Well no, I haven't managed it yet! But after the last fuel price spike last year I tried careful tuning, and various small jetting changes to try to increase the fuel economy from around 30mpg (average) to at least 35. No doubt there'll be other things that will help...

The figures below are for the ACE 76 standard Beetle with a fairly "ordinary"/stock standard 1600 in 'average' condition. Fuel is plain old regular ULP (91oct.). No significant odometer correction (under 1%). No changes to the car (new parts etc) that would impact results.

1. Tired standard carb. 34PICT-4, some vac. leak st throttle, with 130main: 29.8mpg mixed hwy/local driving over 5 fills.

2. A better identical carb with no sig. vac. leak,127.5 main: 32.5mpg (hwy 12 fills) & 31.4mpg mixed 5 fills)

3. Same but 125 main (ran hotter): 31.8mpg (mixed over 11 fills)

4. Same but 127.5 main again: 32.4mpg mixed over 6 fills.

Has anyone done significantly better with a similar engine or car?

[ Edited on 11-2-2006 by ACE_76 ]

[ Edited on 14-9-2006 by ACE_76 ]

you are doing real well with those figures

I have not got those sort of numbers - but most of my driving is city

LAtely i have got - like just under 30 with a 1916 and a 34 pict (unknown jetting) with long peak hour drives to the west (50km runs against traffic)

Over about 3ooo kms i have averaged like 25mpg with heavy city 60%, light runs 20% and high way 20%

what about other stuff like increased tyre pressure, all the extra shit outa your car, brakes with new caliper seals and well adjusted drums etc????

Hi

In the 80s when my parents moved to back to Queensland and I would often drive up to see them from Sydney. With a 1640, a bit of headwork, slight compression increase, a well sorted holley bugspray, power pulley and extractors I could get 42 mpg on these trips, this was in a 72 Superbug with some aerodynamic aids. I was also able do 18.00 on the 1/4 with this combo.

Steve

i have achieved 40 with a 1776, Weber IDFs in a L bug.

This was driving from Sydney/newcastle/woolongong/sydney

It is possible

Thanks for various answers & comments! I feel we won't get much better from this engine unless it's re-built with better compression, balancing etc. Not sure what else can do with carby (we're keeping the standard setup) - the smaller size jet didn't help. Maybe a 009 distributor would help , but I tried one years ago on another standard 1600 and couldn't really tell any difference.

Yes we've got the highest tire pressure that seems sensible. The car is fairly heavy, and it's got the usual lot of spare parts & tools in the front! The drum brakes are correctly adjusted, but it will be getting new rear bearings soon. How do new calliper seals affect the running? Can they cause drag?

The thing that seemed a bit surprising was the constancy of the figures. Usually going on highway you'd think would lead to much better economy...

A SVDA dizzy is suppose to be much better for fuel economy

http://www.aircooled.net/new-bin/viewproductdetail.php?keyword2=IGD0001&cartid= 

Thanks, sounds interesting. Have never seen one. It looks as 'stock' as the original, from pic. on A-C.net (We want this car to look as standard as possible). Are they for sale in Victoria? Has anyone tried one and found it to improve economy significantly?

lol.. another forum I'm on has people boasting/comparing/discussing getting 34mpg from 5.7-litre V8s

my boast is 43 mpg in super beetle - 1640cc, Progressive
Weber, advanced as much as could bear,motor all balanced,
Extractors, mild cam, full Highway Figure, yes it was very Lean - Ran Hot and I needed to jet it up after this Run to avoid
damage. So not really sustainable (maybe with EFI monitoring
o2 you could build in safety).
So with the standard one you are doing very well.
Explain your driving techniques because this could make
huge difference.
- I recently had to nurse a slipping clutch on my oval , so
was driving with never more than 1/4 throttle.
Taking off at almost idle and feathering it to slow cruise speed,
backing off 100m before red lights to avoid stops.Gee I would hate to have been driving behind ME.

I managed 45 mpg one day in South Australia while crossing the Nullarbor in my buggy, when I had a very strong cool tail wind all day. Because of the strength of the wind the engine ran very hot, as it did not get enough cooling air. I ticked along on a feathered throttle and I suppose it ran a bit too lean for its own good. The next day things were back to normal, 45 degree heat and a head wind.

Driving techniques are "normal"-everyday - not speeding, but not drivng purely for economy. Speeding up smartly from the lights so as not to get hit by the Hyundais behind, but cruising with a light foot when at speed. Not "pushing car hard" much. Some hills in area and keep the speed up on them though. Do around 105 on 110kph freeways and 95 on the 100kph highways.
The best single reading I've had lately was 34.2mpg. I only look at the averages however as one reading can be misleading.

