Wanted - gas mileage estimate for Ghia with 1,600cc dp

[Greg Rickard]

I am looking to establish a reference point for the range of gas mileage (city versus freeway) that my '71 Ghia should be experiencing given its current engine set-up. I do not know how many miles are on the engine, but supposedly there are fewer than 10,000 per the prior owner.

I have tracked the fuel use of my car and do indeed know what it is, but I have not included that information in this post. Why? I am interested in getting input about what it should be rather than getting the discussion off track as to why it is not.

The engine is a 1,600 cc dual port with stock internals, and it has an "AD" series engine case number. Performance mods include a Weber Progressive 32/36 DFEV, 009 distributor, Pertronix ignition module, Magnacor spark plug wires, and monza exhaust.

The engine runs smoothly and quite well. I do all maintainance including valves, ignition timing, carb set-up and adjustments. Engine oil pressure is 28 psi at 2,500 rpms, and cylinder compression is Cyl. 1 = 137, Cyl. 2 = 137, Cyl. 3 = 145, and Cyl. 4 = 147. Timing advance is set to 30 degrees at 3,000 rpms and falls to 8-10 degrees at 825 rpms idle. Plugs are Bosch W8AC with gaps set at 0.030 inch (versus 0.028 factory spec) because of extra ignition zap from Pertronix module and Magnacor wires. Spark plug electrode color is a consistent tan / gray on all four plugs.

There are certain engine changes / upgrades that I'd like to make, but this is the current set-up that I am interested in getting mileage feedback about. Thanks!

[FJCamper]

Hi Greg,

I estimate highway at 25 to 30. Maybe 32 with a light foot and 60mph.

Heavy foot city may be 20-25 mpg.

Really good gas mileage was a 1200cc asset. The 1.5 and 1.6 litre cars, city and high combined, did well to average 25mpg.

Our 2011 2.4 family Sonata cruises at 70, with air conditioning and auto trans, at 30+mpg. And it amazes me.

FJC

[Greg Rickard]

FJC, thanks for the guidance. Your numbers are consitent with what I expected.

My Ghia's recent fill ups indicate about 14.5 mpg for suburban driving using "premium" gas (California, need I say more?). While it runs well, something is clearly wrong given the mpg. There are no leaks in the fuel line or gas tank. It does not get driven regularly, but that should not hammer mileage down to 14.5.

It makes me wonder if switching to a SVDA from 009 dizzy would help with maybe 2-3 mpg (from what I have read)?

Also, during the recent compression check, I observed that the cylinders pumped about 90 psi on the first turn over, about 120ish on the second turnover, about 135ish on the third, then hit the 140s on the fourth. Is that normal, or is compression a bit low on the initial turn overs?

Yes, gas mileage on modern cars is pretty good. My '02 Audi barge with a 2.7 twin-turbo and awd returns 25mpg at 70, and my '06 Lotus Exige 32mpg. Your Sonata is really sippin gas - a good thing.

[helowrench]

I get 23-25 depending upon:
state of tune
Time since last oil change
Percentage of highway driving

1600dp 34pict3 , extractor style exhaust, transistorized ignition(points still there, triggering the module, module fires coil)
I have been back and forth between the 009 and dvda and dvda used svda style, the smoothest driveability was with the svda set u
The svda did yield aconsistent mpg increase of 1.5 to 2.0 mpg.

[doc]

How about a look at the plugs? Running really rich/black? How about the choke? Is it shutting all the way off after warmup? Does the car idle high? Is gas dumping down the bowl due to a sticky needle & float in the carb? All common problems.

14.5mpg is too low, I think. Something amiss.

doc

[Greg Rickard]

doc, thanks for the suggestions. Spark plug coloration is consistently a tan/gray across all four of the plug's electrodes. The electric choke works as it should when the engine is cold and fully releases, with idle settling down at around 825 rpms, once warmed up.

I'll pull out my Weber 32/36 Progressive DFEV manual and check the specs on the needles and floats.

[volksbugly]

I had a progressive, I also had a wideband02 sensor hooked up. Initially I went progressive because I wanted performance and good gas mileage. I ended up having to run the progress fat to keep it idling well. Its an issue with heat on the runner. The center mount carburation really isn't good for economy. There is to many places for puddling to happen.
if your really wanting to go the economy route I would suggest you buy a widebandO2 sensor so you can dial in your tune.

