Rb25/30 Na High Comp Build Up

[342Four]

the extra throw on teh rb30 crank is too big for the rb25 from all accounts

it would almost be as expensive to do all that as it would be to do the engine build....

edit: you can get a rb25 out to about 2.7 litres if you want

throw in a r34 gtr crank (yes, they fit no worries), bore it 20thou over, throw in a set of custom pistons - voila

(mate of mine here in wa done that - with a to4z it makes around 570rwhp)

Edited October 29, 2007 by 342Four

[GTS4WD]

GUESS WHO GOT PRESNETS!?!

They look very good! Almost brand spankers!

ARP bolts look as new! Linish job is very good!

Im concerned about the amount that was taken off the end of them when they were balanced (see pic) and also the brown build up.

Is there any way you can tell if they were shot peened? The seller said they were, but I would like to confirm.

All comments/feedback very welcome!

mm.. sexy..

How do I get rid of this? Should I be concerned?

Shiney!

Note the differences in the curve from the balance

[dori34]

this will be a good write up. ill be keeping an eye on this.

good work giving it a go champ

[342Four]

brown stuff looks like surface rust - me says that they been sitting around for a bit possibly in a bit of a humid environment - just hit it with steel wool and rub them down with a bit of motor oil to stop them rusting again while they sit around..

interesting about the amounts taken off at the small ends

if ur worried take em past a performance shop and ask their opinion on em....

[GTS4WD]

Guys.. I need feedback!..

Much feedback!

The more and more I think about this build the less and less Im motivated.

To extract good power I need good cams -$600

To get the air in.. I need Front facing plenum/Rb26 plenum with more TB's $500-$1200

To make an air filter fit in I need to relocate battery

To rev the engine hard enough to make good power with cams I need new rods -$800

To tune this so as it runs safe I need AT LEAST Z32 NA NVCS ECU with tune - $1000 or stand alone ECU and tune - $1800

I could go down a different path,and not go all out. Although I will want more than just that.. Because I knwo Ill never be satisfied!

SKiT's path:

"Extractors, exhaust, twin tb, safc untuned, billet f/wheel, reground surecams, 10.5 compression, 18 degrees timing, 98ron ultimate"

What did this set you back skit? Pm me.

Good for 150kw 507Nm!!!

But this includes:

Bearings - $70

Rings - $80

Block - $150

Balance - $200

Timing Belt - $150

Front diff adaptor plate $700 (im trying to see if I can get something for less)

Crank collar - $70

Thats ~$1500 BEFORE the mods!

Im starting to really struggle justifing this.

Yes the torque is HUGE! And powerband is large and cool factor is definately up there!

When, at home, I have an R33 Turbo, exhaust mani, R33 ECU, SMIC AND DET Forgies!

DE+T or DET.. take your pick..

Onlything I need is:

Injectors - $200

Fuel pump - $200

And then Im pushing 183.88 flywheel KW - Couldnt tell you RWKW

The down side is its only 319Nm @ 6400RPM and then im exactly like every other Tom Dick and Harry with a skyline - turbo.. And I really REALLY dont like being ANYTHING LIKE Tom, Dick OR Harry!

The second catch.. I can only drive a turbo 18 months from now.. Now fair enough.. I could spend this time on: suspention, brakes, Weight loss etc. which, by the time I go turbo ill have a pretty well set up car.. but like Tom, Dick and Harry!

So.. Spend 2K.. Take 3-4 weeks off the road with ALOT of work.. all for much more Nm and a little more power

or

wait too long.. Take 2 hrs of work.. spend $500 and have less Nm and slightly less power

help guys.. I need input.. Even if you ramble.. just write something..

Each side has their GREAT pros.. and also REALLY shitty cons..

I want more power.. The brakes/box/suspention can handle it. But I dont think I can wait!!!

Am I making out to be worse than it really is?

Somone slap me back into line and motivate me!

Edited November 18, 2007 by GTS4WD

[Eug]

hahaha... i think you're in the position i once was eh.

look at it in terms of your financial position and how much you really really want it. if you can afford it and want to do it then sure by all means. budget is a key factor, if you cant do it all in one go - plan it and see what you can do later on.

