[s-cars] Re: Cheating the Dyno

[JShadzi at aol.com]

Right, and not only is there no airflow to the IC, there is no airflow to the airfilter, which inevitably starts sucking hot air unless you've got a real good sealed inlet to outside of the car.  I rigged up a water mister on the IC for the drag racing and just hit the IC with a mist during each dyno run.  In any event, I still had a good temp increase, though not terrible, from about  30C to 58C by the end of the 3rd gear pull (an indicated 100 or so MPH, yikes!), see below for the datat plot of one of the runs:

http://www.newtsplace.com/90tq/plotter.php?file=Jshadzi_dyno_datalog_Aug26_230WHP.csv&dir=.

Also, on the freeway at a sustained 70mph (light load)  I hit the IC mister for 10 seconds, you can see the effect on the data log below, temps dropped for 40C to 36C

http://www.newtsplace.com/90tq/plotter.php?file=jshadzi_effect_airtemp_IC_waterspray.csv.csv&dir=.

Nice thing to know is that if the results on the dyno are good with hardly any airflow, they must be even better in the real world.  The Dyno at ATP had only a small fan blowing on the IC, only good way to do it on a dyno is to build a sealed shroud on the front of the car and have a fan forcing air into the radiators that way, BTDT before.

Javad


>--
>[ Picked text/plain from multipart/alternative ]
>When I go to the dyno, it's with a plant sprayer full of ice water.  This
>give real world performance figures, because as you increase speed (in the
>real world), the flow thru the IC increases as well.  On the dyno, as you
>increase engine and boost, there is no increase in airflow.  The best way to
>do this is to spray the IC until it reaches a stable temp at idle (I used a
>davtron and/or the IR temp gun) - as close to ambient as you can get.  Just
>before your run (or if you really trust the straps, have someone stand there)
>hose the crap out of the IC.
>
>Brandon, comparing this method to real world driving immediately afterwords
>confirms that a big fan in front of the IC isn't enough when doing the dyno
>run.  The davtron actually indicated that you were better off driving the car
>on the street for the highest IC efficiency.  Better yet, do a sprayer mod on
>your IC for real world driving.  Many folks have BTDT.
>
>HTH
>
>Scott Justusson
>In a message dated 8/29/02 10:48:12 AM Central Daylight Time,
>brogers at terrix.com writes:
>
>
>My guess is that the above practice would not produce real world power and
>performance figures-- seeing as how we don't have ice water being sprayed on
>our IC's when we drive--although that sure would be nice!
>volunteers...anybody...anybody...
>
>
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