fuel consumption - Alfa Romeo Bulletin Board & Forums
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post #1 of 12 (permalink) Old 08-20-2018, 04:42 AM Thread Starter
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fuel consumption

Hello
I am a bit surprised with how high my fuel consumption is on my 2600 sprint.
Saturday, I drove 200 km on mixed highway ( max speed 90 - 100 km per h) and road (max speed 70 - 80 km per h), I ended up with approx 20 liters per 100 km. I noticed the same on previous trips.
According to the tech spec, it should be 14,5 liter per 100 km.
So that might be an indication that something is wrong with my car or that the spec from Alfa are optimistic even though it is from a time when they did not really care about consumption...
Thanks for your comments !
Lionel
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post #2 of 12 (permalink) Old 08-20-2018, 06:58 AM
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Hmm. I don't speak metric, but 14,5 liter per 100 km works out to 6.9 km/L, which Google tells me is 16.2 miles/gallon (a value that I can relate to). 16 MPG is a pretty high rate of fuel consumption and may suggest that your car is running rich.

But be aware that older, carbureted cars were never that efficient. We are now accustomed to electronic fuel injection, emissions regulations, etc. all of which lead to much better fuel economy.

Jay Mackro
San Juan Capistrano, CA

'63 Guilia spider
'65 Guilia Sprint GT
'67 Duetto
'91 164L

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post #3 of 12 (permalink) Old 08-20-2018, 09:03 AM Thread Starter
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Hi Jay,
Actually 14,5 l per 100km is what is in Alfa tech spec. I am much higher than that with my car since I do 20 l per 100km, which acc. to google is 14 miles per gallon.
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post #4 of 12 (permalink) Old 08-20-2018, 09:28 AM
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Quote:
I do 20 l per 100km, which acc. to google is 14 miles per gallon.
100 km per 20 liters = 5 km/L, which works out to 11.76 MPG (assuming US gallons). 5 km/L also equals 14.12 miles/Imperial gallon, which is the measure formerly used in the UK (perhaps Brexit will bring it back). I used this site: https://www.thecalculatorsite.com/co...onsumption.php to convert km/L to miles/gallon.

Regardless of the exact numbers, I agree that your 2600 was never very fuel-efficient, and may be poorer now than when it was new. Reasons might include:

- Lower octane fuel available today (that is certainly true here in California; not sure about Sweden).
- Engine wear resulting in lower compression.
- The engine's state of tune (ignition timing, carburetor jetting, ...)

Without knowing more about your car, it is tough to diagnose why it uses so much fuel.

Jay Mackro
San Juan Capistrano, CA

'63 Guilia spider
'65 Guilia Sprint GT
'67 Duetto
'91 164L

Last edited by Alfajay; 08-20-2018 at 09:40 AM.
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post #5 of 12 (permalink) Old 08-20-2018, 11:01 AM
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Quote:
Originally Posted by Alfajay View Post
Without knowing more about your car, it is tough to diagnose why it uses so much fuel.
I second that. Driving style matters, too (e.g. what gear and RPM range you're driving in). Constant speed and RPM on a level, uncongested freeway (i.e. a very boring drive) are the best way to get comparable results.

Although I don't trust Alfa's published fuel consumption rate, I would say your fuel consumption might be high for Solex carbs (I recall something like 16l/100km), but no big surprise if you use Weber 45s (or even Weber 40s).

-Ruedi
[SIZE="1"]'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, the car in my avatar, sold as resto project to Austria)
Maintainer of a private 2600 SZ register (not the one in the Netherlands).[/SIZE]
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post #6 of 12 (permalink) Old 08-22-2018, 08:05 AM
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MPG

I did 45 laps of Goodwood last month and got 8 mpg so that gives the bottom figure . 22mpg is good on a long run but a bit of a push on and it drops to 18 mpg. I am running tripple dellortos and high lift cams
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post #7 of 12 (permalink) Old 08-22-2018, 10:31 AM
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My 2300 engine (a developed version of the cast iron 2000) gets about 11-12 around town, and 23 during “brisk” highway driving.

It has high lift, reduced overlap cams, and 45 DCOEs with matched manifold.

The highway mileage is slightly better than I recall with an old 2000 using the 44PHH Solex carbs, but worse around town. My carbs are early 45DCOE9s that achieve their low RPM driveability by having rich transition circuits.

If you’ve got the original Solex carbs, they tend to wear in all the wrong places. This leads to mismatched fuel/air ratios from optimum, and even air flow and fuel ratio differences between carbs. Any of these things will negatively impact fuel consumption rates.

When they are new or freshly restored, they’re kind of fun carbs. The cost to correctly restore them is what leads many to switch to Webers, but that can be its own bag of monkeys.

