After Some Help With Rb20 Rebuild

[grandmasterb]

Ok so my RB20 went pop due to blow by shortly after i finished having it tuned.

Now im stuck in two mind sets at the moment, ai was going to build a RB25 HYBRID but i want to get out of this for a little less that what that would cost me.

So i was thinking of just rebuilding the 20 with forgies or looking into a 23/24 kit for it.

I haven't had much luck on finding a 23/24 kit in Australia at all and i realise that i would just have to source the parts myself.

Becuase of this im steering more towards the forged 20 with my current running gear and a few extra's.

My current set up was as follows:

Rb20 stock

TD-06 20g high mount

custom 3.25" dump into standard cat back

GReddy external gate

Turbotech boost control (14psi)

stock injectors (did have additional injector in intake plenum) and stock AFM

it was making just over 203rwk's on 14psi

Now i know that everyone will just say buy another 20 and stick in it, they are cheap and you get warranty.

Well that is true but we are building this up as one of our promo cars and want it to be able to handle the punishment its going to cop

Any suggestions would be much appreactiated as well as best place to go through for a rebuild kit.

Cheers GMB

DrifTas

[Dobz]

i'm guessing the ecu is an aftermarket one and the fuel pump is a stocker.

upgrading the fuel system with a better pump, regulator and injectors would be a good idea to make sure the engine has good fuel supply when pushing over 200rwkw because thats about where the stock rb20 fuel system starts to run out.

i just rebuilt my rb20 with forged pistons, i cant remember exactly what everything cost but i'v got a fair idea.

arias forged pistons 20thou up $1100

machining of the block to suit pistons $550

genuine bearings $250

genuine head gasket $150

genuine head studs $100

aftermarket manifold gaskets etc. ~$60

labor for assembly of engine $150, that was only for the bottom end i put the rest together myself.

that seems like a lot but at least you'll have a fresh bottom end that will withstand the mid 200rwkw mark with a bit of abuse.

Aaron

[grandmasterb]

i'm guessing the ecu is an aftermarket one and the fuel pump is a stocker.

upgrading the fuel system with a better pump, regulator and injectors would be a good idea to make sure the engine has good fuel supply when pushing over 200rwkw because thats about where the stock rb20 fuel system starts to run out.

i just rebuilt my rb20 with forged pistons, i cant remember exactly what everything cost but i'v got a fair idea.

arias forged pistons 20thou up $1100

machining of the block to suit pistons $550

genuine bearings $250

genuine head gasket $150

genuine head studs $100

aftermarket manifold gaskets etc. ~$60

labor for assembly of engine $150, that was only for the bottom end i put the rest together myself.

that seems like a lot but at least you'll have a fresh bottom end that will withstand the mid 200rwkw mark with a bit of abuse.

Aaron

Running a GTR pump and it was getting plenty of fuel hence why we did away with the extra injector.

Running a rechipped stock 32 ECU

Cheers GMB

[Blitz]

2.4 Stroker

[grandmasterb]

2.4 Stroker

I'd love to go a 2.4 stroker but the costs involved just dont really warrant the outlay.

If i was going to spend that much i would go with the 25 as a starting point instead!!!

PLUS i cant find anyone that stock/sell a 2.4 kit or info on what exactly is involved (general knowledge but not 100%) so that was another reason why i wasn't leaning towards the 2.4

Cheers GMB

[iz32]

im currently at the same situation your at grandmasterb except my 200rwk rb20 is only just holding together. i nearly went for another second hand motor but thought why not go better if spending some cash.. im after around 220-240rwkw...

i've been askin around for options on the 2.4 and what i have been advised from a reputable tuning shop in perth is a GTR crank with forged toyota 4agze pistions. i think he also mentioned using rb25 or 26 rods aswell for their strength.. bit of machining and u got a 2.4L (please feel free to correct me anyone)

but is it worth it if a strengthened 2.0L can make 240rwkw as dobz mentioned... what turbo setups are advised for this kind of power?

as the little gt2510 has no chance....

i

[FATGTS-R]

From my knowledge only tomei sell an Rb24 kit and it isnt cheap. Nor is going about it on your lonesome and sourcing all the parts and the required machining hence why its a very rare excercise down here.

The 2.3/2.4 capacity is obtained by a combination of an increase in stroke from a 25 or 26 crank and larger bore from oversized pistons.

As you are planning on using forged pistons with the build, you could meet the 24 idea halfway and not use a different crank but use the oversized pistons and have a 2.1-2.2 litre. How far you can go will depend on how much meat is left and how straight the bores are. This will add to the cost of the pistons though and will only have the engine being 5%-10% larger in displacement.

So in theory, at the rpm where the turbo made maximum boost previously, you could subtract 5-10% of that rpm and assume thats where the new max boost rpm would lie.

i.e if it made max boost before at 4,000rpm, with a 2.2 litre it would be in at 3600rpm.

All that extra money and mucking around for 400rpm? Is it worth it? A decent boost controller and well matched BB turbo could yield the same if not better results on the stocker.

Food for thought. Do a search if you want any more RB24 info.

[Roy]

Another thing to consider iof you are rebuilding the Rb20 is what boost are you realistically going to run, and what fuel you have available to you.

Looking at the RB25DET, if i was rebuilding an RB20 wth forged pistons i woul dbe tempted to bump compression to close to, or maybe even 9.0:1

[grandmasterb]

Another thing to consider iof you are rebuilding the Rb20 is what boost are you realistically going to run, and what fuel you have available to you.

Looking at the RB25DET, if i was rebuilding an RB20 wth forged pistons i woul dbe tempted to bump compression to close to, or maybe even 9.0:1

Boost wise i wouldn't be looking to run more than 1.2/3bar but seeing as the car is a daily driver it would only be about a bar.

It would be tuned on BP Ulitimate 98.

As for dropping the compression ratio i take it you mean with a metal head gasket Roy???

Cheers GMB

[lwboosted]

did you mean raise the compression roy? in doing this would u expect boost to come on a little earlier?? or is this only changed buy the size of the engine?? raising the compression on a rb20 would be good because u woulnt have to run as higher boost to make the power u want.. leigh

[Roy]

Yeh, was suggesting increasing the compression ratio a little.

[grandmasterb]

did you mean raise the compression roy? in doing this would u expect boost to come on a little earlier?? or is this only changed buy the size of the engine?? raising the compression on a rb20 would be good because u woulnt have to run as higher boost to make the power u want.. leigh

Yeh, was suggesting increasing the compression ratio a little.

sorry guys read that last one in a hurry and same with my post.

It is a pretty valid point though Roy and also something i guess i should consider!!!

Looks like i may of found a 26 crank

[Roy]

I just wish teh RB family of heads didnt suck so bad...though i guess they are now 15 years old

The new Golf 2L has 10.5:1 compression, the things are little rockets and with chip, IC etc can still run 10-12psi. I would hope a cleaned up RB20 head could run 9.0:1 compression, though you would want to be sure that you have good inlet temps and fuel quality