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Air density altitude

Started by RECHRGD, July 30, 2015, 06:06:07 PM

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RECHRGD

I have always been told that Spokane had "lousy air" for making power.  Today I ran across an old dyno sheet from years ago when I did a head/cam change with much help from Ron here.  In the fine print at the bottom of the read out was all the info I needed to do an on line calculation of the air density altitude at the time of the dyno run.  Although the dyno shop sits at about 2000 feet, when I put in the info into one of those online calculators it came up with 4931 air density altitude.  I think the best dyno I ever had was around 332 rwhp.  This one read 325 rwhp, but when I plugged everything into other calculators it came up with a possible 370 rwhp at sea level.  Never realized how much difference in power there is due to air density.  Makes me want to take a trip to a strip on the coast for some fun.......
13.53 @ 105.32

cdr

was your print out ,, corrected or not?  it will say on the print out.
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

RECHRGD

It doesn't say anything about it.  But, it has a number that I don't understand.....SAE: 1.04.
13.53 @ 105.32

RECHRGD

OK, my Google research tells me that the 1.04 figure does calculate a correction.  Now I'm sad......
13.53 @ 105.32

Dino

325 rwhp is nothing to be sad about.   ;)
Extraordinary claims require extraordinary evidence.

cdr

what a dyno says is not what is important, you know what your car runs at the track, That is what tells HP    :Twocents:
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

BSB67

Quote from: RECHRGD on July 30, 2015, 07:44:50 PM
OK, my Google research tells me that the 1.04 figure does calculate a correction.  Now I'm sad......

Usually dyno data is corrected.  Nobobdy want to see the actual hp.

The good news is that if you get to a lower altitude with a low DA, the car will still be faster.

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

cdr

Calculate HP From Weight and MPH
MPH    Weight    
      

Your Horsepower computed from your vehicle weight of 3900 pounds and MPH of 105 is 360

this is from Wallace Racing,,, also based on 10% loss at the rear wheels, so i come up with about 330 rear wheel hp
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

cdr

like BSB67 said , better air, the more power you make.
LINK TO MY STORY http://www.onallcylinders.com/2015/11/16/ride-shares-charlie-keel-battles-cancer-ms-to-build-brilliant-1968-dodge-charger/  
                                                                                           
68 Charger 512 cid,9.7to1,Hilborn EFI,Home ported 440 source heads,small hyd roller cam,COLD A/C ,,a518 trans,Dana 60 ,4.10 gear,10.93 et,4100lbs on street tires full exhaust daily driver
Charger55 by Charlie Keel, on Flickr

myk

Quote from: Dino on July 30, 2015, 08:17:43 PM
325 rwhp is nothing to be sad about.   ;)

I'd say that many of us would be glad to be officially putting that much power down.  I know I would...
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Dino

Quote from: myk on July 30, 2015, 10:06:41 PM
Quote from: Dino on July 30, 2015, 08:17:43 PM
325 rwhp is nothing to be sad about.   ;)

I'd say that many of us would be glad to be officially putting that much power down.  I know I would...

Officially?  Hell, I'd be glad if I could lie about it.   :lol:
Extraordinary claims require extraordinary evidence.

RECHRGD

Quote from: Dino on July 30, 2015, 10:08:34 PM
Quote from: myk on July 30, 2015, 10:06:41 PM
Quote from: Dino on July 30, 2015, 08:17:43 PM
325 rwhp is nothing to be sad about.   ;)

I'd say that many of us would be glad to be officially putting that much power down.  I know I would...

Officially?  Hell, I'd be glad if I could lie about it.   :lol:

OK, you guys are making me happy again.  Thanks!!!
13.53 @ 105.32

Dino

Extraordinary claims require extraordinary evidence.

myk

Shoot if I was putting down more than 250 I'd be sincerely shocked.  Is your block untouched, OP?
"imgur-embed-pub" lang="en" data-id="a/mB3ii4B"><a href="//imgur.com/a/mB3ii4B"></a></blockquote><script async src="//s.imgur.com/min/embed.js"

1974dodgecharger

like I said in another post are cars are not hp kings.  U have 4 bangers that have more hp than our old school iron.

330hp to wheels is nice for 440 tq was probably 425?

HPP

Try living in Colorado where out actual altitude is 6500 and our density altitude can be a high as 10-12k. I can't tell you have many 500hp big block claims  I've seen that are putting 275-325 to the wheels.

BSB67

Quote from: RECHRGD on July 30, 2015, 10:31:18 PM
Quote from: Dino on July 30, 2015, 10:08:34 PM
Quote from: myk on July 30, 2015, 10:06:41 PM
Quote from: Dino on July 30, 2015, 08:17:43 PM
325 rwhp is nothing to be sad about.   ;)

I'd say that many of us would be glad to be officially putting that much power down.  I know I would...

