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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: team39763 on December 15, 2008, 08:38:45 am
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I finally relocated my battery and added a cutoff switch.
Can ya'll explain some things to me. Why and where do I need an inline fuse? From what I've been reading, it says within 12inches from the battery terminal. But before I moved the battery, I would just unplug my battery at night and connect it on days that I drive it. It didn't have a fuse back then, what's the difference now?
What about this alternator thing? My alternator is connected by the factory wiring going to the starter solenoid. Do I need to pull that harness apart and single out the alt wire and run it to the cutoff switch? My positive battery cable runs directly to the starter solenoid. I don't know if that's how things should be, but that's how my truck's been running for the last year.
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You're running a long unprotected cable through your body/chasis and need to install circuit protection. The closer to the battery the better. That's all you have to do.
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Ok. I'll order that inline fuse ASAP.
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I used a 50 Amp Maxi fuse. I bought the maxi fuse holder at PepBoys.
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I was reading and a few other guys used 200 amp fuse. Does it make a difference?
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Team, There are a couple things you need to be aware of. Per the IHRA/NHRA rules "The master cut-off switch must SHUT THE VEHICLE OFF when turned to the off position & must be clearly marked as such". The way you have it now, the alternator will keep the truck running. You need to run a wire back to either the + side of the battery or the battery side of the kill switch. I prefer to install a Ford type solenoid (some tractors/equipment have some similar or Painless has one too) near the battery, this leaves only a foot or so of live big wire. The rest to the front will only be live while cranking. The wire from the alternator should be fused/circut breaker, the current will flow both ways technically (from the alternator when the engine is running, but from the battery when it's not), so where to put the fuse/breaker is a toss up. Hope this helps, Lorne
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Your starter can pull well over 200 amps of current so if you don't want to be changing fuses like crazy make sure if you're going to install an inline fuse to use a 300 amp breaker. Do you need a kill switch that will kill the engine? If so there are several ways you can wire it up.
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Yes Vile, The rule states "Anytime the battery is relocated, a kill switch must be added to SHUT THE ENGINE OFF & ALL electrical power to the car from the rear of the car able to be clearly seen by track personnel".
This is one of the rules that has some gray things about it. A guy can drive up in a car that came with the battery in the trunk or worse, under the back seat & race without the kill switch & go real fast (something like 9.50) as long as he didn't move it. Move the battery to the trunk or the bed in our case, do a first class install (rubber hose protection, insulated clamps, ect.) & now you need a kill switch regardless of the speed. Especially with a truck, this seems kinda wrong to me. The battery is safer in the back & getting to it in a wreck would most likely prove to be easier than under the hood, but they make the rules. Lorne
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He never stated if he was relocating it for track rules or not.
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Yeah, it's for track rules.
Hey what's the minimum thickness I can run for the ALT wire to the cutoff switch? I can't afford to go buy 16ft more of 2ga. stock appears to be slightly bigger than 12ga. It's going to be about 16ft long too.
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He never stated if he was relocating it for track rules or not.
+1 I wasn't aware either.
My 50 amp maxi fuse is NOT in the red connection to the starter. It is in the main line powering the fuse panel.
This is my write up on the way mine is wired - I used a Pineless wiring harness:
http://forum.73-87chevytrucks.com/smforum/index.php?topic=7173.0
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Ok so what I'm looking at so far is: Add 300amp fuse in between battery and cutoff switch. Run Alternator wire all the way back to battery side of cutoff switch. That should get me NHRA legal.
Thanks for the link JJSZABO.
Another question - Will I be Ok using 8AWG wire to run from the ALT to the cutoff switch 16ft away?
EDIT: I just thought about it...can't I just wire my ignition controller to the cutoff switch. If I have no ignition, the motor won't run and the alternator can't charge. That would save me from having to run more heavy wire through the truck(found out 8ga won't work for ALT)...Right? My MSD box only requires 12v connection so I could just run that 8Ga wire back to the switch and be fine...Right?
