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Got Her Running... Finally

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Ok so i just completed the MOST BUDGET RB25 conversion in the history of skylines (prob not true)

I thought there may have been a problem because the way i was doing it because the guy wouldnt run after it was mechanically finished.

There was talk of INJECTOR RESISTANCE and CAS compatibility but none of that was an issue.

Turns out the Injectors were seized from sitting around to long.

So my conversion cost me:

$700 RB25DE

$20 to have oil drain welded on to sump

$150 in fluids

$200 for 25DET injectors

Total Cost $1070 RB25 Conversion

Parts I used

RB25 Long Motor

RB20 Gearbox

RB20 Clutch/Flywheel/pressureplate

RB20 PS pump

RB20 Alternator

RB20 Loom


RB25 turbo injectors

RB20 Turbo and ex Manifold

RB20 radiator

As you all know, RB25det's have NVCS and i will have to go to Jaycar and buy a RPM based switch (maybe a shift light kit) to control the NVCS.

So there we are people, dont be content with your RB20's lack of torque of throttle response. next time you throw a rod, seek out a $1000 RB25 conversion.

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sorry for the stupid questions but im not sure on a few things and am keen to learn about this coz im interested in doing this conversion.

first of all, what is the difference between a long motor and a short motor? does it refer to whether the internals are included with it?

was there any modification needed to fit up the RB20 ex manifold and turbo on? also, did u have to alter the compression ratio aswell?

one last question, did the RB20 loom match straight with the RB25 loom, or did u have to rewire it?

Thanks heaps


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So you did all the labour yourself? Thats cool but not many ppl can do the whole thing themselves.

Also you are running the std RB20 ECU on a high compression RB25DE with different injectors ( you didnt mention a head gasket)? How does it run?

Also, you havent mentioned the de-gas or re-gas of the air con, are you still running air con?

Im all for doing the conversion, but how good is the finished result? I imagine to get it running reasonably well its going to cost you at least that amount again.???

Very interested in the results and the power it makes. Curious to know if all the talk of the better flowing head actually means it makes more power with the std Rb20 turbo. Expect it to make more power earlier int eh rev range courtesy of higher compression, head design and displacement.But will peak power be any different?

Good luck with it

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Stephen, long motor comes with accessories bolted onto it. Pretty much a complete motor.

Short motor is usually the head, block, manifolds... just the actual motor itself. No A/C, no power steering, no alternator....

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Stephen: The RB20 Manifold and Turbo bolted straight on with no modifications. I havent modified (dropped) the compression ratio as i feel that any detonation associated with turbocharging this motor can be easily overcome by adding fuel and/or pulling out timing. As for the loom, the RB20 loom was fine for the RB25 save for the soldering of the 6 injector plugs. The RB25 side feed injectors (turbo and NA) use a different plug (generic side feed nippon denso). They were soldered, and insulated onto the RB20 loom. One thing that will pose a problem is that the RB20 loom/ecu has no provisions for controlling the NVCS (which is the variable cam timing on the inlet cam). I can overcome this in a few different ways. PM for details.

Roy: Yeah i did all the labour myself. I cant justify letting a workshop procrastinate on my car for 3 months making excuses all the way like; "we are just waiting on this part"

The CR is standard... 180psi in all 6 cylinders. No metal HG required. It runs RB25DET injectors which are 370cc. I thought it would be too rich, but it seems to be fine.

I never got an AC compressor or condenser with the car when i bought it... some stupid drifter wannabe had removed it. I will be retrofitting it for my driving pleasure.

I anticipate around 170rwkw with a low boost setting. I will have the stock ecu remapped and post results. I fully anticipate this turbo running out of flow around the 6000 mark. The upside to this is it will prob make full boost earlier.

Randy: The motor was technically a long motor, but it was minus alternator, PS pump, brackets, coils, loom.

Sinistagtst: Suck my balls, when you've put in as much effort into an engine swap like this, then you can critise me.

Marki Mark: It idles smoothely but it has not been street tested yet as i havent located any R33 radiator hoses yet and i work 6 days a week!

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Andy, nice work!

I done the same thing recently but used a GT3071R running 1 bar.

Im very interested to see how much timing you are able to feed into it before it pings.

Any idea when you will get the tuning side of things done?

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ill get a RB25 turbo when one comes up cheap, or get a sliding performance turbo.

i have ordered brand spankers top and bottom radiator hoses for it so add $100 to the cost. They are the last thing before its ready to drift.

ill post results, timing and drivability.

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