R33 Rb30 Conversion

[DoughBoy]

Yep, that's what I have found with the 1 X RB engined Silvia I have weighed.  The guy wanted to do it 'cause it weighed 250 kgs less than an R32GTST Skyline.  Then he added the Skyline engine, front subframe, gearbox, tail shaft, diff, drive shafts, brakes, hubs, rear subframe, wheels, intercooler, oil cooler, radiator etc.  Bingo it now weighed the same as an R32 GTST Skyline.  It was a total waist of time, money and effort.

Now that's a sample of 1, maybe not representative.  Let me know what yours comes in at.

It's not a waste. One word - Aerodynamics.

[MonstaS4]

Are there any differences in operation between a N/A fuel pressure reg and a turbo reg? If fuel pressure increases with a decrease in manifold vacuum, does fuel pressure continue to rise when making boost?

What i'm trying to ask is, can i use the N/A regulator which came with the R33 RB25DE head & manifold, or will it be damaged if boost is applied to it?

[Sydneykid]

Are there any differences in operation between a N/A fuel pressure reg and a turbo reg? If fuel pressure increases with a decrease in manifold vacuum, does fuel pressure continue to rise when making boost?

What i'm trying to ask is, can i use the N/A regulator which came with the R33 RB25DE head & manifold, or will it be damaged if boost is applied to it?

NA fuel pressure regulators only ever see vacuum, never positive pressure (boost). We always change to a "turbo" fuel pressure regulator. There are generally plenty of standard ones around because people change to adj, aftermarket ones. You should be able to pick a standard one up pretty cheap.

[Skyrine-Dave]

Hey guys,

I visited my local dyno guys today and there are a few things i'd like to discuss.

1. their recommended run in method:

I enquired about their recommendations to run in my rb30det and their reply was. Due to todays technology and manufacturing processes etc its is pretty much safe to just strap it to the dyno and start the power tuning straight away. They mentioned that clearances and bearing material are more advanced these days and i would be able to just bring the car to them on the base tune and they'd do all the rest on the dyno.

This goes against a majority of what i've read, but is consistant with other peoples views. any discussion on that?

2.

Can you put the rb30 crank into the rb25 to make an rb30det at all? Again someone mentioned and i wasnt too sure about that. I dont want to do it, but could it be done and what would be outcome be?

Cheers guys

[Cubes]

Engine bearings never really are an issue with knocking off their high spots its the bore and ring bed in that is critical.

Thats what my engine builder said anyhow.

He said to rev mine to 3/4 of its max rev (~4500rpm he mentioned) with half to 3/4 throttle.

Load it up then back off and repeat the process. Constantly varying the rev's.

He also mentioned not to load it up or labour the engine in a high gear at low rev's i.e in fourth gear at 1500rpm with your foot flat.

BUT he also said the very most critical process while running in the bores is to ensure the fuel mixtures are correct. This cannot be done if you are tuning it as they will sometimes lean out other times run rich.

Obviously you must bring the engine oil up to operating temp before giving it stick.

[Skyrine-Dave]

Yeah thats my thinking joel, bed the rings in the old way of loading it up and backing it off for a few hunded K's.

I forgot to mention something, i have programmable management. So obiously the tune wont be suited to the 3L. Now to even perform a proper run in i'm going to have to take it to the dyno to get some form of run in tune done. Now this worries me as the car will be brand new <5km old if i drive it to the dyno shop. and straight away it goes on the dyno to get the AFR's checked. This concerns me :S

[Sydneykid]

stocker ecu is long gone

i'll see how things go come time to fire it up

Hi Dave, we just drive them around for a hundred k's or so, then stick it on the dyno to quickly check the A/F ratios. This is not a power run, in fact the throttle never gets over 50% and it never gets over 4,000 rpm. It is just to check that it's not TOO rich or TOO lean, not precise mixtures, close enough will do. Takes about 20 minutes and that includes drive on, drive off and set up time.

Since we only use ECU's with AFM's, the A/F ratios are pretty much self correcting and we hardly ever have to change the tune. They are easily close enough to run the engine in for a few hundred k's. This applies to standard ECU's as well as Power FC's.

If you go straight to the dyno (zero k's) the rings haven't settled in and you get all sorts of screwy A/F results. So that's why we do 100 k's or so.

PS; I assume everyone knows to use 100% mineral oil (no synthetic) when running in.

