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How to Build a Nissan SR20DET

300zx, Cheap Insurance, ECU, Head Gasket

Building a fast Nissan SR20DET powered car can be quite exhausting when your dealing with several hundred moving parts and thousands of electronic wires. But, it doesn’t have to be that hard if you’re properly informed before you begin purchasing parts and building a mean machine. We’ll be discussing the components necessary to build a moderate horsepower S13 or S14 chassis Nissan 240sx with a Japanese domestic market SR20DET engine swap. The engine that we are talking about today is the Nissan SR20DET, a more than capable all aluminum 2.0 liter four cylinder gasoline engine that has the potential to make some serious power levels if properly tuned and equipped. We are going to assume for this article that you already have the car and have already carefully swapped in a fresh JDM (Japanese domestic market) Nissan SR20DET and that all the mechanical components and wiring have been appropriately and tastefully installed giving us a nice clean platform for us to work with to make massive power gains.

You may be wondering why it’s necessary to make more power than what you already have, you could be making anywhere from 205whp to 250whp with a boost controller on a SR20DET. Why? Because you can never have to much horsepower, it’s like having too much money or too many good friends. We need those power levels in case we need to use them, I’m not saying you should race that supercharged Cobra that rolls up next to you on the street or even condoning street racing for that matter, but lets just say you go to the drag strip and everyone’s there watching you in your little import. If you live in a town of rednecks and domestically dominated power plants your going to want to show off what your little “SR20DET rice burner” can do with more technology and four less cylinders; not to mention the cost effectiveness of the build compared to a domestic and the cash you’ll be saving at the pump.

In this article we will be going over the parts necessary and companies you will need to involve to overhaul your tame four banger into a fire breathing monster. So, lets get down to the meat and potatoes of it. First things first your going to need engine management to accommodate your power increases. This should always be the first modification you make, your going to need new fuel injectors, a high powered fuel pump such as a single or double high pressure Walboro 255; in addition to these two fuel mods your going to need to have some additional electronics. You’ll need to swap out you ECU (electronic control unit) and your MAF (mass air flow sensor) with aftermarket units. Depending on the amount of power your attempting to make out of your SR20DET you’ll need to come up with a game plan right off the bat to decide what your horsepower level intentions are really going to be. What ever you do decide make sure to add an extra fifty horsepower on to that because I’m telling you right now you’ll only be satisfied for a short time before your power levels become boring and you thirst for more. Horsepower and speed are like drugs, the more you get the more you want; so try and also be realistic about you goals, if this is a daily driver your going to want to keep your power levels under about 400whp to stay on the safe side. It is known that the robust Nissan SR20DET has taken as much as 530whp in it’s stock internal form with the only upgrades being forced induction and fuel delivery. But, keep in mind 400whp is nothing to scoff at especially given the light weight nature of the platform we’re using. Your SR20DET powered vehicle will have a very optimal power to weight ratio, but on a note of caution these cars have a short wheel base and can get out of control very easily with the back end scooting around at high speeds, there isn’t very much weight back there to keep the rear of the car on the ground. As I go through this article explaining parts and modifications needed I will be including a list of links and facts needed with part numbers and horsepower levels indicated at the end of the article.

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So what are your options for injectors, maf, and ecu? Well, there many options out there, but we’re only discussing tried and proven methods of gaining horsepower. Stock Nissan SR20DET fuel injectors are measured at 370cc and are what’s known as high impedance side feed injectors. You can only use high impedance side feed injectors unless you are changing your fuel rail to utilize top feed injectors, but we’ll get into that in a moment. A typical Nissan fuel pressure regulator operates at what is known to be a 3 bar system or 44psi of fuel pressure. It can however run at a higher level which will make the power threshold of your fuel injectors a little higher with an aftermarket fuel pressure regulator, this is known as 4 bar or 59psi. Your stock fuel injectors on your SR20DET are only good up to 250whp before they run out of steam and become overworked, on the flip side if you were using an aftermarket SR20DET regulator and turned up the fuel pressure to 4 bar you could get approximately 290whp out of them. If your beginning to catch on, fuel pressure is a trick to get more out of your expensive injectors; and injectors can be very pricey, but your just going to have to bite the bullet and get them. You don’t want to fool with any so called SR20DET Ebay injectors that are not of a known reputable brand.

