blinx9900
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- Dec 5, 2006
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i recently talked to Joseph Davies (wiring guru) about grounding points, he provided me with excellent info so i thought I'd post it in this thread, below is our conversation:
(6:14 PM 3/23/2008) blinx9900: sorry to bug but your the wiring guru after all, i have my ground like this: 2 from tranny to frame rail, 1 from back of valve cover to shock tower, is there a better way to do it?
(7:13 PM 3/23/2008) Joseph Davis: New unibody cars do a good job, but as these cars get older you see a LOT of weirdness. Partially due to engine harnesses rotting, ground straps rotting, unibody spot welds flex/crack slightly and create resistance.
The engine block is THE ground in the system, run everything TO it not to something that bolts to it or bolts to something that bolts to it; that being said the thermostat housing is a weird place to put the sensor ground for the engine. Think about it, aluminum bits that immediately form aluminum oxide (corrosion) with coolant flowing through part of it, and steel bolts that do the weird aluminum-steel corrosion thing. The OEM grounds are NOT what you want to follow, Honda only had to worry about 70-160whp for 3 years/36000 miles of warranty after that they could care less.
Anyway, I'd make sure:
- All wiring (ground straps too) is mechanically connected (crimped), electrically connected (solder), and environmentally shielded (heatshrink).
- Don't stack grounds. Between each layer you form corrosion no matter what you do, and the ground two or three places away from the block with have ~2-3 times the resistance blocking current.
- Alternator is THE power source in the system, the battery is just a reservoir. The alternator is grounded to the block. The battery is grounded to the frame which is connected to the transmission which is connected to the engine which is connected to the alternator... it's stacked grounds all over again.
- Replace anything that draws current and uses the unibody as ground path with REAL wiring, grounded to the block. Fuel pumps are perfect examples of this. Run fresh 10-14 gauge wiring for both power and ground... I've made 360whp on a stock ITR pump with 12 gauge before it started leaning, made in total 375 leaning to 13:1 AFR. I've also made 636 off a Walbro 255HP with 10 gauge wiring, but it went full rich because a hundred shot is too much to pass across a SC44 at 26 psi, meaning there was a lot more fuel (power) available there.
All in all, I'd consider cleaning the thermostat-block connection, and cleaning the thermostat housing ground. Run some welding cable from the block (as near the thermostat housing as you can) to a ground distribution point/block and run all your fancy stuff off there from battery to chassis to aftermarket electronics (widebands logged through the ECU *especially*). Keep it clean and do whatever you can to prevent corrosion.
(8:14 PM 3/23/2008) blinx9900: wow, thank you VERY much for all that info
(8:16 PM 3/23/2008) blinx9900: would you mind if i copy that info (siting your name) and start a thread on ek9.org and sticky it? a lot of the guys on ek9.org ask questions about this sort of stuff and this would be very helpful to them.
(7:46 AM 3/24/2008) Joseph Davis: Go for it!
(6:14 PM 3/23/2008) blinx9900: sorry to bug but your the wiring guru after all, i have my ground like this: 2 from tranny to frame rail, 1 from back of valve cover to shock tower, is there a better way to do it?
(7:13 PM 3/23/2008) Joseph Davis: New unibody cars do a good job, but as these cars get older you see a LOT of weirdness. Partially due to engine harnesses rotting, ground straps rotting, unibody spot welds flex/crack slightly and create resistance.
The engine block is THE ground in the system, run everything TO it not to something that bolts to it or bolts to something that bolts to it; that being said the thermostat housing is a weird place to put the sensor ground for the engine. Think about it, aluminum bits that immediately form aluminum oxide (corrosion) with coolant flowing through part of it, and steel bolts that do the weird aluminum-steel corrosion thing. The OEM grounds are NOT what you want to follow, Honda only had to worry about 70-160whp for 3 years/36000 miles of warranty after that they could care less.
Anyway, I'd make sure:
- All wiring (ground straps too) is mechanically connected (crimped), electrically connected (solder), and environmentally shielded (heatshrink).
- Don't stack grounds. Between each layer you form corrosion no matter what you do, and the ground two or three places away from the block with have ~2-3 times the resistance blocking current.
- Alternator is THE power source in the system, the battery is just a reservoir. The alternator is grounded to the block. The battery is grounded to the frame which is connected to the transmission which is connected to the engine which is connected to the alternator... it's stacked grounds all over again.
- Replace anything that draws current and uses the unibody as ground path with REAL wiring, grounded to the block. Fuel pumps are perfect examples of this. Run fresh 10-14 gauge wiring for both power and ground... I've made 360whp on a stock ITR pump with 12 gauge before it started leaning, made in total 375 leaning to 13:1 AFR. I've also made 636 off a Walbro 255HP with 10 gauge wiring, but it went full rich because a hundred shot is too much to pass across a SC44 at 26 psi, meaning there was a lot more fuel (power) available there.
All in all, I'd consider cleaning the thermostat-block connection, and cleaning the thermostat housing ground. Run some welding cable from the block (as near the thermostat housing as you can) to a ground distribution point/block and run all your fancy stuff off there from battery to chassis to aftermarket electronics (widebands logged through the ECU *especially*). Keep it clean and do whatever you can to prevent corrosion.
(8:14 PM 3/23/2008) blinx9900: wow, thank you VERY much for all that info
(8:16 PM 3/23/2008) blinx9900: would you mind if i copy that info (siting your name) and start a thread on ek9.org and sticky it? a lot of the guys on ek9.org ask questions about this sort of stuff and this would be very helpful to them.
(7:46 AM 3/24/2008) Joseph Davis: Go for it!
Last edited:
Thanks for sharing 
