Tuning FI for altitude with Wideband O2

[Mike R.]

Re: Tuning FI for altitude with Wideband O2

You could be right, it has been a long time since I have flown a normally aspirated piston airplane without automatic altitude mixture compensation. My thought was that high altitude operation is analogous to part throttle operation which intuatlvely produces less exhaust heat. A brief google search failed to deliver a definative answer. Anyhow, I will report back on the results with the O2 monitor when I have them.

Mike

all the data i have seen there was no correction for altitude

[James B.]

Re: Tuning FI for altitude with Wideband O2

John, You mentioned on one of these posts about buying a Ford paper air filter in place of the foam element. Can you give me more details- what Ford model car does it fit or what is the part number? Does the ford element fit tightly enough in the original housing that unfiltered air does not leak around it?

[James G.]

Re: Tuning FI for altitude with Wideband O2

Mike, Here is some more info for you fellows living in CO, etc altitudes with thin air as you climb.
Now this info came from a friend/customer so I don't know how scientific it is. Saying that to protect myself from a beating here by the talented gearheads. LOL
As you climb in altitude the engine vacuum drops. As the engine vacuum drops then the Fi tends to run a tad richer. Say you get up 11,000 as my friend does. He says he looses a ton of power but makes it thru by putting the pedal down and romping it. The higher up he goes the more idle issues he has.
So now you have two minus factors. Less engine vacuum and a lack of air. That in itself puts a hurt on the old FI's as they run on a vacuum principle and even at sea level they could use more CFMs.

See Jerry Gollnicks post on his race engine.

Mike, Ask your FI restorer if he used the correct 30-30 enrichment diaphragm spring. That's the short one-the hot rod spring we call it. JD

Mike,
I lived in BIG BEAR LAKE, CALIFORNIA from 1980 until 1999. It is at 6850 feet, with mountian top at 9100 feet.

I owned many Rochester fuel injection cars, including a 64 fuel race car similar to Jerry Goldnick's during these years. I also was a licensed smog tech at my Chevron Service station that I owned for 17 years.

All that time, the idle speed screw "may" have been adjusted on the street fuel cars (57's and 65's), but that was the only adjustment I ever made. The cars definately had 'more power' as Tim Allen would say, at sea level, but no other adjustments were ever made.

I used the big nozzels on the race car, and the phleumn was modified as well as the air meter diameter was honed out to the max. We got the "cfm" up to about 725 on that car, which was my most fun Corvette I ever owned.

Also, send me your vin number please. I and about 10 other 65 fuel injection crazy owners have been keeping a 65 ROCHESTER FUEL INJECTION SURVEY , a REGISTRY of sorts since 1977. We have about 535 cars logged of the 717 built. Details are very complete on many cars, and very incomplete on some where we only have a vin number on a unit spotted at a swap meet. I would love to share this SURVEY with you. You never know, it may be already noted and old history prior to your ownership will benefit your ownership history of the car.
Regards,
JIM GESSNER
909-794-7905
jim@vettefinderjim.com

[Mike R.]

Re: Tuning FI for altitude with Wideband O2

I found the Ford filter today. It fits a 2001 Expedition and it fits the FI housing perfectly but is 1.5" shorter. It probably wouldn't move but I put a 1.5" thick donut shaped foam spacer in. You will see when you have one. This is a great tip as the ford part probably has 5x the surface area.

Mike

John, You mentioned on one of these posts about buying a Ford paper air filter in place of the foam element. Can you give me more details- what Ford model car does it fit or what is the part number? Does the ford element fit tightly enough in the original housing that unfiltered air does not leak around it?