As far as setup is concerned, I have a stock '73L bug (1600TP) and a stock '71 auto fast back (dual carb 1600TP)

In normal mixed driving the beetle gets much better economy than the fasty, as you'd expect with an auto and almost double the weight to push.
I am suprised though on the highway the fasty easily gets the same economy as the beetle despite the weight and auto disadvantage (both ~30mpg or just under)

The big difference motor wise, the beetle has vac only advance and single solex carb. The fasty has dual solex and stock SVDA dissy, both probably help economy. Airodynamics may also play a part.

So for you, it would be an easy swap to put a type 3 dissy on the beetle, and for your stock setup probably better than a 009. The carbs would need new manifolds and linkages to fit though.
Other simple changes could be upgraded ignition (coil, leads, electronic pick up) and plugs, and possibly try higher grade fuel (cost per klm may work out better).
One thing many people forget is the effect of a blocked air cleaner, but given your figures, and being a '76 with paper element filter I don't think this is an issue for you.
Another one, again not really for you, but the choke adjustment can have an effect if you do a lot of short trips.

Andy :thumb

Thanks for comments & ideas Andy, have noticed exactly the same re Auto Fastback vs. standard Beetle. The '71 Fastback gets much better economy on hwy trips (~31mpg), approaching that of the beetle.
73 beetle should have vacuum/mechanical advance for standard dist?
Our FB has original FI distributor which is a bit different to the standard type of the time.
Have tried a 009 on a different stock 1600 bug before & couldn't tell any difference really.
Hadn't thought of putting a type 3 distributor on beetle though...
Leads are new (copper), plugs replaced regularly (Beru), coil old but Good, good points used & adjustments as they should be. Choke is open. Air filter not pristine, but I hate replacing it too often due to cost. Gets a bit of oil-fouling on the end near the case-breather.
Haven't tried extended running with better fuel, as assumed that low (standard) compression motor wouldn't be able to make use of it. I think this is the next step though...

Cheers Ace_76.
Your getting better economy than me in both cars by the sound of it so your doing something right!
You have me wondering now, I'm sure I have vac only on the super, but will check tonight.
I have not run an FI dissy on my fasty (PO removed everything), but I thought the only difference was the extra pickup for the computer? I have not looked to see if advance curve is different.

As for premium, I did try it for a few tank fulls both on the beetle and 2L type 4 in my kombi (also stock), niether had an appreciable increase in economy.
For a number of reasons I run PULP only in the beetle, ULP + additive in the kombi and straight ULP in the fasty. None seem to suffer any side effects.

Keep searching though, I'm sure there are improvements that will help, you just need to find them!

Andy

Thanks Andy,
There is a good write-up on distributors in Bill Fisher: "How to Hotrod VW Engines", which was published ~1972. In it he implies that the Type 3 FI distributor could be a good "hot" setup as it has a LOT of advance available at fairly low revs. (40o crank at 2500rpm). 009 has about 21-22o at 2500rpm, I think. (Also implies Auto S/S beetle on could be a hotty.) We have a spare FI one too... Hmm. Could be another thing to try.
The distributor for the Carby'd type 3's at the time had the vacuum retard for starting (double-acting vacuum advance). Don't think it had as much advance as the FI one.
I thought the SVDA was a special unit from US? Are these available in Aust?(Comments previously in thread).

Cheers Ace.
Here's a good source to compare all VW-Bosch dissy's.

http://www.oldvolkshome.com/ignition.htm 

Take this with a grain of salt though as things are often different in the US to here.

I've never had a dual vac dissy, but thought the purpose of them was to retard on deceleration, but am not sure on that one.

SVDA is "single vacuum" dissy. So many VW dissy's are "SVDA" but all have different advance curves.
But you are right, in the states there is an aftermarket dissy made called the "SVDA" and I'm sure there will be a few VW shops that stock them here in Oz. They are supposedly better quality and a better advance curve for VW, but like anything it should be tuned to the set-up of the motor, so not sure what that means for our stock setup. They are pretty pricey though, hence the popularity of the relatively cheap 009
If I have $$ to spend I would look at the mallory distributor. Never had one, but only heard good things about them.

As update on the above posts from Feb:

Have tried 95 octane Premium & got no improvement (actually went from 32.4 to 30.6 mpg - but only measured over 3 fills).

Have had G'box rebuilt (by Imported in Melb.) - actually replaced with the correct single side-plate type with slightly taller diff I think - & made no difference to economy (but doesn't jump out of reverse now!).

Overall averages for last 12 months:

Highway/Country/Trips: 32.7mpg (36.5 best, 30.4 worst).
Mixed (local/City/suburbs): 31.0mpg (33.8 best, 28.2 worst)

Overall average: 31.5 mpg... Not close enough to the 35 region was hoping for! The 32.7 mpg(8.64L/100km) average on trips isn't too bad though i suppose for a car over 30 yrs old. Haven't tried different distributors yet.

[ Edited on 11-9-2006 by ACE_76 ]

[ Edited on 14-9-2006 by ACE_76 ]