Background
I've been in the GT-R game for over a decade. I purchased my first one back in 2006 just after they were eligible for import in Canada. Boy, did I ever beat that car to death. Much like many young car enthusiasts, I let me emotions take control of my spending. The first GT-R I purchased was imported into Canada for the sum of just under $6000. It had 82,000 km on the clock, and appeared to be in great shape. Was I ever mistaken. Now - nearly 15 years later, I've lost count of how many GT-Rs I've owned. When I started Boost Factory in 2014, I had no idea what I was getting myself into. I knew a lot about Skylines and Supras, and that was the foundation of the business.
We started purchasing shells shortly after opening, with the intent of building them to enjoy as a sort of shop project. That pet project eventually became an entire division of the business, taking on about 1-2 full time employees currently. We've purchased crashed cars, rusty cars, mint cars, beat cars, you name it - we've bought it. We've traveled from the west coast to northern Manitoba to purchase these things, in whatever condition they are. We've learned a LOT about buying cars in doing this, and today - I'm going to share with you everything we've learned about buying a car so that you don't get burned like I did when i was 19 years old.
BODY
The most valuable component to a GT-R is most certainly the body. A car with bad paint, missing exterior panels, or collision damage is extremely expensive to repair. With the surge in pricing, the shortage of GT-R OEM panels, and buyers with cash waiting to upgrade their GTS-T into a GT-R look-alike, the spare GT-R parts have become non existent.
You'll want to first make sure everything is there. The hood us unique to the GT-R, and worth about $1000 new from Nissan, plus paint, trim, seals, etc... The fenders? Out of production. You couldn't get Nissan to make some for you regardless of price. So if your car is missing fenders, be ready to dish out $800-1200, and then get them painted. Side skirts are becoming more and more valuable, but really only worth about $250-400. The OEM wing is worth about $400.
Second off, you'll want to make sure all the panels are painted the exact same colour. I would say that almost every single GT-R we've come across has some paint work done to it. Look at it under different angles, inspect the texture of the paint. Often, even if the colour is matched properly, you'll find the texture of the paint is off. Pull back the mouldings to inspect the paint there, because if the car was re-painted quickly, there will be evidence of masking and an edge where the new paint ends. Bring a fridge magnet with you, try it in a few places on the quarter panel, ensuring it sticks. Fridge magnets don't stick to bondo very well.
Look at all of the gaps between panels. Make sure they are all evenly spaced. Anywhere you see a gap that doesn't look symmetrical, or gets narrower / wider at one end, inspect that part of the car for evidence of collision. While different gaps don't necessarily mean collisions, they are evidence of tampering, or work, and should be checked out.
Underneath the car, you'll often find the frame rails to be bent upwards, as well as the rocker panel pinch weld. This is evidence of the car being lifted with a floor jack and not a proper lift. This also means that whoever owned the car, did work him/herself, and didn't really give a S%&T about denting the under body of the car. Wouldn't you? I would. You'll also want to inspect the floor underneath the car for ripples. If you find a ripple, it's strong evidence of a big collision. Often, the car compresses and shortens on the side that was impacted, and is then straightened on a frame machine, but they can never get all of the damage out of it.
Inside the trunk, you'll want to take the trunk lining out - inspect the spare tire area, the floor to each side, and ESPECIALLY the rear end below the tail lights and the inside of the quarter panels. Most of the R32 GTRs we've seen have been in rear end collisions, and they are not often repaired properly. You'll find curmpled metal, non OEM sealant joining panels, rivets, etc... Anything that stands out - investigate. The right rear quarter panel interior is very prone to rust - as there's a sort of vent inside that the moisture gets into and causes the quarter to rust from the inside. From the inside of the trunk - you'll also be able to see the inside of the quarter panels where you'll find evidence of any body work done to the exterior. If it isn't completely gray, smooth, and untouched - it's likely been in a collision, and repaired, or rusty and filled with bondo. It's quite a shame really, as many skylines have been repaired poorly in Japan.
Looking at the roof, you'll find sun faded paint sometimes, evidence of a car being left outside for most of its life. You may see kinks or ripples in the roof too, which are 100% evidence of very strong collisions.
Make sure the doors line up properly in the door frame. Sometimes, the hinges are worn out and the door doesn't latch easily. If you lift the door while it's open, you'll often find worn out hinges. If the door doesn't fit properly in the frame and the hinges are tight - you've got a much more serious problem.
