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badufay Samba Member
Joined: December 13, 2010 Posts: 361 Location: Olympia, WA
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Posted: Thu Dec 22, 2011 12:12 pm Post subject: DIY: Here's how to add a Relay to an electrical circuit |
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VW Beetles push a lot of power through the ignition switch. This part (IMHO) is the biggest contributor to voltage drop in VWs. Even with new wires, connectors and switches, these cars can easily exceed 3% in voltage drop (13.5 volts at batt w/ car running, then no electrical item should have less than 13.1 volts)
This is why I run relays on every major power consuming item in my car (wipers, headlights low & high, coil, rear defroster, and after market heater assist fans) ...here is a picture of your standard 12 volt relay setup you can buy at any auto parts store for around $6.
Adding a relay simply uses the original power wire as a switch to the relay with minimal power required. I'm sure this will offend many because it didn't come stock, so feel free to call me "The P.O."
Besides improving the electrical systems overall performance and safety of your car, it can also help with engine performance gains (calm down, I'll explain). Again, voltage drop in these cars is going to happen...The (+) wire to the coil runs a long way before it actually reaches the coil, this added distance and things mentioned earlier can often times leave your coil 2 whole volts below the battery voltage. This alone will impact voltage to the spark plugs, thus reducing power and fuel economy. A full shot of power to the coil and from the coil will have your ignition system running like new, if not better. It has been my experience that voltage issues to the coil are the biggest problems with point replacement products like pertronix (that and being hooked up backwards). Pertronix states that when using their product, spark plug gaps can be increased by 0.005", which means you can gap your VW plugs (NGK B5HS) to about 0.030"! I know some will argue that its nothing but a points replacement part, I can tell you on my 1600 w/ a relayed Bosch Blue coil and pertronix, my car runs amazing with a gap of 0.030".
Feel free to disagree, but hopefully this can help some people out.
Below are some diagrams I made to show exactly what I'm talking about...(note, some circuits have the fuse on the other end of the on/off switch, but the principle is still the same)
here is a picture that shows the stock setup....lots of amps being pulled a long way and through a ton of contacts and switches
now here is a picture showing a relayed circuit. The "switching power is reduced to minimal (can be as low as 4 volts in a lot of cases, putting "zero" load and stress on the VW system. The main power comes directly from the power source through the relay (which is made to handle 30-40 amps, plenty for a VW system)
_________________ Current: 1976 VW Bus, 3 spd auto 2.0L FI; 2017 GTI S, 6 spd man; 2017 Jetta SE TSI, 5 spd man; 2006 Golf GL 2.0L, auto
Previous: 2015 Golf S TDI, 6 spd man; 2015 Jetta SE TDI, 6 spd man; 12 Jetta 2.5L, 04 Jetta 2.0L, 02 Golf 2.0L, 98 Jetta 2.0L, 98 Golf 2.0L, 98 Cabrio 2.0L, 95 Golf 2.0L, 87 golf GTI 16 valve 1.8L, 86 Cabriolet 1.6L, 80 Audi 4000 1.6L, 76 Audi Fox 1.6L, 76 VW Beetle 1.6L, 74 Audi Fox 1.5L, 69 VW Beetle 1.5L |
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Joel Samba Member
Joined: September 04, 2006 Posts: 11099 Location: NSW Australia
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Posted: Thu Dec 22, 2011 1:37 pm Post subject: |
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I run a relay on mine for the ignition circuit too and it made a huge improvement.
When I had a VW engine still I saw a 2 volt increase at the coil but the biggest improvement was how much faster my wipers operate when they are actually getting 14 volts.
Only comment I will make is if you run any sort of fan in the car on the ignition circuit it can cause feed back which holds the relay coil in.
I was having problems when my A/C was on if I turned the ignition off the car would run for about 1-2secs after till the fan stopped spinning as it was acting a generator and holding the coil in.
Took me a while to twig what it was, I moved the evap fan power to the "X" circuit (74 bug) to get it off the ignition circuit and problem gone.
A diode would also fix the issue. _________________ Quick little bug, you got a Porsche motor in that?
