Jump to content
SAU Community

Rb26 V Rb25 V Rb30

quincy777

By quincy777,
in Engines & Forced Induction

 Share

Recommended Posts

nedb Proficient

nedb

Posted
Posted (edited)

230rwkw is plenty for a street car which is daily driver but if you can get more with the right turbo setup that would be even better. Also, considering it's an auto I prefer nice and early spool over full boost high in the rev range.

Any one got a "recipe" what needs to be done to the 25de to handle the power apart from the valve springs. What can you reuse from the rb20det and the rb25de?

Would you end up with 2.5l capacity or can you also use gtr crank and rods with different pistons and change the capacity?

Edited by nedb
B0oStEr Mentor

B0oStEr

Posted
Posted
230rwkw is plenty for a street car which is daily driver but if you can get more with the right turbo setup that would be even better. Also, considering it's an auto I prefer nice and early spool over full boost high in the rev range.

Any one got a "recipe" what needs to be done to the 25de to handle the power apart from the valve springs. What can you reuse from the rb20det and the rb25de?

Would you end up with 2.5l capacity or can you also use gtr crank and rods with different pistons and change the capacity?

I'm still in the rebuild process.

Rb26 rods with arp rodbolts and head studs are good insurance.

I found a 2nd hand rb26 crank and had the oilpump collar done but the capacity increase (70cc) is minimal for the cost.

The capacity with an rb26 crank will be the same as an rb26 with std bore 2568cc.

You need rb26 pistons as the pin height is different even though the bores are both 86mm

I'm using 87mm rb26 wisecos and the capacity will be 2628cc.

The r32 rb25de is just an rb20de with a longer stroke, bigger bore, bigger valves, inlet ports and runners.

Everything else is interchangeable.

I decided to use an r33 rb25det block so I could keep the piston oil squirters although it's not essential.

B0oStEr Mentor

B0oStEr

Posted
Posted
I'm sure many will agree with me..

220-230rwkw is actually not that fast... 250rwkw+ is whats needed.

The R32 Rb25de will be fine. Be sure to change the valve springs. :D

No doubt new valve springs are a good idea but are the std rb25de valvesprings weaker that rb20det valvesprings?

In the r32 manual they are rated as having the same seat pressure as the rb26 at 24kg at installed height.

Cubes Grand Master

Cubes

Posted
Posted
No doubt new valve springs are a good idea but are the std rb25de valvesprings weaker that rb20det valvesprings?

In the r32 manual they are rated as having the same seat pressure as the rb26 at 24kg at installed height.

Seat pressure is only one measurement. There's also open pressure.

The RB20det valve springs are the same as the r32 rb25de, the big factor here is the rb25de runs larger valves so more difficult for the valve springs to control, in n/a they are fine, push a bit of boost and exh. back pressure in to the equation that places pressure on the back of the valve to hold it open and this is where you begin to run in to trouble.

Read around half way down of the following doc. http://www.cranecams.com/?show=faq&id=5

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • MBS206
      M35 Aftermarket Fuel Pump

      By MBS206 · Posted

      Pressure when IDLING, is meant to be 51PSi... So that amperage value needs to go up a fair chunk... I'd personally be factoring for more like 12amp at least on those runs, and at that point you need to hope the already there wiring doesn't drop you a volt or two, as that's a lot of fuel pressure flow drop off from 13.5 to 12V! Taking idle pressure of 51psi, means the pump will be drawing a MINIMUM of 9amps all the time based on your reading of the graph (3bar base, then allowing an extra 0.5bar for boost = roughly 51psi)
    • Ben_D
      Wanted to buy R200 longnose LSD 3.9 ratio

      By Ben_D · Posted

      Hi all,  I am in the market for an R200 longnose diff out of a Z31 300ZX, or S12 RSX, DR30 skyline, or similar, in a 3.9 ratio.  Preferably a late model one with the M12 crownwheel bolts.  The only easy to find advert for one of these was my ad back in 2007 when I sold it on this forum.  I sold the diff as I had sold the car it goes to, but as it turns out, after 18 years I got the car back late last year, so now I'm looking for the diff !  If anyone knows where to find a longnose R200 LSD with the M12 crownwheel bolts, drop me a line at [email protected] - Bonus paid if soomeone comes up with the original diff (stranger things have happened !).  Cheers   Ben D    
    • Ben_D
      Back for more after 18 years - and where are the longnose R200 LSDs?

      By Ben_D · Posted

      Hi everyone, I used to post here a bit from 2004-2013, when I owned various Nissans, in particular my S12 RSX gazelle, which was sold in 2007.  As luck would have it, after an 18 year hiatus, the car found its way back to me last year, and over the past 11 months I have had the pleasure of restoring it with my kids.  One thing that I am after in particular is a 3.9 ratio R200 LSD for it.  I actually sold the one out of the car here back in 2007 , and it would be incredible if I could track down who I sold it to, so I can see how they have progressed over the years (and to be honest, to see whether I can get the diff back !).  Anyways, hi all and let me know "where are the R200 Longnose diffs all at these days ?  Cheers Ben D  
    • sonicii
      G35 Control arm and Compression Rods into a V35 Skyline.

      By sonicii · Posted

      Arms will be the same as the G35 or 350Z, but as above, there was a change in the lower control arm where it connects to the ball joint.  That said, you can remove the ball joint cone from your old ball joints and fit them to the new ball joints.  To be honest, I didn't think the ball joints themselves were different. The main ball joint is a bit awkward to replace, you really need to remove the steering knuckle to press out the old one.  Some people have used tools to remove it in place, but it just seemed too hard to get to. If you are going to press out/in that ball joint, then you may as well just replace the bushings in the LCA and the compression rod.  You can buy the compression rod bushing from Nissan, but the LCA bushes, you will need to go aftermarket. Much cheaper than buying the whole arm.
    • Erelyes
      Ceramic turbine damage to engine - what did yours do?

      By Erelyes · Posted

      Ha, well, it's been.... a bit of a journey. Things have taken much longer than I'd hoped. I'll probably put up a thread at some stage. Hopefully soon. The car's not done any kms since my update in June though, put it that way.
×
×
  • Create New...