Why are conventional Nissans so weak?

I'm talking about everyday Nissan engines, not for racing…

Nissan Livina 1.8 only has 122 horsepower, equivalent to a 1.6 of any other brand.

The 2.5 of the X-Trail only churns out 168 horsepower, while a Toyota 2.5 would make it to 180 hp, while a Honda 2.4 makes it to 185. A Hyundai 2.4 can make it to 194 hp.

Nissan Armada 5.6 VK56DE gives out only 317 hp, while a Toyota 5.7 (of the Tundra) has 381 horsepower. A Hyundai 3.8 V6 can do better, with 344 hp!

Even the award winning VQ35 of the Altima would do 10 hp less than any other 3.5 V6

Nissan 1.6's would only do around 110 hp, Honda's 1.5 can do better with 118 hp.

MRA8DE 1.8 would only do 130 horsepower, Honda's would do 140. MR20DE 2.0 does 137 hp (YOU MAD BRO?) a regular 2.0 does 150 hp above!

Can anyone explain why Nissan tunes their engines so weak? Or they are naturally weak?

No there are good

Insurance restrictions and owners actually taking there cars in for horsepower dyno testing. Nissan really does not put peak horsepower readings on there car. To keep things legal

The new 2015 Nissan Maxima will certainly be a 3.5 L V6 24 valve DOHC that manages to achieve 290 hp. Rumor is the fact that this engine will probably be improved energy to about 330 hp.

Some cars have engines designed for HP while others are designed for longevity and gas mileage.

You're mistaking a lot.
Nissans QR25 makes 200hp. The Hyundai 2.4 makes 194hp turbocharged if I'm not mistaken.

Now, the V8s/Hyundai V6 comparison. The Toyota V8 is more powerful overall… But the Nissan gets better gas mileage. Do you need the extra 60+ hp? No. And the Hyundai V6? Yeah, it makes 348hp, but only 295ft-lb torque, while the Nissan V8 makes 385. HP doesn't matter as much in trucks. In fact, HP doesn't really matter on any engine. Look at the Versa's 1.6 vs the Fit's 1.5. Yes, the Nissan 1.6 makes less hp (109@6000 vs 130@6600), but then look at the torque… The Nissan makes 107@4400 vs 114@4600. The 107 is more useful because it's at a lower speed… Lower in the rev range where most people drive it would likely make much more torque and be more useful.

Now, there's another reason… Longevity. Which engine is going to last longer, a high strung 1.6L making 150hp, or a 2.0L making 150hp with lower compression and lower revs? The bigger engine will last longer.

Don't put so much into peak numbers, they don't tell anything. The Hyundai Genesis 3.8 Coupe makes 348hp from a V6 while my mustang new in 1998 with a 4.6L V8 only made 305… Guess which one is still faster? Hint: It's the American car. Why? Because peak numbers don't actually matter.

Ever thought about comparing torque numbers too?