1974 Germanlook 1303 2.5 Suba-Beetle |
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badufay Samba Member
Joined: December 13, 2010 Posts: 361 Location: Olympia, WA
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Posted: Thu Dec 22, 2011 3:28 pm Post subject: |
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good point, I have no radio noise on mine.... mine also is off the X circuit on the ignition. Another nice thing about the relays is you aren't going to overload that circuit either since its just for switching power. The battery is where the large voltage draws are coming from _________________ Current: 1976 VW Bus, 3 spd auto 2.0L FI; 2017 GTI S, 6 spd man; 2017 Jetta SE TSI, 5 spd man; 2006 Golf GL 2.0L, auto
Previous: 2015 Golf S TDI, 6 spd man; 2015 Jetta SE TDI, 6 spd man; 12 Jetta 2.5L, 04 Jetta 2.0L, 02 Golf 2.0L, 98 Jetta 2.0L, 98 Golf 2.0L, 98 Cabrio 2.0L, 95 Golf 2.0L, 87 golf GTI 16 valve 1.8L, 86 Cabriolet 1.6L, 80 Audi 4000 1.6L, 76 Audi Fox 1.6L, 76 VW Beetle 1.6L, 74 Audi Fox 1.5L, 69 VW Beetle 1.5L |
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ret1614 Samba Member
Joined: March 30, 2009 Posts: 130 Location: Sonora, CA
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Posted: Thu Dec 22, 2011 4:48 pm Post subject: |
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Make this a general relay thread?
I'll add a "safe" fuel pump wiring diagram.
The ten second prime function can be removed by connecting R2-85 directly to the oil pressure sender. _________________ 1970 2180cc Baja Bug. All go and no show...
Rattlecan white to cover the hideous 49er warpaint.
Looks like Hell, but she goes the same way.
______________
Mal evolent wrote: |
beer after, not during |
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badufay Samba Member
Joined: December 13, 2010 Posts: 361 Location: Olympia, WA
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Posted: Thu Dec 22, 2011 6:29 pm Post subject: |
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nice! Here is an example of relaying the headlights too... (not mine, but I used this when I did mine, found this from another thread)
_________________ Current: 1976 VW Bus, 3 spd auto 2.0L FI; 2017 GTI S, 6 spd man; 2017 Jetta SE TSI, 5 spd man; 2006 Golf GL 2.0L, auto
Previous: 2015 Golf S TDI, 6 spd man; 2015 Jetta SE TDI, 6 spd man; 12 Jetta 2.5L, 04 Jetta 2.0L, 02 Golf 2.0L, 98 Jetta 2.0L, 98 Golf 2.0L, 98 Cabrio 2.0L, 95 Golf 2.0L, 87 golf GTI 16 valve 1.8L, 86 Cabriolet 1.6L, 80 Audi 4000 1.6L, 76 Audi Fox 1.6L, 76 VW Beetle 1.6L, 74 Audi Fox 1.5L, 69 VW Beetle 1.5L |
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ghia4mea Samba Member
Joined: July 23, 2007 Posts: 478 Location: Largo Florida
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Posted: Thu Dec 22, 2011 7:42 pm Post subject: |
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A sad note about relays:
I have purchased several automotive relays at my local parts chain store.
(Advanced Auto Parts)
The relays are marked as 40 amp relays but when I took them apart, inside was soldered a small 5 amp relay.
These relays are of course from china. They look exactly like the regular 40 amp automotive relays that have been available for years at most auto stores.
I mention this just to make everyone aware of this latest rip-off.
Not an issue if your device is low current, but a big issue if you are trying to operate a high current device.
Good Luck all. |
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BugMan114 Samba Member
Joined: March 22, 2007 Posts: 3744 Location: Ellenwood, GA
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Posted: Thu Dec 22, 2011 7:59 pm Post subject: |
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i work at advance auto, and yes, the cheap ones do suck (the ones that are located on the light isle, and in the horn isle). I use the BWD or intermotor ones in the back (the ones that are for fuel pumps, or horns, or whatever). they are much heavier, and last a hell of a lot longer (i have yet to kill one), but i've killed about 3 or 4 cheap relays. the downside, is the nicer ones cost about $20 each. _________________ 1974 Super Beetle: Custom resto in progress
1972 Super Beetle: Daily Driver
1971 Std. Beetle w/ 1929 Mercedes Benz Gazelle kit
1960 Baja Bug
1969 Baja Bug
Sand Rail- Homemade
Sand Rail- FUBAR
Aircooled Airheads
Why the hell do they call it a gland nut. its obviously a big fat bolt!!! |
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Chris Vellat Samba Member
Joined: April 09, 2004 Posts: 1590 Location: Seattle, WA
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Posted: Thu Dec 22, 2011 9:10 pm Post subject: |
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Relays also don't care about polarity, either 85 or 86 can be wired positive or negative, they just cannot be the same...and on a simple relays with only an 87 that holds true for 30 and 87.
Relays can also supply switched grounds, or be switched by ground, when I wired the relays for the heater booster and rear window defrost in my `69...power is present at 85 and 30 with the key on, and a switch at the dash grounds 86. I used several Autostick insulated lamp holders in the speedometer that also have power with the key, and the switches that supply the relays with grounds also ground the lamps.
