Sydneykid

Personally I would do the RB31 (forged) bottom end, and with the RB25NEO top end it would be a real goer. We have a ~600 bhp RB26DETT and a ~600 BHP RB31DET and I can tell you the RB31DET is much much faster. The max power might be the same, but the average power from the RB31DET is much higher. I have never actually worked it out, but it would be a good 60-70rwkw from 4,000 rpm to 8,000 rpm. My 20 cents worth.

Re 8.8 mm lift, I have used a number of GTR cams in RB20's and they work fine. PCD = Pitch Circle Diameter. In a camshaft it generally expressed as the distance from the the centre of the camshaft to the point of the lowest lift, valve closed, sometimes called the heel. The point of the highest lift, valve open, sometimes called the toe. The lift of the camshaft is measured by subtracting the heel (distance from the centre of the cam) from the toe (distance from the centre of the cam). Reducing the PCD of a camshaft is a trick used by camshaft grinders to get more lift. Instead of building up the toe they take some off the heel, the follower takes up this loss of PCD (if it can), so you end up with more lift. A few simplified examples; 1. Standard camshaft Distance from centre of cam to heel = 6 mm Distance from centre of cam to toe = 14 mm Lift of camshaft = 8 mm 2. Reduced PCD camshaft with higher lift Distance from centre of cam to heel = 5mm Distance from centre of cam to toe = 14mm Lift of camshaft = 9 mm Will not require machining of head as toe is 14 mm from centre of camshaft 3. Standard PCD camshaft, but with higher lift Distance from centre of cam to heel = 6mm Distance from centre of cam to toe = 15mm Lift of camshaft = 9 mm Will require machining of head as toe is 15 mm from centre of camshaft 4. Increased PCD camshaft with higher lift Distance from centre of cam to heel = 7mm Distance from centre of cam to toe = 15mm Lift of camshaft = 8 mm Will require machining of head as toe is 15 mm from centre of camshaft I have never seen a #4 for an RB but it is possible, so I always check the PCD quoted by the cam grinder. Hope that helps

Well, the theory is by having a recirculating BOV, the hot air goes around again. Whereas an atmospherically vented BOV gets rid of the hot air and makes room for fresh (colder) air. There is also the cooling effect from the overly rich mixture that the engine runs after the atmosphere BOV has vented. Some people say that this overly rich mixture also reduces lag on gear changes as it burns in the turbo and helps spool it up. You can overcome most of the stalling problems associated with an atmosphere BOV with tuning, it is a bit of fiddling though and I am not sure if it is worth it on a road car when you add in the legal issues. On the race cars we always have atmosphere vented BOV's. Hope that helps

OK, the questions sounds simple but it's not, the particualr issue here is PCD. If the camshafts have been ground with standard PCD, then 9 mm lift may need a slight (very slight) touch up on the clearances. There are pictures on other threads on where to machine, but is is bloody obvious when you have the cams in the head. Don't be afraid, it's a die grinder and about 1 minute per lobe. If the PCD is smaller than standard, then ~9.2 mm is OK. But you will need to check your valve lash clearances as there are geometry issues with using smaller PCD cams. These may require offset followers to correct the geometry. Bottom line, don't just grab the first pair of cams you see with the highest lift that say you don't have to relieve the head. My recommendation is, make sure you get standard PCD cams. The second issue is hydraulic followers, I personally haven't had any success with cams over 9 mm lift in RB20's. I end up with follower rattle every time, probably because the engines have done a lot of k's and the followers are worn and leak a little. Hope that helps

Hi guys, maybe we should put some numbers down, it might help answer the question. The turbine is at 750 degrees, ambient air temp is at 30 degrees (it's summer time) and radiator water temp is 85 degrees. If you had a 100% cooler then the water would go down from 85 degrees to 30 degrees before it went into the turbo core. There is of course no such thing as a 100% efficiency cooler, about 70% is a pretty good effort. So that would make the water temp 44 degrees. Personally I don't think the 41 degree lower water temp is going to make much diference to 750 degrees, especially since it is going through the core which is isolated/insulated from the turbine. That's probably why I have never seen this technique used, the most common turbo cooler is ducting blowing ambient air over the whoile turbo. That's arguably much more efficient method. Interesting subject though....

Are they RB26 cams or RB20 cams?

Hi Nick, I purchased ours direct, there were ~18 Stageas that week, all autos, not a single manual. Ours was a Grade 3 1997 model and cost 490,000 Yen (~$6,500 at the exchange rate on the day) I looked for around 6 weeks and only saw one manual and ~90 autos. That 1997 manual, Grade 4, went for 1,450,000 Yen (~$19,000) and the bidding was pretty fierce. All up mine cost $17K, the manual would have been ~$32K. It was a later chassis number, had travelled a few less k's and Grade 4 (compared to Grade 3) but the price is pretty comparable. So I strongly suggest you do a bit of research before making a final decision. Hope that helps

Hi Gav, this is pretty much the same result others around the world have achieved with 2.6/2.7 litres and GTRS's. I didn't tune Mark's car (lucky him) but it is very comparable. Personally, for what I would use the car for, I would have gone to 3.1 litres but for Mark's purposes I reckon it will be great.

