This is my first post. Thinking about a 2.5S. I know all about the old OR25 as a former SE-R owner. And I know how people rave about the VQ. V6 is out of the question due to cost.

So... Has Nissan really improved the QR25?

This is my first Nissan and first QR25DE, but from my experience it is a good engine. I can't tell if it is "improved" over anything, but researching it revealed that there were problems in earlier versions with spinning bearings- even without boosting horsepower, but that issue has allegedly been resolved in the newer QR25. It's definitely adequate for the vehicle it's in (I have a sedan). It's torquey and pulls like an old school V6 (def not VQ tho), good on hills and with passengers, plus it's smooth, quiet and gets good fuel economy. In Altima form though, it needs to be "uncorked", as it sounds stuffy and cheap. Add an intake and exhaust and you'll be good to go.

If you are interested in increasing power, it's a very strong 4cyl platform, the head is just awesome as far as 4cyl go and the block is like a racing block. You probably knew that already! It has a few weak points, namely it's long stroke, which limits revs to around 7200 even with stronger valve springs and such. I also understand the balance shafts are bad news for these engines and can safely be removed. The QR25 Sentra crowd knows about this. I bought mine for the fuel economy first and price second. Even though I know the QR is good to build with, I'm not interested in making crazy HP, but I like to add a few things to gain some more push from my daily driver. I'd def recommend it if the VQ is not in the picture. Good luck and welcome!

I agree with the above poster, its got enough pull for a 4 banger and to be quite honest its the best competitor in its class. I just recently got my exhaust and have had an intake for some time now but honestly just modding those two things alone I feel much more throttle response than stock. I can't believe how restrictive the stock muffler alone was.

Search the Rogue forum...the Rogue comes with only 1 engine choice, and it's the new QR25, and the moderator provided a ton of information on it. I have the Rogue and love the engine and tranny. Let me know if you can't find the link and I'll post it.....

Well first I've only owned 2 nissans, 95 240sx and 07 altima 2.5CVT. I dont know much about the old QR but I do know I've been 110% satisfied with my QR25. Plus I've heard Stillen is in the midst of building a non-intercooled turbo for the QR25 CVT. So even if you are interested in building a little extra horses of the QR there are already a few mods out there plus more coming into the market. Welcome to Nico.

This is why I fear the QR (again).

http://myspecv.com/f/t151978-0....html

I "always" heard bad stories from Sentra guys, but not from Altima guys. You guys been here longer than I. I'm about to cross Nissan off my list

Hello, I'm Philip from the Rogue Forum.

I have owned both the 1st gen QR ('03 Altima) and 2nd Gen QR ('08 Rogue).

The 1st Gen motor has been plagued with 3 major problems:

1) Pre-cat failure on '02-04 Sentra's and '02-03 Altima's. My Alty actually had this failure and the engine subsequently replaced under warranty. The catalytic converter overheats due to improper air fuel ratio, the ceramic substrate in the pre-cat breaks down, and the 'dust' gets sucked back into the motor via the exhaust valves. The QR like most recent Nissan's uses valve overlap to suck some of the exhaust gases back into the cylinder similar to the EGR system. Anyway, the ceramic dust scores the cylinder walls and causes high rates of fuel consumption. The problem was fixed after '03-04 by updating the programming in the ECU. See Nissan tech bulletin NTB03-070.

2) Lost throttle butterfly screws. The 1st Gen QR features a dual path for improved hp across the rev range. The butterfly valve that opens the shorter high-rpm intake runner has had issues with the screws holding the butterfly plates coming loose. The screws get sucked into the motor causing valve and piston damage. See Nissan tech bulletin NTB05-058

3) Excessive oil consumption on late '06 Sentra and Altima. Improper specification piston rings result in high oil consumption. See Nissan tech bulletin NTB06-082.

Now for the good part:

The 2nd gen QR addressed many of the problems from the 1st gen. Here are a list of the changes:

- A simpler, larger diameter single path intake manifold replaced the old dual path design. No more troublesome butterfly valves. (Note: California emissions models do have a swirl control valve located in the intake)- Compression ratio has been upped to 9.6:1 from 9.5:1- The balancer system has been moved back slightly from the crank pulley to a more central location in the block. This also means JWT's balance shaft removal kit for the 1st gen QR will not work.- Revised cam timing- Reduced friction likely through Nissan's extensive use of coatings on pistons, bearing journals, etc.- Additional engine mount on the top of the motor, pulley side.

IMHO, the 2nd gen motor is far smoother in operation and so far more reliable. Many of the issues from the 1st gen have been fixed and the improvements to the 2nd gen make this motor even better.