[squish72]

So I have a draggy unit and tested my car today and ended up with a 12.79 @ 110.63. I know that's nothing to brag about but the altitude here is 6700ft and the da was 8999ft.

I have ported intake and throttle body, rotofab and 2" kooks . Does that seem about right for an auto car?

[JonD]

DA hurt you big time, I battle higher DA here in AZ from 3,800-5,000

[Rodan]

Each 1000ft of DA is, roughly, a 3% loss of HP in a naturally aspirated car.

[ULTRAZLS1]

Every 1000 ft is roughly a tenth.

At sea level you would be high 11s no doubt

The dragy is actually very accurate too

[KingLT1]

pretty good for 9k DA imo.

[squish72]

Originally Posted by KingLT1

pretty good for 9k DA imo.

Good to hear. I have to keep telling my self that I can't compare my numbers to any others especially the negative DA numbers. Just wish I could find some cars to test against in my area

[Booher]

12.88 is my pb, and I did it in Vegas during ls fest. I'm a manual, obviously lol,, and I have secondary cat delete, rotofab intake and ps4's on stock rims. The da up there is so bad, my other option is up in pheonix, so I try to go to the Vegas one. Idk if I used the da calculator wrong, but the da was 7770. When is the next test n tune?

[squish72]

Dang the da was that bad at ls fest?! Wow. I was there Saturday morning (without my car) left to go to supercross. Usually going from my hometown to Vegas makes the engine feel like it gained 2 more cyls.

I don't know when the next test and tune is. I live about 3 and a half hours away. They used to do something like every other Friday night or Saturday night to cut down on street racing but I think it's now moved to a week night.

[Booher]

Yah, I'm 2 1/2 hours away, it's a trek. I wish it was every other weekend again, I don't know why they changed it. There's no good places around here to race.

[squish72]

Agree with you there. I've been hoping our airport starts something up as for right now "Mexico" is the only thing in a 250mile radius.

[wnta1ss]

Originally Posted by Booher

12.88 is my pb, and I did it in Vegas during ls fest. I'm a manual, obviously lol,, and I have secondary cat delete, rotofab intake and ps4's on stock rims. The da up there is so bad, my other option is up in pheonix, so I try to go to the Vegas one. Idk if I used the da calculator wrong, but the da was 7770. When is the next test n tune?

I believe your calc is wrong. The 27.65 pressure that you used from the Dynojet sheet should be a station pressure, not a corrected one. Therefore the atmospheric pressure entered in your calc is lower than reality, and the calculated DA is higher than it really was.

[Booher]

I thought something was up, but couldn't figure out why. So next time, I need to get the atmospheric pressure from a weather station, to be more accurate? I'm obviously new at figuring out da hah.

[wnta1ss]

Originally Posted by Booher

I thought something was up, but couldn't figure out why. So next time, I need to get the atmospheric pressure from a weather station, to be more accurate? I'm obviously new at figuring out da hah.

The other input I would wonder about in that calc is the dew point. Was the dew point really 8.2 degrees, or was that a humidity of 8.2 percent? I think that you can find a calc that will accept a humidity percent if that's the data you are getting.


If that track is 2100' ASL then I'd say it's roughly a couple tenths slower than low altitude in similar temp/humidity, due to the lower pressure. I found that running an NA motor at a mile high was about a half-second slower than it was at low altitude. So roughly a tenth per 1000' ASL that you go up, rule of thumb that has been posted before, seems to make some sense.

[Booher]

I checked the da a few days after I got home and pulled all of the info off of the dyno sheet minus elevation, I looked that up, so no clue. /shrug