Why?? two spark plugs per cylinder on my car???

Question

My Wife owned a Smart (3 cyl) ( and I own a Honda (4 cyl). both cars had two spark plugs per cylinder. my question is =
(1) What advantage does 2 spark/plugs give.????
(2) Do both plugs "fire" at the same time, or is there a minuscule time lag between "firing" ????
(3) Does It give a cleaner burn ????
(4) Have you any other interesting (to me anyway) comments/remarks on this type of arrangement ????
(5) Is the Alpha Romao "twin spark" a similar set-up
(6)THANK YOU

Answer 1

(1) What advantage does 2 spark/plugs give.????
Cleaner burn, more efficient, greater effect at maximum acceleration = more fuel pumped through engine / stroke
(2) Do both plugs "fire" at the same time, or is there a minuscule time lag between "firing" ????
Depends on the car
(3) Does It give a cleaner burn ????
Yes
(4) Have you any other interesting (to me anyway) comments/remarks on this type of arrangement ????
Developed for racing cars initially, I know Porsche used it for the 911 RSR in 1973, the easier option to extract more power is go for a bigger displacement engine but where the engine size is limited for the class, in that case under 3l they have to try everything to extract more power
(5) Is the Alpha Romao "twin spark" a similar set-up
Yes, and dates back to the 80's (for their road cars anyway

The only drawback as stated above is increased cost 2 x plugs and leads and coil / distributor etc.

6) Your welcome

Answer 2

Smart Car Spark Plugs

Answer 3

This problem to me is a basket case to answer after all your saying it fired up without 2 plugs in the engine but now it won't fire up.Do you even know if this engine has HEI or point ignition or do you know the difference.Secondly i would strongly suggest a new set of plug wires and along with that are you sure you got the right plugs.Some of the plug you have might be the wrong length or size.Plugs for some engine have short threaded plugs so they can seat into the heads all the way without any of them sticking up above the spark plug holes.Check to see if you have the wrong plugs if you have the long threaded type get the right ones for the right engine at a parts store and while you are there get new plug wires for that type of engine.And one other thing you might really check is to see if this suburban has a neutral safety starter switch that can cause a starting issue cause it is responsible for it not starting if you have no spark or to were it won't start at all.I am not there to see what you have to fix it for you but you also didn't say what type of engine and so forth you have.All I can do is just tell you in the dark of what your problem might be without knowing what type of car or whatever you have.But if you do get this started I would suggest to take it to a electrical shop to have a free electrical check done on it which would be the charging system check.

Answer 4

1) Just like in Prop Airplanes multiple spark plugs gives you less chance of a misfire or no fire on a cyclinder. Basically one backs up the other incase it fouls out. Not to mention it should enhance gas mileage Possibly anyways
2) Plugs fire at the same time typically per cylinder depending on distributor being hooked up properly
3) It does have the chance to burn off more "deposits" but my guess on this one would be no an explosion is an explosion
4) Not really except it's better to have two of everything than 1 right?
5) NOT SURE
6) Hopefully it helps

Answer 5

To get the kind of economy that they manage with these new world cars they have to every trick in the book , most people do not realise that petrol engines are only 70% efficient , which means 30% of your fuel leaves the car unburnt , then they developed catalytic exuasts ,that burns of the some of the residue to help clean up the enviorment but does nothing to help the economy of the car , Putting two plugs per cylinder burns about two more percetage of the fuel imparting an extra percentage of thrust . Result more economy

Answer 6

With two spark plugs per cylinder, they do not fire at the same time, One plug will fire on the compression stroke, and the other will fire on the exhause stroke. This cause the unburned fuel to be burned causing the car to run "cleaner". In my professional opinion it does not make any difference in the preformance of the car, it does, but for the cost of what you gain with a duel plug setup, it doesn't make that big of difference. Companies are using it as a nessisity rater then an option now. Remember when power windows were options, not it seems every car has them. its only a matter of time before every car goes to this set up. I am a mechanic, and when doing tune-ups on cars, the duel plug set up costs about dubble the price because you have dubble the plugs, only makes sence.

Answer 7

Hi tige
the whole two design is to meet emission standards
it is not a performance thing at all.
the second plug fires after the primary plug in doing so.it burns off left over combustibles thus reducing
the hydro carbs let out into the air we breathe
That da skinny from Kenny

Answer 8

because two spark plugs give it more of a chance to burn all of the fuel up and get the most out of the fuel. It's a very unique and fuel efficient design.

Answer 9

I had a Nissan Multi with 2 per cylinder, one is exhaust and the other an intake. It was for the sole purpose of cleaner emissions and it worked because the car was 20 years old and had passed every e-tests to that point. On mine they always fired(alternating:intake/exhaust) except under heavy load, then the intake fired alone.

Answer 10

to burn gas faster and more efficient // to comply with epa regulations// bunch of politics