# QR25 vs SR20 acceleration



## salimsaid (Jun 5, 2017)

Hello guys, i registered in this forum 2 weeks ago, i've already found ton of useful info. This is the most useful car site i've ever visited. There is a lot knowledgeable users in the site.

I currently own a 2005 nissan xtrail with a QR25 engine, I feel like the QR25 is a bit slow on getting from 0-80 km/hr, 
I really like the xtrail; i don't want to change cars so i am looking out to find a possible upgrade in power, 
I've heard people saying that the SR20 is more powerful than the QR25 and has faster acceleration.

Is is true that the SR20 can get from 0-80 km/hr much faster than the QR25 ? Should i swap out the QR25 with an SR20 ? is it worth it ?
And how about noise? is the SR20 as quiet as the QR25 ? or i should be expecting very loud noises ?


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## otomodo (May 23, 2008)

Everything is a question of budget. 

Is your xtrail manual or(zzzzz) automatic?
Awd or front drive?

By upgrading the engine, you ll need to upgrade the clutch,brakes,etc. 
Will your transmission handle the extra power?


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## salimsaid (Jun 5, 2017)

@otomodo , i dont mind buying another xtrail which comes with a factory fit sr20; if at all i will get better acceleration.


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## quadraria10 (Jul 6, 2010)

They were only sold in Japan as the Xtrail GT, and you would need to have one exported from there. Otherwise the QR25DE was the most powerful and fastest model compared to the diesels or QR20 gasoline versions.
Iridium spark plugs and premium fuel will give you a minor speed increase. Oversized tires will slow it down, and of course the health of your engine and transmission have an impact.


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## salimsaid (Jun 5, 2017)

quadraria10 said:


> They were only sold in Japan as the Xtrail GT, and you would need to have one exported from there. Otherwise the QR25DE was the most powerful and fastest model compared to the diesels or QR20 gasoline versions.
> Iridium spark plugs and premium fuel will give you a minor speed increase. Oversized tires will slow it down, and of course the health of your engine and transmission have an impact.


Now that i know the QR25 is faster than SR20 , maybe i should consider replacing my engine. The engine has already done 140,000miles or ~224,000km.

Thanks for your input.


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## MikeHJ (Mar 7, 2017)

There are tons of articles, websites and threads debating the pros and cons of the QR25 versus the SR20 engines. All I have ever got from reading some of them (not even most of them: my eyes glaze over) is that the QR25 is designed for emissions control and torque versus the SR20's penchant for acceleration and lower weight. Most of the debate is centered around the lighter nature of the SR20's rods, pistons and other components.

I don't think the debate is so much about which is the better stock engine as it appears that the stock QR25 is a clear winner, but rather about which has more potential after various modifications. In that case, the SR20 appears to have an edge.

But again, the debaters all seem to be track enthusiasts for whom an extra 5 horsepower is a big deal.

If I lived in the mountains or did a lot of towing, I'd probably care more. But I don't, so I don't


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## MikeHJ (Mar 7, 2017)

quadraria10 said:


> premium fuel will give you a minor speed increase.


I assume by premium fuel, you mean higher octane gas? If so, how would a non-high compression engine benefit at all?


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## X-hale (Apr 17, 2017)

MikeHJ said:


> I assume by premium fuel, you mean higher octane gas? If so, how would a non-high compression engine benefit at all?



Premium fuel is more expensive thereby lightening your wallet more. This gives your car a better power to weight ratio. Therefore you get better acceleration from premium fuel.
I'm using humour to avoid YET another fuel debate which I am personally sick to death of.


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## MikeHJ (Mar 7, 2017)

I was being polite. Premium fuel does nothing except in high compression engines. Octane is a measure of compressibility, nothing else. Most premium gas is regular gas with ignition retardants.

High compression engines generate more power from the same volume engine block by using longer rods to increase the piston travel. Because they "squeeze" the space above the piston at top dead center so much more, they require a fuel that does not prematurely ignite from the higher pressure before the piston head reaches top dead center. So they need high octane fuel or they will have deadly engine knock and run-on (dieseling). The fuel, itself, does not produce more power, it merely enables the engine to run higher compression without destroying itself.

