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Mixture correction for chnage in altitude
#1009698
06/08/11 11:11 PM
06/08/11 11:11 PM
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Joined: Feb 2005
Posts: 528 SW CO
HemiSportFury
OP
mopar
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OP
mopar
Joined: Feb 2005
Posts: 528
SW CO
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I just moved my car from the Midwest at 700 feet above sea level to SW Colorado at 7,000 feet. I have a Demon carb with 83 primaries and 91 secondary jets. I know I will need to lean it out but does anyone have a suggestion about how many steps down would be a good starting place?
Thanks for any help or suggestions.
'64 Sport Fury, 528 Hemi, FiTech EFI, 4-speed, 4.10 Dana 60 '57 Belvedere 2dr sedan, current project in process '19 Cherokee Trail Hawk Elite '03 Ram 2500 CTD HO, 6-speed 214,000 miles and still going strong
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Re: Mixture correction for chnage in altitude
[Re: HemiSportFury]
#1009699
06/08/11 11:48 PM
06/08/11 11:48 PM
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Joined: Aug 2003
Posts: 8,716 Baltimore/Denver
64Post
master
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master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
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I'd start at 81 & 89 respectively; Maybe end up at 80 & 88. You might also get away with bumping the initial timing up 3º-4º and advancing the curve a bit quicker.
Last edited by 64Post; 06/08/11 11:51 PM.
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Re: Mixture correction for chnage in altitude
[Re: 64Post]
#1009700
06/10/11 12:31 AM
06/10/11 12:31 AM
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Joined: Feb 2005
Posts: 528 SW CO
HemiSportFury
OP
mopar
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OP
mopar
Joined: Feb 2005
Posts: 528
SW CO
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Thanks for the suggestions. A step down of 2 or 3 is what I was thinking too.
'64 Sport Fury, 528 Hemi, FiTech EFI, 4-speed, 4.10 Dana 60 '57 Belvedere 2dr sedan, current project in process '19 Cherokee Trail Hawk Elite '03 Ram 2500 CTD HO, 6-speed 214,000 miles and still going strong
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Re: Mixture correction for chnage in altitude
[Re: 64Post]
#1009702
06/10/11 08:24 AM
06/10/11 08:24 AM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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yup. hp up there is horrible. you gotta build a car to make power at altitude, but then you can't take it down to sea level without needing race gas
my stock 383 2bbl cuda with just a 4bbl carb swap and everything else stock--and 2.76 gears, was running around 18 seconds in the 1/4 mile on a hot day at Bandimere. (track is around 6,000 feet, DA typically up around 10 from what I've heard, don't know what it was the day I was there, but it was a hot spring day)
I think it picked up 3 seconds when I brought it back home to Ohio!!
but...some of the best scenery in the country is out there in Colorado!
if your motor was running on premium pump before, you might be able to get away with low octane now.
**Photobucket sucks**
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