A customer of mine, who lives in Napa, has a 70/914 he bought new. somewhere he had a 2056 engine installed w/44 webers. Says he has terrible gas mileage, like 100 miles to the tank terrible. He is 83 years old and needs help so he can drive his car. can any body give me a recommendation that I can forward to him. Post or PM me, Thanks folks!

A customer of mine, who lives in Napa, has a 70/914 he bought new. somewhere he had a 2056 engine installed w/44 webers. Says he has terrible gas mileage, like 100 miles to the tank terrible. He is 83 years old and needs help so he can drive his car. can any body give me a recommendation that I can forward to him. Post or PM me, Thanks folks!

PM sent.... with a recommendation

Hard to beat a bit of dyno time with Martin ("Marteen") over at RPM Engines in Cotati. He dialed my Webers with the car strapped down. Goal was to improve driveability and fuel economy, but we picked up 35 hp at the rear wheels in the process. Steve de Jung over at de Jung Motorsports made some minor tweaks to improve driveability further, and did just that.

With that said, the fuel economy is never going to be great with carbs...

Something is amiss. Bad fuel economy for a 914 (even a 6) would be about 300 miles to a tank

It's probably set up pig rich he can read all about how to correct it here:

https://www.thesamba.com/vw/forum/viewtopic...92577243c64d9a7

Tim

VERY interesting link. Thank you.

I'm just starting the process with vintage IDF 40 webers (if the weather ever improves).

I've finished installing a Lambda gauge and ready to start taking some reading.

Note: always better to work in Lambda as opposed to A/F as the A/F values change with fuel type (see the attached chart I made up).

Also, note the listed death zone is for aircooled engines as this is where the highest exhaust and cylinder temps occur.

Tim

Click to view attachment

Hey, THANKS for the help. I'll forward the site on to him, although I don't know his abilities to work on the webers himself. He said that laying down and getting back up is difficult. I just looked in the mirror at myself,HMMM...

THANKS again !! I'm going to suggest he checks out 914 world and even perhaps join it.
always good to get new members right?

The carb jets can be removed/changed without removing the carbs so that part is easy. The Lambda gauge you have to weld in a bung for the ox sensor and wire it up, so that's more challenging.

Tim

100%,seems to come back to the common case of too larger carbs for the engine,makes me think they have been bolted on straight out of the box with no change to the vents and jetting .

Or an unregulated fuel pump. Dave, have your customer pick up the CB Weber book, if only to familiarize himself with carb components.

Everything else has to be right before you start carb tuning. Redline is now recommending 3 psi for webers, the floats have to be correctly set, timing has to be correct, good compression, valves adjusted and etc.

Raby says he gets 35+ mpg highway with his big type IV 4 cylinder engine with carbs and he tunes A/F to 13.1~13.2 throughout. If you set up for lean burn on the idle jet circuit at light cruise mpg's can be very good with carbs.

Note: you need a vacuum advance distributor to go the lean burn route.

Okay, now you have me curious: What's the best fuel economy someone has seen with triple-throat Webers on a 911 engine?

The best mileage I have seen at Thunderhill is just under 9 mpg. Lap times were really good though