivets that hold this on. Either cut or fold the rubber and foam so it won't impede.

(4) Revealed will be two 40mm diameter inlets. Who knows why they were there, only to be blanked off...Using a small saw, cut out the bottom of the inlet assembly, I made a large oval shape and smoothed the edges.

(5) Thats it! There is now a supply of cool air (from the same source that feeds the intercooler) for the intake. Optionally blank off the original inlet. Put everything back on the car.

Postscript: a temperature probe in the airbox reveals that the air in there is now roughly 2-3° cooler than before. The car feels to have a sharper response, and fuel economy seems to have improved.

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Coil Diagnostics

Most of the ignition system is hidden under the cover with “Nissan Twin Cam 24 valve” embossed on it.

Each platinum spark plug has an individual coil mounted on top. These coils are fragile (so I’m told) and it may be a good idea to leave this one to the professionals. But if you have the skills, the cause is usually one of two things: either a coil failure or an amplifier (also known as an ignitor) failure.

The amplifier is the black box at the back of the block, which controls the coils. A faulty coil can be diagnosed by swapping the coil from the misfiring cylinder with another. If it still misses on the same cylinder, the problem is with the amplifier.

The amplifier / coil system is used on the R32 and the series 1 R33. From the series 2 R33, the amplifier is integrated into eack coil.

(1) Ignitor (detail in inset) (2) Turbo (under the heat shield) (3) Coils (located under the rocker cover, detail below)

Another way of testing a coil is to measure the resistance between pins A and B on the coil pack. It should read 0.7 ohms for a healthy coil pack.

Oil pressure.

Like all normal vehicles, good oil pressure is essential. The following figures are the workshop manual specification for oil pressure on the RB20DET...

1kg/cm2 @ 600 rpm
3kg/cm2 @ 2000 rpm
4kg/cm2 @ 6000 rpm

Skylines seem to have a high failure rate of the oil pressure sender. It's quite cheap to get replaced at service time. Otherwise consider fitting an alternate oil pressure gauge such as an Autometer.

What are the specifications of my RB xxxx donk?

Nissan makes engine identification easy - all those letters and numbers have meanings!

RB - series of engine

20 / 25 / 26 - capacity (20~1998cc / 25~2497cc / 26~2597cc)

D - Double Overhead Cam (or DOHC)

E - EFI (Electronic fuel injection)

T /TT - Turbo or twin turbo

RB20E	97kw@5600rpm 172Nm@4400rpm
RB20DE	116kw@6400rpm 184Nm@5200rpm
RB20DET (Red top)	134kw@5600rpm 225Nm@4400rpm
RB20DET*(Silver top)	160kw@6400rpm 263Nm@3200rpm
RB25DE	142kw@6400rpm 231Nm@4800rpm
RB25DET	187kw@6400rpm 295Nm@4800rpm
RB26DETT	208kw@6800rpm 368Nm@4400rpm

 

110 k/ph speed warning.

Sounds horrible doesn't it? Remove the plastic panels under the driver's side dash. Drop the steering column (using the height/reach adjustment), remove the instrument cluster. The small aluminium box on a bracket behind the cluster is the noise-maker. Disconnect the spade terminal, and remove the ding-dong box.

Reset the ECU back to the factory defaults

Try this one... Disconnect your battery and press the brake pedal. This will reset the ECU, and force it to re-learn.

Both a friend and I have done it to our GTS-t Skylines with good results. My friend reports a smoother drive, and more free revving. First impressions on my car were that it starts quicker (not that it ever cranked for more than a second or two), feels smoother in the low rev range, and seems to have a little more torque in low speed acceleration.

Just do it. If there is an essential Skyline tip then this is it.

I have a dyno chart of my R33 GTS25T having the ECU reset. The ECU remaps the ignition curves very quickly, advancing until the knock sensor tells it to retard. This is the saw tooth shape.

Remove or gut the catalytic converter

NB: check the legal stuff before you do this. If you did this modification in California, you could be stung with a US$20,000 fine.

I had my R32's cat gutted for $45 down at my local muffler shop.

Gutting is something that can be done at home - if I knew how simple it is I would have done it myself...besides I like taking things to pieces! I stood and watched them at work, and here is what they did....

Basically the cat has a shield on the underside (remove), and flanges at both ends with bolts. Hard part is removing the bolts, plenty of CRC/WD40 does the trick. Undo the temperature probe, and drop the cat out. Put in a vice, and use a hammer and whatever to smack the guts out (looks like a ceramic brick and heaps of metallic gauze in there)

The contents of my cat filled the best part of a household bucket. Put the shell back into the exhaust system, bit of sealer on the flanges, maybe some anti-seize on the bolts, put the temperature probe back in. Shield back in place (optional)

The car now seems to comes onto boost quicker.

Replace the fuel filter

Just do it. A clogged fuel filter can show as all sorts of drivability issues. Once you have replaced the filter, cut open the old one and you will be supprised that the car ran at all with the original filter.

R33 Fusebox translation

Dashboard Fusebox

Note that the engine bay fuse / relay box has a fuse key printed on the inside of the cover in english.