Well after a lot of pleading, here’s our first FAQ section for the KA24DET. I’ll be keeping this thread updated quite frequently so make sure you check back often. If you have something you’d like to see posted on here please email it to me @ [email protected]

I’d like to take this time to thank everyone that helped with this project….I’m not going to list all the names for fear of leaving someone out and crushing there feelings. You know who you are.

DISCLAIMER: Any modification you choose to make to your own vehicle is completely your responsibility. Neither myself nor anyone else on these Forums can be held responsible for any accidents or malfunctions that happen to your vehicle as a result of any modifications that you or anyone else has made. It’s a sad world that I would have to post a disclaimer like this; lets ponder that for a moment…

WHAT CONTROLS THE AMOUNT OF BOOST A TURBO PUTS OUT??

In modern turbo engines the boost is controlled by a wastegate. This can be either an integral wastegate that is part of the turbocharger (usually the case in factory turbo applications), or an external one. When boost is applied to a diaphragm in the wastegate actuator, it will open a valve that lets exhaust go past the turbine wheel. HOW DO I ADJUST MY BOOST?? Bleeding off part of the boost signal coming to the wastegate so that the pressure at the diaphragm is less than actual manifold pressure. This can be done by a simple bleeder valve or an electronically controlled one... some are more accurate than others. Disconnecting the wastegate hose completely is not recommended.

Preloading the spring against which the diaphragm acts. This can be done by either shortening the rod (some Garrett T3’s have a threaded rod making adjustment very easy), adding shims under the bolts holding the actuator or by bending the rod (crude but will do the same job). Note that this method works only with integral wastegates; external ones don't have an actuating rod.

Using a stiffer spring.

WHAT IS A BOOST CONTROLLER??

Well their are 2 different types of boost control. The price range is huge, from a $20 bleeder type, to around $600 for a nice electronic type with lots of cool lights and some of that fuzzy logic stuff. Both types do basically the same thing. They tell the wastegate when to open. The bleeder type is exactly that. It bleeds off air pressure going to the wastegate to a predetermined amount, which you set, therefore fooling the wastegate into staying closed longer to increase boost. Or open earlier to decrease boost. Each wastegate comes from the factory with a predetermined spring pressure. This is the setting the wastegate will open at to relieve boost. You can’t turn the boost any lower then that setting, even with a boost controller. So it's important to get the right wastegate when you are planning your kit. If your motor will only handle 7psi, you need to make sure the wastegate will either open at 7psi or before. Then you can use a boost controller to increase the boost later on.

HOW MUCH BOOST CAN I RUN ON STOCK INTERNALS??

I think this one has been asked 10,000 times. The answer depends greatly on the fuel system. With the appropriate fuel system to support, stock KA’s will handle 12psi with no problems. The engine can be taken beyond this point. But the chances for detonation increase greatly. I would personally run 15psi on stock internals. But I also have complete faith in my tuning abilities. The average person should stay at or below 12psi until he or she feels comfortable with the concepts of preignition and what it takes to eliminate them.

WHAT HP CAN I ACHIEVE BEFORE HAVING TO REBUILD MY MOTOR WITH FORGED INTERNALS??

This is also covered by the previous question. Since the HP a KA will make is directly related to amount of boost and fuel it consumes. There are ways to raise the compression without using forced induction, but that will not be covered in these FAQ’s.

WHAT OPTIONS ARE THERE FOR TURBO'S AND TURBO KITS??

This question appears quite a bit as well. However coming up with a specific and understandable answer almost made me unswallow my lunch. There are a few Kits made specifically for the KA24DE and the different models of 240. I’m not going to list them all right here, as I will be attaching a long list of Nissan links at the bottom for all of us to enjoy. I’ll also be attaching various informative links.

If your looking to piece a turbo kit together yourself, this will be a little more difficult. Especially if you don’t have an understanding of trim sizes and the flow rates of different turbo’s. There is a general consensus that the Hybrid T3/T4 series turbo is the best turbo for a 2-liter engine. I personally prefer the HKS 3037 series of turbines. But as with most everything else, HKS is fairly more expensive.

WHAT DO I NEED TO INSTALL A TURBO ON MY KA??

This is another one of those questions…Literally tons of possible situations. But I’ll try to explain this to the best of my ability. Well first of all your going to need a turbo and exhaust manifold for the turbo to mount to. There are 2 types of exhaust manifold to choose from, top mount and bottom mount. It’s as simple as it sounds really, top mount means the turbo mounts on the top and bottom means the turbo mounts on the bottom side of the manifold. I prefer top mount do to the ease of plumbing. I’m not going to go into the difference between log style cast manifolds and stainless tubular manifolds. Most available manifolds are cast log style.The manifold may or may not need to have an external wastegate port, depending on whether or not the turbo is internally wastegated.

