Fitting Dyna coils to 900SS with Bosch ignition

wa_pete · Post by **wa_pete** » Sun Oct 17, 2010 12:09 am

I've got a 5ohm Dyna coil kit ready to connect. Do I still use the ballast resistors?

thanks

Pete

rwhc80 · Post by **rwhc80** » Sun Oct 17, 2010 3:56 pm

G'day Pete,

We have just fitted a set of 5 ohm Dyna coils to a 78 SS with good results so far.
As far as the Ballast resistors go, we were told they were not needed, so have done away with them. Some body with much more knowledge than me may like to chip in as to why, but all good thus far.

The hardest part was fabricating a new bracket, as the Dyna's were a little bit bigger than the OEM coils, and as such did not fit the original bracket.

Cheers Rick

Geoff · Post by **Geoff** » Wed Oct 20, 2010 8:14 am

5ohm good without ballast resistors; I have 3ohm dyna plus 1.5ohm ballast with a Rita on my SS; with 3ohm alone the coil burnt out after 3000miles

wa_pete · Post by **wa_pete** » Wed Oct 20, 2010 2:27 pm

OK, thanks for the replies. I'll be onto it when I get home later this week.

Pete

MitchB · Post by **MitchB** » Wed Mar 16, 2011 7:46 am

Geoff -

I'm wondering - when your 3 ohm coils burnt out, did you then go to 5 ohm coils?

If not, curious as to why not? Is there an advantage to using 3 ohm coils with the ballast over the 5 ohm?

Geoff · Post by **Geoff** » Wed Mar 16, 2011 7:50 am

Good question! I had a spare dual output 3 ohm (they're usually sold in pairs) so that's why I used a 3 ohm with the ballast resistor. Same result, just using what I had to hand! The 5 ohm would be fine I'm sure.
Best
Geoff

MitchB · Post by **MitchB** » Wed Mar 16, 2011 8:09 am

Got it!

Just got a pair of 5 ohms for my '81 Darmah. Wanted to make sure I got what's best for me and other info confirms they work best without the ballast. Will be trying them this weekend...

Cheers.

Post by **BevHevSteve** » Wed Mar 16, 2011 9:49 am

Hi Mitch, yes as the product info says, remove the ballast on your bike when you fit those coils. Also, everyone else note that for the stock bosch pickups etc, 5 ohm coils works best on all street applications period. If you are going to install on a race bike and are willing to mount the coils lower and out in the wind so they can cool, then you can use 3 ohm coils without the ballast and not have any problems. If you install 3 ohm coils in the stock place or anywhere up under the tank etc where they will not get any wind they will self destruct due to heat very quickly.

The coil mount brackets that we stock will save heaps of time over fabricating something to mount your coils although they will most likely still need further modification to fit your specific application.

By the way, I shipped your shocks out yesterday Mitch you should get them today or tomorrow.

MitchB · Post by **MitchB** » Wed Mar 16, 2011 10:09 am

Cool.

I'll be looking for them then.