Sydneykid

It has been my experience that speed related vibration is nearly always a balance problem. Have you had the tyre balance checked on the car? That will determin if it's a fitting problem, it will also eliminate other out of balance items like brake rotors. It may also be worthwhile trying the rear wheels on the front, even if it is only for a short drive down the highway. I have noticed a tendency lately for tyre shops to only balance to the outside of the rim. I always have mine balanced inside and outside. Some brands of tyre are well known for having this problem. Hope that is of some help:cheers:

What tyres?

For the oil pressure you will need at least a T piece (adaptor) that screws into the block to replace the standard oil pressure sensor (for the dash warning light). The standard sensor and the oil pressure gauge sensor then screw into the T piece. Oil temperature is little more difficult. What sensor did you buy? You can get sensors that replace the dipstick, or one that replaces the sump plug, or simple a screw in sensor that needs mounting though the side of the sump itself.

In the real world it simply doesn't happen like that. If you have spent enough money on the outside of the engine (bolt ons) to make what you describe possible, then you have enough money to upgrade the internals. You will have spent something like this; Exhaust manifold ------ $1,500 Exhaust system ------ $1,400 Hi flow cat ------ $500 Turbo ------ $3,000 POD, AAI, heat shield ------ $400 Inlet manifold ------ $1,500 Camshafts ------ $1,400 Valve springs ------ $600 Adj pulleys ------ $500 Radiator ------ $700 Oil cooler ------ $800 Clutch ------ $2,000 Power FC ------ $1,100 AFM upgrade ------ $400 Boost controller ------ $500 Intercooler ------ $1,500 Injectors ------ $700 Fuel pump ------ $400 Head work ------ $1,000 Fitting labour ------ $4,000 Tuning ------ $1,000 Gauges ------ $800 Total ------ $25,700 So after spending $26K on the engine, what's another $1400 for a set of plstons? And finding that situation, plus one where nothing has gone wrong on the development path, is very unlikely. I have certainly never seen it.

Looking at the power graph, my first guess would be that the ignition timing is all over the place. Since the boost and A/F ratios are stable, that's the only logical alternative. It's up and down more than 20 rwhp in some places. Very interested in seeing the A/F ratios graph and what happens when you run the timing light over it.

I am certainly not the only one that has found that the RB25DET Tomei Poncams don't need adj pulleys, Croydons have reported the same on a few cars as well. The standard internals RB30 is not a big rever, so it doesn't really need big duration cams. The 256's should work VERY well. The 8.5 mm lift is not "limited by the RB25 head", I have used the Jun 256/9.3 mm in an RB25, but the valve springs needed to be changed. As for camshaft selection, it was suggested to me that the RB20DET 256/8.5mm camshafts would work OK in an RB25DET cylinder head with adjustable camshaft pulleys. I have not personally tested this though, but the source is reputable. Hope that is of some help:cheers:

I have used the Tomei Poncams (256 for RB25DET and 260 for RB25DET Neo) in a few engines and they work very well. I have tried an adjustable exhaust camshaft pulley on 2 of them and found no improvement. They appear to be very well timed standard.

Ok, I give up, how do you get 4 cylinders? My thinking is, they have 2 chambers with 1 rotor in each chamber and each rotor has 3 sides. So it's either 2 cylinder (meaning 1 chamber = 1 cylinder) or its 6 cylinder (meaning 3 rotor sides X 2 rotors). Personally I reckon it's 6 cylinder.

In the "Number of Cylinders" box it used to say "N/A", don't know what they use now.

My 20 cents worth........ This tyre thing is a joke, half the field were trying for good tyre wear. Sounds like my uncle who used to brag (all the effen time) that he could get 40,000 miles out of a set of tyres. Next they will put a fuel limit on and turn it into an economy run. I am not a Ferrari fan, but it peeeed me off when Rubins retired because of no tyres left. And the pit stops are so boring with no tyre changes, just fill 'er up and drive off.

Ah no that's not actually correct. The 13B is a 6 cylinder 3.9 litre engine and as such has about as much exhaust gas flow as it should. The 1.3 litre is using Mazdas measurements which are factually incorrect. As evidenced by the amount of fuel and air the engine consumes. Consequently it is pretty unrealistic to compare a turbo off a 1.8 or 2 litre with one off a 3.9 litre.

