High altitude carb kit

[byynow]

Those that are far more Corvair knowledgeable than myself please advise me. At some time I believe I heard that a high altitude kit was offered for the turbocharged engine. I think it consisted of a main jet and metering rod. In this case I am dealing with a 1964 model.

I am at 4800/4900 ft. altitude (Minden Nevada). Engine, carb, turbo are all rebuilt with 500+ miles of breakin. Ignition is electronic (Ignitor II), I have the vacuum retard/advance sourced from Clark's and the timing is correct. The engine starts and runs well enough but is somewhat rich throughout all rpm and load ranges, from idle to full throttle. I have the fuel pressure regulated to 2 1/4 lbs and have checked the float level. The spark plugs are dark, but not fouled, checked after about a ten mile drive. I haven't tried a full throttle shut off reading but I don't think it's necessary as I am sure it is consistently rich. I am well versed in carburetor operation and adjustment.

Did a high altitude kit exist for this model? If so I'm sure it is now unobtainable but would anyone have parts to duplicate it?

The car is driveable but just isn't quite right. I appreciate any help.

[66vairguy]

Those that are far more Corvair knowledgeable than myself please advise me. At some time I believe I heard that a high altitude kit was offered for the turbocharged engine. I think it consisted of a main jet and metering rod. In this case I am dealing with a 1964 model.

I am at 4800/4900 ft. altitude (Minden Nevada). Engine, carb, turbo are all rebuilt with 500+ miles of breakin. Ignition is electronic (Ignitor II), I have the vacuum retard/advance sourced from Clark's and the timing is correct. The engine starts and runs well enough but is somewhat rich throughout all rpm and load ranges, from idle to full throttle. I have the fuel pressure regulated to 2 1/4 lbs and have checked the float level. The spark plugs are dark, but not fouled, checked after about a ten mile drive. I haven't tried a full throttle shut off reading but I don't think it's necessary as I am sure it is consistently rich. I am well versed in carburetor operation and adjustment.

Did a high altitude kit exist for this model? If so I'm sure it is now unobtainable but would anyone have parts to duplicate it?

The car is driveable but just isn't quite right. I appreciate any help.

Your altitude is similiar to the Denver Colorado area were Steve Goodman has a shop. Steve is considered the Corvair turbo expert, especially at higher altitudes.

I'm not aware of a "high altitude kit" for the Corvair, turbo or not. Steve told our club about reducing the fuel pressure for the Carter carburetor from factory 4-5 PSI to 3 PSI. It improved the engines performance and fuel mileage. At 5,000 ft elevation, Steve has suggested 2.5 PSI. You'll need a precision fuel regulator. NO the fuel filter with a feedback line on 64 turbo Vairs does NOT regulate fuel pressure. It helps prevent vapor lock and excess fuel pressure at engine shut down. Call Steve -- https://www.rearenginespecialists.com/

[byynow]

Thank you for that. That's where I will go.

[66vairguy]

Thank you for that. That's where I will go.

Your welcome --- One nice thing about a turbo is when boost comes on it compensates for the lower atmospheric pressure at 5,000 ft.

At 5,000 ft you loose about 15% HP. A naturally aspirated 110HP Corvair would drop to about 94 HP. On boost a 150 HP Corvair will still make about 150 HP at 5,000 ft. It's not exact as the Corvair turbo controls were simple, but today's computerized systems work well at higher altitudes.

[erco]

This China seller accepted my $25 offer on this low pressure regulator, which works fine, 1-4 psi. Fast delivery too, 8 days.

https://www.ebay.com/itm/Low-Fuel-Press ... 6281654560

This is the special low pressure version with continuously variable adjustment, supposedly preset at 2.8 psi but verify, it's a Chinese knockoff.. Loosen adjustment screw to lower pressure. I've heard bad things about the traditional flat-dial type of regulators that lock into one of several discrete pressure positions. Some info at https://www.google.com/url?q=https://ww ... W13AhEzqbZ

[66vairguy]

This China seller accepted my $25 offer on this low pressure regulator, which works fine, 1-4 psi. Fast delivery too, 8 days.

https://www.ebay.com/itm/Low-Fuel-Press ... 6281654560

This is the special low pressure version with continuously variable adjustment, supposedly preset at 2.8 psi but verify, it's a Chinese knockoff.. Loosen adjustment screw to lower pressure. I've heard bad things about the traditional flat-dial type of regulators that lock into one of several discrete pressure positions. Some info at https://www.google.com/url?q=https://ww ... W13AhEzqbZ

You post is confusing. You post an ebay link saying the shipper is from China, but the ad says it is a Holley part? So was this a counterfeit China knock-off of the Holley Regulator???

You say to avoid dial type regulators with a link to the Holley pressure regulators implying the Holley units are a problem (they are not like the simple restrictive flow units, which are not really regulators).

I've read comments from folks that have used the Holley 12-804 on Corvair turbo cars and they reported the Holley unit works without issue. One problem with ANY fuel pressure regulator is vibration. You should mount the regulator on body, NOT the engine which requires flexible braided fuel lines for safety. Years ago the SCC club installed the Holley 12-804 fuel pressure regulator on a troublesome 63 Turbo car per Steve Goodman's recommendation and it solved all the carburetor issues.

Keep in mind this is only recommended for the turbo cars with the Carter carburetor that is very sensitive to fuel pressure. The naturally aspirated cars use Rochester carburetors that are happy at 4-5 PSI. Now that the mechanical fuel pumps are no longer reliable, or fuel pressure accurate, the basic 4.5 PSI Facet electric fuel pump solves the fuel pressure issued for Rochester carburetors so NO fuel pressure regulator is required.

[erco]

Yep.