ENGINE
The RB26DETT is a fantastic engine that has quite a few problems. Many of them are old and worn out, and fail shortly after being purchased. I like to call them glass cannons. They're powerful and magnificent, but they are very fragile when handled and used wrecklessly.
When inspecting the engine, you'll want to obviously perform a compression test. Any values between 120-160 are normal. Don't get too upset over low numbers, as long as the engine doesn't have any issues and the numbers are all relatively close to one another (within 15 points, about)
You'll want to inspect the exhaust on a cold start, to make sure no blue smoke is present on start up. You should be taking the temperature of the exhaust manifold with a laser thermometer before cold starting, just in case your seller isn't too honest and wants to trick you. Once you've started the engine, listen to it carefully. RB26s sound like big sewing machines. The valvetrain can be noisy, and the injectors can sound as loud as modern diesel engines. This is quite normal, don't get too worried about this.
Inspect the engine bay, looking for things that stand out. I like to look for zip ties in hard to reach places, that show the engine has been removed, and reinstalled for whatever reason. Look at the MAFS - make sure they still have the brackets that bolt them to the shock tower - otherwise you'll likely need MAFS too, as they've been bouncing around for who knows how long.
Take off the oil cap, inspect the inside of the oil cap looking for sludge. It may have a dark oily residue to it, which is normal. It may be a little milky too, which is usually evidence of blowby and condensation forming. Put your hand over the oil cap with the engine running, you may feel gentle pulsations, but nothing too strong. The pulses you feel are blowby. Some is okay, a lot is not good - especailly if it's the original engine. Those usually have very little or no blowby. Check the engine oil, inspecting the oil on the dipstick - does it smell like old engine oil, or does it smell like fuel? Does it drip off the dipstick like water, or does it run like oil? While these won't necessarily tell you the exact condition of the engine, it will certainly tell you the current owners' take on maintenance.
Rev the engine up and listen to it carefully under the hood. Does it make any funny noises? It should get louder, but no new noises should manifest themselves.
ROAD TEST
During a road test, you'll be able to test the brakes, steering, and suspension of the car. While i do strongly recommend using a lift to inspect the car, you will never know how it drives unless you actually drive it. If you're buying a shell, you're taking a huge risk in assuming that the car will handle straight and properly.
Drive the car gently as it warms up. Make sure that the car behaves as you would expect. It shouldnt misfire, stall, or shudder. Try some stop and - go driving. Does the engine catch idle properly? Does it droop down below the proper idle speed? Does the engine even have the right idle speed? (Should be 950RPM +/- 50RPM)
Take the car out on the highway once you're satisfied with the low speed stuff. Make sure to pay attention to the transmission for grinding when shifting, especially into 4th gear. Once you get on the highway, accelerate to 100, 110, and 120 kmh. Taking a pause at each speed, and trying different gears - 3, 4, and 5. Listen to the engine, the transmission, the wheel bearings, the differential - you can actually hear all of these things. There shouldn't be any howling, humming (although some tires to make a lot of noise) or other strange noises. The car should be relatively quiet and comfortable. GT-Rs do not feel like "race cars" unless they're poorly modified or built for racing purposes. While driving at highway speeds, pay attention to the steering wheel, the seats, and the shifter for vibrations. Any vibrations are abnormal and will most likely get much worse with higher road speeds. This is usually bent wheels, bad tires, loose steering or suspension parts. You'll also want to let go of the steering wheel to see if the car pulls left or right, paying close attention to the road to make sure you're not in a rut or uneven surface. If you feel any pulling, vibrations, or strange noises, the car has problems. Problems can cost a LOT of money on a GT-R.
Make sure to test the brakes out properly. Apply the brakes firmly at highway speeds, paying close attention to the brake pedal for feedback oscillations. This is indication of warped brake rotors.
THE INTERIOR
The interior of a GT-R is not incredibly valuable at this points. A lot of the parts are shared with the GTS-T. You will want to make sure that the seats are in good condition - as these can go for $800 a pair in decent condition, used. The door panels are unique to the GT-R and have different fabric - as does the roof liner. The GT-R Cluster is also unique, and pricey to replace - about $300-400.
The dashboards are the same as GTS-T. You will often find ugly dash pods screwed or glued into the surface of the dash, ruining it. The dash vents also often break due to people installing air freshener clips into them.
The window regulators are sometimes tired and struggle to raise the window all the way up, and appear to bind. The window mouldings often tear and crack, and are very expensive to replace.
All in all, I would say the interior is the least difficult and valuable part to replace / fix, and if you're looking at a car with incomplete or damaged interior, it's easy to negotiate.