I got from 7mpg to 27 mpg dual port and what I think is a 1600 cc


Cheers and good luck!

[Greg Rickard]

doc, the wideband02 sensor is a great idea. I'll check it out.

Yes, I chose a Progressive for the same reason - economy, with a little more performance when needed.

I am aware of the runner issue, but (when chosing the Progressive) I figured it would be less of an issue or not an issue at all given my location in Southern California.

The engine shows all signs of being happy - from decent compression, smooth idle, no flat spots, no oil use, no smoking, no gas odors, good acceleration (relative to a stock VW) - but the fuel mileage is obscene, which is why I have been stumped.

[volksbugly]

Your in the same boat I was, I have a question. Is it the empi progressive or the weber one? If its the empi one throw it in the trash.


I had continual problems with it. For one the power valve assembly didn't seal well. I ended up replacing it with a weber one. That improved idle tremendously.
If it has ever backfired you will want to replace the power valve assembly..(spring with a diaphragm)
another thing, pull out the fuel filter. is it a piece of crunched up plastic? mine was.

Also, I spent about 100 bucks on jets and emulsion tubes. and about 50 bucks on books. bleh! is all I can say.

This is a really good site for the proggie
hmm there used to be a thread about it on the samba, can't find it.
http://vw.zenseeker.net/WeberProgressive.htm



I love my EFI Now.

I would strongly suggest going with something like a pic-34, and then doing some sort of trigger system such as megajolt.

[Greg Rickard]

It is the Weber 32/36 DFEV.

[supaninja]

Your best bet for economy is to run the stock setup. The progressive weber has it's issues on ACVW engines and the 009 is what is really killing your mileage. 009's only us rpm's to determine the timing, with a vac advance dizzy it will advance your timing while cruising (low load). My motor is a type 4 motor so it's a bit of different animal but I'm running 45 of timing under low load. It makes a world of difference for mileage and throttle response. Don't read my thread because you'll want to go fuel injection, especially after seeing my mileage

[Greg Rickard]

Thanks for the tips. I am familiar with the 009 dizzy short-comings and am eyeing a SVDA set up. I used a Mallory Unilite SVDA dizzy on my '71 Morgan +8 when I souped it up and was thrilled by the ability to tweak the advance curve by just swapping springs...really dialed it in.

Fuel injection is a sweet set up.

My desire is to just get reasonable mileage given the Ghia's current set up...not chasing mpg or max performance. It is my wife's weekend ride, and adding the Progressive fed the hamsters enough to allow the Ghia to cruise at 70 mph on the freeway without feeling like the hamsters were verging on collapse.

[FJCamper]

Hi Greg,

Dual carbs are more fuel-friendly than a single center-mount stock or 2bbl. And the SVDA or almost any vac advance distributor is better for general economic street use than a full mechanical.

Also, slightly higher compression increases fuel mileage. I could count on getting 30mpg highway or better in my 1966 912 at a 70mph cruise.

A drop in fuel efficiency where all else looks good is often the beginning of a vac leak somewhere, making the carb run a little richer, but the extra air mixes with the extra fuel, and you don't see a rich condition. Of course, once the leak gets worse, performance symptoms appear.

Lastly, you might be getting doused with extra ethanol, and the more alky in your gas, the less mileage you'll get. 10% more ethanol mix means 5-10% less mileage.

FJC

[Greg Rickard]

Thanks for the feedback and tips. doc, the zen web site is a nice find. I had not come across that one before.

Being that I am the persistent type, I will take another crack at the Progressive set-up. I will try John's/Aircooled's set-up specs, check the float and needle while inside the carb, and make sure there are no air leaks at the manifold gaskets, boots and blocked off vacuum line.

Once performance and mpg are dialed in, I will then switch the 009 dizzy (came with the car) to a SVDA. Presently, I know what I have with the 009, and it is not a problem child like fuel consumption has been.

I plan to pull the engine just for kicks and inspect everything, and that will give me the opportunity to do some mild porting of the intakes and consider a bump in compression.

One thing that I have learned over the years while playing with cars is to - whenever possible - tweak one thing at a time.

[Slow 1200]

what exhaust are you running? does the manifold have adequate heat?

a warm air intake like the stock air cleaner has would help mileage a lot in cold weather

myself I would just run duals and have better mileage and power