Officially?  Hell, I'd be glad if I could lie about it.   :lol:

OK, you guys are making me happy again.  Thanks!!!

You have to let go of the hp numbers.  It is a game.  Dynos are tuning tools.  The only time you can compare the hp numbers from 2 different motors is from the same dyno by the same operator.  If your dyno sheet said 280 hp would you be more disappointed?  If it said 375 hp, would you be happier?.  None of it makes a difference when you strap you butt in and drop the hammer, it is what it is.

I don't remember your build, or track conditions.  But for a car that is a driver with a stockish build and a non-techie, not-into-the-weeds motor guy, your doing better than 90% in your same category with a 105 mph.

Take joy in knowing that you are making more power (because your car is faster) than most Mopar hobbyists like you that have way more go fast parts than you.


500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

RECHRGD

Quote from: BSB67 on August 01, 2015, 11:08:05 AM
Quote from: RECHRGD on July 30, 2015, 10:31:18 PM
Quote from: Dino on July 30, 2015, 10:08:34 PM
Quote from: myk on July 30, 2015, 10:06:41 PM
Quote from: Dino on July 30, 2015, 08:17:43 PM
325 rwhp is nothing to be sad about.   ;)

I'd say that many of us would be glad to be officially putting that much power down.  I know I would...

Officially?  Hell, I'd be glad if I could lie about it.   :lol:

OK, you guys are making me happy again.  Thanks!!!

You have to let go of the hp numbers.  It is a game.  Dynos are tuning tools.  The only time you can compare the hp numbers from 2 different motors is from the same dyno by the same operator.  If your dyno sheet said 280 hp would you be more disappointed?  If it said 375 hp, would you be happier?.  None of it makes a difference when you strap you butt in and drop the hammer, it is what it is.

I don't remember your build, or track conditions.  But for a car that is a driver with a stockish build and a non-techie, not-into-the-weeds motor guy, your doing better than 90% in your same category with a 105 mph.

Take joy in knowing that you are making more power (because your car is faster) than most Mopar hobbyists like you that have way more go fast parts than you.



Yes, the car does run strong.  I've always wondered what it would be capable of at sea level and that's what got me looking at the old dyno sheet.  Haven't been to the strip in years, but it was fun being competitive with cars that I thought would clean my clock.  Nothing too fancy about the build.  30 over 440, mopar aluminum 452 heads, comp cams extreme energy 5.25 lift cam, crane gold rockers, ebrock rpm intake, Holley 750 double pumper with ProForm main body, Hooker 1 7/8" competition headers, 2 1/2" exhaust run through ultra flow mufflers, 727 with trans go shift kit, 3.55 rear gears and 275/60/15 street radials.  The latest additions are a aluminum driveshaft and a Firecore RTR ignition.  It seems to be running better than ever.....
13.53 @ 105.32

1974dodgecharger

WELL SAID!!!!!  :2thumbs:

Quote from: BSB67 on August 01, 2015, 11:08:05 AM
Quote from: RECHRGD on July 30, 2015, 10:31:18 PM
Quote from: Dino on July 30, 2015, 10:08:34 PM
Quote from: myk on July 30, 2015, 10:06:41 PM
Quote from: Dino on July 30, 2015, 08:17:43 PM
325 rwhp is nothing to be sad about.   ;)

I'd say that many of us would be glad to be officially putting that much power down.  I know I would...

Officially?  Hell, I'd be glad if I could lie about it.   :lol:

OK, you guys are making me happy again.  Thanks!!!

You have to let go of the hp numbers.  It is a game.  Dynos are tuning tools.  The only time you can compare the hp numbers from 2 different motors is from the same dyno by the same operator.  If your dyno sheet said 280 hp would you be more disappointed?  If it said 375 hp, would you be happier?.  None of it makes a difference when you strap you butt in and drop the hammer, it is what it is.

I don't remember your build, or track conditions.  But for a car that is a driver with a stockish build and a non-techie, not-into-the-weeds motor guy, your doing better than 90% in your same category with a 105 mph.

Take joy in knowing that you are making more power (because your car is faster) than most Mopar hobbyists like you that have way more go fast parts than you.



c00nhunterjoe

With density changes at tracks, our supergas car will vary from 145 to 156 mph.....

BSB67

If you have the track conditions (or the track/date and time) when you ran, you can calculate sea level et and mph pretty well.  

500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes
4150 lbs with driver, 3.23 gear, stock converter
11.68 @ 120.2 mph

c00nhunterjoe

Quote from: BSB67 on August 05, 2015, 05:48:40 PM
If you have the track conditions (or the track/date and time) when you ran, you can calculate sea level et and mph pretty well.  

The car always runs 9.900.  ;)