Check this out? How can we actually know? I heard on this board that Nissans' cars tend to overstated their HP rating for marketing purpose.

http://www.caranddriver.com/xp/Caran...ai_hyundai.xml

Is 260 HP significantly different from 255?

 

The closest thing to a scientific determinant of how much hp you're producing is a dyno run. I'm not aware of anything that'll test the hp at the crank...

 

The link didn't work (for mw anyway).

255hp is only 5 less than 260, only about 2% less - not enough to make a difference on its own. However other variables like TQ, TQ curve, gearing, TQ converter, and weight can make a big difference.

For instance, the TLS makes 260hp at 6100rpm; 232lbs TQ at 3500rpm out of 3.2L. The 3.9L LS makes 252hp at 6100rpm; about 270lbs TQ at 3500rpm. About the same hp, but more TQ out of the LS. But the LS makes 40lbs more torque and has RWD - so it can put the TQ to the ground better. It makes it harder to judge which one is more powerful. Also consider where the TQ and HP peaks are - the lower the TQ peak, the better (i.e. 250lbs at 3000 is better than 250lbs at 4000). Also if the HP of two motors is the same, the one with the lower rpm peak makes more TQ (at the peak rpm). Put it the good things in a package and you end up with a LS1 Vette that makes 375lbs of torque, 350hp and can run 13.0 or better in a big, heavy car without having to rev it past 6000rpm.

I like the idea of using a dyno to measure hp - it takes out a lot of variables that otherwise couldn't be compensated for. However most manufaturers use an engine dyno, which measures hp at the flywheel. Most dynos that test cars like the TL measure wheel hp, and sometimes there is a disparity. The wheel hp dyno is the best way to fine tune a car's power curve - it measures power at all rpms in a controlled environment. For a modern car like a TL is can only measure - there is only so much to adjust. But for a carbed car or a race car a dyno session can unlock 20-50-100hp (or more) just by tuning and for a nominal fee. Definitely worth it if you seek ultimate power.

I don't think Nissan overrates their hp figures - most manufacturers are honest, if not conservative.

 

U know funny thing is that my mom has a 2001 TL only at 225 and when i drive it the power or the pull is about the same as my 03TLS untill u get ppl in the car , now take off and speed gain is a bit faster in my car, but not that great diff.... My cousin has a 2000 TL with Intake and Headers and we were racing around the other day and about the same, i only have a intake, some runs id take him some runs he takes me... just depedns on other variables the horsepower.... but his car opens Vtec sooner then mine for some reason... hhmm.......

 

260 isn't significantly different from 255 on paper -- but it's another world in marketing. When a new model comes out and enters a market that's occupied by a 260hp model, would you want to advertise that your ALL NEW model has "only" 255 when a competing model has had 260 for 2 or 3 years?

 

Considering the 350hp M45 and Q45 can't get to under 6 sec in the 0-60 sprint to save their lives, yes Nissan overrated it.

BMW on the other hand, is very conservative.

 

HP does not accelerate a car, torque does. The lower the torque curve the better is a misstatement depending on your use. A Peterbilt, yes - A Formula 1 race car, no way. Rememebr, HP is a determinant of top speed and flexibility in the higher rev range. Torque accelerates a car and pulls things. Formula 1 cars accelerate fast because they are light, but are geared and tuned to make tremendous velocity as well. Yet, they could not pull a trailer from rest, while a Peterbilt, with 1/3 the HP, can.

The height and breadth of the torque curve is essential. That is how a 2003 Cobra with a chip and/or a pulley can out accelerate a Z06, which weighs 400 pounds less. The fact that they make similar or more HP is the reason that, unlimited, a 2003 Cobra can got near 170mph with that weight and less good aerodynamics.

 

the nissan 4.5L v8 in the q45 and upcoming m45 makes 340hp, not 350.
next year it might lose another 5hp and be 345, hehe.

and yes, bmw is very conservative on their hp ratings.

 

The reason why the
Cobra can outaccelerate the vette is the fact that it has more torque and horsepower, enough to make up the 400lb handicap and more. Put enough hp in a minivan and it'll hit 170mph too.

A 405hp Vette can hit between 185 and 190 (if GM geared it right).

 

Nissan/Infiniti should be next with 340hp 0-60 in 6.6 sec duds...