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MG MGB Technical - High Altitude Tuning

MG 2009 is getting close. What's the latest techniques for tuning an MGB for the Rocky Mountain's high altitude? My 1980 MGB with HIF carburetors runs fairly well at altitude, but feels a little weak and tired around 10,000 feet. Any advice?

Chuck
Chuck Hassler

Chuck - Unless you are going to live up at 10,000 ft, don't bother adjusting the carbs, just be content with dropping down to the next gear. A number of years ago, we took our TD and MGB all over the western US up to 14,000 ft and never had any real problem. Yes, neither car was as efficient at that altitude as they are here at sea level, but we were still passing most other cars going up the passes. Cheers - Dave
David DuBois

Where I stay, Johannesburg RSA, we are 5500/6000ft above sea level and experience a 17% drop in power. That equates to 3% drop in HP per 1000ft. If we are going to spend a lot of time at the coast or need to make use of the extra oxygen/power, a slightly richer mixture and slight ignition retardation is needed (a well tuned altitude engine pinks slightly under heavy load at sea level).
Going the direction you are for the short non racing period, no need to make any changes. Just get used to the loss of power at altitude or take costal power with you in the form of a "turbocharger".

Regards,
Richard
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RH Davidson

Thanks Dave,

I really didn't want to touch the carburetors or adjust the timimg. We will be living at 8,500 feet for the summer with trips above 10,000. I can live with some lost power for the summer. However, the car does run pretty well at 8,500 feet. I did increase the idle speed to bring it back to 850 and that helped a lot. The idle had dropped a few hundred rpm while looking for oxygen molecules.

Thanks again for the reply

Chuck
Chuck Hassler

Richard,

Those are interesting numbers. We've been at 5500 feet for the past two months, and your numbers relate to our expereince with a slight MG power loss.

Unless Moss sends me a free turbocharger, I'll leave the car alone and live with whatever power the car provides at altitude. I've already had it over an 11,000 foot pass, so it should take us where we need to go. Thanks,

Chuck
Chuck Hassler

Chuck...
When living out west in Boise ID I set up for a higher altitude and it ran very nice...for those times I would be above 5000' for more than a day...I turned the mixture richer by 2 flats...just remember to turn it back when you get down to your normal altitude...it doesn't take but a minute to turn 2 flats...
Bob Dougherty

Certainly not a problem anymore in new hampshire!!!
Bob Dougherty

This thread was discussed between 31/05/2009 and 01/06/2009

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