CA18DET FAQ

This FAQ is a general reference for those interested in the CA18DET swap.

What is the difference between a front clip and a motorset?
A front clip, also referred to as a half cut, is the front half of the car. Although more expensive than just a motorset, the front clip will include everything you need to complete your swap with the added benefit of seeing how the motor and its accessories are connected. Conversely, you will have to pull the motor from the front clip before you can install it into your car. On the other hand, a motorset is just the motor and transmission. Depending on where you order from, the motorset may or may not have the ignitor chip, a wiring harness or an intercooler. First time swappers should opt for a front clip if possible.

What are the specs of the CA18DET?
DOHC 4cyl. 16valve 1.8L turbo
Displcement – 1809cc
Horsepower – 175hp @ 6400rpm
Torque – 166lbs/ft @ 4000rpm
Bore – 83mm
Stroke – 83.6mm
Compression – 8.5:1
Block – iron
Head – Aluminum

What additional parts are needed if I ordered a motorset?
In addition to the motor, transmission and turbo, you will need an intercooler and plumbing,
an ignitor chip, ecu and the lower electrical harness.

How do I wire the motor?
The wiring is identical to the SR20DET swap. Furthermore, using solder and heatshrink is the
preferred method to connect the wires together. Simply twisting them together will make your car prone to shorts and all sorts of electrical demons.

What gauge cluster can I use?
Pretty much any gauge cluster off of a 240sx can be made to work but for a bolt in install, you will need to use a non HUD cluster from a DOHC KA24DE.

What motor mounts can I use?
Any motor mount that is made for the KA24DE motor can be used on the CA18DET. If using the Nismo mounts your motor may sit slightly higher than stock but it will fit. Conversely, if using the Cusco mounts, your motor will sit lower. Neither scenario is a problem.

What turbos can I use?
Any t25 or t28 turbo made for the sr20det will bolt directly to the CA18DET’s turbo manifold. You will however have to clock the compressor housing in order to allow the water return line enought clearance. otherwise it will hit the top of the manifold.

What is clocking the turbo and how is it done?
Clocking the turbo is when you rotate the compressor housing. The compressor housing is secured by a snap ring. All you have to do is use a pair of snap ring pliers to compress the snap ring and the housing will rotate freely. If facing the air inlet on your turbo, you will want to rotate the compressor housing about 8 degrees clockwise to provide enough clearance for the water line. Note: Loosening the 4 bolts on the exhaust housing and rotating the exhaust housing will not fix the clearance issue with the water line.

Where can I find replacement parts for my CA18DET?
You can get most of the parts you need by requesting parts for either a 1988 Nissan Pulsar SE or a 1986 Nissan 200sx with the CA18DE motor at your local auto parts store. To be absolutely certain of the right part, just take the part you need replaced up to the store and compare it with the part they have.

How much boost can I run?
The limits of proper tuning and stock internals have never been fully explored on the CA. However, don’t boost over 14psi on the t25 turbo and never boost more than 14psi without some sort of fuel management, including larger injectors, period. if you are concerned about reliability, do not push
the t25 over 12psi. A t25 at 12psi can yield anywhere from 180whp to 220+whp depending on your setup.

Where is my blow off valve (BOV)?
The CA18DET did not come from the factory with a blow of valve.

I added a BOV and now my car runs rich, what gives?
Chances are you have vented your BOV to the atmosphere. What happens is when the BOV discharges, you are venting air that has been metered by your mass airflow sensor (MAF) to the air. Since your car has already measured the air, it puts fuel into the combustion chamber for air that is no longer there. As a result, your car runs rich and hesitates in low boost. The simple solution is to run a recirculated BOV. A recirculated BOV uses a hose to vent the air back to your intake, behind your MAF. Therefore, relieving the surge on your turbo and keeping the air in the system.

What is a wastegate?
A wastegate is a boost sensitive actuator that opens and closes a valve that regulates the exhaust gasses passing through your turbo. Without a wastegate, your turbo would simple build boost till redline. All things considered, this is not a good situation. Blown turbos and engines result from too much boost.

What is the difference between an internal wastegate and an external wastegate?
An internal wastegate is an integral part of the turbo. On the t25′s and t28′s, the internal wastegate is the solenoid with a rod sticking out of it that sits on the side of the turbo. An external wastegate resides on the turbo (exhaust) manifold and reduces the amount of exhaust gas entering the turbo to decrease boost pressure.

What is fuel cut?
The CA18DET MAF is limited in the amount of air it can meter. Fuel cut results when your MAF has maxed out and the CA18DET will not add any more fuel. This is a safety mechanism built into the car to prevent over boost situations.

