403 LS2 FD - LS7 Build for 2020!

[MPbdy]

Mmmmmmmmmmm needs one more.  Final install on the hangers and all flanges torqued.

[MPbdy]

Where the hell do you put the front relay box with a samberg radiator? I thought it just flipped over and screwed into something on the bottom but I'm obviously not smart enough.

[Jordan Innovations]

Where the hell do you put the front relay box with a samberg radiator? I thought it just flipped over and screwed into something on the bottom but I'm obviously not smart enough.

Yeah that's what most people do.  Inelegant, but until I decide to pre-make tucked/loomed front harnesses, it's the easiest way to keep 100% functionality.

[halfspec]

Daniel my boy, it's time to expand your wiring prowess with an easy project 

Relocate that bitch! Think through it. What's in that relay box you need? It's got the following:
Fuel Pump relay
Airpump relay
Heatlight Retract relay
TNS relay
Horn relay
AC relay
Radio relay

I know you don't need the AC or air pump relays and I doubt you need the fuel pump or radio relays so that probably leaves you with just 3 needed relays. TNS, RETRACT, and your horn. If that's the case....

Buy one of these and ~ 50 of the associated 14-12AWG terminals plus seals:
http://www.waytekwire.com/item/46345/MINI-FUSE-AND-MICRO-RELAY-RTMR/

Two of these:
http://www.waytekwire.com/item/46085/MOUNTING-BRACKET-ATO-ATC-/

Three of these:
http://www.mouser.com/ProductDetail/Omron/G8W-1C7T-R-DC12/?qs=%2fha2pyFaduiZBuFWxFHNzuOxgp4akhLLY%2fwkeExxd5vJLgXLXnDj6g%3d%3d

One of the $32 ECT 005 crimpers here (and maybe the two piece $12.95 Terminal Extraction and Removal tool set):
http://www.cycleterminal.com/crimp-tools.html

Maybe some TXL, heatshrink, and butts for any extensions (nice to have around even if you don't need it for this):
http://www.wirebarn.com/TXL-Automotive-Wire-by-the-Foot_c_129.html
http://www.wirebarn.com/Heat-Shrink-Tubing_c_11.html
http://www.waytekwire.com/item/31060/16-14-GA-BUTT-CONNECTORS/
If getting the butts above, make sure to talk to joe@cycleterminal.com and get the optional die for the $32 crimper that can crimp these butts. Then you just crimp the butts and heatshrink over them.

Then get familiar with the following pages in the FSM and start moving the wires over to the new relays:
Z-60
Z-66
Z-56 (*Note* The TNS relay in the FSM is the only major error I've found in the FSM. It's shown as being normally closed on the R/L wire position but it should actually be NC on the R/Y wire... If you wire it the way the FSM shows your headlights will be at rest in the popped up position)
All the rest of the wiring can be deleted back to the closest joint.

You won't even need any fuses as the relays you'll be moving are fused outside of the stock box.

Mount it like this under the driver's side headlight:
http://s464.photobucket.com/user/rehanvey/media/White%2094%20FD/FanRelay.jpg.html

I think that's it. You'll need a good wire stripper, but most folks have something around that works. I will say a good stripper makes all the difference


Don't be a chicken. Do it!
Lane

PS
You need to get your car to a crankable state and make a video as I need to hear this exhaust stat!

[4packet]

Have a look through our build thread. Managed to relocate the relays inside the rad without extending the harness. Relocated the fan relays to the other side also.

[MPbdy]

Damnit guys now I have to do something nice...  I thought it just stuffed in there and the bumper covered it up haha.

Lane, I know I have you AC controller, but I thought the OEM switch on the dash went to the factory relay and then back to your box?  The "plug and play" connector eliminated the factory relay?

Fuel pump relay is part of my logic circuit for my fuel pump wiring so I'll need that.  One relay is triggered by the key and the other is switched by the PCM for a bit of redundancy.

I have the Bose radio - I think I need the radio relay?

That means I have:
Radio
Retra
Fuel Pump
TNS
Horn

Too many for your bussmann box I think.

Those ratcheting crimpers are very nice.  I have a set of those in the garage.  Have a pile of those splices too.  I've done quite a lot of wiring on this car.  I have now decided that if I ever do a project like this again I'm building my own harness.  Too late now.

[halfspec]

Lane, I know I have you AC controller, but I thought the OEM switch on the dash went to the factory relay and then back to your box?  The "plug and play" connector eliminated the factory relay?

