simpletool

Could be one of about 10 -bypass hoses and connections under the intake manifold. I have just changed all my hoses. There is a collection of 1/4, 1/2 and 3/4 inch hoses that are mostly water connections under the intake manifold and one into the block at the drivers side rear bottom of the block (and a 4-way splitter joined to that). It CAN be done by yourself, but be patient and prepared. You will also need the factory heater hoses (4 of them) since it is a very tight space and the bends really cannot be done with generic hose as there is far too little clearance. The other smaller hoses can be made from generic straight hose (like Gates hose from Repco) and one short 120degree bend (19mm or 3/4inch hose). I suggest you replace all these bypass hoses - and the 1/4 inch 90 degree bend at the coolant return from the turbo at the read of the head near the intake. I didn't quite put mine on correct at one join - the back bottom rear and it leaked cold after a few days of not leaking - so I'm still working on it today to sort that out. Your hoses by now would be in very average condition.

I've got 7 of these downstairs. Got 6 about 2 months ago at Bursons here in Brisbane. Found another single one lying around from the AE86, must be 8 years old.

Here are the diagrams for all coolant hoses EXCEPT 2 more which are also under the manifold and attached to some kind of weird device near the oil filter. I have had these diagrams for while - but have only now taken all the by-pass hoses off from under the manifold. It's a pain of a job, took out the starter motor to get some access from underneath.

Or you could have glued shut the PCV valve with high temp silicon or similar - that's what I did. totally internal job then But now I need a new PCV gasket anyway.

Anybody double up the turbo oil return line as breather (to atmosphere) - could be handy to prevent pressure build up preventing oil flow through turbo ? Also, I can't help but think that this oil retention in the head issue is made worse when using higher viscosity oils. My thoughts are that because of shear thinning of the oil when going through the oil pump the thicker oil affects draining more than pumping. Nissan specifies a 30w oil, where the ratio to draining and pumping effort is higher than a 50w oil. Occurred to me the other day. This is a bit of a moot point obviously since high rev, higher blow-by engines are going to require some sort of oil modifications for track use anyway. And you can't use 30w oil for high loads.

Explained another way: Compressor maps are actually fairly easy to read. A google search will take you to the Garret website under "turbo tech" or to lovehorsepower dot com. Both pretty good. The basics are you plot a y-axis and x-axis for a few rev points, at least 3 points: one coming into boost, one just on boost and one at maximum revs. On boost the y-axis we can assume will be constant - a flat line. X-axis is the flow of air - which is almost directly related to power. On a well tuned engine you can APPROXIMATE will be 10lb/min of air to 100hp (AT THE ENGINE). My initial assumption of using 11lb/min per 100hp is a 10% increase that means you have some headroom on the compressor before running into choke and also that a turbo engine is usually tuned pretty fat - so it needs more air to make the same power. Y-AXIS Plotting pressure ratio on the y-axis. Pressure ratio = (absolute pressure / pressure at mouth of compressor) Absolute pressure = boost + atmospheric (or boost + 14.7psi) You can use bar or psi or mmHg if you want - just be consistent since it is a ratio. X-AXIS: at each rev point you work out the engine power, and convert to air flow in lb/min. Remember and easy approximation is 10lb/min air for 100hp at engine. And that's it. Just don't run into choke, which is on the far right. The line on the left is the surge line - the speed where the compressor starts to grab air properly. The line on the right is when the compressor is creating too much heat and going to fast to be efficient. Then size this to a decent sized turbine (outlet a touch smaller than the compressor inlet) , and don't skimp on the A/R ratio so it doesn't either backup exhaust pressure (limiting flow through the engine head) or come on boost like a light switch and be too sensitive to throttle. Disclaimer: All my thoughts are theory based with a touch of pracise - but at least I did thermodynamics in school

