Wouldn't real life conditions yield better gains then dyno's? How much air is actually given to the engine of a car during a dyno compared to actually being out driving? J/W

 

How would you measure it to get whp? An accelerometer would not compensate for road surface, weather, humidity, road incline, wind velocity and direction and air temp.

 

And on another note, what would it matter? I mean, the only place that I know of to get somewhat accurate numbers is on a dyno, and that's where everyone goes. Without being able to compare your numbers to other cars, it would be hard to get an accurate gauge on your car's performance. Say you found some way to get "street" numbers... those numbers would be meaningless next to someone's dyno numbers.

 

he's just questioning the accuracy of dyno results. To answer this question, they are not 100% accurate. Much more air will be delivered to the intake while driving, especially if you have a snorkel. On the other hand, I assume there is less load on the driving wheels while on a dyno: spinning the dyno wheel vs pushing a 3000lb car.

 

If you only did a weight reduction to your car, would the dyno still read the same results?

The thing I see is that even if the dyno doesn't measure that an exhaust provides signifcant gains, the car should be quicker on the track do to weight savings. Correct me if I'm wrong.

 

You're correct. The dyno doesn't care how much your car weighs, only how much power it's making/putting down.

There are two main factors in the acceleration of a car: Power and Weight. The dyno measures one of the two.

A very loose approximation (emphasis on VERY) is that each 100 lbs is worth 0.1 sec in the 1/4 mile, and 1-2 mph in trap speed.

 

awww yeah, bench racing (dyno) and the real world. NA cars are pretty consitent IMHO unlike tempermental turbo cars. The dawg and Viper ACR ran dead even until 120.* Once I shifted into 5th .... Mopar aerodynamics kick in


Bench Racing: Mopar wins(+30rwhp and -200lbs)**

Real World: Dead even to 120.

Explanation: +50rwhp (est) when the weather is boooooooooooooost perfect vs noon.




* concluded after 100 runs (only one day run)
**cars dyno'd on same day.

 

Dynos are not roads. They are only a tuning tool.

You may be interested in this:
http://www.charm.net/~mchaney/homedyno/dynokit.htm

but again I would not call it very accurate.

 

Here is what I am getting at.

Car 1 = Car 2

Car 1 gets an intake, exhaust, headers that shows 35hp on dyno.
Car 2 gets an intake, exhaust, headers that shows 20hp on dyno.

Car 2 is faster in real driving conditions.

There is no way to know if this can be true because there is no such thing as an equal car/driver. But, how do you know if a dyno with just fans blowing in all the wrong places holds any true value?

 

probably cause max hp and max torque are not the most important things