I've used 75amp relays to add additional fuse panels to my Bus and my Beetle...and fuse the igntion coil off of that fuse panel. |
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ret1614 Samba Member
Joined: March 30, 2009 Posts: 130 Location: Sonora, CA
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Posted: Thu Dec 22, 2011 11:10 pm Post subject: |
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Be careful about the polarity switchup with 85 and 86. Some relays will burn up if you hook them up backwards... Like the one I use for the 10 second delay. They usually are marked on the diagram on the side positive or negative if it does matter. _________________ 1970 2180cc Baja Bug. All go and no show...
Rattlecan white to cover the hideous 49er warpaint.
Looks like Hell, but she goes the same way.
______________
Mal evolent wrote: |
beer after, not during |
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Chris Vellat Samba Member
Joined: April 09, 2004 Posts: 1590 Location: Seattle, WA
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Posted: Thu Dec 22, 2011 11:15 pm Post subject: |
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ret1614 wrote: |
Be careful about the polarity switchup with 85 and 86. Some relays will burn up if you hook them up backwards... Like the one I use for the 10 second delay. They usually are marked on the diagram on the side positive or negative if it does matter. |
Oh yes, I meant to say when using simple 'automotive' 12VDC SPST 20/30/40A Bosch/Tyco/Hella style relays.
Quote: |
Tyco Electronics has acquired the automotive relay business of Robert Bosch GmbH and is now manufacturing this relay to the original Bosch specifications. |
http://ecx.images-amazon.com/images/I/419Oc8wOw3L._SS500_.jpg
http://www.amazon.com/HELLA-003510082-SPST-Relay-B...mp;sr=1-25
Last edited by Chris Vellat on Thu Dec 22, 2011 11:22 pm; edited 1 time in total |
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ret1614 Samba Member
Joined: March 30, 2009 Posts: 130 Location: Sonora, CA
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Posted: Thu Dec 22, 2011 11:18 pm Post subject: |
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Submit requests for relay wiring diagrams? I'll make them, just give me the wiring diagram for the load and the supply. _________________ 1970 2180cc Baja Bug. All go and no show...
Rattlecan white to cover the hideous 49er warpaint.
Looks like Hell, but she goes the same way.
______________
Mal evolent wrote: |
beer after, not during |
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dingdow Samba Member
Joined: December 13, 2011 Posts: 20 Location: Clearfield, Utah
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Posted: Fri Dec 23, 2011 1:11 am Post subject: relay wiring |
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I would like to change my headlight, wipers, emergency switches to toggle switches. (I like they way they look and feel). Can you design a wirng diagram to do this for a 68 bug for me?? Thanks - Ding |
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MagmaJctAz Samba Member
Joined: November 26, 2011 Posts: 289 Location: Mesa, AZ
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Posted: Fri Dec 23, 2011 4:26 am Post subject: Re: DIY: Here's how to add a Relay to an electrical circuit |
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badufay wrote: |
Adding a relay simply uses the original power wire as a switch to the relay with minimal power required. I'm sure this will offend many because it didn't come stock, so feel free to call me "The P.O." |
I'd only complain about you being the "P.O." if you screwed things up. I prefer to keep things stock, don't get me wrong. But a few "enhancements" never hurt. When people start gutting systems because they have no automotive background, and they don't understand, and refuse to learn anything, it upsets me.
This holds true for vehicles other than VWs. I've seen where a vacuum operated vacuum control valve was connected backwards causing a constant vacuum leak. To "correct" that, either the same person, or the next in line disconnected several vacuum lines from the solenoid bank and plugged them with screws. With so many things disabled, no wonder there were problems.
What you are doing is improving an old and worn out system. I've used a relay in my starter circuit for over a decade. Despite popular belief, Ford started solenoids are not needed to bypass the starter circuit in an ACVW. In fact, they pull nearly as much current as the VW starter solenoid. A good automotive relay will work the best because it pulls a small amount of current vs. the Ford option.
I made the change after a trip to emissions here in Arizona. Unfortunately I moved here during the month of July, so my emissions requirement is forever in the summer. I was sitting in line for about an hour. It was so hot I would get out of my Bug and sit under a tree leaving the engine idle. When I pulled in I was instructed to shut the engine off. To my disappointment the "driver" wasn't able to get the engine to start, nothing. They made me leave, and gave me a push. I pop started it as they pushed me out of the bay and drove home.
When I got home I shut `er down and started `er right back up. I was pissed. I went to Radio Shack and bought an automotive relay and installed it under the back seat. I've never had a failed start for that problem since. (I have had rabbits eat my starter wire however!) _________________ 1974 Super Beetle. Owned since 1995. Daily Driver. Turned over odometer twice!
