No Choice, Have To Change Engines, Rb20 To 25 Please Help

[335]

Hello

Before I asked everyone if I should put a RB25 in my R32 GTS-T. Most people said keep the original engine. I live in Japan(American).

Well I have to change engines anyway. The previous owner of this car put a wide body rear fender kit on the car to make it look like a GTR, he did not register the change. So when next year's inspection and road taxes come, it will change the price of my car's road tax and class and plate series. So I might as well put a 25 in the car. It will cost the same, meaning that for the extra money I have to pay for taxes it will be the same wether I put the 25 in or not.

How do I put the 25 in ?, I mean is there a site that gives tips about what to do when changing engines? There will be people there to help me who know what they are doing but I want to learn as much as possible before I do this. It will not happen until next year early but I want to know what I am doing before I start.

What parts besides the 25 engine, computer, engine wiring harness will I need? Fuel pump needs to be changed?

Any and all info and suggestions about this please give me.

Help please.

[R31Nismoid]

Plenty of conversion threads mate - have a bit of a search.

Otherwise its very simple.

Loom, motor, ECU.

If you plan to chase power i would most certainly put a RB25 gearbox in there as well. Not sure whats required for a R32-t tho (i know a HR31 needs crossmember mod).

Fuel pump - well that largely depends, in stock form it should be OK, but wont hurt to change it of course for a couple hundred.

[335]

Plenty of conversion threads mate - have a bit of a search.

Otherwise its very simple.

Loom, motor, ECU.

If you plan to chase power i would most certainly put a RB25 gearbox in there as well. Not sure whats required for a R32-t tho (i know a HR31 needs crossmember mod).

Fuel pump - well that largely depends, in stock form it should be OK, but wont hurt to change it of course for a couple hundred.

What about the shaft? Do I have to use one off of a 25? I have to cut it?

Edited August 31, 2010 by 335

[335]

I read that some people use the RB20's loom, sensors and computers, coil packs. Is this possible?

[boostn0199]

You would still have to re wire the existing loom for the rb25 pin outs and ecu and also probably add some stuff like vct

[335]

You would still have to re wire the existing loom for the rb25 pin outs and ecu and also probably add some stuff like vct

What if I run the RB25 without VCT? So best to get the wiring harness for the 25?

[R31Nismoid]

I wouldnt run without VCT personally.

You can adapt it to the RB20 loom (im dead certain there is a detailed thread somewhere with the wiring info)... but IMO if you have the RB25 loom & motor combo, go down that route and keep the VCT. Its overall a cleaner end result as well

[toddlls]

I wouldnt run without VCT personally.

You can adapt it to the RB20 loom (im dead certain there is a detailed thread somewhere with the wiring info)... but IMO if you have the RB25 loom & motor combo, go down that route and keep the VCT. Its overall a cleaner end result as well

+1

[DR 32R]

http://justskylines.com/knowledgebase/conv...conversion.aspx

Follow that bookmark

[Rolls]

I read that some people use the RB20's loom, sensors and computers, coil packs. Is this possible?

You will need to change the TPS to a series 1 R33 unit if you plan to use the rb20 ecu, you will obviously need to remap the computer as well, a nistune is the best option here as it makes retuning the ecu on the dyno very easy.

[335]

You will need to change the TPS to a series 1 R33 unit if you plan to use the rb20 ecu, you will obviously need to remap the computer as well, a nistune is the best option here as it makes retuning the ecu on the dyno very easy.

I read through Predators post, long. I think the easiest option is to use the 25 loom but than there are problems with the wipers and ac. Is this easy to fix? I do not know about the wiring on the car. I would be lost unless I had a step by step instructions and also shown what wires are what. What about the Hicas problem? Will it still work since The R33 is electronic Hicas and the R32 is hydraulic?

Will it be easier to use the RB20 loom and wiring? What is a TPS?

My car is a manual. So it said that I would only have to cut the yoke off of the RB 25 tail shaft and weld it onto the RB 20 tail shaft and that is is it for modding the tailshaft? The gear box mounts do line up?

Sorry, learning here.

[Rolls]

Personally I would use the rb20 loom and get the computer remapped, sounds easier to me, less sensors need to be swapped over. Sounds like you are going to need an auto electrician and pay them a lot of money if you can't do it yourself though. The only way to do it is to get a copy of both electrical diagrams and figure out what needs to go where.

[335]

Personally I would use the rb20 loom and get the computer remapped, sounds easier to me, less sensors need to be swapped over. Sounds like you are going to need an auto electrician and pay them a lot of money if you can't do it yourself though. The only way to do it is to get a copy of both electrical diagrams and figure out what needs to go where.