These injectors are crap and they’re still expensive so stay clear of those, your looking for brands like Sard, Nismo, Tomei, and MSD or other stock and after market injectors that I will mention at the end of this article. There is an alternative to expensive side feed injectors they are called top feed, for this example we will be using proven MSD brand injectors, although they are cheaper they will require a new top feed fuel rail and new injector resistors because these injectors are low impedance and will need to be converted to make use of them. MSD injectors and rail can be found at www.jgycustoms.com as well as many of the other SR20DET products I will be mentioning. However, an SR20DET compatible maf sensor is something you will most likely be able to find at a local junk yard or on Ebay. There are many different kinds of stock Nissan maf sensors that can be used on the SR20DET for a variety of horsepower levels, anywhere from 250whp to 600+whp. These maf sensors come off of fairly common cars too and I will again mention them at the end. So, you’ve picked your maf sensor and your injectors, now what ecu are you going to use. Well, you could use the stock Nissan SR20DET ecu and piggy back onto it with an auxiliary fuel management system such as an Apexi safc or Greddy E-manage, but even though these systems are affordable to get and easy to obtain they can be very difficult to tune by a novice. So it is recommended that if you go the cheaper route that you take it to a dyno to be tuned by a professional, in the end after paying a few hundred dollars for the dyno service and the headaches of wiring and soldering in a system you might have been better off using a preprogrammed ecu such as Jim Wolf Technology or Enthalpy offers.

These ecu’s are simple to install and have already been flash tuned to work in conjunction with the fuel and metering components that you have installed; but a word to the wise, call them first to hear what their suggestions are for your intended setup. These companies have years of experience and their knowledge and advice should not be taken lightly. Their main intentions are for you to not only buy their products, but to also benefit from them with the power and drivability goals that you have in mind. For first timers I always suggest the usage of a “plug and play” preprogrammed ecu. These ecu’s are not cheap on the flipside, but they are very comparable in price to auxiliary ecu’s after purchase and tuning. I have used these types of ecu’s for years and have no complaints nor have I ever had a problem with them.

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Now you have your fuel management ironed out it’s time to select a new turbo and intercooler that will support your choice of power levels. Pushing the tiny factory T25 turbo to it’s limits with excessive boost that it was not designed for is not only a bad idea, it can be harmful to your turbo and engine. By the compressor and turbine spinning at speeds that it was not designed for it can create shaft play and oil leaks from the seals on the turbo, not to mention the possibility of detonation in your engines combustion chamber. Pushing the puny factory turbo to it’s limits will not gain you more than a net of 245-255whp so you should make the conscious decision to upgrade your turbo with in accordance to your power goals. There are many different types of turbos out there and they can vary dramatically in price. Your going to want a turbo that has good spool characteristics and will meet your power needs at the same time. They say that bigger is better, yet with turbos this rule does not apply. You want a properly sized turbo that will work in conjunction with your ultimate power goals while still providing drivability and minimal lag. The bigger the turbo the more lag you will discover. Nissan SR20DET’s are not an engine that revs very high even with bigger camshafts (which we will get into later); So, your going to want a turbo that spools (comes into it’s power range and max boost) quickly and efficiently. For an SR20DET powered street car that you may be doing some occasional drag racing with and possibly some drifting I suggest a smaller turbo such as a Garrett GT28R or GT28RS that will make gains up to 300whp and 340whp respectfully, while still providing reliability and optimal efficiency.

These turbos offer little to no lag when compared to their little brother the T25. For a slight increase in power and a few hundred rpm’s more of lag I suggest the GT2871R which is good up to 440whp on a stock SR20DET, these turbos are T2 flanged so they are made to be direct bolt on replacements to your factory exhaust manifold and they are designed with ball bearings so that they spool up quick and have added longevity when compared to a typical journal bearing turbo. These turbos are great for moderate drag racing and can get you into the mid to low 12 second range and depending if you go with the larger GT2871R you may be able to see times in the high 11 second range. If your looking for more power than this then your more than likely going to have to step it up to big brother of the T2 flanged turbos, the T3. This will require a new exhaust manifold that will accommodate the different flange and bolt pattern. Some T3 flanged turbos can increase your power levels up to +/- 640whp such as the GT3582R ball bearing turbo. If your ego and your wallet compel your thirst for more power than this not only are you going to have to have some serious accommodating engine mods; but you will have to step it up to big uncle, the T4 framed turbo. When turbo sizes increase, so will the need to efficiently cool the air charge. A link to a companies with good intercoolers will also be provided at the end of this article.

