wiszmaster

Who here has put their e60 on a Dyno?

1. What did you put down?

2. Did you encounter any issues during/after the dyno?


just as a teaser ... i dyno'd mine ... i'll post the chart up soon.

Peter530i

can't wait to see your datas of the 530i

UUronL

Do they have a big powerful fan to cool the engine? Cars don't make power when hot and any good tuner floods the front end of the car with an uber-powerful fan to give the same cooling that the engine would normally have at those speeds (say on a highway). If they don't have such a setup, expect the figures to be low and unrepresentative.

Car and Driver was at Dinan where they were shown a modified E39 M5 on the dyno with the hood down and no airflow. It only produced 334hp at the rear wheels on the dyno. Using a $7000 fan blowing 38,000 cubic ft. of air per minute at 75 mph, the same car and engine on the same dyno produced 411.4hp, just shy of Dinan's claim of 415. Page two covers most of what I've paraphrased.

http://www.caranddriver.com/article.asp?se...0&page_number=1


The article also had this to say:

"More important, did your car run on the dyno as it would on the street? If it's the latest model, chances are good it may not have, says BMW tuning wizard Steve Dinan. An afternoon spent at his Bavarian speed emporium in Morgan Hill, California, convinced us that cars are gradually becoming too computerized for the simple dyno test."

wiszmaster

Yeah .. don't get me started on the air subject ... i hate nothing more than having only 1-2 fans sitting infront of the car blowing this little breeze at it.

and yes, my numbers were low, very much likely due to the lack of air supply to cool it down ... it was about 93*F i believe with a humidity around 55% ... and we have 4 "high flow" fans istting infront of the car .. NOWHERE near sufficient.

UUronL

Dang. It's hot and humid here too. One of the hottest summers in DC in recent history.

tomwid

So what does the 530i put down at the rear?

UUronL

...on that dyno, in the aformentioned wretchedly hot and humid environment with no cooling...


While we're at it, can you also hand time us a 0-60 run? While going through 5 inches of water?


This data is going to be horribly skewed and will likely look terrible.

wiszmaster

LOL. you aren't a comic by profession, are you? but then again ... ... ... none of what you just said was wrong.

once i get the chart, i'll post it up.

tomwid

As long as we know what the conditions are, the numbers will be ok. When people post their 1/4 times at the drag strip, they always tell you the elevation/temp/drag radials or street tires, etc. We all take those into consideration!

So the next time you drag race someone in a flood, don't forget to mention the flood part!

BTW, I don't think the "cooling" is the most effective part in making power, it's getting the AIR into the engine. Thus the function of forced induction systems such as turbos and superchargers.

If cooling is all we need to get power we'd all have liquid nitrogen cooled engines!

UUronL

Yeah, I don't know how much of a factor cooling may or may not be. I was simply going by what I read in that article. It's a good read if you haven't already taken a look. I wonder though, if it's simply a matter of cooling the intake charge, why go to the trouble of buying $7000 fans? Why not just hook the intake up to a hose blowing the requisite CFM of air at the appropriate temperature?

I guess I'm out of my element, but I was always under the impression that the heat of the engine had a little bit to do with it in addition to the temperature (density) of the intake charge.

I think it would be harder to compute the compensation for the variables in a dyno setting than in the real world on a test track. There are more variables in the dyno setting and many of them are hard to accurately measure. Like the effectiveness of the cooling that may or may not be reaching the engine. When a car is running for real, we know it is getting the proper cooling - it's out of the equation. Ambient temp, humidity, elevation - those are easily measurable variables.

I'd be interested to see how this is addressed, but my gut tells me that this kind of dyno testing is only good for testing the effectiveness of tweaks on the same car, or to compare one car to another car - as long as the testing is done back-to-back on the same dyno with the same environmentals.