Carb tweaks | 356 Speedster, 550 Spyder, Replica, Automotive Community

zumwoll

I moved to 4k above sea level and of course car had driveablity issues, which I was unable to resolve with jetting etc. Met a VW drag racer up here---he built himself a 2.6 and installed it in the REAR of a VW pickup so he knows some stuff. He said to go back to big idle jets but start with idle adjustment cam screw "just touching the cam plate, then turn each in one turn." After I did that I checked the balance and one carb needed a full extra turn to be in sync. Right off it ran better. Then tweaked the mixture screws until it purred. Of course all that is in teh CB book on Dells but it is a lot to remeber.

8/27/058:08 AM

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zumwoll

I moved to 4k above sea level and of course car had driveablity issues, which I was unable to resolve with jetting etc. Met a VW drag racer up here---he built himself a 2.6 and installed it in the REAR of a VW pickup so he knows some stuff. He said to go back to big idle jets but start with idle adjustment cam screw "just touching the cam plate, then turn each in one turn." After I did that I checked the balance and one carb needed a full extra turn to be in sync. Right off it ran better. Then tweaked the mixture screws until it purred. Of course all that is in teh CB book on Dells but it is a lot to remeber.

Ralph, assuming your car was jetted correctly at sea level, you should be jetting down to compensate for the lack of oxygen content at higher altitudes.
If your car is running fine now with the same jets you were running at sea level, you were probably running too lean at sea level.
At 4,000 feet, expect your power to drop 10-12% even after re-jetting.

zumwoll

David :
I have noticed a drop in top end power. THe folks up here are running 34 degrees full advanced.

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