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Hey SAU,

Killed an engine a while ago, and have my other engine sitting there waiting to be put in. Before I start ripping shit off, there's something I need to know.

The engine I have is a series 1 RB25det. The engine I'm replacing it with is an RB25det series 2. I need to use the loom I already have to wire the engine up.

Will I have any problems with variances in the engine wiring loom?

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Hey SAU,

Killed an engine a while ago, and have my other engine sitting there waiting to be put in. Before I start ripping shit off, there's something I need to know.

The engine I have is a series 1 RB25det. The engine I'm replacing it with is an RB25det series 2. I need to use the loom I already have to wire the engine up.

Will I have any problems with variances in the engine wiring loom?

may be not the way you want to do it but just use anything from the S1 on the S2

Edited by mr-r33

The problem with that is until I know for sure that things will work like that, it's sort of a big gamble.

I guess I'll just do it and see what happens.

Still, the answer would be awesome.

I would think that the sensible approach would be to use all the engine electrics (sensors) from the S1 engine .

Things like water temp/knock sensors/oil pressure switch/complete throttlebody and TPS/02 probe/CAS .

Possibly the original resistor and coils as well .

Most people find that if you use the complete set of engine electrics from their native car things tend to work better .

I can't remember if they're different with R33s but it probably wouldn't be a bad idea to use the original alternator and power steering pump , if they are in good working condition its something less to screw up when you start the replacement engine . The S2 ones may or may not be the same so why not go with a known quantity . Same with AC comp .

Your call but I wouldn't miss the opportunity to inspect the clutch and replace anyway its throw out bearing before its installed and any problems discovered when its all together .

Also I'd ALWAYS remove the flywheel and replace the rear main bearing oil seal , its a shame to find it leaks and have to then remove the gearbox/clutch/flywheel to get at it later .

Optionally you could fit a new water thermostat and front crank pulley oil seal .

I'm just suggesting these things because they are so much easier to get at with the engine out of the car , must check all water and vacuum lines whilst you can reach them easily .

Its what I'd do , cheers A .

The engines are pretty much identical. Its the electrics that aren't the same.

Heres how I would do it:

1. Take out the RB25DETS1, leave all wiring in the car.

2. Remove all sensors from the RB25DETS2, and put them in a box, and put the box away.

3. With both engines on stands next to each other, remove the sensors one at a time, from the RB25DETS1 and put them on the RB25DETS2.

**Special note** Here is an example - I do know the TB position sensors are different. If the S1 sensor won't bolt onto the S2 TB, then put your S1 TB on.

4. Drop the RB25S2 back in after you've done your maintenance (Timing belt, pulleys, rear and front seals, etc)

only differences between the S1 and S2 is wiring, sensors and turbo. But this is all interchangable.

I did this swap a while back and everything will work back except for the following ie. assuming you are using the S1 loom

You need to use the S1 throttle body and TPS

You need to use the S1 AFM

You need to use the S1 coil packs, ignitor and wiring loom

Easy as.......

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