R33 Rb30 Conversion

[JNR24]

Originally posted by -Joel-

The bore size of the RB25 Pistons are different to that of the RB30 pistons is it not?

www.gcg.com.au have a good range of bolt on turbo upgrades for the RB motor.

Stage 1 450hp - $2200

Stage 2 500hp - $2400

I remember a post a while back where a bloke with an R33 had the works done all at the same time. He used the Stage 2 Turbo on his R33. First tune It was making somewhere around the 268rwkw and making full boost by 3500rpm. And thats on a 2.5ltr. Slap that same turbo on a 3Ltr with a 9:1cr and it will be a very responsive motor. Possibly get extremly close to 300rwkw.

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There is one important question.....  

What Injectors to use on the RB25DE Head?  

Is it possible to use the GTR injectors with an Adj. Fuel pressure reg if we run out of duty cycle?  

Reason I ask is that I am unsure if the RB25DE uses top feed or side feed. I have a gut feeling they are side feed.  

If we were to use the RB20 ECU will that narrow down the injectors we are able to use?

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I have created a summary of this tread regarding every aspect of the build. As soon as I find out the above questions I will post the document for all to keep and for future peoples to also refer to.

I think the RB30 head runs top feed injectors (low impediance),

while the RB25 runs side feed. (high impediance)

[Cubes]

So that means that the RB20DET ECU will obviously have no issues with the injectors.. What injectors can be used around the 440cc size?

I remember Clint32 had issues when trying to get some rotary injectors running well with his in the low and mid range.

He ended up having to go back to stock injectors.

I've also been told that over the RB20DET the RB30DET will use less petrol?!?! Due to not having to rev it as hard and come on to boost.. Not sure how true this is however.

[JNR24]

Also guys, this is probly a good idear when you have the block on a motor stand withall the guts out of it.

Get a drill with a small fine, stone piece on the chuck. and on the Inside of the RB30 Block remove all excess casting dags on the inside gully of the block. These casting dags are here from the factory casting process of molding the the block, you might notice gouges around the dags were factory workers "went the hack " with a grinder! Once you have removed the casting dags, change the drill piece back over to the sanding piece and then polish up all the crank support rails. Without touching the cutouts in the rails.

Good rule of thum. cleaner & smoother = Less resistance = Better flowing motor = More Durability & more performance.

I am taking photos of everything i do and i will post them in that word doco Joel has nicely provided.

Cheers Joel./ peoples

[matlowth]

Another point, is that a lot of the Merc's that have forgies use offset gudgeon pins which seem to help them when they're cold.

The higher quality materials used in the creation of the piston also means that they have less thermal expansion due to heat, and so the cold "slapping" in the bores you hear with a lot of forged piston motors isn't there.

My RB25/30 uses stock rods (shot peened & nitrided) and makes over 300rwkw, and ran 124mph in street trim so the power is genuine. I've been told that 500 ft/lbs is the safe limit for these rods and no more than 7500rpm. 550 and they will bend within a short period of time.

My car is sitting on both and has been running fine for over a year.

Cheers,

matt

[matlowth]

I think you're referring the hypereutectic (high silicon steel) pistons? These seem to be the mid-way between forged pistons and cast. They're almost as strong as forged but retain the low expansion rate of cast... Probably a better option in a daily driven street car...

BTW - Forged pistons are a lot harder on the rings than regular cast pistons too...

I've got stock big ends in mine, and so long as your engine has good clearances and you use a high grade oil, you should be right there... Just make sure you've got an enlarged sump (baffled if possible), and an oil cooler if you can afford it. Oil temps are one thing you don't want to mess around with.

matt

Originally posted by JNR24

Good point Sydneykid, i guess the modern car industrie does pretty much have the forged piston market covered.  I Guess what i would have been refering to is a forged item would take alot longer to induce thermal expansion (on a cold start) inside the bore thus creating alot more cylinder wear as well as piston wear, as compared to these unknown Thermo-pudic pistons? As you know 80% of motor occores of the first flick of the key.

