Gas Mileage

Hi Steven- What do you know about the engine- yeah, it's 1600cc's, but what does it have for a camshaft? are the heads stock or bigger valves? ported? compression? stock or dual carbs, and if dual what are they? exhaust tubing size?

 

Normally a 1600 (unless it's a 7500rpm screamer) should get better than not quite 20mpg. When in town you can cruise around using lower rpm's at light throttle settings, realizing that at putting your foot into it (hills, for example) at lower rpms' will create heat and you'll have to downshift to get the rpm's and the fan speed up to where the engine will be making more torque and be able to cool itself better.

 

A number of factors will have a bearing on mileage- has it been properly aligned? do you know or are you taking the word of the previous owner? are all the tires inflated correctly? Is the engine tuned correctly (carb(s), valves, ignition)? does the car have a mechanical (is the advance plate moving freely) only or a mechanical/vacuum (is the vacuum canister working properly and is there enough vacuum from the carb) distributor? Even running thicker oil can be a (albeit small) factor in the car's mileage figure. To my knowledgable colleagues- if I've missed anything feel free to chime in...Al

That is definitely lower mileage than I would expect with a 1600.  I have a 1915cc with big Webers and average 25 mpg.  I tend to enjoy (ahem) the power I have but could almost certainly get better mileage if I behaved myself.

Maybe because my Speedster is not a daily driver and is one of the 'toy cars' owned I do not get concerned with 'gas mileage'. The Cobra gets around 13mpg, the '55 Chevy around 15mpg and the worst one for gas mileage was the pro-street, BB Ford powered '48 Anglia, with dual Carbs, and a wicked cam and my leadfoot it got around 7-8mpg.

 

I do not know the mpg for the Speedster yet but am pretty sure it is in the 20mpg range based upon our trip to and from Vail...we left home with a full tank, drove close to 400mi and returned with home with about 1/8th tank showing on the gauge.

 

If it is a 'toy car' why worry about mpg?

Fill it up with ethanol free gas and mileage will jump 4 mpg.  These old air cooled engines are polluters too - good thing they are exempt from emissions testing.

 

The '72 VW sales brochure said 25 mpg with 1/2 load at 3/4 top speed (of 81 mph so that's only 61 mph). 

 

Interesting site (scroll down to 70's):

 

http://www.fuelly.com/car/volkswagen/beetle

Wolfgang, that's a nice site. In looking at 70-72 VWs it looks like I'm right where I ought to be, especially if I take my lead Nikes off and take it easy just a bit. I'm sure I might be around 24-25 + mpg without the lead.

As far as my gas gauge, I thought I was getting 100 mpg, lol, and lucky I stopped to fill up. The gauge read between 7/8 to almost full, but it actually took 4.32 gal. for 85 miles driven, and should have been less than 1/2 tank showing on the gauge.
Any idea how to fix that?

Steven, how are you doing your fuel consumption calculations? Adding fuel and reading the odometer?  I ask because your speedo/odometer could be out. Before I got mine recalibrated it was out by 6 to 7 mph.  If your speedo is out (common with the speedometers in these cars) it could change your mileage numbers.

Check it with a GPS.

Well, a lot of cars coming out of the VS shop with "stock" 1,600 engines tend to run a bit rich, giving a bit lower gas mileage.  Nothing wrong with that, as a richer fuel mix also tends to make the engine run slightly cooler, too.  If you're running around town in 2'nd and 3'rd a lot, of course, your mileage will be lower from that, too.

 

Still, that engine with "normal" gearing should be sitting around 26-28 mpg, highway, after break-in.  Right now, with 900 miles on it, it'll still be tight and should see a few more MPG's by the time it hits 3,000 miles or so.  Patience, Padewan......

 

Find someone who knows how to set the mixture screws on your carbs and try dialing them in a bit better.  If that doesn't help, then the next step is to get the carbs re-jetted, but for that you really should dial them in using a wide-band air/fuel mixture gauge to get them spot on.  Otherwise it's a trial-and-error process that takes time.

 

 

One way to tell what your jetting is like is to note how it responds from cold to hot- if it runs like a champ (after the first couple minutes) and seems to be a little flat when at operating temps it could be a little rich; if it doesn't run well until it's fully warmed up it could be a bit lean.

 

If the tailpipe is pretty black and you can adjust a carb, check what size idle jet (or jets it it's dual carbed), source 1 size smaller, install, tune, and see how it runs. You'll know when you go too small. Accurate tuning before widebands was possible; it just took longer and was a little more trial and error. 

 

PS- Steven- does the engine have a mechanical/vacuum advance distributor (commonly called svda) or a mechanical only? If the engine has an 009 (or clone) with only mechanical advance, that's 3-4mpg lost right there. 

ALB good point on the Speedo/odo being off.  Especially true if not running stock size tires for which gauge was designed.  OEM VW/356 would have been 155-165/80x15 which is becoming hard to locate these days.  I always like the Miata tire size calculator for comparing tires size and rotational/revs per mile differenced. Folks even spend extra to re-gear their transaxles and then fit smaller tires - resulting in no change at all.  The new SE/Beck VDO repro speedos are GPS based so speed and odo are accurate.

 

http://www.miatatirecalculator.org/

GR, I wish I got that kind of mileage. From what it sounds like, 400 miles on an 8 gallon tank, you're getting almost 50 miles to the gallon. Yikes.

Good point. I will definitely check it with a gps. I've been taking the trip Miles and simply dividing it by the gallons at the pump. Hopefully the odometer is not off in the wrong direction, making my mileage worse ������

Drive a measured mile at 60 mph indicated, should take exactly one minute. Or turn on GPS in your phone and read the speed.

 

Gas gauges are all pretty inaccurate. You can bend the arm some, but I want accuracy at the empty end of the gauge. As it is, I usually get gas once the needle goes down past 1/4 tank.

 

I have a very well tuned and powerful 2165, and I get 25-27 around town. I get 32 on long interstate trips as well.

I thought of this last week, but have been away for a few days:

 

Does your speedo show in miles per hour or kilometers per hour?  

 

It should tell you somewhere on the bottom of the face. (M/hour or K/Hour or something like that)

 

Just curious......

Gordon, you are exactly right. I just drove from NY down to Maryland and visited Bruce and Cory in my Spyder.

 

I initially was very pleased to have returned 28.5 mpg to Bruce's house! But I soon figured out that my speedo is a little fast, indicating a few more mph and miles on the odometer than actual. At 65 it is about 5-6% off, so more like 26.5 mpg. which is totally fine considering I was running anywhere between 70 and 100! 80-85 mostly, for LONG stretches of interstate. Not bad for a little "kit car" with plenty of power, good jetting, and tall gears(3.44:1 final, not a typo).

 

P.S.: My speedo is in smiles per mile......

"My speedo is in smiles per miles..."

 

Danny, that's a great phrase!  I hope I feel the same soon.

 

It's going to be hard for you to smile at speed when you look like this:

 

 

That'll be me going across the Prairies...

I think you should be looking at it from the right side.... 

28.5 mpg, mostly 80- 85 mph interstate driving on the last tank. First one since the twin-plug deal I haven't been standing all over it on back roads.

 

I've bot done worse than 22 mpg since I got my wide-band and started playing, no how idiotic I'm being.