Are Altitude, Temperature and Humidity a Factor?

[victor]

Hi guys, i went to track last night with my R18. I know my 60 isnt that bad but still all my 3 runs was consistent 16.8. I know the R18 is slow but how can other people pull at 15.7 and 16.1? Does Alititdue, Temp and humidity a factor?

Heres my run

Altitude : 2100Ft (pretty high)
Temp: 39F (Pretty Cold)
Humid: 35%

R/T: 0.093
60': 2.545
330: 7.055
1/8: 10.735
1/4 mile : 16.827
MPH : 82.76

[Shark Tek]

Your altitude is the only one affecting you but the humidity and the temperature is helping you a lot.

In PR we have almost sea level tracks but the humidity and temperature are affecting us pretty bad. Temperatures in summer are usually high 90-95 and the humidity is on the same range of %. Now on these days is pretty cold around here 70-77F. Isn't much but compared to summer is a lot more pleasant.

[mattSi]

What kind of car is a R18?

[AbsoluteGG]

Originally Posted by mattSi

What kind of car is a R18?

A honda civic, non si.

[6spdChick]

[quote=Shark Tek]Your altitude is the only one affecting you but the humidity and the temperature is helping you a lot.QUOTE]

I'm pretty sure heat/humidity hurts you not helps you

[xlur8ed]

Look into "density altitude".... It takes all the factors (humidity, heat, pressure, etc...) and creates a altitude "as if" you were racing at that altitude.

Example is:

Your local track is 900' above sea level

Temp is 90 degrees
87% humidity
etc...

The density altitude may equate to say 2300'..... All the weather conditions play a huge roll in racing.... Hense why Atco consistantly has ridiculously fast cars, and is considered one of the fastest tracks in the USA...There true altitude is low, and their weather is a drag racers dream which equals low density altitude and low ET's.

[Shark Tek]

[quote=6spdChick][quote=Shark Tek]Your altitude is the only one affecting you but the humidity and the temperature is helping you a lot.

I'm pretty sure heat/humidity hurts you not helps you

Sorry chick but "Your" is a very important word here.

I mean that by looking at his numbers the only thing that isn't helping him is his altitude but the temps and humidity are more than great.

[COMplex]

pssh 2100ft! I WISH I was that low...

At 5280ft here in the Mile High, I lose about 50whp compared to sea level.

When I drive through the mountains @ 8000 - 10000+ ft the power loss is exponential! SUCKS!

[SRT4toCivicSi]

Seeing as how i'm a Pilot and fly LearJets every day lemme tell ya somethin or 2 about all this...

The higher up in altitude you go the thinner the air becomes...thats the basics that everyone hopefully knows...whihc is why a 9 second civic in Denver runs 7's in Chicago.

As far as temperature goes...for every 1,000ft you go up in altitude you lose 2 degrees CELCIUS...which is a good and bad thing. Good because colder air has the particle that make UP the air more condensed so it takes LONGER for them to get heat soaked as there coming into your intake/motor. However on the reverse side...hot air is spread out and very thin so its already sort of "pre-warmed" if you will so when it hits your intake your really not gaining anything in performance. HOWEVER...take that cold air and a higher than average altitude (say 2100 for your sake) then your not only losing 4.075 degrees celcius of temperature (good thing) but your also 2,100 feet MSL (mean sea level) which is the feet above sea level which wil make the air thinner and not as much air is available.

Now...humidity...you'de be suprised on this one...humidityis the amount of water vapor present in a unit volume of air. It can be a good thing IF ITS NOT WARM OUT. If its your temp and humid out you'll have some visable moisture which is good and bad again...good because it can help to cool down the air temps (it kinda acts like a intercooler sprayer but for your intake). However on the bad side car related...it'll bring your traction down obviously...

Something else that will affect your performance is Dewpoint. Dewpoint is the temperature at which a vapor (as water) begins or would begin to condense. Ex.) 78° outside and the dew point is 63. Basically what that means is at and above 63 degrees air will become so supercooled (even tho its 73 degrees) that moisture will start to form. Also, this as you guessed it IS DIRECTLY RELATED TO HUMIDITY AND TEMPERATURE!!!

I hope this helped. It's A LOT you probably won't remember but...coming from a pilot that has to monitor ALL OF THESE and 100 other tasks at once...you should feel smarter :)

[sickyute]

repped for the above.

[RomesKdUB]

yes they do...jsut like a sports game..or a running race..those three affect just the same in a road race

[victor]

I really felt bad on my time. I was like 16.8 OMG i suck, i mean my 60ft wasnt that bad. but my 1/4 was terrible for an R18 5M/T

[RWatters]

They can raise your power output or lower your power output, so yes they are huge!

http://wahiduddin.net/calc/calc_da.htm

Before I even leave for the track I plug my numbers into that website and calculate it. The closer to sea level the better, with the best conditions happening when it calculates a below sea level condition.

The lower the DA the higher power output you'll have, thus in return the faster you can possibly go at the track (depending on driver and traction).

http://www.wunderground.com

That's, IMO, the best weather website to use to get most of the numbers.

[SRT4toCivicSi]

wtf... you cant get density altitude unless you know how to use an E6-B which is a flight computer... (which I know this gives it to you but if you wanted to figure it out you need an E6-B)

BTW.. SEA LEVEL ALTIMETER UNIVERSAL SETTING IS 29.92!!! The HIGHER the altimeter setting the BETTER PREFORMING THE ENGINE WILL BE!!! The LOWER (below the 29.92 the altimeter setting is the WORSE the engine will perform. It's good to be and know a pilot :)

[xlur8ed]

Originally Posted by SRT4toCivicSi

wtf... you cant get density altitude unless you know how to use an E6-B which is a flight computer... (which I know this gives it to you but if you wanted to figure it out you need an E6-B)

BTW.. SEA LEVEL ALTIMETER UNIVERSAL SETTING IS 29.92!!! The HIGHER the altimeter setting the BETTER PREFORMING THE ENGINE WILL BE!!! The LOWER (below the 29.92 the altimeter setting is the WORSE the engine will perform. It's good to be and know a pilot :)

Good info man! The guy that runs our street legal races at the local track, is also a pilot, so he always comes over and bs's with us, and tells us whether to hot lap today, or get a run or two in and call it a day (bad DA).

[RWatters]

Originally Posted by SRT4toCivicSi

wtf... you cant get density altitude unless you know how to use an E6-B which is a flight computer... (which I know this gives it to you but if you wanted to figure it out you need an E6-B)

BTW.. SEA LEVEL ALTIMETER UNIVERSAL SETTING IS 29.92!!! The HIGHER the altimeter setting the BETTER PREFORMING THE ENGINE WILL BE!!! The LOWER (below the 29.92 the altimeter setting is the WORSE the engine will perform. It's good to be and know a pilot :)

Ohh I'm by no means saying I can calculate it myself I just know that the website I linked above is a good helper. It'll typically tell me whether to head out and have some fun or just stay at home and save money. When the track opens here in March we'll typically see a week or two of DA's in the -1500ft range which is when I'll typically take my car out. In the past (with my Spec V) it was a half a second difference between the weather then and the weather in the summer. It'd be the difference of a 14.5 at 95 versus a 15.1 at 91. These little N/A motors are definitely picky to conditions.

Also, thanks for the nice read on the previous page!