Advice Info On Rb23/24 Engines

[Madaz]

  Tuffr32 said:

Have to add my advice on this topic

I just cant see the point of rebuilding and stroking the rb20, I love my rb20 and reckon its awesome for a 2tlr motor but at 250rwkw the gearbox becomes unreliable if it costs 5000 just to build the motor then your gonna need to upgrade ecu, turbo, intercooler, tune, etc.

Ive been searching around for a rb25det + gearbox and they cost around 3500 why not go the 25? it will be waaayyy more reliable and good for more power plus the extra torque.

Or you could do the rb30det option that cubes and bl4ck recommend, the later 2 options will be cheaper and give more power. Why go go through the drama of putting together an rb23/4?

My 2 cents

i agree make a RB30 you could proly modify the head covers to say RB20 for regency

and RB30 make heaps more power easily too

my 2c

[Cubes]

Not with the rb20 head plonked on top.

Its not that they make heaps more power easily as they will still make the same peak power as the rb25 on the same boost level.

The head is what governs the peak power at any given boost level. Being a larger motor it will simply make more 'average' power.

----

I still fall back to my view of a cheap rb30det though. Grab a cheap r32 rb25de head, a running second hand rb30det bottom end push a little boost in to it, set the rev limit to 7200rpm and off you go.

If the motor should let go just grab another cheap rb30 bottom end and throw it under the head.

Building up an expensive motor and then thrashing the nackers out of it is a little scary, as on occasions things do go wrong and they do pop. Your then all depressed and thoughts of simply pissing the car off runs through your mind.

Or just throw in a second hand rb20. Troy style, his has been holding rather well at 20 odd psi with his td06 making 240-250rwkw.

Nothing like torque to turn tyres in to smoke.

^ RB30DET, TD06-20g, 10psi 240rwkw, 12.19 1/4.

Enjoy the car.. Thrash the crap out of the motor and replace it with another cheapo when IF it lets go.

[Cubes]

Oh yer.. .Madaz, its only the Series 1 RB20deT's that say RB20.

The Series 2 with their slightly larger turbo and a few other nice little bits are just plain. No rb20 markings. The RB25 and series 2 rb20 look identical.

[Madaz]

yeah but would regency know if he had to take it over the pits of paint the cover silver and they just think its a ailver top RB20

[Cubes]

The R32 RB25de rocker covers are silver also..

They literally look identical.

I've painted mine black as I have a think for black.

[Cubes]

I've grabbed a pic of the old rb20det engine bay and posted it above the now rb25 head engine bay pic.

I wasn't able to track down all the old pics of the rb20det before I pulled it out.

As you can see they really do look identical apart from myself painting the rocker covers black instead of leaving them the standard silver colour. Ignore the larger bleed bolt as I stripped the std one as the alloy goes a touch soft when it is really hot. Also ignore the slightly different looking rocker cover join breathe hose and rocker cover -> pvc as the std ones were split.

[Bl4cK32]

note the disappearing dipstick

[Cubes]

The RB30's added 38mm deck height doing.

[32 4whore]

I appreciate everyones advice very much.

My reason for not putting a 25 in my car is due to parents freaking out as it is with my current engine.

Yes i will eventually fix my problem of speed and want more.

But for the time being i would like to build up a strong engine thats not going to fall to bits in 3 months as a 2nd hand engine will/ most likely will with my poor judgement of engines.

I think the 23/24 idea is past right now. To much of a head f@#k to do this time so i think i will just rebuild my rb20 just to make it run smoothly, get it tuned, convert my car to manual, run R33 turbo, get FMIC, up the boost a little bt and hope she holds together.

Im going to need a bank loan to get the money asap as my parents are wanting to sell there cars to buy a new one so we dont have 5 cars in the family with 3 in the actual family.

As above I appreciate everyones point of veiw and yes i will take them all on board. I might need a mechanics for dumbies book to understand it all. But yes i will continue in the thread and explain what im doing for my build up.

damm you christmas and your giving presents.

By the way.

Dads pissed off now because I put a Velo fixed back bucket in yesterday so now he and mum cant drive it.

The RB30 bottom end is still my fav right not.

Just have to figure out what cubes means by the head not being able to run well or what not.

Back to the drawing board

[Deluxe]

  R32_4door_drifting said:

Dads pissed off now because I put a Velo fixed back bucket in yesterday so now he and mum cant drive it.

Ahhhh good ol Leon hey, he barely sat in that thing too!

Prob is a good thing your just gonna build up the 20! Go check out Kelly Mckinnons and see what he has done to his! that thing seem to put up with the dori thrash!

Edited December 14, 2006 by Deluxe

[Bl4cK32]

  R32_4door_drifting said:

Just have to figure out what cubes means by the head not being able to run well or what not.

Back to the drawing board

I think he was pointing out how bad the rb20 head is when compared to the rb25de head which flows great, ie u get lots o power from small amounts of boost as the head flows better - rb25de being the head u use to build the r32 rb30det.

[32 4whore]

Oh ok now its mkaing sense.

ok total retard question. RB25de head will it fit on the 20det bottom end. Or will the compression rates be completely different and eventually die and i wil be back in the situation I am now.

