R33 Rb30 Conversion

[Cubes]

Its not like the drifto rb25det's are rev'd harder than 7500rm all day every day anyway.

[Sydneykid]

were they designed around a 6250 limit or is that the limit imposed on them due to longevity requirements, vehicle performance envelope etc and hence where holden put the redline on the tach?

All of that, the head/inlet/exhaust specification wouldn't let them flow enough air to rev more than that, so they engineered the rest of the package to the same limit. Like a chain, it's no use having one link stronger than the others, the weak one will always give up first. The general exception is the crank and block, most often they are over engineered compared to the rest of the package, as failure there would be catastrophic

i could probably second guess, but what's 'efficient' revving?

Where the power output actually increases with the extra rpm, doesn't drop off. Simple logic, why use 7,500 rpm and 600 bhp when you can use 7,000 rpm and 700 bhp? As you accelerate the car, the engine moves through an rpm range that is determined by the gear ratios. The route to the fastest (most efficient) acceleration is to use an rpm range that results in the highest average horsepower. If you use an rpm range (too high or too low) that results in a lower average horsepower, then you are reving it inefficiently.

The trick is knowing the gear ratios and the resulting engine rpm drop on each upchange and then overlaying that with your dyno horsepower read out. Then you can easily work out what is efficient and what is inefficient rpm ranges to use.

Cheers

Gary

[Dabro]

Some randomn things to add;

RB30E/RB30ET's were designed around a 6,250 rpm rev limit

Every 500 rpm increase in the rpm results in around a doubling of the force exerted on the crank, bearings, rods and pistons.

RB30's have a far superior rod length / stroke ratio than any other RB, this means less side force on the bores, rods and pistons.

This helps to ofset the often quoted higher piston speed argument

By far the most RB engine failures I have seen are due to oil control issues, then it's daylight, then some more daylight, then overheating.

If you rev an RB30DET/TT effeciently to 7,500 rpm thne you will be making over 750 bhp, so the first question you have to answer is "is my power target over 750 bhp". If it isn't, then why would you want to rev it to 7,500 rpm inefficiently, much smarter to simply change up a gear and take advantage of the faster acceleration.

The reason why I have an RB30 is so I DON'T have to rev it to make enough power, hence it lasts longer and costs less to build and to maintain.

Cheers

Gary

You are correct,

I was really just tackling the harmonics question, theres always more that can be added.

Oil issues are another conversation but are very common.

Interesting point on the piston speeds though, Have you done any numbers on the comparison RB30VrsRB26?

Also why rev an RB?? We all the answer to that, they are one of the best sounding engines out there when on song and running well and sometimes you dont need the faster acceleration!

I cant really see much difference between instant loss of licence and instant loss of licence, Remember I was talking street cars, RB30DET/DETT's have a natural tendancy to be plenty fast enough for the street no matter what the configuration unless the whole setup is out of whack completely. Track/strip cars are a different kettle of fish where accelleration, speed and handling are the sole goals. I want my revs, midrange pull (remember you can always shortshift if you want) , creature comforts and some reasonable fuel economy (if thats ever going to be possible again) all packaged in a quick, nice sounding and reliable daily driver hitting 7,000 rpm just for fun and sounding so sweet with some cubes behind it.

Dabro

[HR31DRFT]

I have seen oiling issues, i currently building this engine rb30/26 wif 7ltr sump and tomei pump full length collar etc, have any1 used a tomei h/v b4 on this setup?

[GTRgeoff]

youll need to make sure u use the correct injectors to suit the chosen power fc

im not sure on the sensor side of things though sorry

Wrong on the injectors shane old mate. If using a 25 PFC with 26 (or other low impedance) injectors then make a resistor pack.

If using a 26 PFC and high impedance injectors then no resistor pack. If using 26 PFC with low impedance injectors then you need a resistor pack.

Easily made for about $10.

[Sydneykid]

You are correct,

I was really just tackling the harmonics question, theres always more that can be added.

Oil issues are another conversation but are very common.

Interesting point on the piston speeds though, Have you done any numbers on the comparison RB30VrsRB26?

Also why rev an RB?? We all the answer to that, they are one of the best sounding engines out there when on song and running well and sometimes you dont need the faster acceleration!

I cant really see much difference between instant loss of licence and instant loss of licence, Remember I was talking street cars, RB30DET/DETT's have a natural tendancy to be plenty fast enough for the street no matter what the configuration unless the whole setup is out of whack completely. Track/strip cars are a different kettle of fish where accelleration, speed and handling are the sole goals. I want my revs, midrange pull (remember you can always shortshift if you want) , creature comforts and some reasonable fuel economy (if thats ever going to be possible again) all packaged in a quick, nice sounding and reliable daily driver hitting 7,000 rpm just for fun and sounding so sweet with some cubes behind it.

Dabro

I defy anyone to tell the difference in sound between an RB30 at 7,000 rpm and an RB30 at 7,500 rpm, listening inside or outside the car.. In fact anything over 6,000 rpm sounds like a lot because of the size of each bang, keeping in mind that it's 20% bigger than a RB26 bang. An R25/B26 can be a bit buzzy, so you need the rpm to sound tough, whereas an RB30 is noticeably deeper in its note.

With the old RB30 in the GTR I was always getting comments like "I didn't think RB30's revved to 8,000". They don't, the standard tacho just reads 6% high, but I kept forgetting to tell them

Cheers

Gary

[Bliksem]

Need some serious help guys,

My Oil pressure issues have returned. Im only reading around 5psi on idle with cold oil (external electronic oil pressure gauge) running castrol 20W50 GTX to run in the motor.

