QR25DE Engine

(Difference between revisions)

Revision as of 07:06, 25 June 2012

The Nissan QR25DE engine is the replacement for both the KA24 and SR20. It is more powerful than the SR20, yet lighter than either. It will make a nice swap into a Datsun 1200.

Will you be the first to fit one of these beauties into a 1200? They've been on the market six years now ...

QR25DE Engine

QR Series Overview

The QR design is similar the superb Cosworth BDA 2-liter engine but much much improved for naturally aspirated (non-turbo) setups. Features Micropolished crank, 152.9 mm rods (136.3 mm sr20 very poor 1.585 stroke ratio vs 1.9 for the QR20) and short piston pin height, BDA style valve actuation, s2000 style ladder sump with mains, bigger bore, shorter stroke, smaller more compact thank to the lighter pressure die cast rather than sr20 sand casting process and it has so many other things going for it.

I has 150hp base but with proper exhaust, induction 15hp is freed and removing the counter balance shafts another 10+ hp. That's 175-180hp without a sweat and with the right mild custom cams and ecu another 40-50hp is available even more with more aggresive cams.

Horsepower

200hp from a stock Sentra/Altima engine?

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quote:The cylinder head ... flows exceptionally well--better than any SR20

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Compare to the SR20DE in the SE-R Spec V at "only" 175hp. The run-of-the-mill QR25DE in all Sentras makes 170hp. The SR20VE (Neo VVL) only makes 187hp.

CVTC (Constant Valve Timing Control) varies cam at all times, which is better than the Nissan SR20VE or Honda VTEC -- which only has two positions.

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the new enigne is 13 percent lighter than the SR20DE and ... 30mm shorter

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Features

• 132 kW/180 ps @ 6000rpm
• 181 lb. ft. /245 Nm @ 4000 rpm
• 9.5:1 compression
• direct ignition (coil-on-plug)
• sequential Multi-point EGI (EFI)
• variable cam timing (37 degree range for intake)
• twin balance shafts
• drive-by-wire throttle body
• dual intake runners
• non-rising rate fuel pressure

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The QR25DE was designed to eventually replace both the SR20DE and the KA24DE ... light and powerful like the SR20, and fuel efficient and torquey like the KA24DE.

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pic

Fitments

Used in:

• 2002 and up Sentra
• 2002 Altima
• 2000 and up X-trail (not sold in USA)
• Presage (minivan)
• Bassara
• 2005-up Frontier Pickup (RWD)

You could either use the entire wiring harness and throttle (try to buy a whole car). You may need a key unlock on some models.

or

1. Adapt up an EDIS distributor-less spark system
2. Use a Megasquire DIY EFI system. Or adapt a carburetor.

Transmissions

available with 4-speed Automatic (E-ATx) or the XTRONIC CVT trans -- all FWD layout with or without awd. How would this fit to a rwd vehicle? An adapter plate could be fabricated. But which transmission would work best?

In RWD from the 2005 and newer Frontier Pickup. This is the higher-torque engine, but has all the pieces needed for a swap.

Tuning Potential

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It is the light valve springs, not the long stroke, that are responsible for the low, 6100 rpm redline.

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This engine was designed for efficiency, not ultimate performance. So all the parts are lightweight.

• 200hp is possible with custom exhaust
• redline extension might need new pistons and conrods
• boost would need new stronger pistons
• QR20DE (Japan model) short-stroke is only 150hp -- but can rev to 8500 rpm?
• QR18DE

References

• www.sportcompactcarweb.com/tech/0104scc_atunersguide
• www.nissanperformancemag.com/december02/ask_sarah
• www.autospeed.com/cms/article.html?&A=1378
• www.sportcompactcarweb.com/tech/0307scc_projser
• www.freshalloy.com/cars/nissan/nissan_engines.html