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The Great SR20 Vs QR25 Debate

The QR25 engine – is it really better than the SR20?

Some say no.

Some say yes. See below:

QR25 Turbo Kit
Turbo Kit – courtesy

The link to the item above is that of an eBay item:

Have you had your QR25 engine replaced recently? Maybe a while back? Nice engine or a dodgy piece of design?  The forums are full of dragstrip wannabes telling us of the pitfalls of the QR motor. Having read about thirty odd pages of drivel I was encouraged after reading an article about how brilliant the QR motor is and we all have nothing to worry about.  The snag is, much of the accolades were given by Nissan themselves.  I am a firm believer that the QR motor is indeed a better motor, possibly not equal to the SR for performance gains at relatively low cost but based on the very important fact that emission control kills engine performance and the QR engine is designed around emission control and quietness. The QR engine is also designed around torque – the X-Trail is a case in point.  Thinner connecting rods, lighter parts and with 4-cylinder balancer plus a rather high sitting top compression ring I have no intention of turbo charging this engine. Or would I?
Nissan QR25DE 2.5L Straight-4 DOHC Engine on 2007 Nissan Murano – courtesy Hatsukari715

I can get a brand new SR2 for U$1500. The repairs to the damaged cylinder of the QR cost about U$2300. Not something I want to talk about. While the engine was stripped I should have paid the extra and had a turbo fitted. Reason being that I could have made some money back if I had decided to resell or at least killed myself with a smile on my dial.  Back to the SR20. I note the campaigns against the QR. They have merit. Just like the old Ford V6 Essex motor which only stopped South African production in 2000. Yet, my friends, there are many older engines that we can boast about, going back to the 60’s and 70’s that proved themselves over and over again. While I know of many Toyota motors still running today after 40 years of service I must admit I never once thought of race tuning any Toyota motor that had two valves per cylinder.  Toyota was seen as the reliable force to reckon with, Nissan the young man’s street racer. Nissan had worse trade in value, their engines ran but their bodies died.  Toyota Camry is a case in point. 500 000 to 600 000 miles and going strong is a common occurrence. Nissan’s don’t carry this mileage only because I think in many cases they are used for purposes other than the original design intended. I won’t knock Nissan, I won’t knock the QR motor either. Under standard driving conditions and the cat doesn’t decide to flake on your older model they should see many miles of useful service. Unfortunately most of them don’t. The negativity on the forums covering these motors is a case in point. The newer engines don’t suffer from the same issues as the older versions.  Nissan did have recalls to remedy the situation. No finger pointing.  So just where are we sitting then?

The QR25DE motor was not designed to have enthusiasts dipping into their wallets to hit the race track. It can be done though if you don’t mind reading:  Extreme Engine Tech: Jim Wolf Technology’s Turbo Nissan QR25DE Powerhouse Part 1.  Let’s get this straight, Nissan built many great cars and continue doing so today. They also built the GT-R. If they built something for racing you’d know about it or your neighbour will at least tell you if you didn’t, that’s how popular Nissan is. I don’t recall reading one article that boasts of the QR motor being phenomenal for race-tuning. What we do know though is that looking at low revving engines you can be rest assured they will have been designed more around torque. If you build something around low end torque we aren’t talking Formula one racing. Drive a car with an SR motor and the first thing quite apparent that they rev much higher, they pull harder at high revs and feel like they are powered by a performance motor.  The QR motor pulls up a 2Km stretch of hill which I believe is about 30 degrees inclination without dropping from 60mph in 5th gear.  It is quiet. You can feel the power. The SR2VET is noisier and thanks to the over square design makes it feel like a performance vehicle. (modified Pulsar). A twenty year old won’t like the QR motor. Neither a 60 something petrol head.  My QR accelerates very rapidly at 4000 RPM in third. No, I lie – it really chucks.  But there is no comparison between the QR and the SR2VET at 6000 RPM. But there is also no comparison between the two engines – again, is it torque versus performance?  If the SR2VET is so much better why don’t they put that into the X-Trail? In fact they did, Japanese models, the X-trail GT came out with the SR2VET turbo charged motor. Why not a turbo charged 2.5L QR motor?  Compact SUVs are not made for cornering at high speed so if the intention is to show other road users your slickness from robot to robot, then fine. As long as the robots aren’t separated by dangerous curves. For this one we need to speak to the Top Gear clan because it makes no sense.

