Rb26 Or Rb 30

[Swiper the Fox]

Haha maybe you are just discovering than twin turbos AREN'T actually better than a good single Twin GT3037s also probably flow similar to or more than a GT4508R..

Really depends on the application...If my car was a circuit racer id have added quite a few seconds to my laptimes...but ill now have more top speed down the straight. Ive gone from the ultimate all round set-up to the ultimate drag set-up.

[donkeypunch]

so i just did a 8.6 1/8 mile with clutch slip in 2nd and 3rd (brand new HKS twin????) then it didnt slip the next 2 passes? RB26 lost by .4 sec to 2 big V8 drag cars

i think i will stick with the RB26 now ha

[Swiper the Fox]

so i just did a 8.6 1/8 mile with clutch slip in 2nd and 3rd (brand new HKS twin????) then it didnt slip the next 2 passes? RB26 lost by .4 sec to 2 big V8 drag cars

i think i will stick with the RB26 now ha

give it a limiter launch with some better rubber and you will be having those guys on toast.

well done

[donkeypunch]

hey thanks dirt,

yeah cant figure out the clutch slip??????

but oh well

[joeleo87]

After i change my gearbox and diff, Ill be looking into rebuilding my bottom end.

In the way of "being cheaper" which way should i go?

Rebuild my R26 bottom end or build up an RB30 bottom end?

im not really that concerned about power. with my setup i can see 330kws easy.

[Swiper the Fox]

After i change my gearbox and diff, Ill be looking into rebuilding my bottom end.

In the way of "being cheaper" which way should i go?

Rebuild my R26 bottom end or build up an RB30 bottom end?

im not really that concerned about power. with my setup i can see 330kws easy.

330KW is a what i call our stage 1 engine....it uses all Nissan items except the pistons...its really just a freshened up stocker with the insurance of a better oil pump, water pump and pistons. Much cheaper and less hassle of doing a RB30 bottom end as everything bolts up and fits correctly .

I ran 467KW at the tyres with one of our stage 1 engines, raced it for 3 years, and did countless dyno comps. This stage 1 engine won us more dyno and drag trophy's than any other we have built...it was all Nissan bar Arias pistons, Tomei sump baffle and Tomei camshafts. The Racepace circuit GTR's use a similar engine and their reputation on the circuit is second to none when it comes to street registered circuit GTR's.

Edited March 1, 2009 by DiRTgarage

[joeleo87]

So just spice up my bottom end?

Im still running my stk oil pump so i want to rebuild the bottom end before the pump goes

[Swiper the Fox]

hey thanks dirt,

yeah cant figure out the clutch slip??????

but oh well

maybe the clutch needed a few runs to show it how to hook up...lol

it wanted to go home early but when it realised you mean business...it decided to play ball.

You may have been riding it a little too much getting it a bit hot also...i find at 300-350KW on regular road rubber holding it at 7000-7500rpm and stepping off it the best method. This is how my mrs does it when she races and she's done a few 1.6 60footers in her time.

Edited March 1, 2009 by DiRTgarage

[donkeypunch]

maybe the clutch needed a few runs to show it how to hook up...lol

it wanted to go home early but when it realised you mean business...it decided to play ball.

You may have been riding it a little too much getting it a bit hot also...i find at 300-350KW on regular road rubber holding it at 7000-7500rpm and stepping off it the best method. This is how my mrs does it when she races and she's done a few 1.6 60footers in her time.

hey thanks for the help, gonna crank her up from 18lbs to 22lbs soon, goodbye V8's, beat a new GT40, shelby, the new 6.1 hemi, corvette etc.....not bad for first timer ha

[bubba]

Sorry I'm a bit late on this one but here is my 2c...

I have a 32 gtr with nothing much done to it. My mate has a vl commodore with a rb30et in it, and I know someone else with an rb30 with a rb20 head (in a stripped out vl that gets raced). My mates vl has more mods than mine but when we have a race and it is the same. The guy with the rb20 head is quicker than us (but has more mods) but for the money and effort I don't think it was worth it. My other friend with a gtr that has had a few mods (but still not the dollar spent on it as the vl with the rb20 head) is only just behind the vl with the rb20 head. My mates rb30 power comes on sooner, mine later (I don't care cause I don't race cars with only 3000 rpm on my tacho). For a light to medium tune I would just stick with what is in the car. I really don't think it matters, each to there own. I wouldn't worry swapping heads on a rb30 either. vl's have been doing 9 sec quarters for a very long time without swapping heads, spend the money somewhere else. I think they both the same, look how many ppl love there rb30 and how many love there rb26. Just my 2c not saying its right or wrong, I just don't think there are any great gain from one over the other.