Once you have figured out what turbine and manifold your going to use, you need to purchase or make the applicable plumbing for your particular turbo. All turbo’s require a supply and return oil line. Some turbo’s require a supply and return water line for cooling. You’ll need to find these things out when you purchase the turbine.

You’ll also need to purchase or fabricate a turbo down pipe. This is the pipe that mounts to the exhaust flange of your turbine. It then connects to your cat and the rest of your exhaust. If you have an external wastegate, you’ll need to have a down pipe made for that as well. I’m pretty sure it’s illegal in most states to have your wastegate vented to the atmosphere, so you’ll need to have it plumbed back into your exhaust piping. I recommend atleast 12 inches down stream from the turbine.

The next step would be getting an intercooler and intake piping. You can purchase a kit or build your own if you have the skills. You should also consider using a blow off valve (BOV). It will lengthen the life of your turbine. Once you have the entire turbo system complete, you’ll need to think about fuel management, which I will cover in the next question.

WHAT KIND OF FUEL MANAGEMENT SHOULD I USE WHEN INSTALLING A TURBO??

By installing a turbo on your motor, you are force-feeding it air that it would not normally consume. So the stock injectors are not meant to handle the demand of increased air pressure.

At a bare minimum, I would suggest set of new injectors along with some type of fuel management, as well as a rising rate fuel pressure regulator. Upgrading your fuel pump is also an excellent idea. The fuel management can come from several different sources. You could install a complete standalone system from Haltech for example. Or you could get a piggyback type ECU from HKS or Apexi. There are a lot of different options for fuel management. I’ll cover those in another question.

WHAT ARE THE DIFFERENT TYPES OF FUEL MANAGEMENT??

An excellent question that always seems to get lots of attention. Once again we need to make a decision on what type of fuel management will fit the need of our motors. The best way to look at this is to set a goal and examine your budget. A complete standalone system could cost thousands. Or you can purchase a piggyback type for a few hundred dollars. Allow me to explain the differences in various types of fuel management.

First I’ll talk about the piggyback type. This type is called piggyback because it works in conjunction with your stock ECU. It simply amplifies or reduces certain voltages going to your ECU. Fooling your ECU into thinking more or less air is actually being ingested. That way you can lean out or richen your fuel ratio by adjusting the voltage. This is the cheapest method of fuel management. But it’s also not the best. The piggyback will only adjust the fuel load so much. For smaller size injectors it works very well. But if your goals include a high hp motor with a lot of boost, you might want to consider another option.

Then there is the ECU rewrite. Jim Wolf Technology (JWT) is by far the most popular name going in the Nissan community. Rewrite basically means that your stock ECU has enhanced fuel and timing maps programmed onto the chip inside. You tell the company what mods you have done to your car and they burn you a chip. This method is by far the easiest. I have never heard of any valid complaints. Other then perhaps JWT has programmed the ECU to run on the richer side of the A/F ratio. But that is only for safety purposes. A lot of people use a piggyback along with the JWT ECU for a little fine-tuning.

Finally there is the standalone system. These also widely vary in price. The standalone system is a completely user programmable ECU. It gives you access to fuel and timing maps. Some kits come with new sensors, while other kits use the stock sensors on your motor already. The standalone is not an entry-level system and should only be tuned on a dyno with a professional that has done this before.

Like I said earlier, motor goals and budget will play a large role in this decision.

DO I NEED AN INTERCOOLER??

In my honest opinion, yes. It is a safety device that you can’t afford not to have. On a hot day, whether your running low boost or not, you have a increased chance of detonation. Or you could have purchased a bad tank of gas, which happens to be lower in octane then your car usually runs on. This will cause your car to detonate. If the detonation isn’t severe, you might not even notice. But your motor will lose performance and you will seriously shorten the life of your block and rotating assembly. No one wants to go through all the work of installing a turbo just to have the motor die. Its far better to do it right the first time. You can source intercoolers from many junkyards if your income does not allow for a brand new $1000 job from the likes of HKS, or any other dealer for that matter. A lot of diesel trucks have nice sized intercoolers. You’d be surprised what you can find lying around a junkyard.

Intercooler piping can be difficult sometimes. Due to the many bends in the system it has to make. You can have a muffler shop make you some piping for a decent price. Or you can try to piece a set together from a local hardware store. I would suggest using the same size piping as your throttle body. Also try to eliminate any sharp bends or bottlenecks in the system.

DO I NEEED TO LOWER MY COMPRESSION (CR) WHEN I INSTALL A TURBO??

No, you don’t need to lower your CR to install a turbo. You may want to consider lowering your CR if your are going to run boost in excess of 12psi. The CR can be lowered in 2 different ways. By installing a thicker head gasket, preferably metal type, and by using lower CR pistons. Using lower CR pistons is the preferred method and you can upgrade to forged internals at the same time.

HOW MUCH HP WILL I GET??

