Coil Relay

[Greg B]

Been reading up on this mod.
Is there any reason to mount the relay close to the coils?
As opposed to say farther back under the seat where there is
more room? (no air box)

[Datsa Noydb]

Main advantage of mounting it near coils is that you can use a lot of the existing wiring, but re-purposing it.

Use the existing wire that powers the coils to trigger the relay, just run one power wire to the relay, then split to the coils.

You could also mount the relay back where you are thinking, then trigger it by tapping into the ignition fuse, which will be real close by.

Nah, no real difference where it's mounted.

[BassCliff]

Hi,

I installed mine under the seat behind the battery box. I thought it would be better away from engine heat and in a place where I could replace it or bypass it more easily.

Thank you for your indulgence,

BassCliff

[salty_monk]

I'm with Cliff on that one. mount it somewhere with a bit of vibration isolation. Stick 3" piece of wire with a male spade in each end in the toolbag. If the relay goes out you can either connect the relay trigger wire to the coils (low voltage again) or hotwire the coils directly depending on how you jump the plug. Just remember to unplug when you stop if you hotwire them.

[koolaid_kid]

Yes.. No. The only difference is the length of the wire. If you use 16 gauge wire, you can locate it where you wish, as long as it in not in your aunt's bra in Toledo. Make your connections solid and test everything, and you should be GTG.

[posplayr]

the main cause of failure for a mechanical relay is vibration. It should be isolated as best you can from frame and engine vibration. Under the gas tank is NOT a good choice because of heat.

I did a writeup for a coil mod that minimized hacking the harness.

http://members.dslextreme.com/users/storagecliff1/images/DynaS_Coil_RelayMod.pdf

[Greg B]

Another question.
The Bosch Relay I have does NOT have the two #87 pins tied with a common.
It has 87a & 87, but the diagram on the side show them as seperate.
Can I still use this relay?
I am wanting to tie the sense wire from a new reg/rec into one of the 87 pins.
Or do I need to get a relay with the #87s tied together with a common when the relay is switched on?

[koolaid_kid]

Yes. 87a has power while the relay is off. 87 has power while the relay is on.

[Greg B]

Is that yes, I can use the relay I have?
Or yes, I need to get a relay where both #87 pins are tied together when the relay is on?

[Nessism]

Yes, that relay is fine.

[Steve]

If you want to use that relay to provide a "sense" signal for your R/R, you can NOT use the 87a terminal.
When you turn on the key and activate the relay, the 87a terminal will go dead, which is not what you want.

You will have to make a splitter for the 87 terminal and use that for your coils and your sense wire. One way is to use a small terminal block so all connections can be made easily.

It is getting hard to find relays with two 87 terminals. I think the last ones I found were at Auto Zone or Advance Auto, in the fog light section. You have to look carefully, as some will have an 87a, others will have two 87s. Look for relays with the Pilot or Blazer brand name.

.

[Greg B]

Ahh. I'll swing by Auozone after work & see of I can get the other relay.
Otherwise I'll go the terminal block route.

[posplayr]

Ahh. I'll swing by Auozone after work & see of I can get the other relay.
Otherwise I'll go the terminal block route.

Alternatively get the mating connector and connect twO wires to the single lead

[Greg B]

Good point.

[1_v8_merc]

Go to a junkyard, there's thousands of them, just pop any hood. Usually they're laying all over the ground. They probably won't even charge you for it... lol.