Warpspeed

A hot wire airflow meter is what you already have in your Skyline. It works on the principle of heating a fine wire to a temperature that is higher than the air flowing through the airflow meter. The air flowing through the flowmeter tries to cool down the wire, so the electronics in the flowmeter bumps up the wire heating current to keep it at the correct operating temperature. That is how they work. As more air flows into your engine, the airflow meter wire requires more heating current to keep it hot, that current also provides the flow signal back to the ECU. The circuit that decides how much current to feed into the hot wire, also needs to know what the air temperature is going through the flowmeter so it can adjust wire current to keep the wire at the correct amount hotter. This usually uses either another wire, or a bead thermistor to measure air temperature. This usually just monitors entering ambient air so it does not normally have to respond very fast to outside air temperature changes. If you installed the flowmeter right at the turbo outlet, the massive fast changing temperature swings would give it a mighty hard time trying to work out what was a temperature change and what was a flow change. A decent intercooler SHOULD keep the inlet air temperature to the engine reasonably constant, or at least it is not going to go up and down by 100C in one second when you change gear.

I agree with Sydneykid, it is a very good idea, but some caution is needed. Provided a decent intercooler is being used there should be no problems, but there might be if there are very sudden temperature spikes reaching the airflow meter. Hot wire airflow meters will track air temperature changes very well, but they were never designed to do this extremely rapidly.

He-he, hello again Sydneykid. I am sure the cams and all the pulleys are manufactured extremely accurately, so the stock cam timing SHOULD be spot on, but it never is. The problem is the cam belt. There will always be some permanent stretch in an old belt, and even a new belt is going to stretch a bit as you tension up the adjuster. Now the adjuster is on the slack side, so as you take up a bit of extra belt length on the slack side, this will retard both cams with respect to the crank. And it does not take much stretch to shift the timing by rather a lot. Think about it. One full turn of the cam is 720 Crankshaft degrees, and the cam pulley has 48 teeth. That is 15 crank degrees per tooth. The belt pitch is 8mm per tooth. There is a fairly long length of belt between the crank and the exhaust cam (not sure exactly how much) and if it stretches only 4mm, that would retard both cams by a huge 7.5 degrees. So you might have a situation where you have four different dead stock engines, but the individual cam timings all over the place by a few degrees because of different belt ages, different non Nissan belts being fitted, and different belt tension settings. And what about head gasket thickness..... ? So everyone retards their exhaust cam by exactly four degrees. Two guys get a power increase ) one guy says it makes no difference :0/ and the fourth guy gets a slight power drop ( I wonder why ? And why do Nissan bother to make the cam position sensor adjustable if the cam position can NEVER vary away from stock? I prefer to set my cams up using a degree wheel and check the exact opening and closing points with a dial indicator on the cam followers. Adjustable cam pulleys allow you to always put it back to what it was when you did that really fantastic dyno run. If you do not do this, in reality you have no clue where those cams actually are, and after a major rebuild there is no chance it will go back together exactly the same. I just believe there is no substitute for measuring and checking things, and if anything is going to change, that very hard working rubber timing belt should be treated with the greatest suspicion. If you really heave down on the belt tension adjustment, you can actually see both cams move slightly !......... Try it and see. While I am sure YOU do all this, a lot of guys just fit the variable pulleys, and back off the exxhaust cam from the marked line, not bothering to actually measure anything. All they really care about is the dyno figure.

If it has really really big wheels, a humongous silver FMIC sitting way out in front, and a four inch exhaust tip, and an exhaust note with real ATTITUDE. And you look about 20yo and wear a baseball cap, the cops will not like you. Trust me on this..................... Much better to hide everything, keep that 400Kw engine really quiet, and enjoy your motoring when nobody is looking.

Just sat an assembled RB25 short block on the bathroom scales, 92Kg. With head and accessories, 150 might not be a bad guess.

VVT only really works with the stock short duration inlet cam. Anyone fitting a replacement inlet cam is very unlikely to keep the VVT. As far as I am aware there are no longer duration aftermarket inlet cams available with the special VVT nose. This is trying to tell you something. If VVT is so terrific for high performance why did Nissan leave it off the GTR ? So if you have a Skyline engine , and are experimenting with different cam combinations, and if you only own one cam of a particular duration, you might want to try it in either location. Quite simple really make it easy for yourself.. I cannot make it any clearer than that.

meshmesh, I would say something in the 256 to 260 range would suit you fine.

Meshmesh, Sydneykid has offered some excellent advice (as usual), and I have tried to explain what effects you might expect, and what to do if the results do not meet your expectations. But really it is an impossible question to give a definite answer to. The mines figures sound pretty reasonable as well. Suppose you could buy six different hypothetical camshaft packages for your engine, and they gave the following results. Cam A +10% @ 4500 RPM + 5% @ 7000 RPM Cam B +2% @ 4500 RPM +10% @ 7500 RPM Cam C -10% @ 4500 RPM + 15% @ 8000 RPM Cam D -25% @ 4500 RPM +20% @ 8000 RPM Cam E -40% @ 4500 RPM +22% @ 8200 RPM Cam F -65% @ 4500 RPM +27% @ 9000 RPM Now someone asks which is the best one to get ? If you were a conservative sort of bloke Cam A might look pretty good with the best overall gain everywhere. But demon Freddie the local drag racer says Cam F is the only possible choice, and he would get a G or an H if he could find one. So which really IS the best cam ?

