Rb26 Engine Choices

[manage13]

I'd like to know how much a DIY RB26/30 conversion costs. Proengines (who's work is A1) charges around $6800 for the bottom end. I like the idea some what like the OS 3ltr; have a spacer plate and sleeves with RB26 block machined up and build the bottom end using RB30 crank. Any one know how much a spacer plate and sleeves will cost to be made up?

Depending on how much you want to spend IMO I'd go a 3Ltr conversion for a street car and a HKS 2.8ltr kit for racing.

[R31Nismoid]

More torque you have, the more you will bust shit

gearboxes, diff's etc.

3ltr's in a GTR are just the beginning of a VERY costly adventure as you wont get away with a stock gearbox (so another 5k for a gearset)

Diffs, transfer case, possibly input shafts/tail shafts etc. All will potentially need attention

There is a very long list, the motor might be built strong, but that leaves you with around another 10k to spend on the driveline at least.

[sky30]

More torque you have, the more you will bust shit

gearboxes, diff's etc.

3ltr's in a GTR are just the beginning of a VERY costly adventure as you wont get away with a stock gearbox (so another 5k for a gearset)

Diffs, transfer case, possibly input shafts/tail shafts etc. All will potentially need attention

There is a very long list, the motor might be built strong, but that leaves you with around another 10k to spend on the driveline at least.

What make you say this, are you talking from expereince??

[R31Nismoid]

When 2.6ltr GTR's can shred gearboxes (usually 3rd) with 350rwkw.

Then just slapping MORE torque and load onto it isnt going to make life any easier now is it?

Couple of drag runs with a bit of traction and it could end quite nasty.

He did say he wanted a reliable and strong package, so that extends to much more than just the motor.

Its more im just raising the issue, he has potentially almost a 20yr old driveline that probably has seen better days so its not something you should 'forget' to consider

[Gts-t]

If money was no option, i would probably put a spacer on the RB30 for about 3.3-5 ltrs

[rev210]

When 2.6ltr GTR's can shred gearboxes (usually 3rd) with 350rwkw.

Then just slapping MORE torque and load onto it isnt going to make life any easier now is it?

Couple of drag runs with a bit of traction and it could end quite nasty.

He did say he wanted a reliable and strong package, so that extends to much more than just the motor.

Its more im just raising the issue, he has potentially almost a 20yr old driveline that probably has seen better days so its not something you should 'forget' to consider

You are certainly right about considering beefing up other things not just the engine.

In terms of the good old stocker gearbox, I reckon there is a fair bit of blame going on the owners and the way they choose to drive.

I've seen pretty stock GTR motors kill 3rd gear in the hands of the brutal, the 3 litres may make being a bastard to your gearbox easier but, you don't have to be a bastard.

The power and torque can be tuned basically by your right foot, it's a long forgotten art, as you load up the weaker 3rd gear.

You can also put a cap on your power curve to limit carnage when you tune, till you save for the beefy gearset. It's the old story of people who 'must' have every last kw of potential out of thier motor for the sake of it.

[rev210]

I wasn't saying it wasn't any good, just not AS good.

Just going off info I have read on these forums and magazines, I was lead to believe that the RB26 block had extra internal bracing to handle second (or third? can't remember) order harmonics present in the high end of the rev range (not entirely sure what revs, but somewhere around 8000). The RB30 was never meant to rev past about 7000, so as long as you don't go that far, the extra bracing probably isn't be needed. The RB26 however is designed to rev to over 8000 where second order harmonics are present, so the extra bracing was added to handle it, even as far as 10,000. The same can not be expected with an RB30 block.

Now I don't pretend to know much about engine harmonics, I'm just regurgitating what I've read, so if any of that is off, I'm qhite happy to have it staightened for me

The RB30's rod ratio means it's actually better suited to high rpm, it's stock single cam head is the reving issue. Bolt the Rb26 head to it and it likes revs. I seem to recall Sydneykids 26/30's going to 9,500rpm quite happily.

The RB30 can make the same power with less rpm, and place less stress on the up and down bits at the same rpm.

Just again for the record; There is NO extra bracing in an Rb26 block. I have had an RB30 / 25 /26 block at one stage at the same time, and you really would struggle to suggest anything different in that department. Happy to stand corrected but, in practice I think its horse %$^# but, thats what seems to sell Import mags these days.

[rockabilly]

hi guys, i would like to add my experiences. i have a 33gtr. the old motor which i rebuilt and sold had cp forgies, std rods, hks 25/30,s etc and ran 620bhp@the fly 445lbs torque, this week i finished my home rebuild of my rb26/30, ( see thread for rebuild pics ). i have jun stage 1 cams 262/in/272/ex 9.7mm lift, twin tomei intank pumps, 720,s tomei 1.0 mm headgasket and 35r/1.06 rear from extreme turbo,s. now first impressions are fantastic, when you run a 600 bhp gtr they are not a comfortable car to drive, twins at that spec can be a nuisance, shuffle etc even on a good map. driving with the 30 bottom end i would no go back now, smooth like i could not believe, engine has done 15 miles so far, been to 4500 rpms and already shown 1bar boost, it spools from 2200 rpm any gear on the avcr,.best comparison is a std 33gts non turbo, they are smooth no drama etc, this gtr is now superbly smooth and sounds awesome with a trust pe2 system. as for dramas fitting, buy the proengine sump adapter, fits superb just need silcone or similar to fit, yes its sits taller and i have a vented bonnet and it goes in no problem, clutch is exedy triple works superb nice and light with very little rattle when depressed. as for price in the uk things are expensive, but i built this myself and got parts from japan and oz, cost wise its is 5500 uk pounds finished. i will be reving this engine to 8000 rpm when run it, the crank and pulleys/clutch was been balanced and i am using an rb25 front pulley.. hope this helps.bernie

[R31Nismoid]

You are certainly right about considering beefing up other things not just the engine.

