Does HEI need a relay?

[Hazegray]

Yesterday I read an article regarding how HEI needs (?) 14 volts to operate at peak performance. I tossed this around in my head last night & was wondering if the HEI can be wired through a relay? Currently, my HEI is wired directly from my 30+ year old ignition switch.. %)

 

[Hazegray]

Anyone know if this is wise to wire your HEI via a relay?

 

[Hazegray]

Ha-ro? I can't believe no one would have an answer on this...

 

[A&Mbronco]

Cant really answer your question but I ran an HEI for about a year just using a 12volt wire from my ignition switch with no problems.

 

[Wes harden]

Yes an HEI can be run through a realy, and probably should due to the current demands. I am running a HEI set up using a Bosh 20 amp relay on a 66 vintage car. Works great and my ign switch doesn't get hot or melt.

 

[Hazegray]

Thanks Wes! Wiring up the HEI via a relay will also give me the opportunity to put in a hidden kill switch for theft prevention.

 

[ElJefe]

I don't know about the 14 volts... I have have driven a chevy station wagon with HEI and a bad alt and it ran just fine down to around 7 volts when it finally quit. I would be concerned with the power requirements... the HEI modules do have a rather large power demand compared to the old duraspark boxes. It may be wise to run a relay just so you don't have all that current running through 30 year old switches and wiring.

Chris

 

[76Broncofromhell]

I'm using the same HEI module (Delco #D1906) on my flat fender and I am wiring it through a 30 amp relay coming straight from the battery. From what I've heard from my buddy who runs these modules, is that they take a lot of power. I would recommend at least a 12 gauge wire for the power, but I went with 10 just to be safe.

 

[Wes harden]

Hei power demands

Remember folks that 1 wire is not only suppling power to the module but also the coil. Yes an HEI will run on less than 12 volts, until you nail it put those plugs under haevy load and you'll start missing. If you use a HP coil you need more power. I ran 30 amp slow blow fuselink ( 4" )and 10 guage wire from B+ power block on firewall, always hot direct to batt. To relay and 10 guage from relay to dist. Then I used 14 guage for the relay control side. On a side note the old coil + wire 7-9 volts will turn on the relay. I just conected to my old coil wire for control ciruit.

 

[Hazegray]

Wes, you made a good point for those converting to an HEI style ignition. With the relay in place, you don't have to replace the resistor wire going to the ignition.

Hey, this would make a great tech article!

 

[CRUZIN66]

i run a HEI, but its only got 12 volts. can anyone post pix so i can see how to wire it to a relay? how do you wire it to your ignition switch?

 

[Hazegray]

Your HEI should really only get 12 volts, but getting a constant 12v from an old ignition/wiring harness is the problem, especially if you have accessories hooked up to it. The relay basically takes power from the battery & switches it directly to whatever needs it, i.e., HEI, Headlights, accessories without going through the 30+old wiring harness.

However, like Wes mentioned, it doesn't need a full 12v to activate the relay. If you're swapping from an old points system to an HEI, the advantage of using the relay is that you don't have to trace down and replace the resistor wire from the ignition switch. Just use the existing wire to "trigger" the relay switch...much easier.

I believe the most common use of relays I've seen are for the headlight harnesses.

 

[Hazegray]

CRUZIN66, follow this link for Bosch relay wiring diagrams:
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=330-070&ctab=7#Tabs

 

[airman]

You guys keep giving me good ideas to do to my Bronco. I bet if I put relays on my head lights and HEI I will stop going through so many voltage regulators.

Are you guys just using the cheap realays like in an alarm or is there a special relay being used for head lights?

Jeff

 

[j.r.nice]

another idea......I run my HEI off one leg (of 3) of a Painless Circuit Boss.

If you are going to be running a lot of extra stuff I would consider one of these.

http://www.painlesswiring.com/webcatalog/cat-fuseblock.htm