COMPLETE INSPECTION
You've probably heard this one before, but here it is again. Get a complete vehicle inspection done, on a lift. You'll find all kinds of leaks, potentially loose parts, rust, abnormal wear, etc... These are all things that will end up coming out of your wallet unless you pick them up on the pre-purchase inspection.
You would be surprised to know that almost every single car that is delivered to the shop for tuning with work done elsewhere encounters one of these three very common issues, and results in additional time and spending required.
Low Fuel Pressure
Non existent, or poor boost control
Engine Misfiring
While we won't be covering the last two points in this article, we will be going into depth about Low Fuel Pressure.
THE BASICS
Let's go over some of the fundamental components of a fuel system first.
Fuel Pump; Typically a single simple pump that pushes the fuel towards the engine.
Fuel Lines; Tubes and hoses that carry the fuel to the engine and return the un-used fuel to the tank.
Fuel Rail; Much like the intake plenum, the fuel rail is a sort of reservoir for fuel, waiting under pressure for the injectors to open.
Fuel Injectors; Electronically controlled solenoid valves that are triggered by the ECU to allow the flow of fuel from the fuel rail into the intake runners (Some engines inject into other parts of the engine, but fundamentally similar)
Fuel Pressure Regulator; A spring loaded valve that opens at a set pressure, allowing fuel pressure to build in the fuel rail and lines. The regulator is also responsible for providing a path for the excess fuel to return to the fuel return line and in turn the fuel tank.
It's important to understand what all of these parts do so that you may understand fuel flow, and pressure - and that they are different. Fuel flow is typically measured in Liters Per Hour (LPH). This really only means that under the given test parameters and circumstance, that the fuel flow would equate to this amount. If you change any of the variables, such as fuel line diameter, fuel pump voltage, fuel system pressure, fuel temperature, or fuel type - the fuel flow will also change.
Understanding Fuel Pressure
Fuel Pressure is also commonly misunderstood. The pump doesn't really build fuel pressure. The fuel pump merely provides fuel flow. Without a restriction, there would be no pressure - pressure is merely resistance to flow.
To understand this, we can make a simple garden hose analogy. If you've ever used a garden hose, you will agree that if you hold the hose without a nozzle the water will simply run out without really going anywhere far. If you block the end of the hose you will feel quite a bit of resistance - the hose wants to straighten out, the water is escaping still but now it shoots out much further. The water supply has not changed - yet we observe two different pressures as well as flow rates.
In fuel systems, we see similar trends. Higher pressures typically mean lower flow rates. Lower pressures typically mean higher flow rates. When picking a fuel pump, it's important to consider the fuel flow rate at the pressure you intend to operate it. Many fuel pumps are very good at operating at lower pressures, but completely fall on their face when operated at higher pressures.
Rising Rate Fuel Pressure
It's actually the spring loaded valve inside the fuel pressure regulator that allows the fuel pump to build pressure. Many of these aftermarket units are adjustable, allowing the user to configure the fuel pressure. On nearly every turbocharged engine, we will see what we call a rising rate fuel pressure regulator.
Rising rate fuel pressure regulators are responsible for equalizing the pressure differential between the fuel rail and the intake manifold.
Imagine you have 40 psi fuel pressure, and 0psi air pressure in your intake manifold - then you inject fuel for 4ms. Now imagine the same, but this time with 30psi air pressure in the intake manifold - the pressure differential is now only 10psi - that would result in about 25% of the fuel volume being injected when compared to the manifold with 0psi. It's the pressure of the air inside the intake manifold that pushes back against the fuel as the injector opens that causes this differential to be problematic.
To address this phenomenon, we've been blessed with the rising rate fuel pressure. Simply said - it's a fuel pressure regulator that is plumbed into the manifold's pressure using a rubber hose - and it will apply the manifold's pressure to the regulator to increase the opening pressure, in turn increasing fuel pressure. This allows for us to have a very minimal pressure delta between fuel rail and intake manifold, and thus much more consistent, predictable, and linear fuel dosing
.
This is all important to understand, because when picking a fuel pump - you think "I'm going to run 43psi fuel pressure" But in reality, you're not. You're going to run that PLUS whatever boost pressure you're planning to run. That could be a total of 70+ Psi for many applications. Lots of fuel pumps won't flow anywhere near their advertised LPH at the pressure you're possibly running.