Hi J, I had the same problem myself, couldn't remember how to check the oil in an autobox. First I had to find the dipstick, I thought someone had stolen it :ufo: The manual GTR with ATTESSA was great, but no one was silly enough to try and drag you off in the rain. The Stagea is way better, stealth and an auto. I smell plenty of victims :bat:

With the RB20 in R32 GSTS, 225 kph into the chase at Bathurst, no brakes or backing off just turn in and hang one. That's from a standing start at the dip on Conrod. Same at Eastern Creek into turn 1, gotta brake there as it was raining. With another 175 rwkw this year, I am looking for 265+ kph into the chase, woooohoo.

Here is one I posted earlier; In the above fun session I simply left it in drive, squeezed the throttle and let the torque converter hold it against the brakes. Got up to ~2,000 rpm and actually started to drive through the brakes it made so much power. Take left foot off the brake pedal and plant right foot on accelerator. No wheelspin, even though it was raining a fair bit. I didn't think it was that fast, until I looked at how far back the wheelspinning Commondoor was. I can't wait to try it with 50% more power, maybe it will wheelspin then. :Pimp2:

Hi Mark, damn good result. Pretty much what we discussed, they make some boost at ~5,000 rpm, really get into their stride at ~6,000 rpm, make max power at ~7,000 rpm and still have plenty at ~8,000 rpm. They will be fun on a cool night, as long as it isn't raining. :wizard:

Centreline or Traction Tyres would be my suggestions in Melbourne, both Andrew and Chris know their stuff.

I have found the spring rates to be OK, so I am not going to change them. Plans are for a set of Konis adjustables and lower the bottom spring seat 25 mm via the circlips. Roll is excessive though, so a pair of Whiteline Stabiliser Bars, 24 mm front and 20/22 mm rear will fix that. Then I am going to add some caster, that should help the initial understeer and give the steering some weight, it's way too light for my tastes. :cooldance

Manuals are hard to get and so cost heaps more at auction, like double. So far I have found the auto to be very nice. Smooth but precise shifts, holds good rpm in Power mode. Torque converter stall rpm allows boost for take off, I absolutely detroyed a Commondoor SS Ute yesterday in the rain. :elaugh:

A UTS boy like me, I went there 'cause the course was better. :thankyou:

Everyone in my team gets credit, that's why it's a TEAM. I have a picture somewhere of Sam Michael sweeping the pit bay at Bathurst, you gotta start somewhere.

Emre, check out the AT= 25 and IT = 82. :headspin:

Carby cleaner = no good, as it leaves a residue. Brake cleaner = much better, as it leaves no residue.

Good discussion guys, I have picked up a few tips from most of the posts. I have only had one experience with cryo treatment and that was a pair of RB26 camshafts. They were used and slightly marked on several lobes when they arrived. This looked to have been an oil feed problem as the hardness test came back OK. So we lightly machined the lobes to removed the marks and then sent the camshafts off to be cryo'd, as an alternative to heat treating them. They have been in the car for nearly a year now and over the Xmas off season, I will pull them out and have a close look at the lobes to see what the results are. But so far they look fine, with no valve clearance adjustments necessary (that's a good sign). I would say that if you are loooking at adding maybe 10% to the horsepower limit of the components, then maybe cryo is worth looking at for new rods, cranks and cast pistons. If you are using well used components I think it probably would be a waste of time and money. They will have been hot and colds thousands of times and consequently any stresses will be long relieved. Ditto engine blocks, although boring them would be something to consider, maybe the metallurgists in the group can add to my thoughts........

Hi Roy, if I look at the data log from the RX7 (the one you saw at Philip Island) it shows Oran Park to be pretty tough on the engine. Philip Island has long periods at high rpm, but they are in high gears (4th and 5th). Oran Park has short runs in low gears, so the rpm climb rate is pretty viscious. With the Modena close ratio dogbox there is very little difference (between the two circuits) in time spent per lap at 7,500 rpm to 9,500 rpm. I would be inclined to the view that rapid deceleration and acceleration in low gears is harder on some engine components than the more gentler rpm climb you get in high gears. One thing is for sure, OP is far harder on the gearbox and diff than PI. Maybe it all cancels out and all circuits can be tough in their own way. Now that bump at the end of the straight at Sandown.......1 diff, 2 tailshafts, 2 gearshifters :headbang:

I dissable HICAS in the Skylines, so no HICAS on the Stagea saves me time and money that I can spend on other things. :wassup:

Ouch I'm hurt. :goddam: I'll bet most people know last year's Bathurst was won by Murphy and Kelly, but how many know who was the Team Manager?

No Problems, valve details follow; RB26 Valve Specs --------------Head-------Stem------Length------Tip Intake-----34.65mm----6.00mm----102.40mm----3.5mm Exhaust----30.15mm----6.91mm----101.55mm----3.5mm