Altitude effects on 1/4 times, diesel's ?

[TrentNell]

so whats the deal here , i hear all sorts of opinions but have never ran a diff altitude track on the same truck set up turbo's,tuning, ect to see the difference . how much does it affect times ? i am really hoping to drop a few tenths at a lower altitude ! i currently run @ a D/A of 4800-6200ft usually

please give me answers lease:

i expect trucks running rich with unburned fuel to have a fair amount to gain just dont know if it would matter with twins ? i have but loads of air for a single cp3 :rofl:

just post up your experience wether it pertains or not ! i know alot of guys have wondered this too !

 

[SteveFord]

I belive it effects turbo/supercharged vehicles more than natually asperated. I'm sure theres a formula but the less dense the air the more they would spin the superchargers faster in top fuel to try and get the same amount of air in at lower altitudes when racing at the Mile High Nationals. With a DA of 5650ft I would say there's a few tenths left in it for sure. I know when i raced bikes and went to Florida I ran over a tenth faster and a few more mph than here at home to give an example. Thats going from a DA average in the 2000ft area to around sea level.

 

[IdahoRob]

Really depends on the D/A of the time you run. A nice cool night at 5000' could have a D/A of 2500'. A sea level track with 100* could be running 2500' D/A.

There are different factors, but you should pickup a .10 at least at a lower elevation track, unless it's a "fast" track like Houston. Then you have two things working in your favor.

 

[tylerrustLB7]

Ya Trent get that truck to HRP on a cool non humid night and you will see a diffrence 0ft.

But that's a hell of a drive for you.

 

[TrentNell]

Really depends on the D/A of the time you run. A nice cool night at 5000' could have a D/A of 2500'. A sea level track with 100* could be running 2500' D/A.

There are different factors, but you should pickup a .10 at least at a lower elevation track, unless it's a "fast" track like Houston. Then you have two things working in your favor.

my 11.80 run was a actual 5634 ft D/A acording to the calculator on this site , it factors in baro , temp , ect . i asume its acurate ?

http://www.dragtimes.com/da-density...set=30.05&rh=25&submitButtonName=Calculate+DA

 

[RPM Motorsports]

I was wondering the same thing for Fallon in a few week's. I normally run @ around sea level and Fallon is 4K ft. Would I need to run more boost to keep things in check?

 

[Kat]

Really depends on the D/A of the time you run. A nice cool night at 5000' could have a D/A of 2500'. A sea level track with 100* could be running 2500' D/A.

There are different factors, but you should pickup a .10 at least at a lower elevation track, unless it's a "fast" track like Houston. Then you have two things working in your favor.

:yup:

Here is what I can tell everyone.

Here are some of Casper times on #2 same set up.



11.50 @ 120 in CO DA ~8000ft
10.95 @ 124 in Bakersfield DA ~2000ft
10.83 @ 124 in Tx at HRP ~2000ft

Heck if you really want to go all out go back east IIRC Atco and Englishtown get neg DA

A N/A car would lose over 1 second and 10 mph though.

 

[mytmousemalibu]

Actually, altitude effects naturaly asperated motors more than forced induction. When NHRA heads up to Bandimere raceway in Denver, the Pro Stock cars are slowed down a couple of tenths iirc. It effects the forced ind. cars too, but not as bad since there creating there own atmosphere. NHRA allows the Fuel clases to run 100% nitro and unlimited supercharger overdrive up there. The air is less dense the higher you go, less avalible oxygen. Like climbers going up Everest, harder to breath. We've taken alot of trips to CO and its nice getting off the mountains, more power and economy. Like Rob said, Your actual calculated elevation/air density is varied by alot of other factors. Here in Wichita, our physical elevation is 1300ft above sea level. When we race, we have a small weather station with us. During most of our hot/humid race season our density altitude is usually between 3000-4000ft and has been as poor as 5000ish. Factor in all our temps, humidity, barometric pressure, water grains, etc, makes the engines fperform like there running at a higher evelation. My dad and I are bracket racers and it plays HUGE in deciding our dial-in time. We would be in the staging lanes, putting on our firesuits while rerading the weather station and righting our dials right before the run!

IIRC, I remember reading somwhere about when ATS has "Diesels on the Mountain" in Bandimere, alot of turbos went boom up there, guys overspooling them in the thin air.

Computech Raceair weather station is what we have and its a nice tool for the racers
They make some nice stuff.
http://www.computechracing.com/index.html

 

[Kat]

Computech Raceair weather station is what we have and its a nice tool for the racers
They make some nice stuff.
http://www.computechracing.com/index.html

That is a great gaget.... I love ours

 

[mytmousemalibu]

Kinda Nice to press a button, have the air sampled right there on the spot, instant weather conditions! Nice advantage to those whom have one or privy to the info when your racin!

Way better than just SOTP....... "well the air feels better huh?, Lets lower the dial-in some" ......and the car actually slows down :rofl:

 

[whitetrash21]

I think Chris Beans uses something similar to chack their D/A after each pass. Like Mouse said, plays a huge factor in getting as close to a dial as possible when running in brackets....

 

[TrentNell]

:yup:

Here is what I can tell everyone.

Here are some of Casper times on #2 same set up.



11.50 @ 120 in CO DA ~8000ft
10.95 @ 124 in Bakersfield DA ~2000ft
10.83 @ 124 in Tx at HRP ~2000ft

Heck if you really want to go all out go back east IIRC Atco and Englishtown get neg DA

A N/A car would lose over 1 second and 10 mph though.

Thanks Kat , like i said i know the tech reasons why higher elevation kills times but wanting actual data from our trucks . still wanting more info like this . i know alot of the trucks that have ran @ RMR for the DPC and such seem complain about being slower . might be finding out soon at firebird , not shure if Fallon or Billings are any lower ?

 

[Roc8man]

When my truck ran the quarter in Mississipi (200' above sea level but not sure what the DA was) it ran 12.5 and when it ran the same exact tune at Bandimere on a day with the DA at 9000', it ran 13.4. Big difference as you go up in DA equivalent. There's a lot of opportunity to improve at sea level

David

 

[IdahoRob]

Trent, I was about .2-.3 slower on average at RMR to my average at Firebird. A good .2 loss was from 60' times though.

Firebird usually is prepped really well and with your setup, should be in the 1.5x 60' range and if it's a cool day, you'll be pushing me off the single cp3 record.

 

[TrentNell]

Trent, I was about .2-.3 slower on average at RMR to my average at Firebird. A good .2 loss was from 60' times though.

Firebird usually is prepped really well and with your setup, should be in the 1.5x 60' range and if it's a cool day, you'll be pushing me off the single cp3 record.

thanks Rob , i am waiting for you to cut the info off for that very reason :rofl:
one if these days your going to tell me to go pound sand for beating your record ! :angel:


or as you put it in your sugestion to Henry ............. you are my "maestro"