EDIT AGAIN: Nevermind, I realized that won't work either.
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Team, The 8ga. from the alternator to the cutoff switch should be fine, you defiantly don't need 2ga for that part of it. I see your edit, yes, your correct in that it still wouldn't shut off. It is still the same problem, the alternator would still feed the MSD box even with the cutoff switch off. The alternator separated from the ignition by the master switch is what you need to end up with. As I mentioned, I just don't like the idea of 16'-18' of unprotected 2ga wire, the 8ga is much easier/cheaper to protect & having a few spares isn't such a big (costly) deal.
While we are on the subject... What do you have for a hold-down on the battery? There are a few rules there as well. May as well get it right the first time. Lorne
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I'm working on building something from the stock battery tray and some long aluminum straps(that used to hold down my fuel cell). But it has to be anchored to the frame right? As far as I know, we don't need a sealed battery box since we have the bulkhead and cab between driver and battery. I don't know exactly what I'm going to do yet though. What would you suggest?
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Team, You are correct, you do not need a box. The rule reads similar to this: The battery must be held in with (2) 3/8" bolts/rods, J-hooks must be closed & welded shut. Some type of metal retainer must secure the battery & be mounted to the frame/frame type structure. This leaves quite a bit to the interpretation of the tech at the track. Anything able to carry the weight & not tear-out if force was applied would seem to count as a frame structure (bedfloor braces, angle iron, square tubing of reasonable thickness across a span all seem to be adequate. You see those 1" or so tubing ones hanging to the outside of the frame on many cars, this all seems to be acceptable. Have Fun, Lorne
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Thanks Lorne. I really wasn't sure what I could get away with as far as holding down the battery. I think I could make some kind of fixture and secure it to the bed brace in the rear. I'll come up with an idea in the morning...LOL...my little peanut is fried from all the info and ideas I've come across the last few days. Thanks for the help everybody. I appreciate it.
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Yes Vile, The rule states "Anytime the battery is relocated, a kill switch must be added to SHUT THE ENGINE OFF & ALL electrical power to the car from the rear of the car able to be clearly seen by track personnel".
This is one of the rules that has some gray things about it. A guy can drive up in a car that came with the battery in the trunk or worse, under the back seat & race without the kill switch & go real fast (something like 9.50) as long as he didn't move it. Move the battery to the trunk or the bed in our case, do a first class install (rubber hose protection, insulated clamps, ect.) & now you need a kill switch regardless of the speed. Especially with a truck, this seems kinda wrong to me. The battery is safer in the back & getting to it in a wreck would most likely prove to be easier than under the hood, but they make the rules. Lorne
I would imagine a stock vehicle setup with battery in back is somewhat safe, since the manufacturer probably did a nice job of securing the wiring. Hopefully anyways.
I can certainly understand why they would want the cut-off switches on vehicles where the owner moved the battery, I've seen some shorted wiring for even just trunk mount stereo amplifiers that left quite the trail of destruction, through the whole vehicle practically. Wasn't pretty. ;D
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A company I worked for had a 2000 CHevy 3500 crewcab service truck burn to the ground because they didnt install a fuse for the crane, and one day it shorted out, and caught the wiring under hood on fire, and went from there. All because they didnt install a $60 200 amp fuse. Truck was totalled by the insurance company.
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I drew up a diagram of what I have in mind. Only thing I don't have yet is the 8ga wire and fuses. Does this look OK?
(http://i46.photobucket.com/albums/f143/team39763/Emmittsbatterreloc.jpg)
http://i46.photobucket.com/albums/f143/team39763/Emmittsbatterreloc.jpg
What does it mean to have the j bolts welded shut? I've seen how they are supposed to go, but what are you supposed to weld?
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Actually, you shouldnt need a 200 amp fuse for the alternator. Most likely you need closer to a 50 amp, depends on you alternator, plus with the sidtance you are running, it would be a good idea to fuse the 8 ga at the battery as well.