Having a look at Jim Wolf Technologies mods on the QR and their complaints about certain aspects of the QR motor I think our petrol heads have a reason to complain. If you are a 45 year old (or older) driver, there is no merit. The QR motor has proven itself besides the earlier CAT problems (expensive).  If you want durability go the 2.2L diesel route or upwards. I don’t know why Nissan dropped the power of the QR motor from 2006. I also don’t know why they would want to put the turbo charged SR2.0L VET motor into a compact SUV.

Back to the beginning: The QR motor nowadays is a great motor. Looking at the forums, I cannot agree with most of what has been said. The SR motor proved itself – cheap and easy to modify. At the time of print I don’t see a comparison as yet, the SR motor is still the petrol head’s motor.  Nissan in many ways may have a huge disadvantage against our expensive players in the field, Porche, BMW and other exotic animals – but where they lack in snob value the one thing that is abundantly clear, they have good engines and modifying these engines dollar for dollar they beat a lot of these snob value cars hands down.

Oh yes, the turbocharged modified QR25 did prove the petrol heads wrong. That’s where American muscle cars show their worth – low revving locomotive pullers.



5 Replies to “The Great SR20 Vs QR25 Debate”

  1. Your article is based on a few assumptions. Nissan didn’t make the QR25 motor NOT to deliver more power. That’s what sells motor cars. Nissan is not necessarily the favored car to race tune. I love Nissan but the Honda Civic is the better deal and this is not based on thumb sucking neither the movies. The QR25DE as you mention is limited because it is a long stroke engine – the Sentra Spec-V is a good place to start. Honda, well just look at their pedigree.

    1. That’s why we have the Wolf and link. If you read the article it’s definitely not favourable to the QR motor. In fact my research still show that the SR motor is way better for mod and tuning, is less like to fail catastrophically and internal components are designed just for that purpose, modify and race. Many of the complaints come from die-hards. The SR still wins many races – the QR loses points because it is a long stroke, turbo the motor but don’t forget the revs – the balancer is not needed and well, it has to be sleeved. That’s about racing though – modern times call for modern technology. Tough calls through legislation don’t offer manufacturers much option otherwise we’d still be racing two strokes. This article is actually written in favour of the QR, not against it. For racing though, stick to where they belong – endurance. There again though, maybe the SR is a better bet – tried and trusted. The internals of the motor are no different from any other engine – it’s just stroked differently. Definitely stock standard not a racer by any means. Nissan make good engines, time has proven this. This one though had just too many expensive teething problems, not all blames on design – the cat was one. And yes, Honda design is often around racing. Just like Toyota / Lexus and the use of Yamaha technology. The QR motor has a very broad power spectrum – the engine feels powerful, thanks to the low end grunt and for modern driving (and cheap) they are excellent for their designed purpose. Not high performance, tyre screaming robot to robot, shit yourself stuff. Then I stick to the SR motor.

  2. The QR motor is not as bad as we are lead to believe. I have worked on Nissan engines for the last twenty years and like all engines it has it’s quirks but it IS a reliable motor – ensure it gets serviced regularly and don’t turbo it without doing the standard changes i.e. drop compression ratio, change crank and con-rods, ECU and possibly cams. Another thing, long stroke engines do get turbo-charged: look at truck engines :-). MotoGP has a bore limit of 81mm so you may end up with a long stroke design. This is where transmissions, clutches and a host of other things come into play. The main difference between strokers and big bore is the ease to drive a stroker. Look at any diesel. Round about town driving, long distances I’d go stroker any day. So don’t be put off by the hype. Nissan engineers aren’t fools.

  3. You had an article on this website on the old 750Z, a Kwacker twin – that was a typical stroker. Nothing worse than riding a bike 150 miles with an engine sitting on 8000 RPM at 80 mph. Harley doesn’t bring out high revving cruisers for this exact reason. Comfort to the ears.

  4. Besides the QR issues with earlier models it is an excellent motor. Fiddling with the dynamics of these motors you need to know a LOT about motors, like any car engine. The engine is designed to be light and torquey. That’s a feather in Nissan’s cap. You cannot slap a turbo in it unless it was designed for it. Most petrol/gas engines are not. Modern driving to cover all environments also calls for more low end torque – at least to my mind. Of course you need to know the age group you are aiming at as well. The X-Trail was ahead of it’s class when it came out – put that down to the engine design. Lots of low end torque. A colleague bought a RAV. After driving the X-Trail he realised he had made a mistake – Nissan had done something right. The X-Trail also had the more HP. No, don’t knock the QR motor, the design wasn’t around street racing. Neither for slouching.

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