2008 Altima Coupe 2.5 Horsepower numbers?

[dldjros69]

http://www.kandn.com/dynocharts/69-7061_dyno.pdf

175 hp - 123 hp = 52 hp loss (175 x .30=52.5)

That seems like a 30% loss. Is that correct?

My next question is

The K&N intake gains 7 whp. How do you do the math to find what the regular hp would be?

Or should i not be doing this?

Thank you in advance

[Forrest80]

Something about that seems wrong. My 2005 350z had a 15-16% power loss and it was rwd.

How can a FWD car be 30%?

maybe thats a weird CVT dyno?

[LinkNuc]

that is a hell of a loss, my 2003 350Z rated at 287hp pulled a 242 on the dj so thats about 16-17% on RWD,

and that 7hp gain, um yeah, be lucky to see 1 or 2.

[dldjros69]

Am i reading that dyno sheet correctly? Or did K&N mess up?

[LinkNuc]

yes you are reading it right, but that is after numerous pulls on perfect conditions, you'll see 1 or 2 hp gain max

[Stumpjumper]

Nissan has been catching some flack in the past for rating the QR25DE much higher than it's actual HP output...I wonder if they still are?

[MagicM]

not just nissan, But majority of the Japanese companies way oversell thier HP rating. Honda is by the far worst one of all. Acura TL used to be 270 next year when the SAE rating changed it went down to 253 a 17hp lose, and the RL went from 300 down to 290. Funny thing is a lot of the American companies ended up gaining HP rating on a lot of their cars.

[dldjros69]

How is that a perfect condition? Both runs were extremely hot. The first run was 93 degrees the second was 100 degrees. That doesnt seem like optimum conditions to me. Since it wasnt moving no air was flowing into the airbox.

So does 30 % loss sound right? That is really high!

[Stumpjumper]

The studies I was referring to took place before they changed the ratings...here's what wikipedia states about the engine:

In addition to the physical problems suffered by the QR25DE, Nissan's official stated power and torque numbers seem to disconnect from power measurements taken by the general public. Though rated for 175 hp (130 kW) and 180 ft·lbf (240 N·m) of torque in the Nissan Altima and Sentra SE-R Spec-V, the actual power of the engine may be significantly lower. Multiple dynamometer readings performed by a range of people in an assortment of cars over several years have shown that the engine more than likely produces ~160 hp and ~170 ft·lbf of torque. Parasitic loss alone seems an unlikely candidate for the discrepancy as automatic transmission loss would be approximately 28% and manual transmission loss 19%.

[vonivo]

http://www.kandn.com/dynocharts/69-7061_dyno.pdf

175 hp - 123 hp = 52 hp loss (175 x .30=52.5)

That seems like a 30% loss. Is that correct?

My next question is

The K&N intake gains 7 whp. How do you do the math to find what the regular hp would be?

Or should i not be doing this?

Thank you in advance

7HP from a intake on a naturally aspirated engine thats a 4 banger....no way never maby 1. Read the fine print on the intakes and such they will say up to 7hp not 7hp gain. Now if you were forced induction then you would be seeing 5-7HP. Also you don't have a cold air intake that would make a big difference you have a hot air intake which hurts performance so you could and when sitting idle at a light probably loosing 2-6HP by having your engine suck up your engine heat saturated air.

[LinkNuc]

yup if you get 1 hp consider it a plus, even a 3.5 maybe 1 2 or MAYBE even 3 on the right day

[LinkNuc]

How is that a perfect condition? Both runs were extremely hot. The first run was 93 degrees the second was 100 degrees. That doesnt seem like optimum conditions to me. Since it wasnt moving no air was flowing into the airbox.

So does 30 % loss sound right? That is really high!

I was referrring to Intake gains, really you might even lose hp

[dldjros69]

i cant see a loss of hp.

[JDRosenberg07]

i cant see a loss of hp.

Your engine is already hot, bein that theres explosions taking place in there, suckin in air thats been in your engine bay instead of through the grill from the outside isnt gonna make you lose hp

[soltys]

I could see a loss - not huge, but a loss. Cold air is more dense then the hot air in the engine bay. More density means more flows to the motor and generates more power. That's why Cold Air Intakes generate more power gains then the Short Rams.

[JDRosenberg07]

I could see a loss - not huge, but a loss. Cold air is more dense then the hot air in the engine bay. More density means more flows to the motor and generates more power. That's why Cold Air Intakes generate more power gains then the Short Rams.

I agree that your gonna see more gains with a CAI than a WAI. But i cant see a loss goin from stock to a WAI. yes your takin in warm air but the heat from the inside of your engine bay will effect the air in your stock setup as well, the box is only plastic and is not insulated. a short ram air is gonna increase the flow of air over a stock setup. More air + more fuel = more power. Most people buy a ram air for the sound rather then trying to pick up a few more horses.

[soltys]

I agree that the engine affects the stock plastic box but the stock setup also has a feed from the front of the car. As pathetic as it is, it does allow fresh air to directly enter the filter. As does the AEM and K&N setups - they are as close as you can get to a CAI.But like you said, no one buys a SRI for power gains - it's all for sound and looks.

[LinkNuc]

yup, and that's perfectly fine, I love how some people claim their "butt dyno" can feel a difference, its all in their mind...but whatever blows your skirt up right?