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Here's what I use instead of fuses. It kinda cleans up everything if installed right.
http://order.waytekwire.com/productdetail/M37/46374
I prefer the black one, but the smaller one is cheaper and works just as well. They have alot of other items you should look into as well. I buy a couple grand a year in parts from them, and am very happy with their service and products
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rest looks good
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I agree with Chop, you don't need a 200 on the 8ga wire, 100 would be fine. I also prefer the relays just like he posted. Myself, I would not want the big wire live all the time, but that's your choice. The way you have the picture will work & be legal though.
The part about the J-hooks is just what it says. If you use them, you need to put them through the hole in whatever & bend the loop-part shut & weld it to the upright part so the loop part can't spread open when put under pressure (the battery trying to fly out) . Lorne
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As far as sizing the breaker, it really depends on what size alternator you have. If the alternator is only a 35 amp, then go a 40 amp circuit breaker, if its a 60 amp alternator, go 65-70 amp. The circuit breaker isnt just to protect the wire, it is to protect the end devices as well, such as if the battery shorts out and causes the alternator to try to over amp, it will trip the breaker and save the alternator. Depending on the amperage of the alternator, 8 gauge wire could even be over kill. But for a run this long, over kill is good. Lorne is definately the goto guy on race specs, I am learning from this for when I start my race truck project. Just want to Thank you Lorne, for what you have taught me.
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I thought my alternator was 105AMP, so I would need a 110-115 right? I've been doing some reading and asking around and I'm not exactly sure what to do about the battery fuse. I heard that the starter can[at times] pull all the juice the battery can give, which would pop that 300AMP fuse right? A buddy said I probably shouldn't fuse the wire going to the starter at all. I believe my Optima Red Top says something about 1000CA and 800CCA.
LOL. I'm an idiot...thanks for explaining that to me Lorne. Hey what exactly can go wrong with my big wire being live all the time? I don't have the money to buy one of the those Ford solenoids, so I'm kinda stuck doing it this way for now. I have insulated clamps. I plan to heat/shrink/wrap the connectors on it too. I'm using rubber grommets to go through any sheetmetal. What else can I do to make this safer? Should I run the big wire through length of water hose to keep it insulated?
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The continuos duty relays ( ford type) are only about $25. They make a loom that you can wrap around the cable for protectionthat is cheaper than a water hose, but if you an old hose and the ambition to split it, why not. It will work just as well. I am not sure on the alternator output. My 81 with the heavy duty alternator was only rated at 65 amps. Let me think a bit, and see what I can find. Hopefully we can get this sorted out without breaking you financially.
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LOL. I think my wife is just about tired of me spending money on this truck and it still hasn't moved more than a few feet in the last few months. I'm gonna need to start selling some parts to pay for this stuff soon. I'm going to Uvalde in the morning, so I'll see what I can find and hopefully get this truck running again. I plan to post up some new videos with all the improvements I've made since the last clips.
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Team, I hate to sound like a "Father figure", however I like to help guys through their problems instead of them working harder, spending unneeded money or getting frustrated. A couple problems I see....If your wife is concerned about your spending, you need to be careful, just like anything else, this can lead to other bigger problems. Unfortunately not every guy can have a woman that is thrilled to get new sticky tires for Christmas ;) Or ask when we are going to spend the $900 or so on a good torque converter, instead of whining about me spending $300 on one, but that doesn't make your wife wrong & maybe her concerns are justified. On the same lines, if you don't have the money to buy the relay...wait until you do. If the truck burns up or even just blows up the battery or melts the coating off of the 2ga. wire, that would cost more than the "correct" relay, Right?
I realize most of us want more/better than we can afford (myself included) however, there has to be a logical "middle of the road" area that you (& your wife) can work in & still have fun.
