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Re: Gas Mileage in the AC Vanagon, 1980

Posted: Fri Aug 28, 2015 4:27 pm
by luftvagon
Colin, just megasquirt your bus already.

luft with squirt

Re: Gas Mileage in the AC Vanagon, 1980

Posted: Sat Aug 29, 2015 7:40 am
by Amskeptic
luftvagon wrote:Colin, just megasquirt your bus already.

luft with squirt
When its current L-Jet fails, we will talk about it (some time in 2037)
Colin

Re: Gas Mileage in the AC Vanagon, 1980

Posted: Sat Aug 29, 2015 9:00 am
by luftvagon
In terms of vacuum, at 3300-3700 RPM, pulling about 65mph, I'm anywhere between 6.23 inHg to 3.57 inHg. I will need to attach GPS to my logging unit to give you exact numbers. Not sure about head temperatures. Probably significantly lower than with the perfectly factory tuned stock unit. I'm recording about 160-190F through the intake runner bolt sticking out of the head on cyl#3.

Anything lower than 3.28 inHg, and my mixture starts to go from 13.5 AFR to 12.6 whilst approaching 0 inHg.

:digital

Re: Gas Mileage in the AC Vanagon, 1980

Posted: Mon Oct 08, 2018 11:41 pm
by 72Hardtop
With lean tune cruising it's important to remember the (1) area to stay out of when under load WOT....

14:0 - 15.5:1at WOT (Highest EGT/CHT temps.

Anything under 3/4 throttle and you are NOT hot enough to worry about being to lean AFR wise.

16-17 AFR is where you'll make great MPG's. No leaner than 17 (lean miss w/light load) Lean cruise tune only with vacuum advance distributor or mapped EFI. Not with centrifugal only. With a cracked throttle one is NOT on the main circuit (carbs/s). Main circuit is over ~1/4 throttle.

See where CHT's go from peak lean EGT (leaner)...

Re: Gas Mileage in the AC Vanagon, 1980

Posted: Tue Oct 09, 2018 5:31 am
by cegammel
Holy thread resurrection, Batman!

Re: Gas Mileage in the AC Vanagon, 1980

Posted: Sat Oct 13, 2018 10:12 pm
by Amskeptic
cegammel wrote:
Tue Oct 09, 2018 5:31 am
Holy thread resurrection, Batman!

Always good to blast reminders from the past. To that end, I have never been able to get a Volkswagen to run at 16 AFR and successfully dive down into the 12s under acceleration without having a dreadful mid-throttle hot zone.
Colin

Re: Gas Mileage in the AC Vanagon, 1980

Posted: Tue Oct 23, 2018 11:36 pm
by 72Hardtop
Amskeptic wrote:
Sat Oct 13, 2018 10:12 pm
cegammel wrote:
Tue Oct 09, 2018 5:31 am
Holy thread resurrection, Batman!

Always good to blast reminders from the past. To that end, I have never been able to get a Volkswagen to run at 16 AFR and successfully dive down into the 12s under acceleration without having a dreadful mid-throttle hot zone.
Colin
The pleasures of an IDF or Dell set up.

Define a mid throttle hot zone.

If your on the main jets (not part/cracked throttle) under load (correct jetting) you should be ~ 13:0 - 13:5 or so. But if you are loafing along on the highway flats or around town there is nothing wrong with a lean tune cruise of 15:5 - 17 AFR.