Don P
Carson City, NV

Past Alfas...
59 102 Touring (first Alfa $500 running)
65 Sprint GT (2nd Alfa, $500 daily driver)
102 Sprint (never did anything with it, but wish I had)
74 Berlina (first new car - now certainly rusted into oblivion)
61 Giulietta Spider G-Prod Race Car (where is it now?)
84 Spider Veloce (rarely drove it, so sold it)
86 Quadrifoglio (Dull car - no more 115s for me)
1971 Montreal "The Full Monty". Fair winds and following seas

Current Alfas
59 102 Touring Roadster - restoration complete, enough Alfa for any rational man. Or irrational, for that matter
Oops. Add to the "present" list, 10204 01488, 2000 Touring Roadster project

And past...
Two 1946 Stampe SV4C (c/n 294 "Rocinante" - wife's favorite airplane. RIP), and c/n 235 "La Bon Temps Femme" (gone to a new home, but never forgotten)
Zlin 50LA (+9 -6 gees, titanium spar, 1200 lbs, 260HP rumored to now be in Brazil)
1946 Luscombe 8A
Starduster Too (recently spotted at the Nevada City, CA airport - over 20 years and an entire continent separating it from our stewardship in Binghamton, NY)
1955 Cessna 170B (wife taught me to fly tailwheel in this)

And present...
64 Mooney M20E ("Rambo". My faithful steed for over 40 years) Over 55 years old, and just returned from a trip to Argentina in him
Newest in the fleet
1967 Piper Super Cub on Wipline amphibious floats (a true "all terrain vehicle")
2010 Triumph Thunderbird


You can snap roll an Alfa only one time...
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post #8 of 12 (permalink) Old 08-22-2018, 10:41 AM Thread Starter
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Quote:
Originally Posted by tubut View Post
I second that. Driving style matters, too (e.g. what gear and RPM range you're driving in). Constant speed and RPM on a level, uncongested freeway (i.e. a very boring drive) are the best way to get comparable results.

Although I don't trust Alfa's published fuel consumption rate, I would say your fuel consumption might be high for Solex carbs (I recall something like 16l/100km), but no big surprise if you use Weber 45s (or even Weber 40s).
Hello
My car is with original Solexes. I changed all rubbers and seals with the help of a rebuild kit a few months ago.
And when I measured the 20 l / 100 km , I drove the car smoothly 99% of the time , between 2500 and 3500 rpm ...
So I probably need to dig into the adjustment of the carbs. Which scares me a bit....
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post #9 of 12 (permalink) Old 08-22-2018, 12:01 PM
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What is the reason this engine is so thirsty? Being more used to 2/3 of the engine (nord) 9-10l/100km (31MPG) are easily doable. Is it just the cars weight?

Learning, learning..
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post #10 of 12 (permalink) Old 08-22-2018, 10:19 PM
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Quote:
Originally Posted by caralio View Post
Hello
My car is with original Solexes. I changed all rubbers and seals with the help of a rebuild kit a few months ago.
And when I measured the 20 l / 100 km , I drove the car smoothly 99% of the time , between 2500 and 3500 rpm ...
So I probably need to dig into the adjustment of the carbs. Which scares me a bit....
How many miles on the carbs?

The throttle shafts and their bores can wear, creating leaks. There are several elements that serve to activate and synchronize the secondaries. These can create problems if they are faulty.

Don P
Carson City, NV

Past Alfas...
59 102 Touring (first Alfa $500 running)
65 Sprint GT (2nd Alfa, $500 daily driver)
102 Sprint (never did anything with it, but wish I had)
74 Berlina (first new car - now certainly rusted into oblivion)
61 Giulietta Spider G-Prod Race Car (where is it now?)
84 Spider Veloce (rarely drove it, so sold it)
86 Quadrifoglio (Dull car - no more 115s for me)
1971 Montreal "The Full Monty". Fair winds and following seas

Current Alfas
59 102 Touring Roadster - restoration complete, enough Alfa for any rational man. Or irrational, for that matter
Oops. Add to the "present" list, 10204 01488, 2000 Touring Roadster project

And past...
Two 1946 Stampe SV4C (c/n 294 "Rocinante" - wife's favorite airplane. RIP), and c/n 235 "La Bon Temps Femme" (gone to a new home, but never forgotten)
Zlin 50LA (+9 -6 gees, titanium spar, 1200 lbs, 260HP rumored to now be in Brazil)
1946 Luscombe 8A
Starduster Too (recently spotted at the Nevada City, CA airport - over 20 years and an entire continent separating it from our stewardship in Binghamton, NY)
1955 Cessna 170B (wife taught me to fly tailwheel in this)

And present...
64 Mooney M20E ("Rambo". My faithful steed for over 40 years) Over 55 years old, and just returned from a trip to Argentina in him
Newest in the fleet
1967 Piper Super Cub on Wipline amphibious floats (a true "all terrain vehicle")
2010 Triumph Thunderbird


You can snap roll an Alfa only one time...
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post #11 of 12 (permalink) Old 08-25-2018, 12:31 PM
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hi Lionel,

Although my car is gone some years already, a 2600 Sprint from '64 with original Solexes, I kept reasonable well track of fuel consumption as I overhauled the carbs and had one of the first 123 Ignition sets. After that I toured France and Spain and would be a bit more fuel efficient than the factory 14,5. I managed around 12 to 13 liters / 100 kms.

George
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post #12 of 12 (permalink) Old 08-25-2018, 11:22 PM
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Hi,
Since the 123 ignition installation my 64 sprint "drink" around 12 to 13 L/kms and before with the marelli distribution it was lot of more, around 16 L/kms.
When I have replaced the old distributor, the 3 carb are opened and seals changed, synchro. Besides synchronization does not last very long,
A walk in the Angevin vineyard does not empty the tank quickly but on an open road or highway, I would say there is no limit too. A trip to Nantes (250 km, go and back) with a cession on the ex-track of Venturi cars had me consumed the totality of the tank.

Laurent
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