A regular compression engine does not have this compression issue, so either fuel will work fine as both will merely be ignited by the spark. The only difference is price.


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## X-hale (Apr 17, 2017)

Yawn, I'm going to bed.
Drop an LS9 in it and you'll have acceleration!


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## otomodo (May 23, 2008)

salimsaid said:


> @otomodo , i dont mind buying another xtrail which comes with a factory fit sr20; if at all i will get better acceleration.


Have you heard about ecu flash?

They do it on pretty much everything that has an ecu. 
Maybe you can find someone who does it and remove some restrictions to help you reaching the desired 0 to 80 in a blink of an eye. 

I did once or twice a "drag race" with my friend on a 2003 chevy s10 v6 and i could see him not too much enjoying the dust he was eating. He never understood why there was no wheel spinning on the exxy at the start.


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## otomodo (May 23, 2008)

MikeHJ said:


> I was being polite. Premium fuel does nothing except in high compression engines. Octane is a measure of compressibility, nothing else. Most premium gas is regular gas with ignition retardants.


This would explain the price difference in various gas stations on premium fuel( i ve seen .30$ per litre.). 

A regular compression engine does not have this compression issue, so either fuel will work fine as both will merely be ignited by the spark. The only difference is price.[/QUOTE]

In your opinion at what compression ratio you start using higher octane fuel?

My yamaha 11,5. 1 regular gas
Toyota 13,0. 1 regular gas.


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## MikeHJ (Mar 7, 2017)

otomodo said:


> In your opinion at what compression ratio you start using higher octane fuel?
> 
> My yamaha 11,5. 1 regular gas
> Toyota 13,0. 1 regular gas.



You use the fuel your engine was designed for. There are a lot of design things that can be done to enable a higher compression engine to run on lower octane fuel (knock sensor, direct fuel injection, etc.) Some run 14+:1 on regular, others need high octane even at 12:1.

It's actually more common to find higher compression motorcycle engines that run on lower octane fuel. 

Of course, then you've got the whole ethanol blend fuel equations, so there's a lot of variables. Stock engines were designed to run on a particular octane rating, so unless you have made serious mods, use the fuel it was designed for. Of course, if you have made those mods, then you already know what is needed.

The "premium" fuel thing is really just marketing. If they called it "high compression gas", then only those who needed it would buy it. People have this perception that premium gas is "better" or cleaner or more efficient. Gas companies have to produce it for various vehicles and hey, if Joe Public wants to pay $0.30/liter more then they're not going to say no. And some companies do put a little more of their cleaning additives in their premium gas so they're not exactly ripping you off


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## quadraria10 (Jul 6, 2010)

Guys I am not saying it is a significant increase, but our engines do have a form of variable valve timing and adjustments are made according to octane. I guess we would need to see how its programmed but in my experience (and what I have read others have experienced) using top of the line Shell Gold gives you a bit more grunt at higher speeds and improves mpg a bit as well, but not enough to offset the increase in fuel price.


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## quadraria10 (Jul 6, 2010)

And if I may add, like Otomodo I have always found the X to be quick off the line. I also find that its ability to go from 80 km to 120 kms/h is pretty quick.


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## MikeHJ (Mar 7, 2017)

quadraria10 said:


> And if I may add, like Otomodo I have always found the X to be quick off the line. I also find that its ability to go from 80 km to 120 kms/h is pretty quick.


I find the same, but that 60-100km stretch is pretty sluggish.

There's an uphill onramp that I do fairly frequently where I really notice the difference between the Xtrail and other vehicles I've had (323south from Mont Tremblant, turning onto the 50W) A steep uphill semi-circular on ramp merging onto an uphill stretch. It's hard to accelerate much on the ramp since it is a tight curve, so you're only doing 60-70 by the time you need to merge with traffic doing120. When you floor it, the engine revs hit 5000, but nothing much happens.


