R33 Rb30 Conversion

[Scooby]

...as well as those N1 pieces of junk.

Hi Geoff, you're not a fan of the N1 either? After much deliberation and discussion with Greg, as well as Harris Engines, I've used one. They both seemed to think that while N1s don't like to be bounced off the limiter repatedly or spun to 9k rpm, they're otherwise OK.

[NickR33]

hey Geoff do you see a real advantage in going for the higher flow oil pumps like the Jun or HKS? they are twice the price of the N1 but are they worth it on a circuit motor in your opinion?

[GTRgeoff]

Not a fan because the N1 is a much more brittle material so doesn't have much residual toughness for things like bouncing off the limiter, but that does happen even if you don't want it to.

Also there is no real justification for much higher oil pressure/flow. All it will do is deposit more oil in the head which you then have to get back to the sump for pickup. Oil system function and efficiency is not based upon the amount of flow or delivery pressure, but the maintenance of the thin film of oil between moving metal components. Oil pressure does not provide lubrication; oil presence and viscosity does it. Some systems use the natural viscosity to pull the oil through without a pump.

It would be great to know that the flow is moving the oil through to prevent overheating and molecular breakdown, but pressure is always a measure of restriction when it comes down to the final analysis so a high flow pump giving greater pressure head is simply showing the restrictions present, and therefore the lack of ability of the high flow pump to really make any discernible impact.

[NickR33]

thanks Geoff, great reply:)

[Adriano]

Im sending off a cranks to get crtogenic'd. Does anyone think getting the oil pump gears(N1)done would be any advantage?(itl cost about $40)

[Al]

As stated previously, i have already purchased an ATI balancer. I came across a thread that discussed GReddy pulleys and thought they may come in handy if they are able to be fitted to the rb25 p/s and a/c pumps.

So i went to Nengun to see how much these GReddy pulleys where, and stumbled across a HKS balancer that i reckon is actually the ATI balancer (Nengun Link - CLICK HERE). What do you guys think?

Now reading the Nengun description got me a little concerned:

...........To install this item, a Mitsubishi alternator must be used (Hitachi's alternator is not supported).

The Mitsu alternator only came out on the S3 R33 GTRs and above. I would like to know what is the difference between the Mitsu alternators and the Hitachi units? As the GReddy pulley kits also distinguish between the two makes.

[Scooby]

10 psi

220rwk@6500 power curve flattened out so prob not much left. Rich, dipping into 10:1

Running really rich also on part throttle when bimbling around, 2nd gear 40km/h etc. Can hear a very slight unneveness/burble but very smooth on boost. Not sure why this is since it's the stock ecu.

Guys any ideas on the part throttle richness? Didn't happen with the RB26, not sure why it should be so rich with the 30 using the stock ecu. Actually feels really unresponsive at part throttle sometimes, almost like it's taking its time to figure out what to do. Once at a certain throttle opening it's 'off we go'.

Cheers

[Cubes]

I think I also had the same thing on the stock rb20det ecu. Not sure if it was rich or what not but it felt as if it would bog down slightly then lunge off. It wasn't all that noticable.

I dropped in the pfc and it was 100% perfect on its base map.

[silver gts-t]

question:

rocket industries says that with arias rb25/30 forged pistons comp is 9.5-9.8:1 (part #ap332105)

and with standard rb30 nonturbo forgies the comp is standard (#ap340754)

which would be better? is 9.5:1 too high? and does everyone agree the information is accurate?

forgive me if this has been answered as im only up to page 160 of so in reading this..

thanks

edit: all good, found this

but is 9.2-9.4:1 too high comp?

QUOTE(VHR32 @ 7 Mar 2007, 12:12 AM)

I updated my piston list from P221

Added a new p/n for a flat top piston from Arias and added compression ratios for the Arias pistons. Two are quite high for a turbo engine!

CP

All compression ratios are based on zero deck height, 1.2mm head gasket (7.13cc), RB25 @ 62.5cc, RB26 @ 64.5cc. They assure me they have done alot of work to make sure the facts are correct.

p/n= CP-RB30/26-.20

Flat top with no valve pockets

8.2:1 COMPRESSION RATIO with RB25 head and bit less with RB26 head

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize but can be custom ordered in any size.

p/n= CP-RB30/26-.20-9.0

6.0cc dome top,

9.0:1 COMPRESSION RATIO with RB25 head and bit less with RB26 head

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize but can be custom ordered in any size.