Ps sorry if it is a bit hard to read I know it jumps around a bit.

If you want to know more about rb30's go to http://www.calaisturbo.com.au/

The RB20 head flows roughly the same as the RB30E head so there's not really much benefit there.. RB25 (DE or DET) or RB26 head would have seen much better gains!

my concern is that I am assuming you need to use the VL block for the extra deck height correct ? Or will the 26 block accept the 30 crankshaft ? If that is the case how do you go legally putting in a block from an 86 - 87 model car into a late 90's car and registering for the street ? Whenever I tried to do a conversion with an older block I always ran into nightmares. Then you get other problems with the increased deck height as Radiator is now sitting lower - need for a header tank so we dont get good ole VL turbo cracked head as was common with them. My choice would be 2.8 litre stroker. Still using standard block keeping things simple. That being said the 30 would be an awesome street motor !!

Less chance of it bogging down off boost

The head is where all the emissions crap goes on though, for a straight swap conversion retaining factory manifolds etc there is pretty much no difference whether the block is a few years older.. RB30's were also in R31 Skylines released here up until 1990.. my block is out of an '87 VL though (mates car that got punished severely, still in the family and going strong! lol).

if the crank fits in a 25/26 block could stop pistons mashing the head with a spacer/sandwhich plate, worked for my l18 with an l20 crank

otherwise ?rd28 crank? and its close enough to legal

Isn't the OS Giken 3L something like that? uses a spacer?

[GETSET]

good luck, hope you make the right choice

Edited March 1, 2009 by GETSET

[_Ryan_]

and how often can you actually use 553kw atw on the street.. all the skylines ive been are capable of losing your licence in 2nd gear.. including my stock as rb20, and it even scrables for traction.. so why is reving to 12000 rpm ridiculous??

look at the R32 GTR paul from hunter thomas auto owns.. it made 553kw at the wheels using twins and standard capacity... and it was waaaay to much for a street/circuit car so he mucked around with the turbos and found the perfect mix of torque and power.. now its making 400kw but its all usable.

the bathurst gtr's didnt need 3L either. and they are only 450kw monsters.

turbos are the replacment for displacment... thats why we love our jap cars. we have been troncing falcodores for over 20 years... why now do we need to go to 3L all of a sudden.

power isnt everything.. the funnest cars on the road are the ones you have to ring the neck out of to get anything, like little NA engines.

i agree, torque is!

[den001]

who cares, they both perform as well as each other in different applications, for the people that got upset with my smart ass comments, i apologies, yous obviously cannot take jokes...

once again, sorry to the cry babies !!

there is no point to get super defensive wen some1 expresses what they think..

Edited March 1, 2009 by den001

[dave32gtr]

Hi just thought I would post something that I found on another web site. I know that this compairs and old RB30 head to a newer rb25 head, and I know this discussion isn't about Rb25's. But I thought it was interesting. I think the grass is always greaner on the other side. How ever if you do read the whole forum they all agree that a RB30 with a 26 head is the way to go. But I still think the grass is always greaner on the other side.

Quote:Originally Posted by vlthunterwhat are you saying exactly?

That people hold the RB30 in too high esteam for their own good. The stock basic form engine isn't magical in its perfromance, in fact you have to start doing some serious type mods to get more than 350rwhp out of on. Take for example Tempests car. It has a full rebuilt and balanced engine, rod bolts, forged pistons, mild port work, fairly decent sized camshaft, springs, rajab intake manifold, GT30 turbocharger, manifold, external gate, CDI ignition, and it makes 380rwhp on 20psi and pump fuel.

A stock RB25 with one of my kits makes 400rwhp on 18 psi with a free flowing exhaust. Do i need to say more?? The RB25 is just an all round better engine. People repeat themselves over, and over, and over, and over..... about teh lack of torque with an RB25. HAve any of you people even driven a decently modified RB25?? I highly doubt it. This is where the whole internet speculation sh1t yet again creates a "theory" that is backed up with nothing more than peoples opinions. I challenge anyone to go for a drive in a well modified example and find its faults, as they have few.

Like I said, if you want to compare figures, the RB25 makes full boost 200-300rpm later than the RB30 with a GT35 turbo, and makes power for an extra 1500rpm, easily, change to some 3.7 diff gears or even 3.9's and at the same road speed, the 25 would out accelerate and outpower the 30 with the same turbo and same boost, seeing as how its making another 80 flywheel hp.

[Lithium]

A stock RB25 with one of my kits makes 400rwhp on 18 psi with a free flowing exhaust. Do i need to say more?? The RB25 is just an all round better engine. People repeat themselves over, and over, and over, and over..... about teh lack of torque with an RB25. HAve any of you people even driven a decently modified RB25?? I highly doubt it. This is where the whole internet speculation sh1t yet again creates a "theory" that is backed up with nothing more than peoples opinions. I challenge anyone to go for a drive in a well modified example and find its faults, as they have few.

