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Posted: Tue Sep 06, 2011 12:12 am
by thrash
panda wrote:try & use as few as possible chassis grounding points. By that I mean its OK to connect 10 lugs under one bolt into the chassis.
What's the theory behind this bit of advice? I thought it was better to have a few thick cables going from the battery to a few spots on the chassis, to eliminate a single point of failure?
Posted: Tue Sep 06, 2011 4:32 am
by Lunacy
thrash wrote:panda wrote:try & use as few as possible chassis grounding points. By that I mean its OK to connect 10 lugs under one bolt into the chassis.
What's the theory behind this bit of advice? I thought it was better to have a few thick cables going from the battery to a few spots on the chassis, to eliminate a single point of failure?
I think he's meaning the earths from all the engine bay wiring loom etc. Having them all on one excellent earth, rather than having them spread out all over the place minimises the risk of one random one being bad, and causing all sorts of electrical mayhem.
Do you mean a few earth cables going off the negative battery terminal? I havn't heard of that before, other than the standard cable going to the chassis then the block.
Posted: Tue Sep 06, 2011 8:37 am
by Tamgesic
Panda you always mention earthing. ..I took your advice. Lol Good to be back on the site and havin a bit of a read :)
Posted: Tue Sep 06, 2011 7:00 pm
by adam169
Exactly what lunacy said it's better to have all wires to one good earth
I install one in a previous car and it made a big difference once installed it stoped voltage drop they are easy to make and I will be putting one in soon as I find the time
Posted: Wed Sep 07, 2011 1:52 pm
by panda
Earthing is a subject that could be debated forever.
Personally I don't trust the conductivity of the metal in the body of any motor vehicle to provide a garanteed earth return to the battery, especially when the car body gets a few years of weathering on it. Thats why I prefer to use a minimal number of connections to the body. This is not so crital in areas like the lights, etc. but in areas where information is collected by sensors for the engine management system, thats where the wiring & earthing is so important. I have even used shielded cable from the CAS to the ECU to prevent false triggering.
Sorry if I confused some of you, but I'm not suggesting a big pile of wires all connected to the battery negative terminal, I'm simply saying try to reduce the number of connections to the body.
Also bonding the engine to the chassis with heavy cables is essential, preferably one each side of the motor in case one gets a poor connection.
panda
Posted: Wed Sep 07, 2011 2:22 pm
by Mick
nothing beats a good earth...
once discovered alot of crap earthsbolted to the subframe behind the rear seat of a starion for stereo shit/fuel pump etc. ran a 2 guage earth from the battery -ve to 50mm within the said crap earth point/ cleaned the contact point as well as re lugging them.
immediately saw a .5V increase in potential at that point... which is a few l/min of fuel pump flow, not to mention lower current flow to whatever it was feeding.