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## otomodo (May 23, 2008)

MikeHJ said:


> I find the same, but that 60-100km stretch is pretty sluggish.
> 
> There's an uphill onramp that I do fairly frequently where I really notice the difference between the Xtrail and other vehicles I've had (323south from Mont Tremblant, turning onto the 50W) A steep uphill semi-circular on ramp merging onto an uphill stretch. It's hard to accelerate much on the ramp since it is a tight curve, so you're only doing 60-70 by the time you need to merge with traffic doing120. When you floor it, the engine revs hit 5000, but nothing much happens.


That s where a manual transmission gives you the advantage of being in the right power band when you need it. 

Have you tried turning off the overdrive before acceleration(at 60km/h)?

I used to do this when passing slower cars on the 148 and it worked very well for a quick pass. 

In a situation like this a turbo charged engine would give a better advantage, with a manual transmission,of course.


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## quadraria10 (Jul 6, 2010)

Now we have proof positive its always better to accelerate going downhill lol. And the manual gets to 100 in approx 9.9 secs, whereas the auto takes 10.3. But it occurs to me that not all of our engines are in the exact same shape and there are a number of things that can rob an older engine of some of its power. For example on MikeHJ's, maybe his fuel pump is not pumping as it once did, hence flooring it is not making much difference. And of course that is a pure guess and all could be normal. Mind you if the X was seriously hill challenged I doubt it would have been as popular as it was and is in BC.
So for the original poster, if I may suggest, have yours examined to see what may or may not be compromising its power.





Also with regard to the non GT 2 litre gasoline models-- they used the QR20DE engine that made 140HP


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## quadraria10 (Jul 6, 2010)

Mmm Just found this

2.5 AT / X-Trail / T30 / X-Trail / Nissan / Database / Carlook

They have the Auto 2.5 being a full 2 seconds slower to 100-- 11.9 secs vs 9.9 for the manual, and the 2.0 taking 13.1 secs in auto form.

The 11.9 seems a bit slow to me. Most other figures I have seen keep it around 10.


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## quadraria10 (Jul 6, 2010)

Actually here is a really good breakdown of the speed times for the 2.5 with auto and awd. 0 to 100 kms 10.4

http://www.automobile-catalog.com/auta_perf1.php

Kind of similar to with my experience of the X losing the ability to accelerate as quickly once you go past 130 kms/h.


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## otomodo (May 23, 2008)

quadraria10 said:


> Kind of similar to with my experience of the X losing the ability to accelerate as quickly once you go past 130 kms/h.


That s the drag effect. 
On a 150hp motorcycle, i can t red line it on the 6th speed. 

Now what for the guy?
Huge engine tune up?
High flow air filter? Bigger fuel injectors?
Dump the spare tire?


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## MikeHJ (Mar 7, 2017)

otomodo said:


> That s where a manual transmission gives you the advantage of being in the right power band when you need it.
> 
> Have you tried turning off the overdrive before acceleration(at 60km/h)?
> 
> ...


I've driven the road in countless other vehicles: some manual, some automatic, some turbo. My ski buddies and I own similar vehicles: smaller AWD SUV's with 2.4-2.8 liter engines and similar weights. Comparatively, the Xtrail is a little quicker off the line and seems to strain less @ 125-130. I just find the automatic transmission gearing less aggressive with or without overdrive and it shows in comparison.


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## Arinesto (Jul 18, 2021)

quadraria10 said:


> They were only sold in Japan as the Xtrail GT, and you would need to have one exported from there. Otherwise the QR25DE was the most powerful and fastest model compared to the diesels or QR20 gasoline versions.
> Iridium spark plugs and premium fuel will give you a minor speed increase. Oversized tires will slow it down, and of course the health of your engine and transmission have an impact.


I don't think you are right if u say QR25 is d most powerful because SR20VET is far much powerful than many Nissan engines. So i would advice you to look for xtrail GH-PNT30 not NT30


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