In terms of the good old stocker gearbox, I reckon there is a fair bit of blame going on the owners and the way they choose to drive.

I've seen pretty stock GTR motors kill 3rd gear in the hands of the brutal, the 3 litres may make being a bastard to your gearbox easier but, you don't have to be a bastard.

The power and torque can be tuned basically by your right foot, it's a long forgotten art, as you load up the weaker 3rd gear.

You can also put a cap on your power curve to limit carnage when you tune, till you save for the beefy gearset. It's the old story of people who 'must' have every last kw of potential out of thier motor for the sake of it.

Yeah driver plays a fair part in many things, also unknown condition of the gearbox as well. Dont know what's happened/how its treated and so on

Transfer case will wear, 32 ones are just old, and old shit needs replacing

I know of 400+rwkw GTR's on stock boxes still, so its a very large combination of factors that decide, adding things like extra mumbo doesn't help the odds

[N1GTR]

With the gearbox its only a matter of time until it breaks (im a realist with an RB26/30), and when it does, replace and upgrade - but in the meantime have fun and try to not smash it

[rockabilly]

agree what r31 nisnoid/n1gtr, mine ran 450 rwkw,s for a year did a few trackdays no probs, you have to select gear particually third properly before you load it up with power, then its fine, bernie uk

[SysLink67]

Thanks for all the advise guys.

rockabilly- You compared your last engine build with this new 26/30 you have built. But you didn't mention if you had cams in the previous rebuilt 26, which I would think would make a difference when compared to the hybrid. Also you have made changes to the exhaust and turbo configuration. So would this be a fair comparison.... ?

I could be way of track, but by having done such an involved build yourself and by the looks of additional hardware you bought for your hybrid it seems you are very biased towards the hybrid.

Although you said you have noticed that the turbos spool faster and its a "smoother ride". But you haven't yet tested it to it's full capabilities yet? nor has it been running a long time so as of yet you can't comment on reliability either...

SO WHAT I'M REALLY AFTER is a person who has had the experience of driving both a well built rb30/26 (well meaning - RIPS built or specialist performance shop built with a history of that particular type of engine build) aswell as have drive a 2.8 HKS stroker kitted RB26DETT motor or 2.7 jun etc etc.

I'm in WA the most known R32 GTR is ANT scali's NFSPEED GTR which runs a 2.8 HKS KIT I believe...

I haven't seen any examples of hybrid out there yet to step up to mark, well at least in WA. But I could be wrong....

Thats why im leaning towards the 2.8 kit step 1 with my current config....

[luke20t]

there is a dude on the forums (i think this one) in WA who has a 2.8L stroker kit with twin GT-RS's.

think his name is gavin but unsure of username.

[SysLink67]

would be handy to talk to "gavin"

[jonn]

Try Gav

[Public Enemy]

yeah it's Gav,

his Dyno sheet is in the RB26 dyno results section. Nice setup.

Personally i went the route of Tomei 2.8 stroker kit with a HKS T04Z kit to hang off it. I did consider the RB30 and OS30. Couldn't justify the cost of the OS kit and just didn't feel comfortable with the RB30. The stroker kits have proven themselves beyond doubt time and time again. I've never seen a post on any skyline forum "Spun bearings on RB28" or any other major failure and most of them are making 600+ hp at the wheels. After all the research i did i felt the RB28 was the best option for torque and Revs. My target is 700 rwhp on pump fuel, doubt i'll make that but it's a target. Anything over 600 is gonna be nutz. My only worry will be cracking blocks, but that's going to happen with RB26 RB28 and RB30.

I agree the RB30 can be made to go hard, all the 9 sec VLs prove that. Just wasn't convinced it was the best option for my GTR.

Perhaps have a chat with NIB (Steve from Top Racing), he has posted up nice results for a RB30/25 in the Hybrid results section. I'm sure he's had experience with both strokers and hybrids.

[bradsm87]

The RB30's rod ratio means it's actually better suited to high rpm, it's stock single cam head is the reving issue. Bolt the Rb26 head to it and it likes revs. I seem to recall Sydneykids 26/30's going to 9,500rpm quite happily.

The RB30 can make the same power with less rpm, and place less stress on the up and down bits at the same rpm.

Just again for the record; There is NO extra bracing in an Rb26 block. I have had an RB30 / 25 /26 block at one stage at the same time, and you really would struggle to suggest anything different in that department. Happy to stand corrected but, in practice I think its horse %$^# but, thats what seems to sell Import mags these days.

What do mean by rod ratio? U mean length of rod : the stroke of the crank?

[Gav]

As above I've been running (actually punishing) an HKS Step2 2.8L kit for well over a year now. I certainly have no problems with recommending this kit.

Presently off the road as I'm downsizing terbs and induction tract to suit circuit work a bit better. You are welcome to drop over and go for a quick spin in a couple of weeks if you like.

Feel free to drop me a PM if you have any queries.

Cheers

Gav

[rev210]

The fully counterweighted HKS kit is a very good setup for someone wanting to get into some big rpm and power (Ant).

However if you are going to be running those relatively small 260 cams and 2860 turbos and really want the best mid range experience then the Rb30 is going to give you more by virtue of its additional capacity.

It will punch out all the flow those turbos can muster before you are in any kind of crazy rpm, where the HKS kit really shines in an Rb26.