To get the air in.. I need Front facing plenum/Rb26 plenum with more TB's $500-$1200

To rev the engine hard enough to make good power with cams I need new rods -$800

To tune this so as it runs safe I need AT LEAST Z32 NA NVCS ECU with tune - $1000 or stand alone ECU and tune - $1800

see... if you add those figures up, you're looking at a cool $2k+ already.

that my friend is the cost of an RB26 head! you won't have NVCS, but you'll have individual throttle bodies, a forward facing plenum, larger valves, stronger valve springs, better camshafts, solid lifters and a head that flows heaps better than the RB25. you could wack that on and later on when you get cashed up again port and polish the hell out of it and put in even crazier camshafts! personally i'd think you'd still be ahead with the RB26 despite not having NVCS.

my suggestion, do the sump + block first. sort out a solid bottom end and the compression ratios. temporarily use the RB25 head (do not modify it). see if you're happy with it, if not save up and change to the RB26 head - you were going to spend the money on the RB25 head anyway and it has to come off for port and polishing.

hope that helps

eug

p.s. - remember my post i put up for you a while back? it's an easy way to throw $10K+ eh? at the end of the day, you have to know that you have one sweet motor which will make girls (& boys) cream. but $10K is no longer pocket change and is something that influences everyday life (houses, education, work, etc) and not just a boyhood hobby.

[H@ME]

wow i only just sawe this thread, looks like your having fun with little project, man, if your going bit power, may as well take u time and go the whole way, get a box that your happy with that can easily handle the power, is this being used for tack or street? go a dog box if track only prehaps? Just take ur time save ur little inome (uni students FTW) and take ur time you'll enjoy the build process, learn alot along the way and when she all done, it'll be awsome!! look forward to reading more in this thread.. gl chris, hame

[GTS4WD]

wow i only just sawe this thread, looks like your having fun with little project, man, if your going bit power, may as well take u time and go the whole way, get a box that your happy with that can easily handle the power, is this being used for tack or street? go a dog box if track only prehaps? Just take ur time save ur little inome (uni students FTW) and take ur time you'll enjoy the build process, learn alot along the way and when she all done, it'll be awsome!! look forward to reading more in this thread.. gl chris, hame

Hay mate.. the gearbox I currently have is more than enough for an NA engine..

As for dog 'boxes.. their BUGGERY expensive! And not really much worth it for a street car that is occasionally driven on a track..

Oh mate.. Im ready to get my hands dirty!.. its been a while since I played with cars now!

Eug,

I think I may have to do that..

3L bottom end - 1K

26 Head - 2K

Then I can sell a complete RB25DE with NVCS with/out frotn diff for $500 -$600

And make some money back!.. Means the car is off the road less..

but question:

Would a stock 26 head still be a higher spec than a 25 head with 2K work done? Ill be getting the porting done professionally.. Everything else will me yours truely..

[Eug]

Would a stock 26 head still be a higher spec than a 25 head with 2K work done?

that's the ultimate question isn't it? i think the 25 head with 2k would be better, but the 26 head would have a higher limit if you wish to go further.

[GTS4WD]

that's the ultimate question isn't it? i think the 25 head with 2k would be better, but the 26 head would have a higher limit if you wish to go further.

Well lets see what 2K gets you:

Ajust Cam gears: $400

Cams: $600

Re-grinded cams: $400

Springs: $50

Then I still need to get:

Plenum/TB's/valves

So i think Ill go 26.. gosh those prices make me dizzy!

I THINK I GOT IT!!!

Ill turbo my engine.. and SELL! BANG! 2K Slap in the fogies so as the CR is correct and I dont sell a lemon.. BANG 2.5K!! Sell with all Ancillaries and 3K? Maybe? Means I can get rid of some parts laying around too!

PROJECT FUNDED!

Hmm.. Its gonna take me a couple of weeks to get home and sort out what parts I have/need for the turbo conversion..

hmmm.. .. its so crazy it may just work!

[GTS4WD]

Well Im just in the process of ironing out a few last details about turboing my RB25DE.. Ill be starting a "HOW TO: Turbo your Rb25DE" thread with photos and step by steps and what not..

Not I hit a snag.. Rb25 headers are not compatible with Rb26 heads.. and the only RB26DE engine released was by a company called Alutech (the same company that transplants Rb26DETT's in Staggy's)..

Im having BIG problems trying to locate a decent head.. let alone such a rare item as 26 NA headers..

