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Rb26 Crank And Pistons Into Rb25

Adz2332

By Adz2332,
in Engines & Forced Induction

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Adz2332 Grand Master

Adz2332

Posted
Posted

Hey all

Currently stashing rb25 forged stuff aside for when my car goes pop...

I know it can be done but what are the benefits of using the rb26 crank and forged pistons or a rb25 crank and forged pistons?

Or even what are the negatives??

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https://www.sau.com.au/forums/topic/444240-rb26-crank-and-pistons-into-rb25/
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XKLABA Grand Master

XKLABA

Posted
Posted

The reduced comp height is to account for the extra stroke, the GTR was originally built with a 25, but cause of the weight of the thing they increased the capacity to over 2.5 putting it in a different class and did so increasing the stroke and corrected it by lowering the comp height :)

I have way way to much time to kill :no:

zebra Grand Master

zebra

Posted
Posted

If you were going to do it that way

have it made with SBC little journal 2.1" big ends and open up 11ty different rod options, use a custom piston with a nice and low comp height and heavy wall tool steel pins.

XKLABA Grand Master

XKLABA

Posted
Posted

Wow, schooled, I'll have to go back and have another look cause I'm sure I have 26 rods and 25 pistons in my 30 block :( but now you have got me thinking, I might have that wrong

I'm also sure it was 2.5 as 2500cc was the class limit and cause of the weight of the 4WD system they increased it 70cc and went up a class, been a long time since I read into it, will try and find it

XKLABA Grand Master

XKLABA

Posted
Posted

No I was wrong, it was a 2400cc to race in the 4000cc class ( x 1.7 for forced induction ) but the addition of the 4wd made it to heavy so they went up to the 4500cc class, and am still it sure what i was thinking of and where I got the 2.5 idea from :/

And it is the 25-26 rods that are the same lenght, 30s are longer, massive fail on my part :(

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GTSBoy Grand Master

GTSBoy

Posted
Posted

I just had a look at the wiki page on the R32 GTR. The limiting factor was the 10" wide tyre required in the 4000cc class. Too skinny to give the performance they wanted RWD, so they added AWD gear the weight of which required that they add capacity to step up to 4500cc. Legend created by process of staggering evolution.

1400r Veteran

1400r

Posted
Posted (edited)

ignore the still learning driving of my mate back then

Japanese built 2.7lt motor is still going now in a s14 in WA that's for sale

after surviving 3 or 4 different chassis's

how many motor's built here are still alive 7 years later

this thing also ran a f-con when it first came over (i.e untunable)

Edited by 1400r

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