[Cubes]

When I bought the VLT valve kit the bloke behind the counter said the only difference between the t and na pumps was the pressure. Later I found that to be totally incorrect.

I called holdens back to get another bloke who told me no they are definately different with the T gears being larger.

I can't remember what the measurements of my RB25DET pump was.

What you posted does sound familiar though.

It is probably a few pages previous where I was discussing it in this thread.

I do remember the RB20DET pumps have a really skinny gear.

[GTR-Ben]

What Main Crank Pully are you guys using as the RB30 one does not lign up with the Power steering pump making the belt go on an angle..

Using a pully from a different engine (GTR) etc would put the whole thing out of balance a they are a lot heavier..

Any ideas?

Different powersteering pump mount? Modify mount?

[the phantom]

Just use an RB25 balancer. Its weight has nothing to do with engine balance. All it does is dampen out the oscillatory clockwise and counterclockwise twist that occurs at the snout of the crank relative to the flywheel as a result of cylinder firing impulses.

I've had a feel of both RB30/25 balancers and the weight isn't all that different, however the construction is. The RB25 balancer probably has a different state of 'tune' (like a tuning fork) to an RB30 as the cranks would have different twisting responses due to stroke and max RPM differences. Interestingly the RB26 balancer is different again. Without physically measuring the crank twist occurring under load it is impossible to confirm which is more appropriate with any certainty. And measuring the oscillations whilst the engine is running is not straighforward for the backyard builder without some specialised equipment, although in principle its pretty simple.

I used an RB25 balancer on my RB30/25 without any obvious long term consequences.

[Bl4cK32]

I used an rb20 one cos it has three section with a ribbed flat belt in each section, where the rb30 one has 3 as well, but the centre section was for a v groove belt.

[Sydneykid]

I used an RB26 one, for the same reason as Bl4ck32.

[GTR-Ben]

Ok thanks guys. I have a RB20, RB26 and RB30. The RB26 is the heaviest of the three. I'm sure it won't make a big difference to my engine which one I use. Probably go with the RB26 one

[Jaws]

Just a question for the guys who are using GT3040's with the standard exhaust manifold or an aftermarket low mount manifold for rb25det top ends.

Are there any clearance issues with the turbo itself and/or the plumbing?.

[the phantom]

You can fit it all in with the standard exhaust manifold and plumbing with the following mods:

Make a new turbo compressor outlet tube that joins to the standard pipe leading into the hole at the side of the engine bay. This is obvious as the turbo outlet doesn't screw on like the standard GTSt turbo does.

Make an adaptor block about 40mm thick (approx!) that fits between the standard exhaust turbo flange and the GT30 with longer bolts to secure it all. This not only moves the turbo further out since it would foul on the manifold body (its much bigger than standard!) but also doubles as a spot to weld on a tube for external gate fitment.

Get a moulded 45 degree rubber bend from a truck supplier that goes from the compressor inlet with a metal reducer that mates with the standard AFM. The reducer can also have a tube welded in for the BOV.

It all fits and looks standard depending on how you mount the gate. Mounting it pointing downwards would make it difficult to spot. With all this your left with about 15 mm clearance between the turbo and the shock tower.

[LOW25T]

is there any way i can print out this entire thread? i'm rebuilding my car and i dont want to stare at the screen for hours...

[Clicks]

yes - you go Thread Tools

Show printable version

[Jaws]

i'm rebuilding my car and i dont want to stare at the screen for hours...

I'm saving every page of this thread on to PDF coz if this thread was to be lost it would be alot of hard work and info lost.

It also can be printed.

Plus I can refer back to any page faster than on dial up.

[teamplasma]

Hey Guys, tried readin all posts there's a lot of crap in amungst usefull info. I'm startin the conversion on my 33. Is this correct - rb30et block rb25de non-vct head, my rb25det manfoilds, can use wolf plugin to run it all? No major or expensive issues to make it all fit?

Second rb25de head? can it use same camshafts as rb25det eg. hks or tomie ones cause i'm in bris and am ordering parts from interstate gotta get the right ones!

[Skyrine-Dave]

rb30et(stock) + rb25de will give a really low compression ratio

rb30e(stock) + rb25de will give ~8.3:1 (better)

the rb30et block would be handy as all the oil/water feeds are there, but a series 2 NA bottom end is exactly the same, just with bungs in it