Another popular question, the hp increase is mostly boost dependent. On average, with a 2-liter motor, you’ll see an increase of 8-10 hp per psi of boost. This will vary on turbo selection and other mods done to the car.

WHAT IS THE DIFFERENCR BETWEEN MASS AIR FLOW (MAF) AND SPEED DENSITY (MAP)??

The MAF sensor is a special device with its own miniature computer. The sensing wire in the air stream is heated to around 100 degrees Fahrenheit above the temperature of the incoming air. As the air is drawn across, it tends to cool the wire, the sensor then tries to maintain the heated wire at its preset temperature, the potential or difference is converted into a voltage that is used by the ECU along with other sensors to calibrate the proper fuel injection rate. What makes the MAF sensor unique that it is capable of measuring the exact weight of the air due to the effect that humidity, temperature and barometric pressure, and rate of flow has on how fast or slow the cooling effect takes place on the sensing wire. It is extremely accurate.

Speed Density relies on a MAP sensor, O2 sensor, coolant sensor, air temp. sensor and throttle position sensor (TPS) to calculate the fuel requirements. People with high hp applications sometimes switch over to a MAP sensor based system because it eliminates the restrictive MAF sensor. Also, most standalone systems use a speed density based setup.

WHAT IS DETONATION??

Detonation is the #1 killer of forced induction cars. Rather then type out a long explanation. I found a great link that explains everything. A must read for all forced induction owners. http://zhome.com/ZCMnL/PICS/de....html

LINKS:JWT Upgrade: http://www.jimwolftechnology.com/ecurest.htm

Greddy http://www.greddy.com/products...anage

SDS EM-4:http://www.sdsefi.com/specific.html

A'PEXi S-AFC:http://www.apexi-usa.com/elect...w.asp

JE Pistons (they don't have 240sx on their list though...):http://www.jepistons.com/sportcompact.asp

Nippon Powerhttp://www.nipponpower.com/index.html

Nissan Motorsportshttp://www.courtesyparts.com/nismo/index.html

Turbo’shttp://64.225.76.178/main.htmLink Engine Managementhttp://sandstallion.com/link_wiem.html

Summit Racing http://www.summitracing.com

Jegshttp://www.jegs.com

Haltechhttp://www.haltech.com/index.html

Cam Installhttp://www.sr20development.com...E.PDF

More Turbo'shttp://www.turbo-kits.com/nissan_turbo_kits.html

Good Intercooler Infohttp://www.swedishbricks.net/faq/tintercooler.html

Phase2 Mototrendhttp://www.phase2motortrend.com/turbokits1.html

XS Engineeringhttp://xs-engineering.com/inde...v.jsp

When I add stuff onto the FAQ's I'm going to do so by creating another post. That way we don't have to reread everything looking for updates:D

Forced Induction is Forced Induction??

A widely misunderstood fact among racers is that forced induction is forced induction is forced induction...period. Now, what do I mean by this? I mean, at the end of the day, a turbocharger, a supercharger, and nitrous oxide all serve the same purpose: to raise motors effective compression level. Although they may use different mechanics to do so, they all fundamentally do the same job.

Well, what is "effective compression?"

Effective compression is the sum of the static compression, plus the additional compression added to the cylinder via some kind of forced induction tool. Static compression is the amount of air inside the cylinder that is compressed. In order to find what the static compression is, e.g. 12.5:1, one must find the ratio of cylinder volume at BDC, and TDC. An equation for effective compression is as follows:

((boost psi / 14.7) + 1) x motor compression = effective compression

So for example: A motor with a 10.0:1 static CR boosting 10psi 10psi/14.7psi = .68……… .68………+ 1 = 1.68……… 1.68………x 10 = 16.8 effective CR

A motor with an effective compression ratio of 16.8:1 is easily daily driven, with proper fuel and ignition upgrades, high-grade gasoline, and tuning.

Well, what does this effective compression have to do with my nitrous, my supercharger, or my turbocharger?

Essentially, as I stated earlier, all forms of forced induction effectively raise your motors compression ratio. Boost is boost, forced induction is forced induction. They all do the same job, they just go about doing so in different ways. There is no one form of forced induction that is inherently safer than any other form. "Safe" "Reliable"...etc., are all words used by manufacturers and retailers to lure you in to their client base. Safety and reliability start, and end, with you.

A motor boosting 14.7psi, with a static compression ratio of 10.0:1 will have an effective compression ratio of 20. (as shown) ((14.7 / 14.7) + 1) 10 = 20 effective CR

Now, can you see how there is no distinction between turbocharger, nitrous (as expressed as a form of boost), and superchargers? Your motor does not make the distinction. All your motor sees is static and effective compression levels.

The links below are a must read in my opinion. I'll label them for your interest...

Engine Managementhttp://www.automotivearticles....eid=6

Turbo INFOhttp://www.automotivearticles....eid=7

Injector Infohttp://www.rceng.com/technical.htm

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