I guess its not so much of a big deal for this Block (considering the whole lot cost me a slab) but more for the fact that i am building this engine with not just performance but also "reliability" in mind. So of course to get reliability you need durability. Dont get me wrong, this motor should be capable of producing 500-600BHP, but its going to produce that power in a smooth and durable way (or as close as possable)

Once last thing sydneykid, bearings. How much and what do you recommend. IAM GONA HIT SUBMIT NOW!!    

[matlowth]

Nope bore on the 25/26/30 are the same... It's the stroke that differs.

matt

Originally posted by -Joel-

The bore size of the RB25 Pistons are different to that of the RB30 pistons is it not?

[Fast31]

matlowth

what turbo setup are you running

[lowlux]

this is great this is one of the best rb30/25 conversion threads ive read,and the most healpfull.

Anyways with ringing up a few places ive found i can chase a rb25det head without VVT now this would be a better choise as u get the better flowing injectors and apparently best valve springs?? but i dont know about that one. Also does any1 have a picture of the rb30 block and the galleries that have to be enlarged???

[lowlux]

also i suggest ppl that u send your rods to get shot peened and nitred and they will be alot stronger,and its pretty cheap aswell ive been told by a engine builder at work that it should be around $200 for me but i rekon not more than $400,

so put that in the document joel

[Cubes]

So what actually is shot peening and nitred?

[lowlux]

shot peening i think is when they make the rod smooth by takeing the imperfections out of it,but i dont know about the other one,

[Steve]

Nitriding is treating the metal to harden it (I think). It only affects the outer layer of the metal, and increases its strenght which is why you wouldnt grind a nitrided crank.

Apparently (from what I have read) kryogenically treating components can have a greater increase in strength - more so than nitriding.

[Skyrine-Dave]

yeh i have also read good things about cryo freezing parts to increase strength.

i think heat treating them hardens the outersurface, whereas freezing hardens the outer surface as well as the inside of the object...

or something like that

[Cubes]

I remembered one crucial detail about the conversion:

The Block.

Make sure it is a VL Series II block that has the provision for the oil line. Or was it the water lines... I forget..

[matlowth]

It's formally a Trust TD07S, but has been modified into a hybrid T66/T04R.

Cheers,

matt

Originally posted by Fast31

matlowth

what turbo setup are you running

[matlowth]

lowlux... Rod preperation work is bloody expensive... You're looking at 6-800 dollars for all that stuff alone.

If you can afford to spend the money, I think getting custom rods are the way to go IMO.

BTW - If you want to know what shot peening is, it's definition and explaination are here (much better than I could ever explain it): http://www.shotpeener.com/learning/story_peening.pdf

Essentially, it compresses the surface metal, and the extra pressure is (to paraphrase) "extremely beneficial in preventing fatigue failures".

Similar to a blacksmith making a sword I guess... Go have a read, it's very interesting stuff.

matt

[matlowth]

Yep that's right... That's only if you want to work with the non-turbo block.

My motor came out of a VERY late model VL Wagon (Non turbo)... The rods in it were slightly chunkier around the rod bolt (see attached photo)...

Originally posted by -Joel-

I remembered one crucial detail about the conversion:

The Block.

Make sure it is a VL Series II block that has the provision for the oil line. Or was it the water lines... I forget..

[Cubes]

Originally posted by matlowth

Nope bore on the 25/26/30 are the same... It's the stroke that differs.

matt

So it is possible to use RB25 or RB26 Pistons then?

[Steve]

I read somewhere that factory RB26 pistons are forged, and are good for up to 550+bhp.

If there is no problem with the CR, they might be a reasonable alternative to aftermarket forgies if not chasing huge hp.

Also they have holes in the bottom for oil cooling, would they have and adverse effect on stregth if not bein cooled by the squirters?

[Cubes]

It wouldn't be hard to adapt the RB20/25/26 oil squirters.. Well apparently it isn't. There is a bloke in Edwardstown that builds up rb30DET's when I asked about the oil squirters he said he always fits oil squirters in to the RB30DET Block.