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Old 05-03-2012, 05:28 PM   #1 (permalink)
JohnAh
EcoModding Apprentice
 
Join Date: May 2012
Location: Vallentuna, Sweden
Posts: 129

Phantom Blot (Spökplumpen in swedish) - '75 Saab 96 V4
90 day: 52.77 mpg (US)
Thanks: 17
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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)