*Care must be taken when using on RB26 with more than 11.5mm valve lift*

ARIAS

Suit RB30/26

p/n= AP332103

flat top

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize (86.5mm).

COMPRESSION RATIO 8.4-8.6

Suit RB30/26

p/n= AP332104

10.6cc dome top

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize (86.5mm).

COMPRESSION RATIO 9.2-9.4

Suit RB30/25

p/n= AP332105

13cc dome top

21mm pin

1.280" compression height

Only stocked in 0.20 thou oversize (86.5mm).

COMPRESSION RATIO 9.5-9.8

WISECO

Skyline RB30 w/ DOHC RB25det cylinder head

1.260" compresion height, 66.5cc head chamber, Dish top -11.3cc, 7.0:1 compression ratio, 21mm pin, 1mm gasket thickness, 1mm deck clearance.

K577M865 86.5mm

K577M87 87.00mm

ACL

6MKRY9608 (VL turbo)

87mm, -4.5cc dished top, 1.261" compression height, 21mm pin,

Standard RB30ET pistons are 7.8:1, with RB25 head it is 7.1:1

These are bumped up to 8.5:1 so with the RB25 head it may give about 7.5:1??

Using http://www.csgnetwork.com/compcalc.html I came up with 8.5 for VLT (spot on) and 7.6 with twin cam head with 64cc chamber.

I entered: 2, 87, 85, 87, 1.2, 64cc, -4.5cc = 7.6:1

BUT these have a lower compression height than the CP/Arias and im sure it stuffs up my calculations but its late and im too tired to look at it any more...

Edited July 31, 2007 by silver gts-t

[Scooby]

I think I also had the same thing on the stock rb20det ecu. Not sure if it was rich or what not but it felt as if it would bog down slightly then lunge off. It wasn't all that noticable.

I dropped in the pfc and it was 100% perfect on its base map.

That's exactly what mine does. Making enquiries now about getting an ecu remap.

[Spunky Munky]

Wow, a VL engine in a beefed up R33 - what can I say... wow!

Do you have photographs mate? Would love to see what your best looks like... one thing that really intrigues me is that if people that are after the "GO" why important is the "SHOW" to them.

Good luck with the build mate....

Cheers,

[Craved]

[CEF11E]

That's exactly what mine does. Making enquiries now about getting an ecu remap.

I just tuned one of these last week. RB30DET using RB30 bottom end and RB25de head.

if you are using the standard R32 ECU an AFM you will expierence this at 2400rpm when cruising and then get on throttle. then it will start to pick up at around 3200 rpm. the 2 factors that make this happen is the RB20DET timing map. bugger all advance. engines need timing to make torque also the AFM reads a lot more flow than it would with the 20det so the TP scale is out by about 30%. this makes the tune rich.

The combination of the 2 things make it a slug. if you put it on the dyno you will see what I mean. I ran 18deg timing on the one i just tuned and corrected the AFR and it came on boost a lot earlier and increase response and made power delivery a lot better

This does not happen with the RB20det because it never accesses the far right TP scale at 2400RPM

It is quite ease to make some minor adjustments to the tune to get it to run the 30det nicely.

[Scooby]

I just tuned one of these last week. RB30DET using RB30 bottom end and RB25de head.

if you are using the standard R32 ECU an AFM you will expierence this at 2400rpm when cruising and then get on throttle. then it will start to pick up at around 3200 rpm. the 2 factors that make this happen is the RB20DET timing map. bugger all advance. engines need timing to make torque also the AFM reads a lot more flow than it would with the 20det so the TP scale is out by about 30%. this makes the tune rich.

This does not happen with the RB20det because it never accesses the far right TP scale at 2400RPM

I have an RB26 ecu.