No sir. I pickup the switching signal straight off of the logicon / ac switch. The stock rx7 ac relay gets triggered by the stock ECU which is already gone so it wouldn't work even if you wished upon a star. All its doing is adding weight to the front of your car 

Fuel pump relay is part of my logic circuit for my fuel pump wiring so I'll need that.  One relay is triggered by the key and the other is switched by the PCM for a bit of redundancy.

Please elaborate on the situation, or point me to a page in your build thread where you discuss it as I am a lazy SOB. It sounds like your FP circuit is overcomplicated but I'll save final judgement until after you explain yourself

I have the Bose radio - I think I need the radio relay?

That means I have:
Radio
Retra
Fuel Pump
TNS
Horn

Too many for your bussmann box I think.

You are correct. If you're going to keep the factory monstrosity, you'll want to keep the audio relay, but in answer to your observation, no, you can load it up with 5 micro relays like this:



Just pick up 5 of these:

http://www.mouser.com/ProductDetail/Omron-Electronics/G8V-RH-1C7T-R-DC12/?qs=sGAEpiMZZMt98bArVJter6X3UEIIJpWoS1rm808lrYA%3d

They're small but they pack a mean punch. Look at the datasheet and you'll see Typical Switching Current = Inrush 90A, Steady State 35A (N.O.) / Inrush 60A, Steady State 20A (N.C.)
All of the circuits listed above take < 15A & 20A except for the audio and FP relays which are 30A, so the majority doesn't even hit a 60% load on what those relays are capable of. They should still handle the 30A circuits just fine, but I still think you can drop the FP relay. If you get it down to 4 relays I think you can fit 1 mini relay and 3 micros in that bussmann box if you wanted even more overhead on the audio relay, I'd have to double check that physically.

Lane

[MPbdy]

Wow I'm really surprised by those tiny relays.  I figured they wouldn't be good for a 30 amp circuit let alone rated for 35!

I think I'll gather those parts then.

This is going to sound like a really elegant excuse on why I was lazy.

I am feeding the pump relay directly from the battery giving it dedicated power.  If the relay failed I didn't not want the pump to be able to stick on when I was upside down on fire.  I am using the ignition switch to switch the low speed fuel pump.  The low speed pump is fed direct from the battery.  When it closes it feeds power to the high speed fuel pump relay that you're telling me to eliminate.

The PCM will switch the high speed pump and send battery voltage to the fuel pump.  I found in the rear of the car where they reduced the gauge of the wire going to the fuel pump.  I cut that out and spliced in larger gauge wire.  (I forget, but it is all either 12 or 10 gauge wire now front to back with nothing else in the circuit).

I know this is blasphemy and I'm supposed to put a dedicated relay in the rear of the car with 2 inches of 00 gauge wire feeding the pump, but I think it's going to work just fine.

Also, it made wiring the fuel pump extremely easy 

Thank you so much for taking the time to write all that out.  I don't have any excuses now not to do it the right way.

[halfspec]

Wow I'm really surprised by those tiny relays.  I figured they wouldn't be good for a 30 amp circuit let alone rated for 35!

I think I'll gather those parts then.

This is going to sound like a really elegant excuse on why I was lazy.

I am feeding the pump relay directly from the battery giving it dedicated power.  If the relay failed I didn't not want the pump to be able to stick on when I was upside down on fire.  I am using the ignition switch to switch the low speed fuel pump.  The low speed pump is fed direct from the battery.  When it closes it feeds power to the high speed fuel pump relay that you're telling me to eliminate.

The PCM will switch the high speed pump and send battery voltage to the fuel pump.  I found in the rear of the car where they reduced the gauge of the wire going to the fuel pump.  I cut that out and spliced in larger gauge wire.  (I forget, but it is all either 12 or 10 gauge wire now front to back with nothing else in the circuit).

I know this is blasphemy and I'm supposed to put a dedicated relay in the rear of the car with 2 inches of 00 gauge wire feeding the pump, but I think it's going to work just fine.

Also, it made wiring the fuel pump extremely easy 

Thank you so much for taking the time to write all that out.  I don't have any excuses now not to do it the right way.

1. How many relays are involved in this operation?
2. How many pumps are involved in this operation?

Sorry, I guess I'm just getting lost in your description.