[Forrest80]

http://www.kandn.com/dynocharts/69-7061_dyno.pdf

175 hp - 123 hp = 52 hp loss (175 x .30=52.5)

That seems like a 30% loss. Is that correct?

My next question is

The K&N intake gains 7 whp. How do you do the math to find what the regular hp would be?

Or should i not be doing this?

Thank you in advance

175x15%=26.25-175=148.75wHP

To assume that a front wheel drive train is 30% loss? isnt that a crazy loss ammount for a fwd car?

The Z has less drive train loss than that and its RWD.

I really dont think thats a correct dyno or im missing a big fact that about FWD or the 2.5 is not really 175hp.

145HPx15%=21.75=123.25wHP

But is the car really 145HP?

My car doesnt feel like only 123whp. I had a civic 2007 rated at 140-hp, 1.8-Liter 16-Valve SOHC i-VTEC® Engineand i had a saturn sc1 1996 it was 110 HP.

My car feels like a corvette compared to these 2 cars.

[JDRosenberg07]

I agree that the engine affects the stock plastic box but the stock setup also has a feed from the front of the car. As pathetic as it is, it does allow fresh air to directly enter the filter. As does the AEM and K&N setups - they are as close as you can get to a CAI.But like you said, no one buys a SRI for power gains - it's all for sound and looks.

I still have air from the outside aimed at my intake too... its not perfectly aimed there but i am getting fresh air to it....

[dldjros69]

Exactly forest. my coupe feels like a corvette compared to my last car. I had a dodge neon with 134 hp. There is no way that my coupe has 140 hp. My coupe is 500 plus pounds heavier and smoked my neon.

JDR - think about taking off the foam/tape seal off of your fresh air inlet.

As to blowing up my skirt - i know now that there is way more throttle response. That is for sure

At this point i say all gain and no loss.

[JDRosenberg07]

yeah thats off already...lol its an old pic

[ESP]

Exactly forest. my coupe feels like a corvette compared to my last car. I had a dodge neon with 134 hp. There is no way that my coupe has 140 hp. My coupe is 500 plus pounds heavier and smoked my neon.

That's not an accurate comparison though... The 140whp for the A/C is calculated after drivetrain loss (hence the wheel horsepower)...you should find out what your Neon was pulling at the wheel for proper comparison. It was probably somewhere in the 80-90whp range. Also, horsepower isn't the most important thing in "smoking" another car...torque is. The QR is probably has the most torque of any four cylinder I've ever driven.

[Forrest80]

That's not an accurate comparison though... The 140whp for the A/C is calculated after drivetrain loss (hence the wheel horsepower)...you should find out what your Neon was pulling at the wheel for proper comparison. It was probably somewhere in the 80-90whp range. Also, horsepower isn't the most important thing in "smoking" another car...torque is. The QR is probably has the most torque of any four cylinder I've ever driven.

Well explain to me why a fwd drive car has 30% drive train loss?

[dldjros69]

You are correct about the neon have 80 or 90 whp.

Im just having a problem with those dyno numbers. Thats alot of loss?(or we were lied to about the 175 hp)Did k&n attempt to dyno a cvt or was that a 6mt?

[08Coupe]

With the new SAE Engine Dyno regulations it's not likely Nissan could overrate there HP readings. Also that dyno run was in second gear and I don't think the Altima second gear is even close to "1 to 1" ratio! As a standard Stick 13-15% drivetrain loss, Auto 15-20%...RWD and FWD not much difference...AWD=19-25%.

And LOL my harley puts down almost what they got from the 2.5

[Forrest80]

With the new SAE Engine Dyno regulations it's not likely Nissan could overrate there HP readings. Also that dyno run was in second gear and I don't think the Altima second gear is even close to "1 to 1" ratio! As a standard Stick 13-15% drivetrain loss, Auto 15-20%...RWD and FWD not much difference...AWD=19-25%.

And LOL my harley puts down almost what they got from the 2.5

Porsche has less drive train loss due to engine over the rear transmission.

I know altima is not a porsche but the theory applys, its less distance it has to travel.

And from this forum i read cvt is all over the place when you run a dyno so its hard to figure it out.

[LinkNuc]

Really It seems that Nissan and others might be under-rating HP numbers, there was a huge question as to wheter the 5.6 was actually putting out closer to 350 vs 305hp based on the numbers the titan was puttinmg down ald there is some speculation on GT-R actual numbers, that car ain't light and it is super-quick..anyway it seems the Z and Alti HP numbers are true...

[vonivo]

Than my friend is a hot air intake. In the winter assuming that you live where it snows you'll see a small gain 2-4hp because of the frigid air but for spring, summer and fall you will see a loss because you are sucking in hot saturated air from your engine. Hot air has already expanded but cold air is much more dense which causes more air to et sucked into your engine causing a bigger bang which makes you go a bit . You state that you et a little cool air with that set up but i disagree the factory intake brought in more cool air into your engine causing better performance.

[JDRosenberg07]

true but even with the stock set up your still sucking in the same air as you are with an aftermarket intake. and if you look at my picture you can see that i still have the outside air comin in my engine bay aimed at my intake so im still getting the outside air to my intake.