Like I said, if you want to compare figures, the RB25 makes full boost 200-300rpm later than the RB30 with a GT35 turbo, and makes power for an extra 1500rpm, easily, change to some 3.7 diff gears or even 3.9's and at the same road speed, the 25 would out accelerate and outpower the 30 with the same turbo and same boost, seeing as how its making another 80 flywheel hp.

This guy you are quoting is comparing an RB30ET with an RB25DET? Quite different kettle of fish if so, I agree RB25DET > RB30ET. However an RB30DET using a decent head is more like 500rpm faster building boost and barely give anything away in terms of peak revs. I've been in a 10s RB25DET powered "GTS" and a 10s RB30DET powered "GTS", a 10s RB30DET powered GTR and a couple of RB26 GTRs making enough power to get around the 10s mark... I know those comments were made by someone else but I thought I'd just give some background to what at least I have been in/driven so I'm not just assuming how the different combinations do their thing, not sure about others but some things I have read suggest a fair bit of assumption is being made.

[dave32gtr]

This guy you are quoting is comparing an RB30ET with an RB25DET? Quite different kettle of fish if so, I agree RB25DET > RB30ET. However an RB30DET using a decent head is more like 500rpm faster building boost and barely give anything away in terms of peak revs. I've been in a 10s RB25DET powered "GTS" and a 10s RB30DET powered "GTS", a 10s RB30DET powered GTR and a couple of RB26 GTRs making enough power to get around the 10s mark... I know those comments were made by someone else but I thought I'd just give some background to what at least I have been in/driven so I'm not just assuming how the different combinations do their thing, not sure about others but some things I have read suggest a fair bit of assumption is being made.

I'm not disagreeing, I did say that a rb30 head was different to a rb25 head, and I did say that if you read the forum this is from, that an rb26 head on a rb30 block was the way to go. I don't have the experiance you do, so I guess that my opinion dosen't mean as much. It just seems that no matter what you got, the grass is always greener on the other side.

Edited March 1, 2009 by dave32gtr

[Lithium]

Yeah it wasn't directed at you Just addressing the fact that there is a perception that RB30s have at best a similar powerband to the smaller engines, just that it comes earlier. I wish it were true, but I have an RB25 in my car and after having been in a few too many RB30s I can really tell where its lacking.

[FineLine]

There is 4/5ths of flack all difference between an rb 25 and a 26. Bore the 25 40 thou over and you have a 26 anyhoos.

Both have a better rod stroke ratio than the rb 30 and all of them can be modded to make ridiculous power and torque for such small displacement engines.

The one given is that they are not making any more of them and as they get thinner on the ground more people will turn to the more readily available 25 as a viable alternative. 26 and 30 engines are being destroyed on an almost daily basis so the well is going to dry up sooner or later. The only limiting factor to the 25 has always been the hydraulic lifter setup but its an inexpensive exercise to convert it to solid operation so that argument isnt valid either.

For those piss moaning that they want more torque why limit yourself to the 3 litre. Go straight to the front and swap out the 4.8 litre twin cam patrol engine. Got torque! Game over.

[Lithium]

There is 4/5ths of flack all difference between an rb 25 and a 26. Bore the 25 40 thou over and you have a 26 anyhoos.

Exactly, and my 2.5 powered R33 with a GT30R on 18psi has far less acceleration EVERYWHERE than a much heavier R33 GTR I have been in with an RB30DET and a T04Z... my car has basically felt like a bit of a joke since going in that

Both have a better rod stroke ratio than the rb 30 and all of them can be modded to make ridiculous power and torque for such small displacement engines.

Actually an RB30DET's 1.77 r/s ratio is closer to what seems to be a generally accepted "ideal" Rod/stroke ratio (1.75) than RB25s and RB26s which are in the 1.6s.

For those piss moaning that they want more torque why limit yourself to the 3 litre. Go straight to the front and swap out the 4.8 litre twin cam patrol engine.

You don't have to change engine mounts etc etc, the head bolts right up and its directly recognizeable as an RB still. All the aftermarket support is still there, there is no re-inventing the wheel - it makes a lot of sense.

Edited March 1, 2009 by Lithium

[FineLine]

You don't have to change engine mounts etc etc, the head bolts right up and its directly recognizeable as an RB still. All the aftermarket support is still there, there is no re-inventing the wheel - it makes a lot of sense.

Have you looked at the 4.8 twin cam engine. Theres no inventing the wheel there either. Its basically a giant rb with a neo head.