Oh Roy, you are getting to be an old toad like me on the streets, I drove all the way to work today with out getting any boost at all :innocent:

Hi Chris, interesting topic, worth investigating..... These are Roy's average power calcs..... On the first to second gear change the drop is ~3,000 rpm. So if Roy has less than 144 rwkw (the power at 4,000 rpm) at 7,500 rpm then it isn't worth reving it over 7,000 rpm. But if it has more than 144 rwkw at 7,500 rpm then it is. The most revealing number here is the power jump from 144 at 4,000 rpm to 180 rwkw at 4,250 rpm. I seems to me that reving it to 7,250 rpm (so it falls back to 4,250 rpm) would HAVE to be of considerable benefit. The 7,500 rpm limit may also be worth investigating as the 198 rwkw at 4,500 rpm is also attractive. Lower rpm limits could be used in second, third and fourth as the gearchange rpm drop is lower in the higher gears ie; the ratios are closer in the standard gearbox.

As the guys have already suggested, ignition timing would be where I would start. Check it with a timing light at 5,000 rpm with the chipped ecu and compare that to the Power FC at the same RPM.

Hi Roy, when drifting, the airflow goes across the front of the car, not straight in and through the radiator as it does when circuit racing or driving on the road. This affects both the water radiator and the oil cooler (maybe even more as it doesn't have a fan). The intercooler suffers in this area as well. Plus you have a much higher engine rpm and load versus road speed equation. The fan does most of the airflow work but it is working against the partial vacuum in front of the radiator created by the sideways motion. A larger radiator will help, but I would stick wiith the engine driven fan. Replacing it completely with electric fans (as big and as many as you can be fitted) usually results in lower airflows. Maybe having both electric and engine driven would be a better solution. And don't forget about the oil cooler. Hope that helps:cheers:

It makes no bearing noise, I will check it while changing the belt. But not usually a problem, unless soemone has over tightened the belt. I am changing the original belt, car has alway been to a Nissan dealer (Dayz) for service. So I don't anticipate that problem.

Any 12 volt boost solenoid will do, I would go for a "normally closed" style.

That's exactly why I ordered an Apexi one, to see how it measures up against the others I have used.

Spoon, don't they make performance parts?

Some suggestions follow; #2. Finding an R32 RB25DE may not be that easy, the R33 RB25DE's have VVT. #3. You will need an R33 GTST wiring harness to go with the R33 GTST Power FC. Back to #2, since you are using the R33 GTST Powewr FC and the R33 GTST wiring harness you can just as easily run the VVT. Especially if you can't find an R32 RB25DE cylinder head. #7. Why bother, stick the right turbo on, keep the boost down. Fill up with non synthetic oil (Castrol GTX works well), run engine for 20 minutes (not at idle), then change the oil filter. Check A/F ratios, not necessarily on the dyno. Drive the car to Bathurst and back to run the new engine in. Nice variable conditions, long hills and after 500 k's its as run in as it's gunna get. That's around 1.3 million crankshaft revolutions. Drain oil, change oil filter, fill up with the good oil (Castrol Synthetic Formula R 0W60 in my case), then tune it on the dyno. #12. RB30 Headgasket is OK. #13 A new RB30 water pump is a good investment. #14 Replace all bearings, seals, welsh plugs and gaskets. Hope that is of some help:cheers:

A month, that usually means the Apexi warehouse didn't have any in stock, Nengun can't do much about that. The camshaft pulleys were in stock when I last checked, so fingers crossed..... Looking forward to seeing your results, I have a fair bit of SAFC experience on R33 GTST's but never on a Stagea.

It may not be an RB25DE cylinder head, it is a simple unbolt job to remove the VVT solenoid and actuator. RB20 cam covers cetainly fit.

Ah no! Perhaps a quick explanation of tyre sizes might help 235 = 235 mm wide 255 = 255 mm wide 40 = 40% of the width (that's the measurement from the outside of the tyre to the rim) 17 = 17 inches, the rim diameter So 235 X 40% = 94 mm And 255 X 40% = 102 mm So they are NOT the same circumference. If you want 255/40 on the rear (102mm) then you need 235/45 on the front (105mm). Check the alternatives with the tyre shop that you are going to buy your tyres from, they have equivalency charts (so their customers can keep their speedos accurate).

Exactly Roy, by far the most common engine failure I see in RB25's is pistons, and that's a tuning problem. The second is valves and guess what, that's a tuning problem as well. Bearing damage is not all that common, mostly in RB26's and that is related to oil surge more than rpm.

My first suggestion would be to do a search on "RB24", there have been quite a few threads on this subject. Angry and Roy have passed on most of what I have learned. I would certainly look at changing over to solid followers, even if you simply lock up the standard ones. Valve springs are usually a necessity, at the very least shim them up for more seat pressure. Once you have done those 2 things you can use any RB26 camshaft. I would be looking at 264's at least, and 272's if you can find them at a reasonable price. I have seen a video of an RB24DET in an R32GTST doing a 9 at a HKS drag meeting on street legal tyres. So there is plenty of fun to be had. Hope that is of some help:cheers: PS; We use 8,250 rpm all the time in our RB20.