Common mistakes made when installing a high flow fuel pump
I would say that practically every single fuel pump installation we inspect is done incorrectly. The fuel pumps often come with instructions that are very simple and clear, but most people seem to think they don't need to follow the precautions or that they won't have any issues if they just "drop it right in"
Fuel Pump Power Supply; The fuel pump originally in your car likely ran off a 10-15a power supply. The high flow fuel pumps often require a 25-30 or even 40a power supply. This entails not only upgrading the fuse, but also the wiring, and connectors - ensuring that every component can carry the additional load. Anything in this circuit that can't carry the full load will become a source of resistance, and heat - potentially melting the connections and even starting a fire - Near your fuel tank - does that sound like a good time? No, fires are bad. Very bad. So be sure to upgrade every component leading up to the fuel tank - Including the electrical bulkhead connection at the fuel hat if necessary.
Installing an upgraded relay; Almost every high flow fuel pump will recommend that you install a 30-40a relay to supply the power to the pump. Most cars don't come with a 30-40a relay. They typically have a 20a relay - which may work, for a bit, but in the end you'll end up with low voltage when the contacts inside of it are burnt, and then - well, your fuel pump slows down and you melt your engine while racing for pink's.
Fuel Pump Ground; Sometimes, people go through all the trouble of upgrading the power supply wiring, and then they leave the skinny little ground wire as-is. This also needs to be able to carry the additional load. Nearly as much as the power supply side does. Upgrade the ground wiring and all connections. One of the most common mistakes people make, is they do everything we just went over, and then they bolt the ground down to a completely painted surface. This is just as bad as forgetting to do everything mentioned above! Clean, bare metal surfaces, or directly bolted to a common ground that can carry the additional load, or even directly to the battery if it's in the trunk. Any poor connections are likely to result in low fuel pump voltage, and in turn reduced fuel flow. That leads to engine failures.
When we get around to tuning cars with improperly installed fuel pumps, it usually becomes apparently right when we're doing wide open throttle cars. We always log fuel pressure and have a special table set up to compare the fuel pressure to the intake manifold pressure to ensure the pressure differential remains constant. If we see any change in the relationship, you've got fuel pressure problems. If you continue to tune and disregard the issue, you may be able to temporarily work around it, but you're likely going to end up with melted pistons or detonation. We all know that's a hell of a lot more expensive than upgrading some basic wiring and cleaning grounds.
If you don't follow instructions, you could end up with pistons that look like this.
What AFR is appropriate for my engine?
This article assumes a basic understanding of AFR Fundamentals and will focus on applying the basic knowledge to practical application.
It is our opinion as well as strong recommendation that tuning only be performed by qualified individuals, using proper tools and training. This information is to be taken and used at your own risk. You are solely and entirely responsible for any damage done to your engine through the use of this technical article as well as verifying whether or not is is applicable to your set-up. Each and every engine as well as the unique requirements of each application are different. Understanding the fundamentals of AFR is essential to yielding satisfactory results.
Some important considerations need to be taken before even beginning to map an engine. Prior to investing time into mapping an engine, the tuner must understand the main variables affecting the target AFR.
Fuel Type; Depending on what type of fuel is used, you may see different mixtures being ideal. For this article, we are focusing on Gasoline (91-94oct and our AFR charts are taken directly from a running RB26DETT)
Camshaft Overlap, Duration; Camshafts with very little overlap, short durations, and gentle ramp rates allow very high vacuum (Suction) forces to be attained at low engine speeds. This equates to smooth idle and low engine speed operation. High overlap, long duration and aggressive ramp rates are suitable for high engine speeds as they promote proper filling of the cylinders at high engine speeds - of course this also means that idle quality and low engine speed is sacrificed. Engines with low vacuum have poorly filled cylinders as well as disruptive airflow in the intake, and thus require more fuel to idle smoothly. (Big cams = Richer idle AFR)
Engine Power; Engine power will also have a fairly large impact on what the appropriate air fuel ratio would be. Engines can be leaned at idle with no negative effects other than poor idle quality. Engines making high power running lean can lead to melted pistons, knock, blown head gaskets, cylinder wall damage, and all kinds of things you really don't want to happen. It's very important to understand where this limitation is so that we can extract the most power out of the engine without damaging anything, all while remaining fuel efficient.
Knock Threshold; Understanding knock is fairly complex for the typical enthusiast. We won't get into the fundamentals of knock in this article, but we will say that the air fuel ratio will have a very important relationship to the knock threshold on knock-limited fuels. Knock will destroy your engine, without a doubt, so it's important to understand how the air fuel ratio can be used as a knock deterrent.