Oh and Darren, yeh Leon looked after that seat very well. Looks hot as in my 32. except the rails dont line up so good old drill and files for the win.

Ok im going to stop whoring my own thread.

I will ring around a few places tomoz after work and see whats the best option for a steady amount of power without having to go over board with my engine.

Oh and Kelly Mckinnon has just bolted a massive turbo on his engine. I think the turbo he has will be worth about the same as me recondionting my whole engine.

[scandyflick]

simplest explanation for what cubes is saying.

get a drinking straw and say, a toilet paper roll... (sounds stupid already eh? )

imagine the drinking straw is the RB20 head, and the roll is the RB25 head,

blow through the straw, you get minimal flow and very high pressure at the end,

now do the same with the roll, higher flow at a lower pressure.

again, thats a very crude explanation, but thats how i see it, lol.

but onto the subject at hand, the RB23/4, bang for buck, just isnt going to cut it.

if i was in your position, id definitely be going for the RB25/30 combination with a DE head (id imagine the non turbo nomenclature would make them cheaper as a bonus compared to DET heads).

get a '30 block, non turbo should be right, but if you can find a turbo block for the right price, snap it up, bolt the 25DE head on top, strap a turbo and fmic on it, and enjoy life.

and if youre worried about the 30 blocks just going pop from age, log onto the 31 club forums (clicky), and have a look through the members ride section (youll need to sign up) or through the technical sections, a lot of members have turbo'd their 300,000+ km RB30E's without any problems. i think 'SLO-031' is running close to 400rwkw with a near 300,000 km engine, on close to standard internals (afaik, only pistons have been changed.)

Edited December 14, 2006 by scandyflick

[johan.p.g]

thats why u turn up the boost n its just a temp 2 c if its worth it as no1 has really bothered tryin

n i am familiar with the rb30 iv been in a couple n yes i love them but i want 2 du something different on the cheep

[Cubes]

Sky30 managed slightly over 300rwkw for ~$5000 using an Rb25/30.

Thats bang for buck.

[J_Red33]

Personally I'd say just get a working RB25 Engine & gearbox & stick the bugger in for now.

You've then got a solid base to upgrade on later when you get the money rather than stick your neck out & get a loan.

My 2c

[johan.p.g]

its 2 predictable i want something diff explore the unknown also i like the idea of having a free reving hi tourque engine

[scandyflick]

proper sentence structure, use it, please.

cubes and bl4ck32(?), how much power and torque are you guys making? and at what RPM's?

[Cubes]

Mines a crap setup.. I went and spend a shit load on the motor and then wasn't able to spend $$ on the bolt ons.. I'm almost there, got everything now but the turbo.

Last time I had it on the dyno it was valve floating.

With the stock rb20det turbo it made 176rwkw on 9psi at 4400rpm, power held to ~4800rpm then nosed over. It was making 100rwkw by 2000rpm.

It was making roughly the same tractive effort as an r33 rb25det making ~310rwkw. ~390nm of tractive effort.

Consider 100rwkw at 2000rpm + drivetrain losses. Thats somewhere around 150kw at the fly.

So it feels like a big diesel but is surprisingly quick for the power it was making.

I got sick of the big diesel as you simply don't use the bulk torque between 2000-3000rpm, I dropped a VG30DET (same as an RB20det turbo just with a bigger compressor housing and turbine housing, compressor wheel is a pissy little rb20det compressor wheel) turbo on it, power now holds well to almost 6000rpm vs 5000rpm with the smaller turbo yet it feels almost the same as the rb20det turbo. The 3ltr really does change the way turbo's spool.

Sky30's Rb30DET, gt35r - peak power some where around 5500-6000rpm and it was making 312rwkw, some where up around 540nm of tractive effort.

Am-Performance GTS4... gt35r - 15psi ~260rwkw, 17psi ~270rwkw with slight valve float that was killing power. His made peak power around 6500rpm and holds it well to 7500rpm, just a pitty its valve floating. The reason for the higher peak power rpm... He's running an aftermarket plenum.

That is the key for rb30det's not only to rev high but to make peak power up there.

All of the above cars are in Adelaide.

R32 GTS4 + Rb30DET + GT35r really is a monster.

To try and put it in perspective an RB30DET GT35R .82 feels pretty much on par 'lag' wise as an Rb20DET running a stock turbo. But don't forget the more down low power and just more power everywhere.

The stock turbo'd rb20det's are a touch too laggy for myself.. I'd prefer a GT30 .82 on the Rb30DET and shove 20 odd psi down its through to nudge close if not over 300rwkw.

The GT30 on the Rb30DET is apparently the same 'lag' wise as a stock turbo'd rb25det, just with 100rwkw more and a shit load more mid range than an one.

Attached is a dyno comparison of a bloke who ran ran up his rb25det gt3040 on 15psi, slipped an rb30 block underneath the head and ran it up again on the same boost. The before after description of how it drive.... Its an Animal even though it was still making the same peak power it accelerated to that peak power so much quicker.

[Bl4cK32]

i cantr remember exactly but 218rwkw and 420nm or something like that...