Edited July 31, 2007 by Scooby

[CEF11E]

oops sorry... I will have a quick look at rb26rom tonight and see if i can see what's causing the hesitation. from memory cubes was an rb20 ecu user fro run in i just assumed you were too

[Sydneykid]

Guys any ideas on the part throttle richness? Didn't happen with the RB26, not sure why it should be so rich with the 30 using the stock ecu. Actually feels really unresponsive at part throttle sometimes, almost like it's taking its time to figure out what to do. Once at a certain throttle opening it's 'off we go'.

Cheers

The extra capacity (15%) and the better cylinder fill from the longer stroke and superior rod/stroke ratio means the RB30 is using parts of the standard ECU mapping where Nissan considers an RB26 would never go. At 2,000 rpm an RB30 swallows just over 20% more airflow than an RB26, so it has airflow at 2,000 rpm that the standard mapping doesn't expect until 2,400 rpm. Nissan has programmed into the mapping considerable safety margin in the form of retarded ignition and rich A/F ratios whenever the engine gets outside its normal operating parameters. That's why I would never recommend running in an RB30 on a standard ECU, the richness will stop the rings bedding in properly and in extreme cases lead to glazed bores. The retarded ignition results in incomplete combustion which fouls up everything from plugs to cats.

A Power FC on the defaults maps is a far better solution as they don't have the "outside the normal" richness and retard mapping, there is a more logical extrapolation of the "normal" mapping. Just have the knock readings permanently displayed on the Commander and watch them closely. If you have an A/F ratio meter just keep an eye on it for excessively rich or lean readings. Otherwise spend 20 minutes on the dyno and check the readings.

cheers

[CEF11E]

The extra capacity (15%) and the better cylinder fill from the longer stroke and superior rod/stroke ratio means the RB30 is using parts of the standard ECU mapping where Nissan considers an RB26 would never go. At 2,000 rpm an RB30 swallows just over 20% more airflow than an RB26, so it has airflow at 2,000 rpm that the standard mapping doesn't expect until 2,400 rpm. Nissan has programmed into the mapping considerable safety margin in the form of retarded ignition and rich A/F ratios whenever the engine gets outside its normal operating parameters. That's why I would never recommend running in an RB30 on a standard ECU, the richness will stop the rings bedding in properly and in extreme cases lead to glazed bores. The retarded ignition results in incomplete combustion which fouls up everything from plugs to cats.

A Power FC on the defaults maps is a far better solution as they don't have the "outside the normal" richness and retard mapping, there is a more logical extrapolation of the "normal" mapping. Just have the knock readings permanently displayed on the Commander and watch them closely. If you have an A/F ratio meter just keep an eye on it for excessively rich or lean readings. Otherwise spend 20 minutes on the dyno and check the readings.

cheers

much more accurate description than mine . Looking at the standard RB26 map, the AFR's would be 10:1 if using an RB30 bottom end and putting your foot down at 2400rpm.

[R34GTFOUR]

Hi, like everyone has said bloody great thread, im only upto page 60 or so but give me a week and i'll be up to date

I've decided to jump to the last couple pages to see if anyone has discussed using the r34 neo head so i've just go a quick couple of questions. I've read the rb30 DOHC guide and it says that the water/oil galleries are different in the r34 head and the head has less cc's at only 50cc.

So...

1. Has anyone done a rb30 neo conversion?

2. How different are the galleries? What needs to be done compared to the r33 head?

3. What is the compression ratio with the r34 head like?

I have a r34 gt-four (you would of never of guessed with my user name haha) and this is looking very attractive, i also realise that an adapter needs to be bought to fit my sump onto the rb30, but its been done before with the r32 & 33 gts-4's so it shouldnt be to hard

thanks

[CEF11E]

There seem to be a lot of people using the RB25de heads and not replacing the valve springs.

is valve float related to pressure/boost or flow aswell. does anyone have a rating for the RB25de, RB20det and rb26 springs?

are they all interchangeable?

thanks!

[Cubes]

Its boost/rev's related.

The rb26 springs are a couple mm taller + which helps with seat pressure.

Out of 4 motors here in Adelaide there's only 1 that I've seen that has been untouched and had no issues at 20psi. The other 3 required shimming to get seat pressure up to a working level and the other one (sky30's) was fine until around 17psi.

The rb25de springs are identical from what I can see and feel to the rb20det springs. The issue occurs because the spring is attempting to control a valve that is larger/heavier.