Go check it out guy's http://www.altimas.net/forum/showthr...threadid=15446 . Looks like nissan definatly did not underate there HP to 240HP{rather then 255HP}.

 

Man..... that's a very low number.

 

hmmm.... thats low..... maybe they didn't dyno correctly?

 

(Found on the Net) Read this:
I have a nice little side business repairing SuperFlow dynomometers, the
overwhelmingly dominant dyno in the US. Every magazine article I've
ever read used a SuperFlow. The standard SuperFlow is rated at 1000 HP,
10,000 rpm and 800 ft-lbs of torque. The RPM signal is converted to a
voltage by a tach chip before being submitted to an A/D converter. The
torque signal is derived from a strain gauge attached to the absorber.
This signal is also applied to the same A/D converter through an analog
mux. Horsepower before SAE correction is the simple calculation:

(torque (ft-lb) * RPM ) / 5252

This computation is done in an analog multiplier for the analog readout
and by the CPU for the digital readout. So good, so far. But here's
the kicker. The A/D converter is an 8 bit unit. That is, it digitizes
the incoming signal into one of 256 binary values. For torque, that is
800 ft-lbs / 256 = 3.13 ft-lbs per bit. For RPM, 10,000/256 = 39 rpm
per bit. At a constant 6000 RPM, the best HP resolution is 3.5 hp. At
a constant 500 ft-lbs of torque, the best HP resolution is 3.7 HP. This
lack of precision results in the best theoretical HP measurement at 6000
RPM being +- 3.5 hp. Worst case is 3.5 + 3.7 = 7.2 hp. The
root-sum-square (much more representative of the real world) is 5.0 hp.
The precision varies, of course, with RPM. The important point is any
horsepower variation less than about 5 hp is meaningless and is more
likely attributable to quantitizing error in the electronics. Understand
that this does NOT include other systematic error terms such as the
errors associated with the analog electronics or the torque sensor
calibration. I personally attribute no credibility to differences
less than 10 hp.

The other thing to keep in mind when viewing published figures is that
the most frequently published numbers are corrected to SAE Net. This
correction for ambient temperature, humidity and barometric pressure
is only approximate and is really suitable for generating numbers for
ad copy where they are legally required. We have conclusively proved
that the correction is only approximate using a client's dyno cell
that is equipped to control temperature, humidity and baro pressure.

To illustrate the problems involved, I've spent considerable time with a
client because his dyno isn't "producing the numbers he wants". His
engines, which he sells to racers who make buying decisions largely on
dyno sheets, are considerably down on power compared to what his
competition claims. His dyno is spot-on calibrated. He has carried an
engine around to two other shops, one of which is Bill Elliot's shop in
Dawsonville, GA. The span of readings on this engine among the three
dynos is over 80 HP on a 500 hp engine! I have personally checked two
of the dynos and know them to be properly calibrated. The difference is
in the buildup of error terms in this inherently inprecise measurement
system and in the SAE net compensation between Florida at sea level and
here in Atlanta at about 1000 ft elevation.

Bottom line - take any claims of small increases in HP due to "tricks"
with a LARGE grain of salt.

....unless they were tested on the SAME day and on the SAME dyno, which is what Greg did. The size of the numbers is insignificant. The difference is!

 

first, it's an auto

it wasn't a dynojet, so you can't compare these numbers to a dynojet.

fwiw, a tl-s (260 crank hp) makes around 196 wheel hp, ~25% loss.. but that's on a dynojet.

 

civic si boy

 

i30 with navi boy as well... but what does that have to do with anything?

 

why not have it do with something

 

There is no way the Alty would get 0-60 in 5.9 if it had 164 at the wheels. I'm guessing somebody f**ked up calculating the numbers. Also remember, it isn't a dynojet.

 

Thats right. It wasn't done on a Dynojet. The numbers are not messed up, but they can't be compared to dynojet numbers. Everyone needs to stop trying to compare them.

 

#1 its an AUTO
#2 4th Gen's ran 6.6 - 6.8 on 165 fwhp..

 

mine has 168FWHP and it's a 3rd gen SE VE power.

 

 

Seem's like nobody useses dynojets anymore? What's the deal with all these weird dynoes lately? It seems like the only way we will ever get a real # is if I go do it myself .

 

I know the guy that dyno'd the Altima. He works at a local Nissan dealer, and he hosted a test drive event us Org people (mmm...SE-R Spec V..).

Did anyone read his post? He said he saw a 15hp gain from a Magnaflow exhaust! Even though it's a dual exhaust system to begin with, I'm not sure if this is believable or not..

 

I heard that nissan perposaly put a real constrictive crimp in the exhaust system for the Alty, it would not suprise me if a 15FWHP was achieved by replacing the exhaust. If you ask me nissan put a real constrictive exaust on the alty just so my car would have an extra 15 HP.

 

or else nobody would buy the new Max if they could spend less $$$ and get the same power...

 

And we have a winner! Theres a real good chance I still would have picked the max though, if not I would have got something else.

 

Maybe i'm missing the point, but why is everyone so hung up on what a car dynos. What really matters is how fast it is or how it uses the power. Last time i checked both a 5sp or Auto Altima was FAST. Low 7's for the auto, which is better than any pre2k2 maxima auto, and a 5sp that hits low 6's. Whats the problem? Why get so hung up on numbers.

 

Who's getting hung up on #'s? I am just sharing that's all.

 

well if you paid for 240hp, you better get 240hp! remember when ford came out with the '99 "320"hp cobra? it hauled *** but the owners felt that it wasn't pushing 320hp. they brought their cars for dyno tests (mostly on dynojet ) and came up short. they complained to ford and they recalled all '99 cobras. they didn't even produce 2k cobras to take care of the '99s. what was the problem? the intake manifold had a "lip" at the end of the ports and the relocation of the muffler pipe (for the I.R.S) choked the engine to the point that it was making less hp than 98 cobras.

based on the dyno plots (from dynojets) i've seen on stock maximas, automatics lose about 25% of the flywheel hp to drivetrain loss. sticks lose about 15% to drivetrain loss. if the 3.5 is putting out 240 flywheel hp that altima automatic should dyno 180 (which is what most of us were expecting).

going back to my original point. if that dynomometer is correct and his altima automatic does put out 164hp and any subsequent dyno runs with other automatic altimas on different dynomometers put out 164whp, i would certainly not "accept" it as-is. if i paid for 240hp i want 240hp!

this "gjvogel" guy post those numbers to get people excited about his exhaust systtem without posting the graph. i never understand why people do that. it incites people to jump into conclusions. to me its kind of stupid since he's trying to sell these exhaust systems. oh well. lets wait for the graph.

 

Yea and another STUPID *** dynoed in the wrong gear. What the hell is it with all these people dynoing there cars in the wrong damn gear?

He dynoed in 2nd gear idiot!!!!

 

there's the answer to the mystery!!

oh well. so back to the topic. the mossy exhaust gained 15 hp on the wrong gear. i wonder what the gains will be like when the car is dyno'ed using the correct gear. hmm...

 

My thoughts exactly. If I did not go on a huge shopping spree I would dyno my car.

 

Well Mike remember back in may of 1995 C&D got the 95 auto MAX to 60 in 7.3 sec just like they got the 3.5 Altima last month.