Starting My Stroker Build. Lots Of Questions!

[TTT]

rb20 and rb25 injectors are not the same so you won't be able to re-use them

[STATUS]

gt3071r or the smaller td05-18g is a good combo. Even a gt2535

[Joshbigt62r]

I personally would go no bigger than a Garrett gt/gtx3076r. Depending on your power goals top mount, low mount factory manifold ect. For top mount I think a gt3076r would be ok. For factory manifold its hard to go past a hks 2530/2535/2540. Although some would argue the hks 2540 is a extremely mismatched piece of . I'd go a 2535 exhaust, cooler, injectors, decent ecu and clutch and save for a rb25det conversion. A rb20 in miles behind a rb25 in so many ways as status and others have mentioned.

Cheers Josh

[Roy]

So actually trying to answer your questions...

How well do stock rb26 rods hold up?

Fine.They are good things. If you need to get them re-sized, balanced with rod bolts then something like Eagles start to look good and are equally as good. I think they are a few grams lighter than RB26 rods which is also a good thing

Whats a good compression ratio for it? I know turbo motors don't like alot of compression unlike N/A cars.

If you are going E85 I woudl entertain the idea of 9.0:1, if pump then stick with 8.5:1. On E85 people like to run evern more compression then 9.0:1 but I woudl be rather be cautious and build somrthing that trades a bit of reponse for reliability

Whats a good turbo to run? I was told a 35R turbo would be the way to go.

Almost every RB24 kit you see in japan runs a T67-25G or a TD06-25G. I personally would go for a PF 76HTA based turbo with a GT30 turbine or TD06 turbine would be a nice punchy thing

And whats a good LSD.

I run a 1.5KAAZ...seems fine. Have never busted a shaft or diff etc. Some people upgrade to stronger drive shafts of RB26 but until you start popping them I wouldnt bother as it just makes the car heavier.

And for those hating the idea of an RB24. It does have merits why it would be a better thing than an RB25. Consider longer stroke of RB26 but with far smaller lighter pistons. Should give it good balance of rev and torque and ability to pull big revs with greatly rediced bottom end loads.

The fact that they have smaller inlet runners and valves etc is a restriction if you are chasing epic power. But the flip side is they give you higher velocities and better atoimisation of fuel in the mid range and give sharper torque and response. The beauty of turbo cars...if you want tmore power you just run more boost and better fuel.

I know there is nothing really wrong with the std RB20 head at 310rwkws. Only takes 22-23psi to make that power and thats pulling 8,500rpm with std cams, valve springs...just with a tiny 8cm housing and a Plazmaman inlet. At the moment the restriction on my setup is the little 8cm housing. With a bit more compression, a tighter new engine instead of an unknown wrecker engine + 60,000kms then you woudl expect to be able to get away with a 10cm rear housing and by eliminating the exhuast restriction could throw a slightly bigger compressor on it and you woudl be starting down the barrel of a good, strong 350rwks setup that has a bottom end far stronger than any other RB engine

I dont hear people saying SR20s cant flow enough for decent power and they need cams/springs etc to even make 300rwkws. A std RB20 head flows that a peice of piss and people say its no good. 5 years ago before E85 perhaps the cylinder pressures and temperatures woudl have been an issue....but these days E85 is a pretty good bandaid. An Rb25 would be pushing a load more air through so at this time if you threw in some nice high lift cams you will probably bet getting 65% of where you need to be with regards to getting a better flowing "air pump"

[GTSBoy]

We know you love your RB20s, and I agree that they are a good little engine......but why bugger around with a good little engine when you can just as easily have a good bigger engine?

