Quote:
Originally Posted by wstar
We'll find out tomorrow if the 200A breaker works.
As for the grounding issues, I don't see any point in running a separate ground wire along the length of the car. The car's body itself should provide more ground path than any reasonable wire could hope to.
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The conduction of steel is poor compared to copper. Typically copper is used as the baseline as its is the most common and almost best conductor (wow that english sucked but carry on...). Copper is only surpassed by silver for conductivity at about 106% as conductive as copper. Steel for the record sucks hard at electrical conduction ranging from 2 to 18% for pure steel in comparision to copper. I'd expect our sheet metal to be somewhere around 12% ish.
One of the main issues you are going to have with a vehicle electrically is a good path to your power. Grounding to the chasis is good enough for most applications but when you start involving multi sensors and multi computer controlled systems to your vehicle small glitches in signals and poor grounds can cause problems. IIRC Stillen makes a grounding kit for the car computers because of this very issue. In the olden days if you got 14.4V to the coil or 14.3V who cares - its not gonna make a difference but if a signal gets lost and isn't part of a calculation you carputer need to make a decision you aren't going to perform optimally. That's just voltage I'm not even getting into eddy currents, etc. The car is a horribly noisy environment electronically which is why the basics are so important.
The other issue is your connection to the chassis. Once that iron starts to oxidize you are adding resistance which means power loss. Don't forget that bitty screw in the sheet metal is the best contact point to the steel but you've probably got three or four dissimillar metals there. Dissimmilar metals cause corrosion as well. Although you've got huge surface area in the sheet metal your contact point basically negates its huge current carrying capability. In real life these are minor points but in racing most of us want to know the little details and determine whether they are worth addressing or not.
So in short (oh didn't plan that pun...) your set up will work but we are pit racing here so if you wanna squeeze every last drop or optimize your system that's why I'd recomend running a ground line. At the very least I'd run ground wires from the carputers directly to the battery because they are the most likely to suffer ill effects but that's just me....