Would you purchase a Four cylinder car with 8 spark plugs?
What's with Ford and other manufacturers who make a 2.5 litre Four with 8 spark plugs?
And why is this beneficial?
No! These trucks get horrible gas mileage! We've had a few of them as delivery trucks at my job and we were always putting gas in them! The "extra" spark plugs are supposed to fire and continue the combustion process of the exhaust gasses as they leave the engine. Something that GM pioneered back in the mid-60s with their Air Injection Reaction System. The difference is that system doesn't kill your gas mileage. HTH. -Jim
I see, but, you know, the Honda Fit/Jazz uses this technology? I'm not advocating it rather wanted to hear what others think of this. I think its not particularly common and also complicates the ignition system unnecessarily. I thought this was mainly for smog controls?
js08016- here's another question for you, which engine runs cooler and more efficiently, a 2.5 Four or a 2.5 Five? They both have the same displacement, except the Four has larger cylinders as in the Subaru Outback vs. the smaller cylinders in a VW Jetta. Would like to hear your opinion on that. Thanks.
You are correct, Markw1952. It's an emission (smog) control device. Just like GMs A.I.R. system it continues the combustion process in the exhaust manifold. It's designed to reduce hydrocarbons (HC) and CO2 emission levels from the tailpipe. We had a few of these Rangers at work and in addition to being gas hogs they didn't last nearly as long as the Chevy S-10s that we were using. The last Ranger we had was a 2000 model that was retired at just over 200,000 miles when the transmission quit. The S-10s easily hit 250,000 to 300,000 miles. We had one S-10 that was an '88 model. By 2001 it had hit 400,000 miles and was still going strong. Our Corporate Office contacted my Manager and told him he had to retire it. They were concerned about "structural integrity" of the vehicle. I really don't know which engine would run cooler and more efficiently, the 4 or 5 cylinder. But if I had to pick I'd say the 4 with it's larger cylinders. It most likely breathes better so it makes sense to me that it'd run cooler and more efficiently. HTH. -Jim
Jim, thank you very much for your response, very informative. I have to say that my Subaru 2.5L boxer engine runs very smoothly and has plenty of power for me delivering decent fuel economy for the kind of car it is with AWD. Here's a picture of the layout of the engine and some information about how efficient and smooth H4 motors are.
Jim, it seems to make sense that the larger piston and rings of the 2.5 Four and the structural integrity of the larger cylinder walls would make it a stronger motor than a 2.5 Five cylinder. I've heard that Five cylinder engines are incredibly balanced, but, knowing that boxer engines by design are better at canceling out secondary imbalance than inline Fours, it seems hard to conceive for me that an inline Five would be any better at this. The design is still five cylinders that need a counter balance weight to deal with the cylinders moving up and down, whereas the horizontally opposed engine cancels the forces out naturally. Probably the only disadvantage I can think of on the boxer engines is the tight clearance for working on them, but, I don't work on my own cars.
Jim, also see this,
the ford ranger w/8 plugs is a good bet mine got good mileage and could out haul,and tow anything anyone has put out w/a 4cylinder. we we traded to a bigger truck it had almost 300k on it w/everything original except the general maint. stuff.the only reason js had prob is that 1 delivery drivers rag the vehicles and companies don't do proper maint on then
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