Engine Speed; Engines turning at low speed can run at leaner air fuel ratios than engines at high speed. This is simply because the engine isn't exposed to as many combustion cycles at lower engine speed as it would be at higher engine speed (assuming time is the same in both cases). Less combustion equals less heat, and thus we may run leaner air fuel ratios without much adverse affect.
Engine Load; Engine temperature increases significantly as engine load increases assuming all other variables are constant. Higher engine temperatures can be kept under control with richer air fuel ratios (cooler burn) Engines running at cruising speeds can be leaned significantly to the point where we can see about 5% fuel economy with no loss of power or drive-ability in most cases.
Engine Coolant Temperature; Cold engines require quite a bit more fuel to run smoothly. This is mostly due to the fact that fuel atomization is poor at cold temperatures - Fuel tends to want to condense when it's cold, and evaporate when it's warm.
Cylinder Wall Temperature; This is really only important during cold or hot starting. When you read coolant temperature, you are getting a rather delayed reading of the engine's temperature after the heat has soaked through the cylinder walls, been absorbed into the coolant, and then into the coolant temperature sensor. One thing that most people really don't ever consider, is that an engine's cylinder wall temperature changes extremely rapidly and significantly in the first 15 seconds of a cold start. The AFR required to idle and run properly will also change just as rapidly as a result. Cold cylinder walls need rich mixtures.
Idle Stability; In many cases, the idle stability will determine where we set the idle air fuel ratio. This is largely dependent on the camshaft design, the valve overlap, and the ability of the injectors to deliver very short pulse width injections (Somewhat difficult with large injectors), as well as the injector flow balance. If one injector has 10% less fuel injected at idle, we may need to enrich the mixture for that one injector or the entire bank / set to get a satisfactory idle.
Below is about what you would expect to see for a gasoline (94 octane) powered RB26DETT Skyline GT-R. For those of you reading that aren't familiar with metric scales, about 100kPa is atmospheric pressure (Zero for you guys using vacuum/boost gauges in imperial scaling), and about 240kPa is 20 PSI Boost.
As you can see, there are a few trends in this particular map. We see a rich spot around where the engine will idle (20-50kPa and 750-1500 RPM), and then a lean spot above idle at approximately 3000 rpm while the engine is in vacuum (Not running in boost) - This is what we call cruising speed.
The rich area at idle in this engines' case was necessary to get the idle smooth. You'll often find that engines running at idle tend to sputter, misfire, shutter, and just generally not feel right. This is incredibly obvious in almost every RB26 with factory individual throttle bodies (For reasons we will get into in another, yes another article)
You'll want to be careful you don't enrich the idle mixture up too much, otherwise you risk fouling the spark plugs and getting the inside of your engine contaminated with carbon deposits - left behind due to rich mixtures. We seem to see this limitation around 12.5:1 for idle, any richer than that for smooth idle operation and you need to be careful. It's not really something that can damage your engine, but it will cause problems. There really is no adverse effects to leaning the engine at idle, other than potentially losing the idle stability, and reduction in power (we don't really need much power at idle), so we basically set the idle as lean as it wants to run with the upper threshold being ~ 15.5:1, and give it a little buffer. Example; If the engine begins to idle poorly and stumble at 14:1, we will set the target just below that at 13.3 or 13.5:1.
The area of this AFR table that shows the cruising area of the map (3000 rpm row, columns 50 to 90 kPa) show slightly leaner than stoichiometric AFR. We typically will find the RPM at which the engine will be at cruising speed using the dyno and will adjust these cells. The engine speed at which this occurs will be determined by the road speed. In an R32 GTR, because of the transmission gearing, the rear differential gearing, we typically see these engines cruising at 2500-4000rpm - or about 90km/h to 130km/h. Once we've identified the engine's cruising speed, we then adjust these cells to ~ 15.2 AFR (for gasoline) where we find the fuel efficiency is fantastic. It is also important to note that engines cruising slightly lean will benefit from carbon deposit cleaning inside the engine. If your cruising AFR is rich, you will likely have issues with carbon deposits as well as fuel dilution of your engine oil.
The area above cruising engine speed shown below is set to be slightly richer than stoichiometric, as we described in the numbered list above - engines spinning faster benefit from richer mixtures.