At power levels over about 450whp with an SR20DET your going to need to build the internals of your engine with pistons and rods, a new multilayer or metal head gasket, and an upgrade to your valve train with camshafts. I suggest for the SR20DET bottom end internals that you use Brian Crower components because they are of high quality and offer an affordable price tag. You could stroke the engine with a bigger crank if you choose for more torque, again for the crank and rods I would use Brian Crower; as for pistons the affordability and quality of CP Pistons one can’t go wrong. For the SR20DET head gasket I would choose a Greddy or Cometic. Now into the valve train, depending on the size of your turbo and it’s power range the type of camshaft you will select will be directly linked. Big turbo, big cams…Small turbo, small cams. Very simple concept. The bigger the cams go at some point you will need stronger valves springs and lighter retainers to avoid valve float (a condition where the valve dwells in the combustion chamber too long and gets struck by the piston as it comes to top dead center or TDC, which can be a common occurrence on the SR20DET).

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As your power increases so do the temperatures inside your combustion chamber, even though the exhaust valves on a Nissan SR20DET are sodium filled (which helps to cool them) this will not be enough of a precaution to prevent against burning a valve. Again I recommend Brian Crower for stainless steel valves. Also, as a note; when using bigger cams and high reving an Nissan SR20DET your going to want to use some kind of rocker arm stoppers, these are inexpensive and will prevent your rocker arms from falling out of place if you over rev your engine such as missing a gear. They’re just cheap insurance, because putting your rocker arms back in place on the side of the road can be an exhausting experience. Now you have all the major components of a high horse power Nissan SR20DET build, with a little more research on the internet for complimenting parts such as intake manifolds, throttle bodies, different clutches to hold the power, flywheels, lightweight accessory and crank pulleys, blow off valves, drive shafts, rear differential gears, and not to mention suspension components you will have all the necessary parts to make gobs of power. Below is a general list of components and websites mentioned in this article.

NISSAN MAF SENSORS and horsepower potential for the SR20DET

Stock sr20de maf (91-99 200sx se-r/ Sentra se-r) #53j00-01 (50mm)
Stock sr20de maf (00-01 Sentra se)
Stock vg30de maf (95-98 Maxima)
Stock vg30de/vg30dett maf (90-96 300zx NA and 300zxtt TURBO) #22680-30p00
Stock vg30de (90-99 Infiniti J30) #22680-30p00 (75mm)
Stock vh45de (90-94.5 Infiniti Q45) (90mm)
Stock Ford Lightning Supercharged maf
*Anything more requires the usage of a map sensor and stand alone management
FUEL INJECTORS and horsepower potential for the SR20DET
*Nissan injectors for s13 and s14 sr20det are all side feed
370cc stock purple top sr20det injectors
(3 bar) 250whp (4 bar) 290whp
444cc stock S15 SR20DET injectors
(3 bar) 299whp (4 bar) 345whp
520cc yellow Subaru STI injectors
(3 bar) 348whp (4 bar) 400whp
601cc yellow Tomei injectors
(3 bar) 405whp (4 bar) 457whp
740cc red injectors
(3 bar) 500whp (4 bar) 580whp
850cc side feed Sard
(3 bar) 570whp (4 bar) 660whp
* MSD injectors do not operate at 4 bar so don’t even try it

T2 FLANGED TURBOS and horsepower potential designed for the SR20DET manifold

*R designation at the end of the part number means dual ball bearing
T3 FLANGED TURBOS and horsepower potential
GT35 (inexpensive)–600whp
GT40 (inexpensive)–650whp
Links to products, services, and information for the SR20DET
SR20DET information database
SR20DET Information database
SR20DET parts and accessories
SR20DET Plug and play ecu’s
SR20DET Plug and play ecu’s