Where can I get the wiring diagrams from?

I want to hear more about using the RB 25 loom before I decide. I do not want to have trouble down the line if not using RB 25 computer.

[Rolls]

Where can I get the wiring diagrams from?

I want to hear more about using the RB 25 loom before I decide. I do not want to have trouble down the line if not using RB 25 computer.

The 20 computer is better as you can use a nistune module and basically get the functionality of a full aftermarket ecu, this is not possible with the 25 computer. The only issue is the 20 computer cannot run the VCT but an aftermarket controller like an eboost street/2 boost controller with an auxillery window can do this.

The 20 computer also wont have issues with the hicas computer not being plugged in (25 one will expect this), all your dash controls will work properly (25 can do this more more rewiring) and you will only need to change the tps and maybe the ignitor module depending on the series of 25 you get.

Also with the 20 computer it means you can buy a 25 without the sensors/loom/ecu and save cash. If you go the 25 computer route you need all of these components.

You should be able to find the wiring diagrams on this forum with some searching, I've found them in the past with about 30 minutes of searching.

[335]

The 20 computer is better as you can use a nistune module and basically get the functionality of a full aftermarket ecu, this is not possible with the 25 computer. The only issue is the 20 computer cannot run the VCT but an aftermarket controller like an eboost street/2 boost controller with an auxillery window can do this.

The 20 computer also wont have issues with the hicas computer not being plugged in (25 one will expect this), all your dash controls will work properly (25 can do this more more rewiring) and you will only need to change the tps and maybe the ignitor module depending on the series of 25 you get.

Also with the 20 computer it means you can buy a 25 without the sensors/loom/ecu and save cash. If you go the 25 computer route you need all of these components.

You should be able to find the wiring diagrams on this forum with some searching, I've found them in the past with about 30 minutes of searching.

I am living in Japan so some parts are easy to find. Not sure how much a Nistune will be.

So basically if I use everything 20 except for engine and transmission, I will only need to have the computer tuned, and make a 2nd switch for the VCT to work.

What if I want to get more power than stock. My goal is 300 rwhp. How will that affect me using aftermarket computers?

If I choose the RB25 loom, will it be easier to use a Power FC instead of the stock computer?

So you are saying if I use the 25 computer I cannot use any aftermarket computers with it?

What is a TPS?

Edited September 2, 2010 by 335

[Rolls]

So you are saying if I use the 25 computer I cannot use any aftermarket computers with it?

What is a TPS?

No if you go the aftermarket path then you can use anything, what I was getting at is the nistune module installed in the rb20 ecu makes for a very stealthy cheap upgrade with basically the same features as a full aftermarket ecu, it is not available for the rb25 computer though.

If you are planning on going full aftermarket anyway then it is a moot point, I'll leave that question up to someone else as I don't know much about the compatibility of other aftermarket computers.

[KiwiRS4T]

TPS is the round thing on the front of your cam cover that controls timing. . Sounds like you are going to need some help - plenty of expertise in Japan - get friendly with a workshop that will do some of the hard bits for you or try and get in contact with some of the members of this and other forums that live in Japan.

You can order a nistune chip by mail or for a quite bit more Mines and other tuning shops can chip the RB25 ecu.

As you have time read a few of the relevant threads to build up your knowledge.

[Rolls]

TPS is the round thing on the front of your cam cover that controls timing. . Sounds like you are going to need some help - plenty of expertise in Japan - get friendly with a workshop that will do some of the hard bits for you or try and get in contact with some of the members of this and other forums that live in Japan.

You can order a nistune chip by mail or for a quite bit more Mines and other tuning shops can chip the RB25 ecu.

As you have time read a few of the relevant threads to build up your knowledge.

TPS is actually the throttle position sensor and it sits on the throttle body reading between 0-5v depending on the percentage it is open. You are thinking of the CAS (crank angle sensor), I'm fairly sure that they all emit the same signal and do not need to be changed.

[335]

TPS is actually the throttle position sensor and it sits on the throttle body reading between 0-5v depending on the percentage it is open. You are thinking of the CAS (crank angle sensor), I'm fairly sure that they all emit the same signal and do not need to be changed.

So it sounds like the rb 20 loom is the better way to go. Only the engine, and transmission will change? So Hicas wont work after the engine change?

How much does Nistune cost?

If I go the 25 computer and loom, I will need what other sensors and parts?

[KiwiRS4T]

TPS is actually the throttle position sensor and it sits on the throttle body reading between 0-5v depending on the percentage it is open. You are thinking of the CAS (crank angle sensor), I'm fairly sure that they all emit the same signal and do not need to be changed.

Oops must get more sleep!