It's important to note that as much most of you enjoy hearing backfires, pops, bangs and the likes on deceleration, it is commonly known in the tuner world that this phenomenon will likely cause valve-train damage. These explosions occurring during deceleration are caused by unburned fuel igniting during the exhaust stroke. The rise in pressure can cause valve shims, rocker arms, and even retainers to be dislodged and result in serious engine damage (Example; dropped valve)
This is the reason why we lean out the mixture to near stoichiometric ratio when under high vacuum (The far left side of the fuel map)
As we approach atmospheric pressure, we enrich the mixture to about 12.5:1 as this is where we yield very good power. We can certainly agree that our priority is engine power at 8000RPM, and not fuel economy - but we must also now consider the knock threshold as we increase engine load.
The highlighted section of the map below shows what we call "Low Boost". This area of the map is where we begin to see the trend change significantly. We can see the air fuel ratio becoming richer and richer quite rapidly as engine speed increases as well as engine load increases.
We do this because we're now getting to the point where one of two very bad things can occur.
1. Melting pistons
2. Engine knock/detonation (91 - 94 octane fuel)
As we stated in the list at the beginning of the article, we know that lean air fuel ratios burn hotter. 35 degrees Celsius hotter inside the combustion chamber per degree. While this doesn't necessarily mean your piston temperature will increase by the same amount, it will significantly increase. As we approach the temperature at which aluminum melts, we must be very cautious and enrich the mixture to prevent that from happening.
The other phenomenon we must avoid at all cost is engine knock. The term detonation is also often used, which we find helps people understand it a bit better. As cylinder pressures increase during the compression stroke, (more boost, higher compression ratios, etc...) the compressed air/fuel mixture becomes increasingly volatile. When the spark plug fires, the air/fuel mixture ignites and expands - it's actually this rapid increase in pressure that instantly detonates the remainder of the air and fuel inside the sealed combustion chamber. This phenomenon is extremely destructive and will often result in broken ring lands, damaged pistons, cylinder heads, bent connecting rods, damaged bearings, cylinder walls, and head gaskets.
One of the ways we mitigate detonation/knock is by enriching the fuel mixture. This simply reduces combustion temperature and thus cylinder pressure.
So - Basically, if you're confident your pistons aren't near melting, and you aren't knocking, you can run slightly leaner air fuel ratios. If you're encountering knock, you can enrich the mixture to deter the knock.
Lastly, High Boost.
This area is where all of the fun stuff happens. It's also where all of the engine damage occurs. Having the incorrect air fuel ratio in this region for any amount of time in excess of 1-2 seconds will most likely cause damage. Prolonged operation of any engine in this area will cause catastrophic engine failure.
We usually set this area of the map to be richer than the target when tuning, so as to not run it lean under any circumstance, as melted pistons and knock amplitude are much more likely to occur in this region of the map.
So, to be conservative, you might want to set your targets to be about a full point below the values in this map, with the lowest value being 10:1, and then make small changes to reach the appropriate AFR.
There isn't much change in targets in this area of the map. In fact, the only reason there really is a change in the higher load cells of this map is because pump fuel (91-94 octane) is prone to knocking at high boost levels. If you are not using a knock limited fuel (example 116 octane) then you may run significantly leaner mixtures. Be very careful in this portion of the map. Any mistakes will certainly cost you a lot of money, frustration, and time.
Once you're done building your AFR table, you should have a look at the 3D model to see how "smooth" it is, and see if the trends follow. You shouldn't really have any unusual dips or high spots, other than the ones explained in this article.
What the heck is a HICAS?!
HICAS /hīkas/ (High Capacity Actively Controlled Steering) is Nissan's rear wheel steering system[1][2] found on cars ranging from the more recent Skyline and Fairlady Z (300ZX) iterations to smaller models like the Nissan Cefiro (A31), 240SX/Silvia (S13 & S15)/180SX and Nissan Serena/Nissan Largo. It is also found on models from Nissan's Infiniti division, such as the Q45, M45/M35 and G37. Unlike many other four wheel steering systems, HICAS and Super HICAS are fitted to improve handling rather than just as a parking aid.
(Wikipedia excerpt)
If you've got an R or S-chassis, you've certainly heard about the issues with HICAS. While Nissan sure did an awesome job leading the pack in the early '90s with awesome features such as four wheel steering - today, it's often a completely defunct system in need of expensive repairs today.
Many drivers who have had the rare opportunity (myself included) to feel what a properly functioning HICAS system feels like are at first startled by it's operation. First, you think - " Holy S&%!, my rear wheels are loose ! " - Eventually, that feeling subsides, and you begin to somewhat enjoy it. It eventually becomes predictable. On the other hand, others describe the HICAS system as being dangerous, unpredictable - as it throws the car into an unexpected turn that was certainly not driver induced.
