Follow our nine step SR20 tuning guide to achieve peak engine performance.
Welcome to our SR20 tuning guide. This guide contains nine tuning tips that when implemented correctly should have your SR20det running at peak performance.
You should consider that running your SR20det at higher power levels will require upgrading to a stronger clutch and possibly a stronger gearbox. The Nissan 350z gearbox is a good candidate for a swap.
You will also need to look into cooling, an upgraded radiator and higher pressure radiator cap will help to keep engine temperatures down. It is also widely recommended to retain the standard viscous fan and fan cowling.
Please also bear in mind that I am an enthusiast, not a professional. I am giving this advice in good faith, if you run into trouble always refer to a specialist garage. Now on with the tips!
My tuning philosophy is pretty simple; I think of the engine as a giant air pump. Air comes in through the air intake, it is compressed on its journey by the turbocharger and then the waste is shot out the back by the exhaust. My approach to obtaining more power is to increase the amount of air coming into the engine, increase the air density by upgrading the turbocharger and to decrease the air flow restrictions of the exhaust system to allow waste to get out as quickly as possible. These nine tuning tips aim to achieve this whilst also keeping your engine running safely.
The first SR20det tuning tip is to upgrade the engine’s air intake. Factory air intake systems are designed with dual purpose; to filter dirty air and to restrict intake noise. An aftermarket performance air intake system is going to be focused purely on getting as much clean air into the engine as possible at the sacrifice of increased levels of intake noise. There are many aftermarket air intake systems available for the SR20det and many of those have lofty power claims. I would take those claims with a pinch of salt.
The MKIV Supra forum published an interesting article testing four different premium air intake kits on the same 2JZGTE, although it is not an SR20det and the figures won’t add up you get a good feel for which filters perform the best.
If it was my money I would pick the APEXi Power Intake. I have used this air filter on my own cars in the past and I have always been happy with it. Unlike the foam filters this is also washable.
As the name suggests the Mass Air Flow Sensor is a simple device that measures the volume of air coming into the air intake, this information is relayed to the car’s ECU so that the correct air / fuel mixture is set. The original SR20det was built to produce 200bhp at the flywheel, the engine used a Mass Air Flow Sensor with generous headroom all the way up to 300bhp however to hit our goal we are going to need to look at the SR20det’s older brother for parts.
A Nissan 300zx Z32 model Mass Air Flow Sensor should be perfect to support our targeted power level and a brand new Z32 can be found here. Another option is to ditch the Mass Air Flow Sensor entirely and go with a MAP sensor setup, this will do away with the ugly looking MAFS but I don’t really see the need unless you are going for seriously high power figures.
The third SR20det tuning tip I have for you is to ditch the stock intercooler and replace it with a large front mounted intercooler. An intercooler is designed cool the air charge – the cooler the air charge, the denser the air, the denser the air the more efficient the combustion cycle. By replacing the standard intercooler with a larger unit and placing that behind the front bumper (rather than in the wing like in most s-chassis) means more airflow to the intercooler and that means better cooling.
Which unit you choose depends on your budget but in my own 180sx SR20det build I used a huge BLITZ Type SE FMIC, it is on the pricey side but it did a great job. There are plenty of cheaper alternatives on the market.
The fourth tip to building your SR20det into a true bad ass is to replace your standard fuel injectors with larger ones. Different generation SR20det’s came with different sized fuel injectors but if you want to turn up the wick on the power then you will want to increase the displacement of your fuel injectors. Standard fuel injectors will work fine with the turbo boost at a stock or at slightly increased levels however to double your engine power you are definitely going to need to increase the size.
A set of four 550cc fuel injectors should do the trick. You can go even bigger in size for safety and future power headroom and just instruct your tuner to turn down the fuel duty cycle for now. The FiveO 550cc fuel injector set should do the job. I haven’t personally used FiveO before but they seem to get good reviews.
Your car’s standard fuel pump has been around for at least 14 years (in the case of a late model Silvia S15) so it is probably due a replacement anyway, an engine leaning out from fuel starvation is going to go bang. In our scenario – with the lofty goals we are aiming for you definitely want to upgrade the standard fuel pump with a larger, higher capacity unit.