Well it looks like 20psi would be the most you could use on those turbos if you want to stay in that map. To plot the pressure ratio: Take your desired boost pressure, add 15 (for sea level pressure) and then divide the total by 14 (which is an approximation of the intake pressure before the turbo compressor) So (20 + 15) /14 = 2.5 to get 2.5 pressure ratio you would want This gives the pressure ratio you can plot on the y-axis. I chose 14psi as that is the absolute pressure before the compressor (after the air-filter) and it resulted from guessing a 1psi drop between the air-filter and turbo intake. This is what is in "maximum boost" by memory. Corky Bell may even use 2psi pressure drop which means the pressure ratio is 2.7 - which would mean you could only use about 18psi. So then to get the x-axis value (for every thousand revs or so) you guess the delivered power, and approximate air flow values from there. I really have no good idea about what the ratio of air value to power on a tuned GTR would be, but my guess is about .11lb/min of air for every hp at the engine. This depends on tuning, it could be .12lb/min. So say a mild GTR at 20psi at peak revs 8000rpm makes( umm I dunno), ~ 550hp at the engine. And at 7000rpm it makes 510hp (assumed less efficient after 7500rpm), and at 6000rpm it makes 440hp, and at 5000rpm it makes 360hp, 4000 it will be off boost. Then divide all these numbers by 2 for each turbo (actually should be a bit less than 2 as you need to assume that one of the turbos is making more boost than the other and you are really only calculating for the hardest working turbo, but we'll use 2) So you convert those hp at the engine numbers to lb/min to plot on the x-axis at the y-axis level of 2.5, and label with revs for info. So you have a line from 5000rpm which is 180hp x .11 = 20lb/min To at 8000rpm, 275 x .11 = 30lb/min. To plot before it comes on boost you need to approximate the boost level of the turbo as it comes on boost and the rev that it comes on full boost is the turning point on the map. so say 4000 it might be making 6psi boost and 180hp, so plot at (180x.11)/2 = 9.9 lb/min at pressure ratio 21/14 = 1.5 Now both these values are at the VERY edges of the chart at 2.5 ratio. So really these turbos are maxed at 20psi and can make about 550hp at the engine with a pair. Yes you can make a bit more but they'll really be cooking. Please remember I have made assumptions about hp to lb/min and all that so check those first.

Actually I read a thread from Thailand (if I remember correctly) anyway, there was strong agreement that there are 3 series of turbos on the R34 - the series 3 had a garrett stamped turbo with steel wheels that had different compressor housing and compressor wheel (all a couple of mm larger). One guy was discussing how he managed to find one at auction in Japan and put it on his R33. So it seems the garrett turbo was stock for the last series (which they didn't sell many of) If you google search you should be able to find it - somewhere.

Does it have a spherical bearing in the top? IF so that is the likely source of the rattle, the clearance between the bearing and housing.

The cam covers must be vented to something that is NOT pressurized. Therefore if you mean intake before the turbo that is OK, if you mean after the turbo (and therefore pressurized air) then it's is NOT OK.

For a very-mild RB25 GTST with occasional track use is it sufficient to just vent the sump (from the dipstick tube) and the vents from the rocker covers into a sealed catch can then into the stock intake pipe spot? ie. Do I need to perform these mods?? I think I need to do something as after long 130kph country drives I find a light cover of all down the rear exhaust side of the block. I figure this is from excess oil pressure in the rocker covers. Perhaps another rocker cover vent at the rear?

You could go to Accurate suspension . But I don't mind fulcrum at Moorooka.

Here are the things I have read that seem to be the accepted norm: Fuel pump can be an issue very early, like 200rwkw. Best to change this, you can do it yourself if you are patient and plan carefully. I can't see how the RB25 AFM can read properly at 250rwkw when at 190rwkw mine reads 85% flow. That seems to indicate it's good up to about 225rwkw. Sure you can get more power from an engine by fooling the ECU but the measured flow/load will be constant so it won't really know what it's doing. The injectors limit is around 220rwkw (with a touch of headroom) on stock base pressure. 370cc rule of thumb is 370hp for a 6 cylinder. 370 x 0.746 (kw/hp) x 80% (drivetrain) = 220rwkw. Clutch - who knows? What type of clutch etc etc etc. Probably also around 220rwkw if it's full-face organic, also depends on how you change gears. Computer is not much good at anything over 9psi on R33 GTST. You can get a remap ECU if you only want to max out the stock turbo - it will give more power in quite a few rev ranges. I have an SAFC II and didn't find it much chop really. with an SAFC II you will be able to make decent peak power but fuel economy, mid-range torque and throttle response will not be anywhere near as good as a decent remap or ECU. Short answer = 220rwkw (if you change the fuel pump)

