Whose Done The 26/30 N/a Conversion?

[GTRsean]

Posting for a mate with an R31, he wants to know if anyone on the SAU site has done this conversion, cause he has just bought an R33 S2 GTR head to do the conversion.

He wants to know -

What power people have made and with what modifications?

What ECU did they use?

What CAMS were used (IF people have done the conversion what would they recomend also)

If anyone has used the N1 oil pump on the RB30 block?

And what size head gasket they used also?

[VB-]

remember reading bout someone that did it, full built motor and GTR head etc, made like 150rwkw, realllyyy not worth it

[GTS4WD]

Posting for a mate with an R31, he wants to know if anyone on the SAU site has done this conversion, cause he has just bought an R33 S2 GTR head to do the conversion.

He wants to know -

What power people have made and with what modifications?

What ECU did they use?

What CAMS were used (IF people have done the conversion what would they recomend also)

If anyone has used the N1 oil pump on the RB30 block?

And what size head gasket they used also?

1-Depends what mods - Nobody does a 26/30 coversion and keeps it stock.. the best of a 26/30 is extracted when modified..

2-Aftermaket seems the go with PFC being the most popular for the ability to tune and every corner store ebing able to tune one. If you do a big project.. you may aswell do it right and extract the most power out of it.. if not.. do a 25/30 and spend the diffrence on the project.

3-Stock ones will work - Modded ones will work too.. the head works as a normal RB26

4-Yes. You need a new cranck collar but an N1 pump is not essential.. Rb205det is enough..

5-Im assuming your going NA? The smallest possible and then shave the head/deck the block to up the compression ratio to something desirable..

have a look at the RB2*/30 thread in the turbo section of this forum..

[GTRsean]

He's getting Mark at MRC to do the work.

Going to be interesting, NA screamer LOL.

Apparently an RB26 harmonic balancer is essential due to revs he's hoping to pull (7500ish).

Think he's aiming for 100 HP per litre.

[342Four]

lol - nothings as easy nowadays anymore

boss 'freshened' up his speedway car motor - by pulling it to bits, shaving the head 20thou (AGAIN!!!!), and then screwing it all back together (holden 253) - then tuning it BY EAR!!!!!

he now has no idea what compression he is running - its at about 15:1 on methanol

the 26 head is pretty good flow wise for a n/a - i would consider HKS step 1 or poncams to extract a decent midrange

powerfc def is a go, although you could keep the stock ecu and tune it with a safc neo and get pretty good

n1 oil pump is not needed, but if you can get your hands on one then you can be rest assured that it shouldnt cause any problems later on (a 25 turbo one should be sufficient)

an oil restrictor in the head would be a good idea aswell to keep as little oil in the head as possible (enough to lubricate everything, but not too much that at high revs everything blows into the pvc/catch can) - tomei do em and hks do aswell i think

[GTS4WD]

He's getting Mark at MRC to do the work.

Going to be interesting, NA screamer LOL.

Apparently an RB26 harmonic balancer is essential due to revs he's hoping to pull (7500ish).

Think he's aiming for 100 HP per litre.

If its NA with cams.. he will be seeing more than 7500.

Make sure he Balances the bottom end.. and if knows it will be seeing more than 7500ish.. he may need new rods/shot peened

[Althotas]

Is it possible to use the turbo loom/injectors or ecu? or should i just go for the N/A ones?

[GTS4WD]

Is it possible to use the turbo loom/injectors or ecu? or should i just go for the N/A ones?

A new stand alone ECU will have to be used as the air fuel ratio's, timing etc. will be completely diffrent

And why wouldnt you be able to use loom and injectors?

[Althotas]

A new stand alone ECU will have to be used as the air fuel ratio's, timing etc. will be completely diffrent

And why wouldnt you be able to use loom and injectors?

So are turbo and non turbo looms the same?

It's a 25 turbo head, so you reckon turbo injectors will be fine on the N/A?

What do you recommend for a stand alone ecu to get? I'm not looking at spend the world for it

[GTS4WD]

So are turbo and non turbo looms the same?

It's a 25 turbo head, so you reckon turbo injectors will be fine on the N/A?

What do you recommend for a stand alone ecu to get? I'm not looking at spend the world for it

RB25DET injectors are good fine for an NA application.. if you can squeeze more than 200kw out of them for a turbo application, they will be fine for a 150 odd kw NA project. You could use DE injectors if the engine has minimal mods.

ECU? How long is a piece of string? How much money are you willing to spend? What mods does the engine have? What tuners are available for you to use?

Have a search.. there are a few 25/30 threads around discussing what ECU's people can/are using. Im sure Skit or one of the other boys can shed more light on the situation than I have as to what ECU they are using.

If its a basic engine with simple mods SAFC is usually the simplest option.. these retail for $250 odd and are a basic air fuel ratio adjusting ECU's that are also cheap to tune.

Off the top of my head.. Z32 ecu's can be remapped and are also compatable with NVCS RB25 heads aswell.. this would be ok for a simple engine too.

[MBS206]

Look up the build that Sydney Kid wants to do.

He reckons it should be good for 400HP if I remembre rightly.

[GTRsean]

Heard the thing come into the blocks this arvo. Sounded like a v8 induction note or something crazy!

He got the car back. All up $16k or so for build, conversion, headers, electronics, new clutch etc.

The throttle response is mad when free reved!

Ok, it runs an adaptronic computer, MAP sensor.

25de pistons and stock rods, balanced rebuilt bottom end

12.2:1 comp ratio

ported head with stock valve train still.

Stock 5 speed still and brass button clutch.

$1000 worth of tuned length headers.

It's running 139RWKW @ 5700 at the moment, stock 26 cams are holding it back, and the rest of the exhaust.

So head needs to be machined to accept 280 deg cams with 10.8mm lift, once he save up some dough again.

The engine is so smooth at idle you could balance your loose change on it! (read needs some big cams).

[GTS4WD]

wow.. thats a really high compression ratio!

140 Na kw.. niiiice..

what kind of torque.. that sounds like one mean engine!

[Nosmo]

Not to piss on your parade but the power seems a little low for the work done...

Being twin cam and four valve the cams shouldnt really be holding it back that much. Perhaps there is gains to be made with cam timing ajustment and more tuning?

If it has GTR heads you should be able to fit bigger than 10.8mm lift cams. 10.8mm is usually the limit for the RB20/25 heads...

I'm fairly sure you can get 11.5mm + lift to suit GTR head. This should work well with a high revving N/A motor.

[GTRsean]

It's still being run in so tune ain't aggressive.

I told him to definitely get cams, and adjustable gears too.

Wasn't a cheap exercise for him lol.

Yep 26 head is used in this one.

I'll post a couple o pics when I see him again.

[Bumblebee]

im totally with Nosmo.. 140rwkw is pretty weak.. same work with less comp on a honda makes more than 150kw @ wheels with a much smaller engine..

somethings def not right there..

[blk180]

Interesting 140kws is the same as a Stock SR/RB25 turbos so its not that bad. Is he running trumpets? yer i think bigger cams 296/302 would bring out somemore power.

[GTRsean]

As promised, the pics:

Enjoy

Drove it and the throttle response is awesome. Power drops off at 6500 though and gearbox is crap for shifting (needs an r33 one). Diff is also on the way...

[Eug]

excellent!!! and in a nice 'ol sedan too!!`

[GTS4WD]

Power drops off at 6500 though

Needs cams then and watch the power fly past that!

Hav you driven a 25DET? How does it compair to that?

Edited September 21, 2008 by GTS4WD