..im stuffed.. RB26/30 looks like its not going to work.. unless I weld on the rb26 flanges onto a set of Rb25 headers..

[342Four]

NOOOOOOOO!!!!!

a good exhaust shop should be able to modify the 25 headers to fit the 26 head no worries

from memory its only the orientation of one or two flanges need to be changed around...

[dori34]

its called autech not alutech hehe

might as well get custom headers to suit the rb26 head.

welding the cast iron rb26 flange to another might crack in future.

not really reliable or safe.

rb25de+t looks the way to go, much better output and cheaper

[meggala]

the research I did ages ago around 300 fly wheel hp is pretty close to the limit getable from an rb25/30 150 rwkw is what you will get. I got 115 rwkw from my stock rb25 de. I would go rb25/30 with the head from a de r32 cast pistons but get comp ratio up to 10.5 -11 to one 272 or bigger cam. and I would consider the cheaper power adder if you was it for drags nos. dont stress about front facing plenum yet get the thing running. 2 1/4 " exhasut. s you would need rb20 det injectors. rb20 box should be plenty.

cheers

have fun

[Eug]

you're never going to find RB26 headers unfortunately - just get the coby ones modified, shouldn't be a big drama.

i've found a few rb26 heads in my years of playing around with skylines, they were expensive as a few years ago. now they seem to be floating around the 2K mark, which blows my budget out. if you really look hard you might be able to snag one up quick for a good price. i'd be more inclined to bring one over from the yahoo auctions.

how's your budget holding together? it can be a headache unfortunately and it's one of those builds that needs time and money.

[GTS4WD]

the research I did ages ago around 300 fly wheel hp is pretty close to the limit getable from an rb25/30 150 rwkw is what you will get. I got 115 rwkw from my stock rb25 de. I would go rb25/30 with the head from a de r32 cast pistons but get comp ratio up to 10.5 -11 to one 272 or bigger cam. and I would consider the cheaper power adder if you was it for drags nos. dont stress about front facing plenum yet get the thing running. 2 1/4 " exhasut. s you would need rb20 det injectors. rb20 box should be plenty.

cheers

have fun

Well Im hoping for more power as the 26 head has larger porsts from stock.. I could always port and polish it too.. So hopefully I could push 150kw a little more..

Rb25DE cast pistons will be the go with CR at about 11.5-12..

bah.. not a fan of the idea of nos on my car.. has crossed my mind though..

And the front facing plenum is a better flowing with an extra throttle body compaired to the more restricted 25 manifold.. And for 150kw.. you will need twin throttle bodies.. so why not just use the 26 head.. I dont wanna far around with adaptor plates for 26 plenum on 25 heads.. but I have a feeling I may have to go down that path..

i've found a few rb26 heads in my years of playing around with skylines, they were expensive as a few years ago. now they seem to be floating around the 2K mark, which blows my budget out. if you really look hard you might be able to snag one up quick for a good price. i'd be more inclined to bring one over from the yahoo auctions.

how's your budget holding together? it can be a headache unfortunately and it's one of those builds that needs time and money.

Budget is getting quite padded out..

We'll see.. the more I work over these holidays.. the larger my budget becomes.. but the less time I have of turboing my engine.. selling that.. and building a second engine..

I think in a couple more weeks i should be in ownership of a head and be mid way through turboing my current engine.. So.. its gonna take a while.. but you gotta love it..

I still gotta get a front diff adaptor plate..

[meggala]

to inspire you this is a photo I got quite a few years ago of an rb30de with 25 head.

the rb26 head has the sodium filled valves as well good luck with it

enjoy

Edited December 9, 2007 by meggala

[Hesh]

"which, by the time I go turbo ill have a pretty well set up car.. but like Tom, Dick and Harry!"

thats the clincher for me....every man and his dog wahcks on one of several turbo options. like Eug says do it in stages and look at it as makeing a trail rather than following a path.

and what ever you do dont keep records of the $$...sure fire way to get demotivated.

[GTS4WD]

Guess who is picking up a working RB25DET head this weekend?

FOR $200!!!!

Still going.. just quite slowly..

Edited February 13, 2008 by GTS4WD

[H@ME]

wow thats cheap! good find man!! glad to hear the build is coming along even if it is slowly...