1971 Fastback. Check out my Fastback resurrection thread!
http://www.thesamba.com/vw/forum/viewtopic.php?t=627711&highlight= |
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ashman40 Samba Member
Joined: February 16, 2007 Posts: 15985 Location: North Florida, USA
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Posted: Fri Dec 23, 2011 5:46 am Post subject: |
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I'd buy the SPDT version of the relays. They have the same terminals numbers plus an additional 87a terminal which is normally closed with 30 when the relay is NOT energized. They are more common and therefore less expensive... even for real Tycho (previously Bosch) brand:
http://www.amazon.com/Install-Tyco-Relay-Volt-Each/dp/B000P61E36/
PartsExpress carries a variety of relays and harnesses:
http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=746 _________________ AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!} |
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banditwolf Samba Member
Joined: April 03, 2011 Posts: 617 Location: oHIo
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Posted: Fri Dec 23, 2011 6:42 am Post subject: |
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Could someone tell me how to wire these relays?
Fused Relay from a 79 rabbit fuel pump #896321, it has 30,87,15,31,31b
Relay from Gm cars #14100455, it has 30,85,86,87,87a
Also how can I tell the Amps on a relay?
A relay would help out power windows right (on another car)? _________________ 1973 Super Beetle l 1981 Trans Am |
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mondshine Samba Member
Joined: October 27, 2006 Posts: 2770 Location: The World's Motor Capital
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Posted: Fri Dec 23, 2011 8:57 am Post subject: |
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The "Rabbit" fuel pump relays are the best way to go for wiring an electric fuel pump.
30 is connected to Battery+ (fused!)
15 is connected to Ignition (+12V with ignition switched on)
31 is connected to chassis ground
31b (sometimes labeled 1) is connected to terminal 1 of the ignition coil; where the green wire from the condenser is connected.
87 is the supply current to the pump; it will show +12V with the ignition switched on and the engine turning.
Good luck, Mondshine |
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Chris Vellat Samba Member
Joined: April 09, 2004 Posts: 1590 Location: Seattle, WA
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Posted: Fri Dec 23, 2011 9:03 am Post subject: |
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banditwolf wrote: |
Could someone tell me how to wire these relays?
Fused Relay from a 79 rabbit fuel pump #896321, it has 30,87,15,31,31b
Relay from Gm cars #14100455, it has 30,85,86,87,87a
Also how can I tell the Amps on a relay?
A relay would help out power windows right (on another car)? |
http://www.truckerac.com/blower-relay-chevroletgmc-oem-22552019814100455.html
The GM relay looks like a regular SPDT relay...there's usually an indication of the amperage limit on the housing...according to this website it may be 30/40A.
The Rabbit fuel pump relay is easy, the German wiring system went unchanged. We know 30 is used as fused power, 87 will feed the device, 15 is ignition coil power, 31 is ground, and 31B is intermittent ground - which in this case comes from the negative side of the ignition coil (same as the tachometer and condensor) |
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johnnypan Samba Member
Joined: October 24, 2007 Posts: 7431 Location: sackamenna
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Posted: Fri Dec 23, 2011 9:50 am Post subject: |
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Relays allow low amperage control switches function high amperage tasks,they are used in modern cars to reduce cost of components and wiring.
Use in Volkswagen applications,from starter relays to headlight relays is generally to mask a failing switch,harness or component.Much easier and less complicated to repair the bad Vw component than to wire in a relay. |
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19super73 Hardcore Stock Nazi
Joined: October 18, 2007 Posts: 4351 Location: Cité Soleil
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badufay Samba Member
Joined: December 13, 2010 Posts: 361 Location: Olympia, WA
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Posted: Fri Dec 23, 2011 10:16 am Post subject: |
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Gotta hard time believing that you're not showing a 3% voltage drop on your coil even with good wiring.... _________________ Current: 1976 VW Bus, 3 spd auto 2.0L FI; 2017 GTI S, 6 spd man; 2017 Jetta SE TSI, 5 spd man; 2006 Golf GL 2.0L, auto
Previous: 2015 Golf S TDI, 6 spd man; 2015 Jetta SE TDI, 6 spd man; 12 Jetta 2.5L, 04 Jetta 2.0L, 02 Golf 2.0L, 98 Jetta 2.0L, 98 Golf 2.0L, 98 Cabrio 2.0L, 95 Golf 2.0L, 87 golf GTI 16 valve 1.8L, 86 Cabriolet 1.6L, 80 Audi 4000 1.6L, 76 Audi Fox 1.6L, 76 VW Beetle 1.6L, 74 Audi Fox 1.5L, 69 VW Beetle 1.5L |
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