Thread: Sr20 vs qr25

Stemmed out of these two threads:

2JR Baby-Spec B13 QR25

http://www.sr20-forum.com/sentra-se-r/53610-awsome-build-2j-racing.html

If you care to read through the messes of both of those.

We are called SR20 nutswingers and they are QR25 nutswingers

Ill start off with the basics of each motor that we know as common grounds.

SR20

Produced from 1989 to 2002 in many versions in both n/a and turbo
The SR20 has proven itself and earned the reputation it has today.
Now a days the parts for the SR20 are getting cheaper and easier to come by with a pretty vast aftermarket support.
The SR20VE being the best version of the SR20 has already been known for its capabilities in both the N/A and Turbo crowd and has already become very common in the RWD SR crowd swapping them onto their rwd blocks.
While the QR25 guys say our SR20 is outdated, old design, and soon to be old news this is not likely for the following reasons:

Aftermarket support has never been higher for the SR20 than it is today, while we have lost some supporters we have gained many more in the last 4-5 years. Production and R&D of aftermarket parts especially for the VE is still going on to this day and in my opinion has just begun. We know the capabilities of the SR20 in general. There are many on this board with stock block cheap built internals putting out 500-600whp very easily. Some have pushed stock motors to the 450-500whp range. The RWD crowd is very popular with pushing stock blocks with internals into the 700-800whp range as well. With companies like Mazworx around, sleeved blocks are becoming far cheaper and possibilites are endless and we have never seen soo many high hp SR's coming out as there is today especially in the fwd and awd crowd.

The major downfall in the FWD SR20 world has been the weak 5 speed trans which is now remidied by the availability of the P12 trans or P12 bellhousing to mate to a cheap to find easily available Spec V 6 speed gearbox using mazworx mount kit and several different flywheel and clutch setups ranging from your normal stock p12 setup, to lightweight flywheel and 225mm clutch setup, lightweight flywheel and 240mm clutch setup, or twin disk setup all depending on your power goals. In all motor applications the 5 speed works pretty well but anything over 350whp or so and the stock 5 speed trans becomes a common problem.

The QR25 guys arguement on why the QR is better is because its a newer engine that is still under developement by both Nissan and aftermarket supporters such as FIR and 2JRacing. They say the QR hasnt had a chance to prove itself yet but its been out now for a decade. Also with few aftermarket companies and most anything nicer that makes good power will cost you more which so far is the case with the QR25. You want nice quality parts that make power they are going to cost more. Especially in the turbo world since the QR25 was never offered so far with forced induction.

Some downfalls of the QR25

When first introduced it made 175whp and 180 ft-lbs of torque at the crank. Not very impressive for having 25% more displacement than the SR20

Known for having a pretty flimsy bottom end with thin rods, weak pistons, 4 cw crank. One good is the one piece girdle/upper pan assembly that ties all mains into the block. Same design as the K20/K24/F20/F22 motors.

Poor rod/stroke ratio thus limiting the engine to low revs especially on factory internals.

Poor intake manifold design also known for issues with losing butterfly screws on the multi length runner setup and causing major engine damage.

Known for precat failures causing catastrophic engine damage due to the way the EGR system with the variable cam timing system works creating a vac in the exhaust during certain low rpm and crusing rpm ranges causing pieces of the catalyst to make its way back into the motor through the exhaust. Solved by removing and installing a catless header.

Open deck block, poor for high hp applications where its been known for sleeves to shift or crack in the 450-500whp range. Only remedy is to sleeve the block

Pros for the QR25

More displacement to work with in stock form
Many factory restrictions that can be fixed fairly easily
One piece main girle/upper pan
Decent flowing head with a simple bucket style valvetrain, no rocker arms or lifters to deal with
Variable cam timing
Comes stock with a very stout, smooth, 6 speed trans with Helical LSD

As of right now the QR25 is still being used in Nissans lineup and Nissan has plans to release a 260hp/260tq supercharged version of this engine soon if Nissan doesnt skimp out like they usually do.

The b16 QR25 went through some changes coming in at 200hp/180tq with changes made to the intake manifold getting rid of the multi length runners and butterfly setup, changes to cam profiles, a slightly stouter bottom end and slightly higher compression.