I have one more to add to Blast's & Chop's stories. I had a pick-up come in the shop years ago with one of those slide-in electric dump inserts. Short version....The control wire comming in the cab chaffed on the floor & well you can figure the rest. We did fix it (the owner got the battery unhooked in time) but the whole Left corner of the cab was melted, burned, ect. Plus the wiring, switch, ect. Unprotected big wires run around & through are a big concern to me.
And I appreciate the Thank You's guys, but it's just part of what we do to make this the good site it is! Lorne
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I appreciate the help Lorne. My wife's concern is that I may be spending unnecessarry money. She likes to see results when I go spend $100 on something. So far the battery relocation has cost us over $100 - $48 for the right wire+cutoff switch + $56 for the wrong wire + $20 in little stuff. I don't even have the fuses/circuit breakers or 8ga yet. I just need to be educated and know what I need[parts/money] before I go ask for money.
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The main reason for breakers and fuses is to protect damage due to human error. Run what you have, put it in the hose, and when you are routing it, pay attention, and think about any cenario where the cable could be cut, pinched rubbed through, or damaged in anyway. Once done, check these possible problem areas often. The thing is, this isnt a truck that you are driving down the highway on a regular basis, and all the world could fall apart at a moments notice. The truth is, if you have a short in the cable, or something, you will most likely be right there cloase to it, and just have to shutoff the disconnect switch. But, as long as you take the time to route the cable away from harm, put it in a hose, doubleup on hose around corners, and tie it up nicely, I doubt there will be a problem. We all seem to forget that the little things get expensive, and not all are required. It depends on the situation. I have just about everything you need other than a 300 amp fuse, to completely wire your truck because I do industrial electronics for a living. I am just not close enough to you to be any help. There are budget minded ways of wiring, we just have to stop and think outside the box. Remember, just route the cables away from harm, wire it i, and enjoy. Is it correct, well maybe not, but like I said, fuses are for human error protection. If the master switch is off when not in use, and you are normally around the truck to turn it off if needed, then you are set.
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YES...that's the simplified explanaition that I needed. I was getting a little frustrated since I'm unable to find what I need in this small town and when I do find it, it costs more than gold. I went to TSC and 4ga wire was almost $5 per foot! At that point I didn't want to know what 2 or 0 cost. Luckily I found some 2ga 45miles away for $44(12ft). I understood the tips ya'll were giving me, I just have limited resources and money don't go far when you live in the middle of nowhere...stores act like everything is super rare/one of a kind.
You're right, I don't drive this truck on the highway at all. Actually, when I'm not racing it, a rarely exceed 20mph(just a nice slow roll). But it won't even see that anymore, it's all track time from here.
On the routing, there's no corners there's no turns other than up over the starter, and up through the bed floor(one time). I have insulated clamps and I'm about to go snag a old water hose to use for sleeving. So I should be good on that. I was only able to find 10ga for the alternator wire, so I hope that will be ok...if not I could always double up right?
Thanks to everybody posted to this thread...I really appreciate all the help. I'll update in a bit.
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10 gauge is good for about 30 amps normally, but will handle up to 50 amps temporarily. Doubling it up wont do any good, because in this size wire, the short will just find the weak link. Since you dont have large amounts of electronic devices, lights, heater blower, radio w/ amplifier, then the output on your alternator will be limited to just what it takes to recharge the battery, and then run what is being used. Alot of the race cars around her dont even run alternators, they just charge the batteries between rounds. I will go out tomorrow, and check the amperage draw on one of mine when cranking, and then running, and we will get a base line as too how many amps your alternator may be putting out. Just because it could have the potential to pull 100 amps, doesnt mean it will. I still recommend a fuse for the alternator, even if it is just a 30 amp inline fuse, just to protect the wire. I doubt it will pull that much with a good battery, and no accessories, but have never checked it. I work on engines all day long that are industrial deisel engines, and run 10 gauge wire for the power supply to 16 injectors and the controls, so we'll find out what we are running. I have several to check, from a 350 w/ the a/c, to one of the new ones with all the bells. We'll get some numbers.