A pump that is flowing more fuel is going to provide a lovely, high pressure fuel stream to feed your larger fuel injectors. These two supporting modifications are going to allow you to safely increase the turbo boost pressure. A good example is a Walbro High Pressure 255 ltr/hr in tank fuel pump.
Like the factory air intake your standard exhaust system is designed as a compromise between providing performance and keeping down the sound level. An aftermarket performance exhaust system will offer increased pipework size and crucially less bends and obstructions to ensure that the exiting engine waste can leave the exhaust as quickly as possible.
As for which system to get you have a huge selection of exhaust systems on the market to choose from. For my choice at a reasonable price level I would pick the APEXi N1, this system has been around for a long time and is a proven performer for a reasonable price.
Our sister site the 180sx Club has written a detailed exhaust guide listing many of the currently available exhaust systems for the Nissan S13, S14 and S15. The guide also includes pictures and videos of each exhaust system so you can get a real feel for the exact look and sound that you want.
The turbo charger is the most complex and the most expensive item on our SR20det tuning tips list. There are so many options, trim levels and intake sizes, exhaust sizes etc that can be selected I would bore you silly trying to cover it all. So let’s keep it really simple; our goal is to as easily as possible produce a solid 400bhp-ish at the flywheel so I would stick with a T2 flange. This means that we can reuse the standard exhaust manifold and fittings and just swap out the turbo charger unit itself.
To produce our power output without an excessive amount of turbo-lag I would suggest a Garrett GT2871R turbo charger. Garrett are one of the most well respected turbo manufacturers and the GT2871R is an ideal pairing with a properly supported SR20det. This turbo is both oil and water cooled and should last you a long time. Garrett parts are also readily available if you ever need to service the unit.
Now that all the supporting modifications in place on the intake side, the fuelling side, the turbo charger and the exhaust side we can look at increasing the boost level. In order to do this an electronic boost controller is the next item on our shopping list. By replacing the standard restrictive boost controller with an aftermarket item we can control the turbo charger boost pressure level from inside the cabin. An attractive control unit will be fitted inside the cabin, normally around the dashboard area and this can be used to set the boost level.
Alongside setting the boost pressure level most modern boost controllers feature a ‘Scramble boost’ setting, this setting is designed to spike the boost for a short amount of time, useful for performing an overtake.
You can probably see that I rate APEXi highly and so it continues with my boost controller choice; the APEXi AVC-R Black is a solid choice. It is a smart and compact machine that is packed with features. Cheaper alternatives are available.
Everything is now in place to double your SR20det’s power output, all that is left is upgrading your car’s ECU and getting it professionally tuned. Standard ECU’s are tough to work with and on some cars require soldering on a chip that contains the custom tuning ‘maps’ which are needed to run your new performance components at their optimum level.
A replacement ECU such as an APEXi Power FC is a plug and play unit that neatly swaps with the standard ECU. This ECU can also use a ‘Commander’ which is a cool little gizmo that you can mount on your dashboard to monitor vital engine statistics, temps, revs etc and also if needed you can create tunes on the fly.
Now that the ECU is in place it is time to find a local tuner. Tuners can be good and tuners can be bad so it really is worth searching around your relevant local owner clubs and find threads recommending a tuner that is familiar with the SR20det. All of these fantastic aftermarkets parts will come to nothing if the tuner you select does not know how to safely tune a car. I am based in the United Kingdom and I have always used the London firm FC Tuning for all of my ECU tunes.
Drifted is not sponsored by FC Tuning, they are simply my personal preference.
With all nine steps of our SR20 tuning guide followed and a healthy base engine you should be looking at the thick end of 300bhp at the flywheel. Further than that your engine should also be putting out some ferocious torque and that is the ‘shove in the back’ that you really feel. Tuners have built SR20det engines to hit even bigger numbers then these but to do that safely they will need to replace internal engine parts with upgraded items (such as pistons, rings, con-rods etc).
There are many other parts to help you get to the 400bhp figure that I haven’t mentioned including aftermarket camshafts, intake and exhaust manifold upgrades, cylinder head work etc but with many of these you will need to open the engine. You could also go down the route of Nitrous Oxide.
What do you think of my tuning tips? Have you broken the 400bhp barrier yourself? Please let me know in the comments below.
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