In any case, I would say that 1 out of every 25 cars has a properly working HICAS system, and 1 out of every 10 drivers actually enjoys and wants it. This leads to the vast majority of drivers wanting it removed - and there in lies the creation of the HICAS lockout bar.
There are quite a few ways to delete it, some better than others. The Turtle Garage HICAS lockout bar was developed by an avid Skyline enthusiast, who just happens to be a licensed and certified welder - looking for a solution to the issues with HICAS without compromise. Many of the kits simply replace the HICAS actuator and leave the inner and outer tie rod ends to be re-used. Those are actually the parts that are most problematic, as they have ball and socket designs that wear out and result in play (toe in / out). Defeating the issue properly required a HICAS eliminator that would address those issues. This is how the Turtle Garage HICAS eliminator was born.
What's in the package?
100% bolt on Hicas delete kit. Very strong. One piece design far superior to the 2 pieces kits on the market. Designed to take the abuse of racing and rough race tracks and never lose your alignment specs. Replaces the Hicas steering rack. Deletes the weak tie rods and outer balljoints. Also acts as a rear subframe/toe brace. Unlike many of the new companies trying to build one piece kits now. This is the only one piece brace on the market that has the ability to clear extended differential covers.
Eliminator braces are built from Canadian mild steel, precision drilled, welded by a CWB certified welder then coated in a beautiful black powder coat for durability. All bolts are grade 8 and zinc coated for corrosion resistance.
What you see is what you get:
Turtle Garage Total Hicas Eliminator Brace
4 Grade 8 bolts
4 Nylon Lock Nuts
2 Energy Suspension Polyurethane Bushings
1 pack of bushing grease.
What you need:
Ball joint puller/press to remove hicas ball joints in the knuckle. Can be bought or rented for cheap.
They are also easily removable with some force with knuckle off the car.
Braces are made in Canada
This kit is tested to fit on R32 Skylines and S13 silvias/240's/180's. may fit more chassis. Please inquire. Will clear Greddy and Gktech brand extended diff covers.
The Turtle Garage HICAS eliminator is available as just the lockout bar and hardware, or a complete kit including adjustable toe arms (GKTech arms)
Conclusion
If you're looking for the best kit on the market, with the most competitive price, and highest customer satisfaction, Turtle Garage has got you covered. It's incredibly easy to install, service, remove. It's never going to break. It comes powder coated in black (custom colours available on request!) and has high quality zinc plated hardware - none of that retail hardware store grade 5 garbage. It will fit just about any chassis that had HICAS, and it will allow you to replace the flimsy, worn out rear steering tie rod ends with robust aftermarket adjustable toe arms.
Introduction
It's commonly thought by many that more expensive parts are superior to less expensive parts. We see this all the time in the high performance industry. Lots of people think that if they spend more money on an oil pump, or a water pump that they'll get better results. This originates in our industry in businesses pushing their sales to increase their bottom lines and profits. "You need this" is something we've all heard. But has anyone ever taken the time to justify that claim?
This mentality has lead to a gross misunderstanding of what's actually better for you, the end-user of said parts. Often times, you'll hear consumers argue what the best part for X application is, bragging about how much they spent, preaching "Do it once, do it right, bro" or about how they "Didn't want to take any chances"
Today, we set the records straight in regards to the N1 Water Pump - which is extremely misunderstood as being a superior water pump. In reality, it's not - it's just made for a very specific application, that 95% of the people buying them aren't taking advantage of. It's actually a downgrade if you aren't using it as it was intended.
Let's go over the technical and visual differences in the two pumps;
OEM Water Pump (RB20, 25, 26)
Part Number: 21010-21U26
Price: ~ $100 USD / $135 CAD
N1 Water Pump (RB20, 25, 26)
Part Number: 21010-24U27
Price: ~ $235 USD / $315 CAD
Comparing them, you can see there are not many significant differences. When looking at the outside/front of the water pumps, there are no visible differences.
The Slotted Hole
Some people believe that the slotted M6 hole was evidence of an N1 water pump. While all N1 Water pumps certainly do have the slotted hole, many OEM water pumps also have the slotted hole. In fact, it's what we see most commonly now.
Originally, Nissan manufactured quite a few variations of the RB water pump. This was to accommodate for different castings in the blocks - as there were many variations of the RB over the span of a decade in time. If you were to try bolting a water pump without the slotted hole to an N1 block, you wouldn't be able to get that bolt threaded into the hole - however a slotted hole water pump will fit on any RB.