[Roy]

_{Why bother with an RB25 when you can throw in a Turbo Barra engine in?}

_{In some states engine swaps are easy, some are harder.}

_{If you actually race the car you need to sometimes keep the original block and or displacement. I am a hack driver who likes to cheat and unlike the other honset SAU folk who punt their GTSTs in Targa Tas who abide by the rules I would be running an RB24 in a heart beat if I ran my car in Targa.}

_{RB25 doesnt have a tunable ecu. So means more money for a PFC and loom changes etc. Not the end of the world but a consideration. I have seen the results of a few RB24s and they all stack up amazingly well.}

_{So RB25s do a good job of making pwer. So do RB26s., 28s, 30s etc. But the whole throw away RB20 if you have an R32 series platform makes about as much sense as telling people to throw away their SR20s if they have an S13/14 platform.}

_{With a leaking headgasket I will put my RB20 up against a similarily turbo'd RB25 and you know what....they wont leave me for dead. Spending more than 3.5k doing a NEO swap in an RB20 is lunacy to me. You mentioned you are running std turbo and what 180-200rwkws. That boggles my mind when for a turbo install you can be rocking 260-280rwkws reliably and you will never worry about a power upgrade. You will be too busy trackign your car having giggles.}

_{I have had my car for 13 years so when I chase power its as much our of curiosity and boredom as it is for more power.}

_{Oh, and my car is so desirable and full of RB20 awesomeness some maggot, scumbag carnt tried to steal it yesterday. Almost got it too if not for neighbour stopping them}

[GTSBoy]

My car hasn't been to Regency yet, so it has to remain standard. Hasn't even got an original solenoid on it so only running 5psi. Can only put the interesting stuff back onto the car after I find a way to get the last things done and get it inspected. Too bloody busy, not enough time, yada yada.

Is much better to drive as it is now than RB20 was with 14+ psi. Almost the same top end power, much fatter bottom end, uses less fuel, isn't starting to leak from every gasket. The old RB20 was a great strong engine, always was a fast car. But it needed a birthday big time. 20 years and 160k km old means a lot of things needed freshening. Start looking at the cost of all those things and compare the benefits against spending that coin + a little extra on the Neo transplant. Only took me 3 seconds to work out it was a good idea. Just took me too many years to justify doing it to the missus.

[jet_r31]

Its been said before. People who put RB25s in their R32 GTSt are the sort of people who will sleep with their mate's wife because she is easy.

If you throw an RB26/28/DOHC 30 etc it's just as bad but you can at least justify it to yourself by saying she is hot and the best bit of tail getting around.

what about if you put a Rb30 sohc in one then?...lmao

cheers

darren

[Roy]

Then you are a purist ... ... intending to use an R32 for a spear a spud comp on a farm

[R31Nismoid]

I know there is nothing really wrong with the std RB20 head at 310rwkws. Only takes 22-23psi to make that power and thats pulling 8,500rpm with std cams

On a 2000cc motor. Would be interesting to see what an increase of 20% capacity would do though to flow, with the smaller rear housing as well. It might just upset the balance enough.

Also depends on use of the car, if it's going to see street duties - RB25 is far more cost efficient than a RB24.

If it's just seeing high RPM/circuit then there is a fair argument to just stay RB20 till it dies and bolt on a reasonable turbo

[Roy]

Would be interesting. But I am simply slapping a 10cm housing on my setup because of the extra 400cc. Drop in back pressure will hopefully bag a few kws and help handle the extra 400cc.

On a 2000cc motor. Would be interesting to see what an increase of 20% capacity would do though to flow, .

RB26 heads are designed around 2.6L, RB25 heads around 2.5L. They cope ok with an extra 400-500cc. Nothing wong with assuming that an RB20 couldnt handle an extra 300-400cc in displacement. I assume Nissan designed all engines around the same basic design targets for gas velocities, cylinder filling etc etc

Also depends on use of the car, if it's going to see street duties - RB25 is far more cost efficient than a RB24.

If it's just seeing high RPM/circuit then there is a fair argument to just stay RB20 till it dies and bolt on a reasonable turbo

Similar thinking is why bother building any engine for the street...why not keep throwing std engines. RB25 makes more sense on the track then street due to legality issues. Not arguing just pointing out there are so many considerations and forums are good when you get the cross section of views so people make their own informed decision.

LOL, I know whats been right for me with my car isnt right for other people.