Anything above idle the pressure comes up eg, it will hit around 70psi at 4k rpm.

Oil pressure sender is mounted on the factory RB25DET oil cooler.

REALLY REALLY want to sort this out as this is a brand new motor that hasnt even been run in yet!!!

[Dabro]

Need some serious help guys,

My Oil pressure issues have returned. Im only reading around 5psi on idle with cold oil (external electronic oil pressure gauge) running castrol 20W50 GTX to run in the motor.

Anything above idle the pressure comes up eg, it will hit around 70psi at 4k rpm.

Oil pressure sender is mounted on the factory RB25DET oil cooler.

REALLY REALLY want to sort this out as this is a brand new motor that hasnt even been run in yet!!!

Do yourself a favor and put a good direct reading gauge into a gallery on the side of the block then see what you have. Sometimes these issues can be hard enough without worring about how sensitive or accurate your electric gauge is. Im not sure what your original problem was but dont forget that the factory oil pressure gauges are notoriously unreliable. My GTR occasionally idles at zero on the gauge but I know it has oil pressure. In saying that 5lb's with cold oil is very low so you should definatelly find out what its really doing just in case. If its a fresh build you have paid for at a workshop put the direct reading gauge on it so you know whether its actually has a problem. If so go back to your engine builder and talk to him, if not fix your gauge.

Dabro

[Bliksem]

im using an aftermarket gauge on the oil cooler.

my engine builder re-used the rb30 oil pump as he said it would be sufficient, wasnt worn out etc.

Does anyone know for certain if the rb25 oil cooler is compatable to bolt up to the rb30 block? I swapped over the slip on o-ring fitting etc but I noticed the cooler has a pressure releif valve, as does the block. Not sure if two valves could affect things though.

Edited January 25, 2008 by MintR33

[mr_rbman]

i personally wouldn't be using 20w50 oil in a turbo motor, try something a little thinner!

[SirRacer]

im using an aftermarket gauge on the oil cooler.

my engine builder re-used the rb30 oil pump as he said it would be sufficient, wasnt worn out etc.

Does anyone know for certain if the rb25 oil cooler is compatable to bolt up to the rb30 block? I swapped over the slip on o-ring fitting etc but I noticed the cooler has a pressure releif valve, as does the block. Not sure if two valves could affect things though.

hey dude, the most common issue with the rb's is their oil system. the thing ive learnt with engine rebuilders is they can build an engine however they dont know everything about every engine. eg the guy who is building my engine thinks im nuts for throwing a turbo at it. its a stock rb30 with 25 head and we all know how they go with turbos.

id be very inclined to get a crank collar and better pump. i was lucky enough to pick up a 33gtr pump for free but can get another one for 200NZD, so id suggest looking into doing that.

its a bit of an expense, but a new set of rings is 250/350 + hone 100 so its already paid for itself there!

[Rolls]

Hey all,

Just chucking this out there could it be possible using the rb20det head getting it ported and putting bigger valves in it just reading the pdf and could it be possible putting in the 25 valves and make it work?

Because i have a rb20det head out of a wreck and a rb30e out of another one.

Just chucking it out there to see if it possible?

Regards

Possible but cheaper and easier to go 25 head. Don't bother.

[GTRgeoff]

i was lucky enough to pick up a 33gtr pump for free but can get another one for 200NZD, so id suggest looking into doing that.

R33 GTR pump = R33 GTS25t pump.

Check the part numbers and flow rates in FAST.

Don't pay extra for a "GTR" pump.

[Al]

R33 GTR pump = R33 GTS25t pump.

Check the part numbers and flow rates in FAST.

Don't pay extra for a "GTR" pump.

Really

Damn, you know how many people have told me "I'm replacing my std pump (gtst) with a GTR pump", because they are too tight to buy a proper pump. Now i read that it is the same pump

[bubba]

I made the mistake of re-using the RB30 oil pump, that combined with not getting the crank machined the first time nearly saw my engine let go

Ordered an N1 pump ($410), got a backup crank machined and a new set of bearings, now she's all good! Using 10W-40 cold start sees ~100psi, once at normal temp. I get 12-15psi @ idle, 40psi a little over 2k, 60psi a little over 3k and 80psi by redline. Watching my oil pressure gauge shoot up make me a happy man after watching it previously bleed off to 0 at idle O_o

[Bliksem]

Checked today (Ricol Automotive btw so they "should" know their stuff) He used a brand new pump.

I think there could be something with the oil cooler, I cleaned it in de-greaser and im starting to think that one of the valves could be shot/stuck but im not sure how the thing actually works.

Another thing to note is that there is no ticking etc coming from the motor and oil is circulating around the head.

Also regarding the oil weight, what should I be using to run the motor in? on around page 48?? sk recommends using castrol GTX which is what Im using...

[Alf]

Castrol GTX is the choice for running in oil for many reputable workshops.

Edited January 26, 2008 by Alf

[Bliksem]

Does the o-ring that goes on the cas affect oil pressure? I noticed mine isnt fitted, but it was on my old motor?

Also I re-located the oil pressure gauge sender to the factory RB30 location but could only fit the mechanical gauge on there. I recorded 10psi cold pressure but there was oil streaming out of the hose fitting so I may have lost a few psi there :-(

[Adriano]

The o-ring is only to stop the CAS flopping around

[Bliksem]

Any places to check for loosing oil pressure then (I dont have any noticable external leaks?) I made 20psi on cranking a few weeks ago... I cant work this out....