I had the same symptom at 3,000 rpm. The solution was installing UE metering needles. Some find UB to be sufficient. Search the archives as there are numerous threads comparing the various needles etc…
ah-ha!!
I’ve been driving without the air filter or the plenum when I found the loss of power at 3000 rpm.
I’ll reinstall and see.
ah-ha!!
I’ve been driving without the air filter or the plenum when I found the loss of power at 3000 rpm.
I’ll reinstall and see.
Lack of aircleaner and plenum will not cause that problem.
I have had my air cleaners etc off before and no change in performance
Tell me HOW you tuned the air/fuel mixture. Did you turn the mixture screws down a certain number of turns from the jet being ion the bridge or tune for fastest idle speed by ear??
Dennis
69 OTS with triple SUs
Again, swapping needles affects steady state performance. When you accelerate, the piston/damper mechanism provides enrichment. If you aren’t having a problem in cruise, then heavier damper oil will be a more correct fix than richer needles.
Thank you all for good suggestions.
I replaced the air filter, AND screwed down the mix screw 1/2 turn.
Took it for a spin [btw, it is 85* here in SoCal] and it definitely accelerated past 4k rpm without trouble. Activated the choke while driving, and it seemed to get even smoother. I’ll repeat when it is cooler outside, and will retune the cards with a flow meter. Perhaps screw mix down another 1/2 turn?
Turn each mixture screw, one at a time, up or down until you get fastest idle speed
Dennis 69 OTS
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Setting mixture at idle is NO guarantee of correct mixture, except at idle.
FWIW, I live in California as well, up in Santa Cruz. My experience is very few E-types will run properly on modern fuel in CA with the stock UM needles. Set best mixture at idle, and you’ll be dangerously lean at higher speeds and loads. Set best mixture at higher speeds and loads, and it’ll be sloppy rich at idle, making for a very uneven idle. UB or UE needles are a much better choice. Any given car will be happiest with one or the other, so I suggest try UB, and see how it runs. If still not right, try UE.
That is very interesting insight, Ray.
it may be our gas??!!
i’ll order a set of UB’s and see if things get even better.
My assumption is it is the gas. Our fuel is 10% oxgenator, which is usually ethanol.
If you want power, and you are at sea level or close use a UP needle. It’s half way between the stock UM and the racing U0. It’s noticable even over a UE. Gas mileage isn’t great but how many miles do you drive?