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Sounds like a plan.
I got all the wires run to where I want them. I'll throw in a 40AMP inline fuse that I have from a stereo system. I wrapped the 2ga wire with my old 1/2" goodyear air hose....MAN! it took me 15minutes just to split 10 feet of it with metal snips. My wife says I can order the 8ga online if I need to if this 10ga won't work. She said for me to just do what I need to for it to run.
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Ok Team, I got some measurement. Now these readings will be +/- 1-2 amps due to meter calibration, b ut mine is calibrated at least once a year. If memory suits me, you have the LS1 engine, so I compared my 01 w/ the 8.1, my 08 w/ 5.3, and my 81 w/ 468
81 3/4 ton 468, nothing else on 01 1ton 8.1/Alllison 08 k1500 w/ 5.3
ignition on only=3 amps 10 amps 24amps/35 w heater fan on high
cranking 281 amps/366 amps (1) 247 amps 239 amps
running alternator output 30 amps 29 amps 61 amps
after 1 min. output 21 amps 20 amps 58 amps
after 5 minutes output 12 amps 18 amps 54 amps eveything on lights/etc
25 amps all acces. off
(1) The 81 doesnt start as quickly as the other two, so the 366 amp ready was hit after a couple of tries, the 281 was initial w/ hot battery.Its the higher of the three, but also has the most compression, and due to the design of the starter, isnt as efficient as the others. Now take into consideration that these number dont reflect how an electric fan will affect the load, I would have to run the 08 for along time before those fans kick on, and they may not be accurate results compared to what you are running. If needed, I can test them later and see what they add, just wanted to get a baseline. If you have after market fans, they should have information to the amperage draw both initially, and running.
The temp was around 40 F so that will also cause higher cranking amperages.
Based on these readings,yours will probably fall between the 01 and the 81. The 08 has alot of electrical on it, so the 10 gauge wire is borderline, but the 81 has 10 gauge for it, and as you can tell, the amps drop off greatly after about a minute, and 10 gauge is sufficient for 20 amps.8 gauge will cover you better, but as long as you have a 35-40 amp fuse inline, then it should pop well before the wire melts.
Hope this helps
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I think I'll go ahead and buy the 8ga, I found some online for around $15 so I think I'll order it. Is it ok if I mount the fuse about 4ft from the ALT? If you were to fuse the ALT wire on the 08 what size would you use...65? Thanks for the help and taking the time to get me that info.
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Actually I would go about 100 on it to start, because the a/c and the electric fans were off, plus the readings dont take into consideration the stereo or the power windows, locks seats etc. 8 would be a good safety factor for you, but I doubt seriously you will be running the same amperage as the 08, probably closer to the 01. I probably have an extra 60 amp circuit breaker that I can send you if you want it, just send me a messsage w/ your address. As far as where, the closer the better, but as long as there isnt any place for it to rub, then it would be ok. Let me know. Email; kelly.wisdom@yahoo.com
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Cool. Thanks. I'll hit you up in just a minute with the address.
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Did you ever get this finished? Would like to see how it turned out
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Have I missed the point here? ??? If your using the truck for track days only why are you using the alternater in the 1st place? When I raced (albeit in the UK) the less power used for the auxillary bits the more power the engine could use?
Andy
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Andy,
I think (at the time) he was driving it to the track.
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Sorry, I forgot to update this one. I'm starting over again since my "Kill switch" doesn't seem to kill anything. Actually, I can take the key out and leave the kill switch on and the truck will keep running....I messed up somewhere. For some reason, it seems like truck changes on it's own. Up until yesterday, I could turn on my fuel pump and fans without the key, now I need it. Also, my headlight switch doesn't seem to work anymore either and all I did was move it. Anyway, I'm re-doing it and this time I'm gonna pay close attention to what I'm doing.