How can I get rid of fuel cut?
Most people get rid of fuel cut by running a KA24DE or RB MAF in conjuction with a fuel controller, such as a s’afc. This works because you can remap the air to fuel requirements and then adjust the signal to something the factory ECU can understand.

Can I use a SR20DET downpipe?
Yes, but only if you use an SR20DET outlet also. However, sometimes things still don’t line up right and you may have to cut, rotate and reattach one of the flanges. The only company that markets CA18DET specific parts in the US in my opinion needs to do some R&D and quality control. Some of their parts work some of the time. So save your time and money and avoid the cheap ebay manifolds and exhausts and just have a good muffler shop weld an exhaust for you.

My turbo is bad, is this a good one?
There are a lot of turbos on ebay that are less than acceptable. If you need a new turbo, buy one form a SR20DET clip or buy a rebuild kit. You will thank yourself later. A rule of thumb, if the price looks to good to be true, it is. $300 should land you a rebuilt SR20DET turbo. $200 will get you a used SR20DET turbo with plenty of life left.

What intercooler should I use?
The best scenario is to buy a front mount intercooler (fmic) that is properly sized for your turbo and power goals and then make your own piping. If you don’t plan on going over 10psi, the side mount intercooler (smic) from a SR20DET will work fine. If you are looking for more power with the
stealth of the side mount, you can usually find ARC smic 3″ cores on ebay. these are more efficient than the factory smic but for the price the front mount is the way to go. Finally, you can a fmic kit made for a SR20DET but you will have to modify the piping in order for it to fit. As a last resort you can purchase one of the CA18DET fmic kits off of ebay but keep in mind that this intercooler is way too large and will result in more lag.

What oil should I use?
You should use synthetic oil in your motor. I use Mobil 1 10w-30 in the summer and 5w-30 in the winter.

What oil filter should I use?
Any filter for a 1988 Nissan Pulsar SE will work.

When should I change my oil?
On any turbo car, it is recommended to change your oil in 3000mi or 3 month intervals. Whichever comes first.

Where is the oil coming from on the top of my motor?
If your car is not overheating and has good compression, the oil on your motor is most likely coming from a bad valve cover gasket. If your car has white smoke, overheats, fuel or oil in the coolant or bad compression, the culprit is most likely the headgasket. Always check the valve cover first, it is a much more common and easier to fix problem.

Can I use a Nismo thermostat?
In my experience, no. The Nismo thermastat will fit in the housing but it will not open all the way when heated due to space issues.

What spark plugs can I use?
Any spark plug for the 88′ Nissan Pulsar SE will work. Hint: The Pulsar came with a CA18DE motor. You can also use NGK Iridiums, # bcpr6-11.

I installed a Walbro fuel pump and now my car is too rich.
This doesn’t happen to everyone but the Walbro pump can overrun your stock fuel pressure regulator (fpr) and cause your car to run rich. The easiest fix is to get an adjustable fpr and a fuel pressure gauge and set the fpr by hand.

Is an upgraded fuel pump necessary?
At stock boost, probably not. However, if you plan on more horsepower, and most of us do, keep in mind that the stock fuel pump has seen better days and your turbo application will eventually overwhelm it. Better to be safe than sorry on this one.

How can I tell if I am running rich?
Excessive smoke out of the exhaust, a black and sooty tailpipe or bumper, fuel soaked spark plugs, fowled spark plugs, bad idle, poor gas mileage, hesitation and stumbling are all signs of running too rich.

What are the benefits of replacing the radiator fan with an electric one?
The CA18DET, just like the KA24DE, comes with a clutch fan that is driven by the crank pulley. Replacing this fan with an electric one removes the drag of the clutch fan from the crank pulley. This results in a small boost in hp but more importantly, it greatly frees up the front of the engine, making the water pump, power steering, ac and crank pulley much easier to work on.

Is a Koyo or upgraded radiator necessary?
In my opinion, no. A stock radiator with electric fans cools the CA18DET just fine.

Why doesn’t my strut tower bar fit?
Depending on which engine mounts you used, the CA18DET’s intake manifold seems to cause clearance issues with a lot of front strut tower bars. Look for a bar that claims to fit swapped cars. Furthermore, I am using a Pilot, aluminum front strut tower bar and it clears the manifold fine. The Pilot bars seem to change in design often so use discretion and don’t lose heart, there are bars that fit.

I have more questions, what now?
Check the tech pages of this site, I go into a lot more detail there or head over to the forums and ask away.