We have encountered instances where the edge of the slotted hole was actually not supported by a machined surface behind the water pump, which resulted in coolant leaking through the slotted hole. There really isn't much you can do in this case, other than get a water pump without a slotted hole, or build a small sealing plate to cover the slot. There doesn't appear to be any rhyme or reason to whether or not the slotted hole water pump will seal or not, but we can say that you have about a 98% chance of never having any issues.
The Impeller and Backing Plate
You surely noticed the N1 water pump has 6 blades on the impeller, and that the OEM water pump has 8. Have you ever wondered why? Why on earth would the almighty N1 water pump have LESS blades than the plain old OEM water pump?
But - Did you notice the plate behind the N1 Pump's impeller? That's an anti-cavitation plate. (We'll get into cavitation in depth below)
We did - and we have researched the issue fundamentally, technically, and through real world experience & testing.
The answer lies in hydrodynamics;
hy·dro·dy·nam·ics
/ˌhīdrōdīˈnamiks/
plural
1. the branch of science concerned with forces acting on or exerted by fluids (especially liquids).
Why did Nissan reduce the amount of blades on the N1 pump?
In order to understand why Nissan chose to reduce the amount of blades in the believed to be superior pump, we need to understand it's intended application, and the issues with the OEM pump design.
The N1 pump was designed to be used in the N1 R32 Skyline GT-R, which competed in various forms of competitive racing.
Group N and A racing is nothing like your every-day drive to work. The engines in these cars would typically operate in the 4000-8000 RPM range, and never really drop below unless mechanical faults, pit stops, or special circumstances occurred.
Do you ALWAYS drive your car in the 4000-8000 RPM rev range? Probably not, unless you're competing in racing.
That is the only circumstance under which you will benefit from the N1 Water pump. If you're a daily driver and weekend warrior, you may benefit from the N1 water pump, but most likely your daily driving will suffer. Many will argue they've got one and never had a problem, which is totally possible. But have they noticed any benefits? Unlikely.
If you've ever watched a movie that featured submarines, you surely have seen the bubbles that follow the torpedoes, as well as the propeller behind the submarine. Ever wonder why or even how bubbles somehow manifested themselves under water? It's not like there's air down there, right?
The answer is cavitation.
cav·i·ta·tion
/ˌkavəˈtāSHən/
noun
Physics
noun: cavitation
the formation of an empty space within a solid object or body.
the formation of bubbles in a liquid, typically by the movement of a propeller through it.
How does cavitation occur? We'll use the submarine's propeller as an example as many of you can relate and understand it fundamentally. When a propeller moves through a fluid (water, coolant, etc...) it displaces the fluid (pumping). This displacement of water causes very rapid changes in pressure - at the inlet, the pressure drops as it is pulled into the propeller, and at the outlet - the pressure rises. This difference in pressure results in the phenomenon we know as cavitation. Technically speaking, the fluids actually evaporating due to the drop in pressures. A reduction in pressure will actually reduce the temperature at which the coolant will boil, resulting in evaporation. This is one of the reasons why cooling systems are pressurized. Pressurized coolant will have a much higher boiling point than if it were at atmospheric pressure.
Evaporation is simply a phase change, much like how ice melts, and water becomes a gas when boiled. You can actually evaporate water at room temperature under a strong enough vacuum. Pressure changes the temperature at which fluids will evaporate as well as condense.
The evaporation of the water (or coolant, in our case) through the process of cavitation results in "bubbles" of evaporated fluid. These bubbles then suddenly implode (or collapse) on themselves, and erode the surfaces on which they are near. The damage appears similar to that of media blasting. Below is an example of cavitation damage on a propeller. You can see how this is not something you want occurring inside your engine.
You can witness cavitation in many every-day things. Any pump with an inlet restriction will likely cause cavitation, or an impeller spinning to quickly for the fluid's dynamics and application for which it was designed.
So, how does the N1 pump prevent cavitation?
By reducing the amount of blades on the pump as well as integrating a backing-plate behind the impeller, Nissan was able to reduce the pressure differentials across the inlet side and the outlet sides of the impeller. Taking two of the blades away actually reduces the flow of the water pump - assuming all other variables are constant (Speed, temperature, fluid type, etc...).
Conclusion
So, simply said, the N1 water pump actually flows LESS under the exact same circumstances as an OEM water pump. It won't cavitate and destroy your block and water pump, though.
So - knowing all of this now, does it really make sense to spend 3X the money on a cooling system downgrade, to prevent a phenomenon that you'll likely never have a problem with?
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