Dyno time

tominator · Post by **tominator** » Wed Nov 19, 2008 4:37 pm

I've decided to go to the dyno shop tomorrow but I have one question, is temperature around 0 degrees celcius gonna hurt my hp number??

Thanks for the help

Post by **racer12306** » Wed Nov 19, 2008 5:03 pm

It might. Cold air is good, but there is too cold.

excon · Post by **excon** » Wed Nov 19, 2008 9:18 pm

racer12306 wrote:It might. Cold air is good, but there is too cold.

????

as long as your car is properly warmed up and you don't turn it on and immediately run it full out with your valves knocking, there wouldn't be any damage to your engine.

32 degrees F is nice and cold. Colder air is dense and therefore more air would be in the combustion chamber at the moment the gas/air mixture is ignited. This results in a better/more efficient/more powerful stroke....

what do you mean it can be too cold....?

Donkeypuncher · Post by **Donkeypuncher** » Wed Nov 19, 2008 10:03 pm

You should be fine at that temp, actually you would probably make more power. Colder air makes for a more powerful combustion stroke, but I'm sure there is a point where it hinders combustion. Kind of like exhaust pipe size, too big and the exhaust cools too fast hindering flow.

Usually the colder the better. Usually traction is the main problem, but on a dyno it won't matter. Elevation plays a bigger role in power, which is why most people in higher elevations have to calculate their 1/4 mile times to sea level.

fusion210 · Post by **fusion210** » Thu Nov 20, 2008 6:30 am

Dynamometers have correction factors in the software to account for the differences in conditions at different times.
I suggest reading http://www.dynamometer-info.co.uk/autom ... actors.htm

excon · Post by **excon** » Thu Nov 20, 2008 10:22 am

tell us what kind of numbers you put down...

Post by **racer12306** » Thu Nov 20, 2008 2:20 pm

won't the computer keep adding fuel? thus causing a rich situation.

Post by **occasional demons** » Thu Nov 20, 2008 3:16 pm

Only if it was stuck in open loop, and the o2 sensor had no input. But doesn't open loop have limits on the parameters to an extent also? I would think it would only feed it as much fuel as the AIT sensor and o2 determined was needed. I'm sure the MAP and TPS would also have some input. ?

Edit: I would hope the dyno shop is heated and the cold air is just being drawn in from outdoors to feed the engine. If the dyno was outside then the colder trani fluid etc would have an effect on the output. I don't think they have correction factors for that. but that would be nuts. I would hope no one keeps that kind of capital out in the weather.