How to Tune a Carburetor for Higher Elevation

We're going to concentrate mostly on the Edelbrock carburetor because they have an amazing tuning chart that helps get the whole problem sorted. Doesn't mean you cant do the same tuning with other brands, but its more guess work.

#elevation #edelbrock #carburetor

[phillippautler]

Thank you very much. I moved from Golden Co to Alamosa Co, So about 5500 ft to about 7600 ft. I run 1406 carbs in most of my old ford and chevys, and been having one hell of a time reseting all of the carbs. My 57 chevy has the 283 with the1406. I should get a 500 cfm carb. But this imfo will help a lot. Thank you very much

[VinoRatRodbuilds]

Never new anything like this, learning new stuff every Sunday👍

[CCAutoWorks]

Awesome info thanks so much for sharing

[ezelk]

I just stumbled across you channel. Great information! I have a 66 Chevelle and A 72 Plymouth Scamp. I will be using this information. Subscribed

[wtty]

Very helpful. I’ve been wondering about this.

[paulhejna-zpsd]

I have a question about what a/f reading is ideal at WOT @ 5000' density altitude. Ideal WOT a/f is appox 12.5. Does this change at higher density altitude. Thank you. Your videos are awesome 👍. Paul

[johnweaver]

Nice video you have this stuff mastered for sure keep the videos coming

[rdperformance]

Amazing video, i have a question, tal king about CR, the higher elevation yo drive is it possible to handle with a high CR engine or easier to handle a high CR engine at sea level ?

[fomocoloco]

So your base tune is determined by the type of engine that you have right? And then you would determine that in another part of the manual and have to remember it when you're trying to tune it?

[jeffdeavours]

Good content as always. Thanks for the info.

[frankglasgow]

I'm running a 1411 Edelbrock and even the stock calibration at 5000 ft in Colorado, my plugs are showing lean. I built a 351m with 10.5 compression ratio bored .060 over, forged flat top pistons.. I have a Howard's rattler roller cam 227/235 @.050 intake C/L at 103° 109° lobe sep. I'm going to buy a AFR gauge .it feels great off idle but is feels sluggish after that. I've went 4% lean on the primaries and rich on the secondaries. Timing with a HEI Ford distributor is at 34° total timing. Still plugs are showing lean. Accelerator pump position is maxed. C6 auto with 1800 stall and adjustable modulator. I need help. Thanks in advance. BTW I'm running 87 non ethanol fuel.

[quadepaul]

Brian, THANK you so much for making this. People often overlook or only talk about tuning based on Sea level numbers. you mention 4 degrees difference in timing from Denver to Sea Level. Is the timing change linear as you go up in elevation or exponential. I know I am outside of the norm, but we live at 8000-9000 Just curious if the timing would need almost a 9 degree difference or more. I realize that the motor will let me know, but a good starting point would be good. Is there a way to estimate initial timing based on altitude? Also would this increase in timing apply to total timing as well? I have currently seen my motor rise to well over 40 degrees of total advance without pinging and it seems like it wants more but I am worried about adding anything else.

[DesertRatFabrication]

Hey Brian I have never heard anyone talk more about timing when tuning, and I think it great, I can see where someone would go from a low altitude to high and miss the timing factor, the total advance would absolutely go up too, is air density what makes this all happen, I know on Diesel’s it’s a big deal, and do you make better gas mileage up high if you lean correctly, very good video, thanks buddy

[joshaudet]

Can you do the same tutorial for temperature swings? I’m in tulsa so we can see 100° all summer and then 30° is a good average for the winter. Obviously the cold increases air density and thus oxygen so it should lean out, but by how much?
I have a 502 big block with a long duration cam

[Winterstick]

Back in the carb days, did the manufacturerers alter their carbs and timing depending on where they would be sold?
I grew up in Flagstaff, Arizona at 6, 900 feet.
Thank so much for posting this.

[thomassak]

Great info. Never even considered timing for tuning for elevation. Just got a '70 Torino Type N/W 351W all stock back from paint that originally was sold in Seattle back then. I'm in the foothills in CO at 7600. I drop down to Denver elevation in about 3 miles from my home where I'll be doing the majority of my driving so I'd guess I need to tune specifically for about 5300. I'd like to keep it stock and not have to go to EFI or a different carb. Again, I have a stock Motorcraft carb - so thoughts on timing/tuning the carb?

[hollisbradburyoutdoors]

What would be your advice if I live at 9300. My closest town is at 7. And I work up at 11k what would be my target area ?

[elchapoyo]

I Live in Arizona,

Elevation in my Rural Area are:
80ft-250ft Above Sea Level.

What type of inital timing would you suggest for a
Chevy 350 SBC?

I have a Edelbrock 1906 AVS2

[drewski]

Great video.
Too bad they eliminated carburetors.
They could have had them automated to adjust themselves (with an ecu) to monitor their performance and make the correct adjustments.
I believe this technology is still relatvent to our modern car to get more gad mileage, less pollution in our environment.
Make the carburetor into a gas vapor system for more mileage, less emissions.
Thanks for the video.

[cd]

Higher elevation: lower air density. Carburetor is pumping the same amount of gas as if it was at sea level but at higher elevations (that is why carbureted airplane engines have a mixture control to lean at altitudes). Therefore the the mixture is rich and hence the need to lean at higher elevation to maintain proper fuel/air ratio.