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Old 05-03-2012, 05:28 PM   #1 (permalink)
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Phantom Blot (Spökplumpen in swedish) - '75 Saab 96 V4
90 day: 52.77 mpg (US)
Thanks: 15
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Thumbs up 10-15% reduced consumption after "engine split" (physically deactivating 2 of 4 cyl.)

Hi guys! This is my first post at this forum. My primary language is swedish so my english may look a bit odd here and there.

I had a small 1981 Fiat 127 with a 4-cyl 1050cc OHC and four-speed gearbox. -A tiny and old-fashioned budget car with fuel consumption like a modern medium sized car. In Europe we don´t use "mpg" to describe fuel efficiency. Instead we use liters per 100km. My Fiat used to consume at least 6,5.

Some years ago I got this brutal idea to reduce fuel consumption by ripping out two pistons from a 4-cyl engine. I thought the modification would reduce the piston- and bearing frictions and increase the combustion pressure or actual compression ratio. Two years ago my already quite worn-out Fiat engine seized in one of it´s big-end bearings and it was not worth the money for a proper repair or engine replacement.

I thougth "what the hell..." and ripped out 3:rd and 4:th pistons with the engine still in place in the car. I also modified the camshaft and lifters to "kill" the valves not needed. The lubrication orefices on the crankshaft for piston 3 and 4 were welded shut. I finally re-used the cyl-head gasket with some "permatex" gasket seal.

To my big surprise and hapiness the engine did not only start and run, it kept on running for over 40.000 the following year and was still running well when I sold the crappy car as spareparts. I consider my theories proven but the reduction in fuel efficiency turned out less than I expected. A reduction of "only" 10-15% at unchanged avrerage speed must be called a success regardless of my expectations.

I have been driving old cars with verry weak engines for many years but with an increased interest for fuel efficiency and eco-driving I learned a lot that year. I now drive a 1975 Saab 96 V4 that is much bigger, about 100kg (220lbs?) heavier but with much better aerodynamics. Maybe one day I will try to repeat my "engine split" with this much more suitable car but since my old Saab is the family car I have to be prepared for some yelling from my wife and children... I guess however that the Saab V4 engine (a 1500cc/65hp V4 from Ford) have better margins than the tiny Fiat engine (1050cc/45hp)

Anybody who havre hearde about this kind of crazy and brutal modification? I suppose a fifth gear will achive at least the same improvement in fuel efficiency but as a relatively easy "quick-n-dirty fix" on an old car with four-speed gearbox it can definitely be a way to reach good results. Combine this with improved aerodynamics and reduced weight and it can be a true success!

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baldlobo (05-04-2012), Cobb (09-14-2012), ECONORAM (11-23-2012), Frank Lee (07-21-2012), MetroMPG (05-03-2012), Piwoslaw (05-04-2012), t vago (05-04-2012)
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Old 05-03-2012, 05:36 PM   #2 (permalink)
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Phantom Blot (Spökplumpen in swedish) - '75 Saab 96 V4
90 day: 52.77 mpg (US)
Thanks: 15
Thanked 53 Times in 29 Posts
Here´s my projetc blog (mainly in swedish but with a lot of photos):

Projektblogg - Fiat 127 engine downsizing

Two movies of the car:





(since I´m new at this forum I don´t seem to be allowed to post URL:s befor my fifth post so you have to copy and paste)
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Old 05-03-2012, 05:37 PM   #3 (permalink)
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It has been discussed and I think somebody did it or is going to do it. I was considering it pretty seriously for a long while but the bottom line is, as long as the car runs well, I'm not all that motivated to mess with it, especially since some of us have predicted the potential econo improvement to be less than 20% which for my car would be less than 7 mpg.

I'm surprised you took out #3 and #4- did it shake and/or sound bad? I'd take out pairs 1-4 or 2-3.
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Old 05-03-2012, 05:39 PM   #4 (permalink)
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Join Date: May 2012
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Phantom Blot (Spökplumpen in swedish) - '75 Saab 96 V4
90 day: 52.77 mpg (US)
Thanks: 15
Thanked 53 Times in 29 Posts
Seems to be a bit tricky to post an URL as a new member. I got a message that URL:s can´t be posted before my fifth post. Gess I will overcome that problem soon...
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Old 05-03-2012, 06:05 PM   #5 (permalink)
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I'm currently working on a similar project. Inline 4 cyl gasoline engine. Cylinders 2+3 run in the conventional manner. 1+4 are steam driven using original exhaust valves as steam inlet and original intake as steam exhaust. Traditional radiator is substituted with a heat exchanger that sponges waste heat from engine coolant. Hot water is then pumped into a water jacket that surrounds most of the exhaust system raising it above boiling temperature. The steam engine purist cringe over this but there isn't enough real estate under the hood to accomodate a perpose built steam engine. I did a similar project a few years back using a radial inflow steam turbine mechanically linked to the crank via a cogged belt. 47MPG highway on a 26MPG epa. 150 rear wheel HP vs 118 advertised HP at the crank. Biggest problem was generating quality dry steam to eliminate water slugs that erode turbine blades. Reciprocating steam engines can tolerate some slugs without catastrophic failure. Have to fabricate custom cam core for this to happen but its in the works.
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Old 05-03-2012, 06:10 PM   #6 (permalink)
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Frank -

Quote:
Originally Posted by Frank Lee View Post
It has been discussed and I think somebody did it or is going to do it. I was considering it pretty seriously for a long while but the bottom line is, as long as the car runs well, I'm not all that motivated to mess with it, especially since some of us have predicted the potential econo improvement to be less than 20% which for my car would be less than 7 mpg.

I'm surprised you took out #3 and #4- did it shake and/or sound bad? I'd take out pairs 1-4 or 2-3.
Is it possible that JohnAh's Fiat engine was "pre-disposed" towards the pistons he picked for removal or is it a case of "all inline fours are the same"?

EDIT: Ok, the YouTube says the engine is "special" in terms of balancing?

CarloSW2
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Old 05-03-2012, 06:20 PM   #7 (permalink)
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Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
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I don't see videos; maybe his engine has balance shaft(s). Still...
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Old 05-03-2012, 06:34 PM   #8 (permalink)
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1999 Saturn SW2 - '99 Saturn SW2 Wagon
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Frank -

Quote:
Originally Posted by Frank Lee View Post
I don't see videos; maybe his engine has balance shaft(s). Still...
Here are "text blurbs" from the video :

Quote:
180 degree crankshaft

It runs more like a single piston 4-stroke than a parallel twin

The engine makes vibrations at low RPM due to the 180/540 degree separation of power strokes.
CarloSW2
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Old 05-03-2012, 07:09 PM   #9 (permalink)
mikehallbackhoe
 
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honda crx - '84 honda crx 1300
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I probably would have only removed the one piston, but good idea for getting some extra miles out of a broken car.
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Old 05-03-2012, 09:00 PM   #10 (permalink)
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Join Date: Jan 2008
Location: up north
Posts: 12,471

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,478
Thanked 3,252 Times in 2,056 Posts
You would have either put it back in or taken another one out within 10 miles! It's that awful.

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cylinder, engine, modification, pistons, saab

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