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rb25 swap

Posted: August 3rd, 2009, 7:03 pm
by Vinesh
swapin a rb20e with a rb25det.. wha stuff i would need to change in a c33 laurel.. thx

Posted: August 4th, 2009, 10:59 am
by 7143
brakes....lol....and suspension to take that kinda pressure......

Posted: August 4th, 2009, 11:38 am
by Conrad
What suspension?

What brakes?


Vinesh you'll need a number of stuff, below is a small list.

ENGINE
1) Complete RB25DET engine and gearbox with appropriate engine harness, ECU and ancillaries (if auto ignore the following 3 items). You said from RB20E so you won't be able to reuse your A/C compressor and power-steering assembly.
2) Clutch pedal and slave cylinder from R32 (S13 will work with minor adjustment)
3) R32 brake pedal or simply cut your stock pedal to suit
4) Handbrake lever (A31 preferably, R32 is ok or as a last resort S13) and for "aesthetic" purposes appropriate center console.
5) Modified accelerator cable. I'm not 100% sure if it'll be the same but on the RB25DE conversion my mech did out of a Stagea the cable was too long and there was minor play in the accelerator pedal.
6) Intercooler and piping.
7) Fuel pump (don't even think about driving without it).
8 ) Modified driveshaft. The stock C33 driveshaft (all come auto as far as I'm aware) will have to be shortened and the yolk for the matching driveshaft to the gearbox you're installing will have to be welded on. OR you can use a RB20 gearbox and use the front half from a R32 with the rear half of your driveshaft but be warned the RB20 gearbox wouldn't last long.


Upgrade your brakes (calipers, rotors & master-cylinder/booster). Not critical right away if you're a responsible driver. 2 line master-cylinders are ABS and most likely useless whereas the 3 line one is the one you're looking for (non-ABS). Use from either the BM-44, BM-50 or BM58.

Upgrade your differential. Again, not critical if you're a responsible driver.
Most like you have a R200 and most R200's will work. Source one from a R32, S13 or A31/C33. You can also swap a complete R32 GTS-T rear end and get the 2 pot brakes in the rear. The stock Nissan R200 diffs. are viscous (not so great as they loose their effectiveness over time) whereas most aftermarket diffs are mechanical and offer better "locking".


Note:

If going with the stock auto RB25 transmission I've been told there's no need to modify the driveshaft.

C35 spindles work for the 5 lug conversion if you don't want to redrill the rotors from the Skyline, Silvia OR Z32.

R32 GTR shocks bolt differently to R32 GTS-T so I'm not 100% sure the complete subframe can be swapped from a BNR32.

C33 engine mounts won't need to change/modify but remember there'll be more strain/torque than what the little 20E offered so it may be wise to upgrade to polyurethane mounts in the future. Same goes for suspension bushings.

Apparently sometimes the sump of the RB25 actually hits and rubs against the stabiliser bar, not sure if cud be as a result of damaged engine mounts, chassis damage, incorrect cross-member or just a bent bar.


If I missed out anything, someone please add. :|

Posted: August 4th, 2009, 3:57 pm
by 7143
Conrad,lard like yuh study dat from a book bai..... nice info pal....

Re: rb25 swap

Posted: May 31st, 2012, 9:31 am
by LedZep
What about doing that in a c35?

Re: rb25 swap

Posted: June 8th, 2012, 7:17 pm
by V2NR 3.0
This should be made into a sticky........Conrad - boss information

Re: rb25 swap

Posted: June 10th, 2012, 11:48 am
by Conrad
The info was/is out there on forums etc. and it just so happened I was researching to do the particular at that point in time.


Wrt the C35 RB25 swap the major difference would be the wiring. Make sure you find a competent electrician because from what I heard it's a bit more involving.

Concerning the handbrakes I'm not sure what center console/handbrake lever could be used for a clean install.

Brakes, the C35 is already 5 stud so you can simply swap over the front and rear rotors and calipers from any R32 or R33 Skyline. The R34 front calipers can be used as well but the 2 bolts holding it to the knuckle are larger so you'd need to enlarge the holes in the stock C35 knuckle.

Driveshaft difference, I'm not sure hopefully someone who did the swap can step in.

The speedo is electrical on the C35 so you should be able to use the R33 RB25 gearbox (stronger, more expensive) without much modification.


In all the C35 would require a mixture of S14/S15, R33/R34 parts and probably a few custom stuff.

Do a search on the net I'm sure the info is out there.

Re: rb25 swap

Posted: June 13th, 2012, 7:51 am
by LedZep
Good stuff....let's keep it going

Re:

Posted: June 2nd, 2015, 10:52 am
by ShIvAm
Conrad wrote:C35 spindles work for the 5 lug conversion if you don't want to redrill the rotors from the Skyline, Silvia OR Z32.


Im going to do a the 5lug conversion to the rear on my C33 but i'm trying to minimize downtime by getting 5 hole rotors opposed to re-drilling the current ones.

Would the C35 rotors work with stock c33 calipers?

Re: rb25 swap

Posted: June 2nd, 2015, 11:00 am
by Conrad
I don't know. From memory they're quite close in size.

Re: Re:

Posted: June 3rd, 2015, 6:13 am
by TurboSingh12
ShIvAm wrote:
Conrad wrote:C35 spindles work for the 5 lug conversion if you don't want to redrill the rotors from the Skyline, Silvia OR Z32.


Im going to do a the 5lug conversion to the rear on my C33 but i'm trying to minimize downtime by getting 5 hole rotors opposed to re-drilling the current ones.

Would the C35 rotors work with stock c33 calipers?

Yes it will they are pretty much the same size :arrow:

Re: rb25 swap

Posted: June 4th, 2015, 9:52 pm
by ShIvAm
Ok thanks...

Re: rb25 swap

Posted: June 8th, 2015, 12:02 pm
by ShIvAm
Diameter was about the same but i need calipers as the C35 rotors are vented and thicker.

Re: rb25 swap

Posted: June 8th, 2015, 12:05 pm
by Conrad
Aaaah

What about the drum shoes? Are they able to make contact?

Re: rb25 swap

Posted: June 8th, 2015, 2:26 pm
by Richard Marshall
Conrad, you real know alot. Who you'd recommend to do conversion work?

Re: rb25 swap

Posted: June 8th, 2015, 2:27 pm
by Conrad
I don't know that much.

I'd recommend a mechanic who you know did the work before.

Re: rb25 swap

Posted: June 9th, 2015, 6:12 am
by TurboSingh12
Richard Marshall wrote:Conrad, you real know alot. Who you'd recommend to do conversion work?


What you need done?

Re: rb25 swap

Posted: June 10th, 2015, 4:53 pm
by Richard Marshall
Planning to buy a 280c and put in an RB by year end/early next year. Already working on one, n/a carb L28.

Re: rb25 swap

Posted: June 17th, 2015, 11:35 pm
by ShIvAm
Conrad wrote:Aaaah

What about the drum shoes? Are they able to make contact?


Yea the shoes worked fine.