Payment sent Can't believe these didn't get sold earlier.

Do you run glycol in your coolant/water? Adding/increasing the gylcol concentration would make the system less efficient and should nudge up the temps. Also means you don't have to worry about boil until even higher temps.

A lot of over-reactions from the nannies.

The nistune guys REALLY need to get onto the R33 gtst computer. My thoughts is that if they don't have it ready by now they never will, must not be possible.

Birds: After reading your posts I admit I was wrong when I wrote that a lot of what you guys said was not false. Almost EVERYTHING you have typed is false if you want to maximise energy and acceleration. It is area under the power curve not torque curve - this can be a BIG difference between engines. Clearly what I wrote is above your level of comprehension if you think what you were typing agrees with what I wrote initially. Mad082 is much more on the ball.

So it's not your BOV......hmmm. OK, I don't have a better idea. Except to change at 6500rpm or below. Birds: OMG haha...unnecessarily bringing energy into? Maximising energy is the point - how are you meant to maximize energy without even mentioning it? It IS about maximizing the energy which is area under the power curve - it is not really related to the rev where maximum torque is produced. Yes, a lot of what you guys said was not false but also not exactly a good answer.

R33 GTST easy but wide fit would be: Front = 18 x 8.5 +30 235/40/18 Rear = 18 x 9 +30 245/40/18 A little roll at rear - with 1degree neg camber both front and rear. Keep in mind that you don't want big changes in track widths front to rear. R34 are a bit bigger so: Front = 18 x 8.5 +24 Rear = 18 x 9 +24 Not that I can think of rims that are these exact sizes. I currently have 18 x 8 +30 and 18 x 8.5 +33 and they sit about 1cm too far in the guards on R33. Come tyre replacement time I will get 245/40/18 for the rear - up from 235/40/18.

ooh rimtruck - you learn something new everyday. 19 x 9 +15 to +18 looks nice

Shhhh...... Not too sure on the various relative pressures on the intake side when cutout occurs but it sounds like you are revving it too hard anyway. Sounds suspiciously to me that the problem might be due to an after market BOV that is causing the engine to give the sensation of "dying" when it hit cut-out. This cutout should not make the car die completely until the next gear. I came to this BOV conclusion since you said it also pops on overrun - so do you have an after market blow-off valve? If so put a stock one on - it will make the car much nicer to drive in many subtle ways - trust me/us. As for the shift point question - it's all about maximizing the amount of work or energy put into moving the car from the engine. This energy is proportional to the area under the POWER curve and is influenced by the RATE of increase of torque before the powerband compared to the RATE of decrease after the powerband. The best shift point (for racing) is determined by shifting at a point where the revs for the next gear will fall to a rev that maximizes the area under the power curve before the next shift point. This is slightly different for each gear as the rev range is compressed as you move up the gears - at least on a road car. For street use I would say shifting around 5500rpm is a nice balance - I would use 6200rpm on a track and maybe 6800 if you want to overtake someone. Avoid rev limiter - unless driving a V-TEC or 4AGE - they love it

Everyone showing off with their OP6 rears..... where is mine I ask ??? agghhhh.

That's pretty good. Even both sides which is nice. I have changed to zero toe front and rear and it makes the car more lively. but it's still perfectly fine. I would suggest you ask for a bit less toe next time. Perhaps zero at the front and 1mm in each at the back.

Buy a HKS GT2835 turbo, sell the current one.