Power For Rb25Det

[Nic19]

Hey guys just rewiring a track only car so it's all new loom being made. I am wondering if I need to relay the ecu power? My mate keeps telling me I do but thought I would check. Is it relayed in the r33???

[The Dan]

Yes, most definitely

[The Dan]

You should run relays for ECU, fuel pump, injectors and coil packs. Don't forget the CAS and Idle control both need a 12V feed so some of the ECU manufacturers fail in their instructions. Then just your normal sensor 5v to the others (TPS and Coolant temp etc)

If it's a track car, make sure you avoid using solder as the vibrations from a high revving track car can cause wiring problems later in life. Pretty much every plug on your engine can be sourced from Superior Connection. Re pin everything for a completely bulletproof loom

[Nic19]

Well it's mainly the body loom I'm re doing. Motor loom is gonna be the stock r33 loom just neatened up. Does the stock loom already have the relays built in for injectors and coilpacks? And it will have the 12v feed for CAS and idle control already I think.

Also with relaying the ecu, do I need one for both constant and ign?

[Dose Pipe Sutututu]

Well it's mainly the body loom I'm re doing. Motor loom is gonna be the stock r33 loom just neatened up. Does the stock loom already have the relays built in for injectors and coilpacks? And it will have the 12v feed for CAS and idle control already I think.

Also with relaying the ecu, do I need one for both constant and ign?

Yes you will need constant & ignition trigger, fuel pump trigger. If you have a look at my link below you will see what you need. Rb25, Rb20 looms are pretty similar NOT identical

[The Dan]

Well it's mainly the body loom I'm re doing. Motor loom is gonna be the stock r33 loom just neatened up. Does the stock loom already have the relays built in for injectors and coilpacks? And it will have the 12v feed for CAS and idle control already I think.

Also with relaying the ecu, do I need one for both constant and ign?

If you are using the factory loom it should already have those relays. The only additional ones you should ever need is injectors and coil packs. It's not mandatory but the more constant voltage you can get to critical engine components, the better.

[Rolls]

If you are using the factory loom it should already have those relays. The only additional ones you should ever need is injectors and coil packs. It's not mandatory but the more constant voltage you can get to critical engine components, the better.

If the loom is rated to the required current draw there should be no need for these, if there is a voltage drop it suggests the loom is damaged or old and a relay is just a bandaid fix anyway, however most people are using old stock looms so there is probably a benefit in using them here.

If you are wiring it all up from scratch just use the correct guage wire and don't bother though.

[The Dan]

Based on what he said in his previous post:

"Well it's mainly the body loom I'm re doing. Motor loom is gonna be the stock r33 loom just neatened up."

Having dedicated relays for spark and injection isn't a bandaid fix for anything. It can be a bandaid fix, but there is certainly ways to improve Nissan's design. Dedicated power is a very good idea if you are chasing reliable horsepower and even more so when you have a track car

[Rolls]

What I was getting at is the standard loom should provide dedicated reliable power to those things at all times, if it doesn't then it means the wiring is faulty, they wouldn't have designed a loom that doesn't power ignition properly under all circumstance, hence adding a relay doesn't improve the situation, unless of course the loom is faulty in which case I think it is a bandaid solution and the loom should be fixed.

Edited January 18, 2011 by Rolls

[Nic19]

One more question. What size fuse should I be running on the ecu power and accessories?