We used the head bolts and main girdle bolts from a and later QR25DE as they are stronger and have a higher torque. We also used the intake manifold from a Rogue. The Rogue manifold has a larger plenum than the old style intake manifold.
It is made of plastic so we are a little worried about how it will hold up to boost but we will try it. We had to slightly modify the head mating surface as the bolt pattern is slightly different. The late model main girdle bed plate bolts were also used, these are stronger as well.
When the engine went together we replaced the heavy front pulley with a lightweight billet aluminum one from Unorthodox Racing which takes about 3 lbs of rotating weight off of the front of the engine. We also used an idler pulley and bracket from a non air conditioned and later Altima so we could eliminate the air conditioning in a sano way. The Unorthodox Racing pulley is machined out of billet aluminum and is 3 lbs lighter than the heavy stock steel part.
Since the long stroke QR25DE does not like high rpm, we have chosen to limit its maximum revs to rpm and make power by adding turbo boost. In our experience, it is difficult to get front wheel drive cars with more than wheel hp to be able to use the power without excessive wheel spin under road racing conditions. In a front wheel drive car, lots of wheelspin quickly overheats the front tires and leads to severe understeer, a condition to be avoided at all costs. To win will take a lot of horsepower.
We are going to target whp with boost mapping to keep wheelspin down in the lower gears. An idler pulley from an Altima without air conditioning allowed us to remove the air conditioner compressor. After these mods, most of which were designed to help reliability, our attention is now turned to the turbo system.
Stay tuned, for our next installment.
It is the same as QR20DE , but new crankshaft with piston stroke mm was installed into cylinder block. Deck height remained the same, mm. Also the engine has mm connections rods and pistons with dish, their compression height is 32 mm.
All that let increasing engine displacement to 2. Cylinder block remained the same. Cylinder head is also the same as on QR20DE. This engine does not use hydraulic tappets, so every 60, miles of mileage 90, km you should regulate the valves to avoid appearing of irritable ticking noise. Also QR25DE uses individual ignition coils and electronic throttle body. As it is peculiar to many large 4-cylinder engines, QR25 also has two balancer shafts, which let the engine working smoothly and diminish vibration.
In QR25DE was upgraded. Intake manifold and pistons were modified, connecting rods were reinforced, balancer shafts were somewhat moved. Also camshafts were somewhat updated, redline was raised and some more insignificant novelties happened yet. Its compression ratio was increased to It uses new pistons and compression ratio is reduced to 9. Besides, 20 HP electro motor was installed on that engine. Nissan QR25DE engine problems and malfunctions 1. Idle problems, jerking. More likely your QR25DE timing chain has stretched.
It often happens on the very first generation of the engines. You need to change timing chain and usually it solves the problem completely. Oil leak. Usually valve cover gasket is leaking. Upon changing it, everything will be all right. High oil consumption. If your oil consumption exceeds 1 qt. It may need overhaul. Fuel injectors and throttle body require cleaning. QR25DE vibration.
It mainly happens because of lame soft ECU, it must be changed. Yet the spark plugs may be the reason, perhaps they have expired. Anyway, it is hard doing it. If the engine was produced till , catalytic converter may fail often. It happens because of lame soft ECU also. It gave a lot of fuel, and burning down in catalytic converter, it promoted its quick destruction. Also thermostat on QR25DE does not have long lifetime, and when it fails, the engine may overheat.
Service life of QR25DE is about , miles of mileage , km at general exploitation by common person. Is QR25DE a good engine? Having compared it with KA24DE, it is evident that QR25 has become more modern and producible, but along with this, it has many shortcomings. While old KA24DE is not that perfect, but thanks to its simplicity, it is rather reliable and durable. QR25DE engine number location It is on cylinder block on the tablet to the right.
Anyway, if you have decided to increase the power of your engine, you will need to purchase some performance parts. When you install everything, it is necessary to adjust ECU. These upgrades let gaining horsepower, nice sound and quite good dynamics. If you purchase QR20DE pistons, compression ratio will increase to It is the reasonable limit, it would be rather expensive to exceed it. QR25DE Turbo. It is not all that simple about it. Stock engine is not suitable for the boost at all, and also connecting rods are quite weak, and pistons may burn through easily.
Therefore you will need forged internals. Buy connecting rods Crower It would also have a sense to install oil nozzles for cooling pistons. Or you may buy QR25DE turbo kit at once, it may be easier.
Unnecessary vibrations are also noticeable in the QR25DE. These vibrations pose serious harm, especially to the moving parts of the engine.
QR25DE Engine Problems and Specs
This happens mainly due to lame soft ECU, which needs replacement. Spark plugs might also be the reason because faulty spark plugs cause the pistons to move more aggressively as they keep on pumping and pumping. QR25DE engine also has little to no resistance to cold weather regions as they find it hard to start up in conditions below -4 Fahrenheit. This is maybe due to damp, frozen spark plugs that affect its burning or sparking capabilities.
Catalytic converters are often faulty, which burns a lot of fuel.
Extreme Engine Tech: Jim Wolf Technology’s Turbo Nissan QR25DE Powerhouse Part 2
Thermostats are essential indicators of operating temperatures. If they are faulty or broken, it dramatically affects the engine performance as you keep treading on murky waters because you have no idea of the working temperature in the engine.
If not adequately replaced, that results in an engine overheat and eventual failure. Summary The QR25DE engine has its fair share of good and bad sides; it has shortcomings and lacks in some departments. But we cannot erase the fact that this engine is modern with its features such as lightweight materials, counter-rotating balance shafts, and many more. In our experience, it is difficult to get front wheel drive cars with more than wheel hp to be able to use the power without excessive wheel spin under road racing conditions.
Nissan QR25DE: Everything You Need To Know
In a front wheel drive car, lots of wheelspin quickly overheats the front tires and leads to severe understeer, a condition to be avoided at all costs. To win will take a lot of horsepower. We are going to target whp with boost mapping to keep wheelspin down in the lower gears. An idler pulley from an Altima without air conditioning allowed us to remove the air conditioner compressor.
Larger QR25DE valves, getting 3 or 5 angle valve jobs and porting and head flowing will also increase bhp and torque, and more importantly will raise potential for an improved bhp and torque increase on other tuning parts. The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes significant power gains.
When the engine is fitted with a turbo upgrades are going to make more power and you will discover turbo charged engines are made using better components.
Nissan QR25DE Tuning
There are practical limits for every engine, with some being over specified and some just sufficiently able to handle stock powerWe recommend you find these limitations and upgrade to more solid crank and pistons to survive the power.
We see many car owners spending a a stack of money on turbo upgrades on the QR25DE only to have the car explode on it's first outing after it's been finished. Bigger capacity turbo units commonly experience a bottom end lag, and little turbo units spool up much more quickly but do not have the peak rpm torque gains.
Thankfully the world of turbochargers is always improving and we now see variable vane turbochargers, where the vane angle is altered according to speed to lower lag and increase top end performance.