Just for my reference stock fuel pump relay works as following:
a. Without 12v across the coil, there is no direct path through the relay so the fuel pump is powered through the stock resistor, therefore low speed.
b. With 12v across the coil there is a path for power directly through the relay so the fuel pump is powered with ~battery voltage and the stock resistor is bypassed therefore high speed.
c. The stock relay coil is tied to 12v switched via the ignition cylinder -> Engine fuse and is triggered with a ground signal via the stock ECU

What it sounds like is that you've tied the stock FP relay's ECU grounded wire straight to ground and it activates via the ignition cylinder sending ~battery voltage through the stock wiring back towards the fuel pump. From there I get lost as I don't know what your FP setup is or how many relays you are using.

Lane
 

[Jordan Innovations]

Those ISO280 relays may be rated for 35A, but they'll cook at 30A N/O.  I've used tons of these things and the Bussman blocks are a godsend for little custom projects and hidden fuseboxes (just wish they had better wire routing out the back), but you can not put a real, constant 30A load on 'em (like dual fans, etc) or you'll start to see the housing discolor on around the 87/30 armature pins and the bottom will melt. 

A 30A ignition circuit, or lights, or something where you're rarely hitting the max is fine.

[digitalsolo]

I use those a lot, but I agree with Jeff, you're leaning hard on them at that point.

FWIW they make a larger relay that fits in the socket (you can put 3x instead of 5x in the box) and it WILL handle 30 amps constant.   I used 2x of them (I like redundancy) in parallel for my fuel pump on my FC.  Worked great.   The little guys got HOT to the touch.   The big ones just got "fresh cookie" warm, which is a-ok.

[MPbdy]

MMMmmmm cookies

Thanks for the feedback on the tiny relays. 

Lane I've got two fuel pump relays and one bosch 044 pump.  The mazda fuel pump resistor crap is gone from the car.  I am reusing their relays, but using my own wiring logic.

I just looked up the Bosch pump and at 4 bar it pulls 12 amps.  It appears the only circuit I'd need to worry about is the radio?  How much current does the bose draw?  Is it going to dim the headlights?  Lol.

Relay 1 in fuse box on the shock tower:
Coil heat - Ign switch
Coil ground - gnd
Power - Positive battery lug
Switched - To relay 2

Relay 2 in relay box on core support:
Coil heat - PCM
Coil ground - GND
Power - From Relay 1
Switched - To pump

[halfspec]

Although I haven't personally had problems using quality micro relays within their datasheet specs, I'll default to Blake/Jeff's experience in the interest of keeping the relays in their operating range's happy spot, which is usually a good target to aim for in a hash environment like an auto engine bay. I'll admit that a closer look at the datasheet only shows applications in the 240watt-300watt range or  20-25Amps so it's probably best to use them <=25A.

Ok, so back to your setup. I can understand what you're doing now and while I think the extra mechanical complexity (more parts possible to break) and voltage drop across the relay contacts and stock wiring is not ideal, you could do a lot worse. I follow your line of logic and think you're ok.

You are correct. The bosh 044 should never pull more than 20A in normal situations and if you do spike during startup / starvation / cavitation / whatever it'll be quick and the micro relay should easily handle it.

As for the other circuits:

TNS = 15A max as it's fused by a 15A Tail fuse
Horn = 15A max as its fused by the 15A Meter fuse
RETRACT = < 1A as it's only activating the headlight actuator coils.
FP = < 20A or it should be as described above
AUDIO = This is the only one I can't grantee. Music is dynamic so I seriously doubt you'll see a continuous 30A load, but I don't know exactly how the stock headunit / amplifier draws current vs what the actual music is doing so... I think you'll be fine but that's just based on my experience.

Lane

[MPbdy]

Before I order any reason not to use these relays that Waytek suggests vs the Omron ones you linked at Mouser?

http://www.waytekwire.com/item/75660/ISO-280-MICRO-RELAY-12V-SPST/

[halfspec]

Before I order any reason not to use these relays that Waytek suggests vs the Omron ones you linked at Mouser?

http://www.waytekwire.com/item/75660/ISO-280-MICRO-RELAY-12V-SPST/

The only reason I prefer omron is that they are true OEM provider and I've seen their relays with my own eyes in every chevy / gm car I've ever dug into. Go pop the lid on one of your Vette's relays boxes and you'll most likely see what I'm talking about.
That's pretty much my only reason for suggesting them. I figure if they are good enough that GM/Chevy uses them they're good enough for me.

The PICKER brand on waytek wire claims to be an OEM but I don't have any direct experience with them. Most likely they'll be fine.

Lane