Difference between cdi box and ignition coil? - Snowmobile Forum: Your #1 Snowmobile Forum

TCOLLINS · 02-20-2008, 10:07 PM

whats the difference between cdi box and ignition coil?

Old Man · 02-20-2008, 10:30 PM

Simply put, the ignition coil provides the voltage for the spark, the CDI box controls the release of that voltage.

ENR_Kyle20 · 02-20-2008, 10:44 PM

I dont know if I can answer your question exactly. But The spark you see is a result of induction. There is 2 coils wound in very close proximity, one is the primary, and the other is the secondary. On a standard Ignation coil there is 12 volts applied to the primary coil at a certin time before spark is needed. Then when spark is needed the voltage on the primary coil is cut off. This causes the magnetic field to drop. the motion of the magnetic field droping induces voltage into the secondary coil wich is directly hooked to your spark plug.

from what I understand on a CDI sytem (capacitive-discharge ignition)they use a capactior on the primary side. So now its got more than 12 volts on the primary side wich induces even more into the secondary winding wich leads to a better spark.

I did a little research and found this.

CDI vs Inductive Ignition systems

Apparently CDI will spark stronger (Across a bigger gap) but the dwell is much shorter. So its good for a dirty engine. Or somehting that will have a hard to light mixture sometimes. but not ideal for everything

TCOLLINS · 02-20-2008, 10:45 PM

Are they both 1 piece?

TCOLLINS · 02-20-2008, 10:49 PM

very nice info. I am wondering if I have an ignition coil on my sled or just a cdi(C.D.Ignition) I have weak spark on 1 cylinder and ordered a new CDI Box. I am hoping this is what I need? I know I have a CDI box now.

98 polaris indy 500

**smallengineguy** · 02-21-2008, 09:12 AM

The CDI (Capacitive Discharge Ignition) controls spark for the coil, and the coil sends it to the plugs. You need a coil, not a CDI. Follow your plug wires backwards, they go into the coil. The small wires coming out of the coil go to your CDI.

TCOLLINS · 02-21-2008, 05:08 PM

Quote:

Originally Posted by smallengineguy

The CDI (Capacitive Discharge Ignition) controls spark for the coil, and the coil sends it to the plugs. You need a coil, not a CDI. Follow your plug wires backwards, they go into the coil. The small wires coming out of the coil go to your CDI.

I am totally confused. My plug wires go into a piece called C.D.Ignition(CDI Box?)From there they go to the bottom of the motor.The C.D.Ignition looks like this picture.I don't see a coil anywhere. Unless it is inside the motor.This part here is the one I ordered. It goes to the spark plugs. The other smaller wires go to the motor. Maybe that is where the cdi is?

TCOLLINS · 02-21-2008, 05:15 PM

Smallengineguy Maybe I am calling this part the wrong name. At this point the part is on the way. What ever it is called I hope its right.Please take a look at the picture and see if it's a coil?

The part In the picture above says C.D.Ignition stamped on it when I pulled it off the sled.

Homey88 · 02-21-2008, 11:58 PM

Quote:

Originally Posted by TCOLLINS

Smallengineguy Maybe I am calling this part the wrong name. At this point the part is on the way. What ever it is called I hope its right.Please take a look at the picture and see if it's a coil?

The part In the picture above says C.D.Ignition stamped on it when I pulled it off the sled.

That looks like what you need, its all conained in the CDI you orderd, from there it gets it signal from the stator.

**RJ Gleason** · 02-22-2008, 06:28 AM

Some of the POoo used a all-in-one CDI/coil unit.
More expensive to replace.

JDS · 02-22-2008, 08:04 AM

All in one; that's the right part. North Dakota, Suzuki, Polaris, Victory, Vespa, Piaggio, ATV, motorcycle, Scooter dealer, Action Motor Sports

lowbudget · 02-22-2008, 09:49 AM

Yup it's all one unit. I just did the one on my girlfriends sled. Polaris wanted 250.00 for one, plus dealer didn't have it. I got mine at my local bike shop from WPS as Parts Unlimited didn't show one. It was only 125.00.

TCOLLINS · 02-22-2008, 04:27 PM

Okay now it makes perfect sense. I thought I was losing my mind.