As of right now with the aftermarket support offered by 2JRacing, their test car has put down right at 220whp with stock internals using their new custom fit b16 intake manifold, header, exhaust, cams, pullies, flywheel, and uprev tuning. Before this it was hard for most QR's to even hit the 200whp mark using what little aftermarket there was available. While things have just started getting going with QR25 parts developement the numbers to me are not that impressive especially since there are soo many SR20VE's even on stock internals making close to that. Some over that with factory sr16ve pistons and some minor head cleaning and other good parts. Not to mention overbored and/or sleeved 2.2L and 2.3L motors and 2.4L big bore/stroke motors. Motors easily eclipsing 240-260whp with basic parts and factory nissan cams.

In my opinion the QR is not all bad of a motor but its still far away from being comparable to the SR20. It doesnt have a legacy other than for massive recalls when the first 4-5 years they were out there. Recalls that cost Nissan millions.

Id like to hear everyones opinion and like to keep this civil. Again we are all Nissan lovers here just of different motors. Im gonna post the same thread on B15u so its not a biased one way discussion.

lol, mainly started it to keep the debate crap out of the two threads that 2j has started on the QR25 into b13 build. And I was bored so figured why not.

I had a 02 spec v and had zero issues out of it. I made 180whp and 180lbft with basic bolt on parts minus cams. To get there I had to fix the tune with a safc-2 and do the knock sensor mod. My biggest problem is its a over square motor with a terrible rod to stoke ratio. this ratio results in f1 like piston speeds. Its also a open deck design which complicates forced induction. I kept my car n/a and enjoyed it very much in part to the hlsd 6 speed. It does make for a good daily driver motor. It also does well at autox due to the low end torque.

Ive driven a couple of them and while torquey the fun factor was just not there at all. Loved the trans though. But fact of the matter was my se-r bone stock with a fresh jdm motor and advanced timing to 19 deg walked two of my friends spec v's with intake header and exhaust. Not by alot but still enough, both from a roll and dig just so they couldnt say it was all driver being I had alot more racing experience than both put together.

Havent driven a b16 spec v yet but from what i hear with the the changes, higher rev limit, and more power its a decent difference and then with bolt ons 200whp is easily achievable.

yeah but the b16 is fatter than a b15. Its a common trend in the auto industry just look at the civic. Its heavy now too.

Yep, with more power they add more weight. The high powered lightweight cars have come and gone. Why i believe the new toyota and suby will sell so good even though they are underpowered to start but the aftermarket support will be there and as suby and toyota have already mentioned there will be forced induction platforms soon available for them. But thats a whole other conversation.

Thanks for making the thread Ashton. The debate really was ruining the thread and needed to move elsewhere. I wasn't going to add my two cents in the thread because it didn't belong there, but I will add it here.

For me it is simple. I prefer a square, or over-square engine. I also love overbuilt rods and pistons. Engines with longer strokes than their piston diameter do absolutely nothing for me. Engines with weak internals do even less for me. All else being equal, I'll take the engine with the shorter stroke. I like strong internals as well. The larger displacement, earlier power, and other "benefits" of the GR25 are not benefits in my eyes, they are drawbacks. Also, the real benefits of the engine (better girdle, cam on bucket is very nice) don't even begin to make up for its abysmal 9:10 bore/stroke ratio, and balance shafts make me cry.

That was another point I had, Nissan didnt learn from the VE or what when they used the 4cw crank and then on the 20v p12 motor they went back to an 8cw crank. lol. Seems as though the balance shaft was just a bandaid for the 4 cw crank they used to try to keep the rotating assembly light. What they didnt realize was that the balance shaft was robbing more hp than the lightweight crank was making up for.

Im not saying the QR is a horrible engine, while Nissan has made improvements on it to make it reliable and make a bit more power the QR in my opinion is far from a performance based engine. I dont think Nissan ever intended it to be a tuner/performance based engine. Hell same engine offered in the altimas and so on. What makes it any different being in an SE-R. Besides the spec v given 10 more hp and called a performance version. WEAK!!

Dont get me wrong, i get why the b15 guys are trying to work with what they have and make it better being that swapping an SR back into the b15 requires extensive work especially with the VQ being such an easy direct swap now into them. Why would you go to the SR motor unless you wanted to be different or just wanted the higher aftermarket support. I can see if your plan is to boost the SR with some serious power or go with a nicely built VE but yeah they would be crazy to put a stockish VE in as it would make no difference other than the VE has more n/a capability right now in stock form for the time being.

so they say the qr is a far Better motor than sr eh. So that's why buddies fully bolt on 06 spec v is sitting in his garage worn out burning up lots of oil and knocking with only 52k miles. Yea it's a great superior ass motor alright that my buddy wants a ve in there. Wow.