If you only change one cam, change the exhaust cam. A longer duration exhaust will open up the middle and top end without losing any low end torque. It is possible to go fairly radical on the exhaust side without getting into too much trouble. A lot of guys just retard the exhaust cam a few degrees and that is a low cost option, but what it really wants is more exhaust duration. The stock cam was designed for light throttle fuel economy and idle emissions, very important to Nissan. If you are more the full throttle type of driver, more exhaust duration is going to make a big difference. The inlet cam requires a whole lot more thought. As you add more and more duration, at first the whole curve lifts for a really mild upgrade. As you go more radical, the low end falls away faster than the top end gains. So really give some thought as to if this is going to be a good thing. Finally a really long duration inlet cam can lose you power everywhere unless everything else is upgraded for sufficiently high RPM and airflow. In brief, there are more gains to be had on the exhaust side than on the inlet side from a camshaft change, and the inlet side is what can get you into trouble if you go too far. Remember also that if your engine is not making good low end torque it is not going to be putting out much low end exhaust flow. The turbo is not going to spool as hard, so if you want a tractable engine do not overcam it. Hint........an exhaust cam fits into either side of the head because it has the little tang to drive the optical sensor. An inlet cam can only be used as an inlet cam. So if you decide to experiment with some different duration cams, buy all exhaust cams if you can.

Some excellent explanations of cam terms chaps. The only thing I can add is to say that the amount of overlap a turbo engine can tolerate has more to do with how much total exhaust back pressure there is than anything else. So if you run a stock turbo with small exhaust turbine and stock exhaust system, do not try to run too much valve overlap or exhaust reversion will kill power everywhere. With a larger turbo you can run more aggressive cams. But it will be more peaky. The worst thing you can do is overcam your engine. so big turbo big cam, little turbo little cam is the way to go.

Matching should NEVER be a problem, that is why they have paint codes. I agree white acrylic paint is easy to apply and it is visible at night and poor weather conditions. It also reflects a lot of infrared if you park out in the sun. Metallic paint looks great, but it can fade and then be impossible to match. Metallic is good if you buy a new car and do not plan to keep it long. A fifteen year old metallic car always parked outdoors, that has some resprayed panels can look horrible. Look at some of the really old Nissan Z cars to see how metallic paint can really deteriorate. Ignoring all the dings and stone chips, an old car with acrylic paint can come up quite well with a cut and polish.

Yeah, I like white as well. It is a very practical colour for a whole lot of reasons, and there are probably more white vehicles around than any other colour. In most commercial vans you cannot buy anything else these days. But that is the problem. It is so damned common. A lot of people hate white because it is so ordinary looking. Ever noticed though there are very few of those giant 4WD monster tractor SUV things in white ? My car is white Hehehe (chuckle).

I suppose if you are gay, pink might be appropriate. Or if you are an old style hippie, a flowered paisley design on your GTR with large ban the bomb signs painted on the doors. There is and old Corolla getting around Melbourne covered in what looks like green outdoor carpet. How about white ceramic floor tiles ? Dare to be different........................

I also bow before the awsome knowledge and experience of Sydneykid. And he is such a nice guy too. If all the people that he has helped each shout him one very small beer, he is going to die of alcohol poisoning. Cheers to Sydneykid, my hero................

Force, I think the Nissan GTR coolers vary slightly depending on which model GTR they came from. Not absolutely certain, but I think R32 cores have one less tube than R33 and R34. Also core thickness changes very slightly (5mm?) as well. For all practical purposes they are really all the same, if you are thinking of adapting one to another car it does not really matter which one you use.

8 seconds might be quick and it might not, it depends in what class you are in, and what everyone else runs. It is all relative................ If you turned up in an 8 second AA fueler you would be laughed off the strip. Comparing a street driven car running on unleaded petrol to a methanol, nitromethane, or nitrous powered track freak is not a fair comparison either. AA fuelers do not run intercoolers either, and they are the fastest accelerating cars of all, so what. Back to reality. If you drive a petrol powered road car, and it has forced induction, an intercooler is absolutely a must have.

A lot depends on how far you have to cut it down to make it fit. If you get a cooler from a 600 BHP truck that is four feet high, and cut it down so its only one foot high, it then might be ideal for a 150 BHP truck. There are too many if's. It might be o/k and it might not. I am with Steve on this, get a proper aftermarket cooler, or a GTR cooler is a pretty good start for a lot of things. Even if Garrett cores are the finest designed cores in the world, they still might not suit a totally different application.

I am an old fart, I admit it, but I was young once, and know exactly how it is. And I am not trying to put anyone down. The insurance companies are a business with only one thing in mind, to make money for themselves and their shareholders. They are not there to help you, or perform charity work. Young drivers are a higher risk than old farts. That is a fact. It is also a fact that ANYONE is more likely to prang a high powered car than an underpowered slug. So saying I am young, and have a high powered car, where can I get cheap insurance, is really a bit of a problem. If I was an insurance shark, I would say sure, sign here young fella. Then when you prang. Sorry buddy, read the fine print you are not covered, read paragraph xxx clause yyy.

Look at it this way. He is either a very careful driver, never speeds, never drag races, and is not going to smash up his car. If that is that case he does not need any insurance. If he is a bit of a hoon, planning on hotting up his car and having fun in it, he is almost a certainty for a prang. Insurance companies know this too well, and either will not insure him. or make sure they are going to be very well rewarded for taking the risk. If he does fork out the big dollars and writes it off, expect the insurance company to do everything they can to get out of paying up. This is easy if he is drunk, breaks the law in any way, or has modified his car. Read the fine print on the policy and be surprised at what it actually says. Best bet is to just put five grand away in the bank. At least you know the bank are not going to tell you to piss off when you go to draw it out again. Another way to look at it is, get five of your mates and each put up four grand. The first one to write off his car gets the lot. Would you trust five of your mates never to have an accident ? Why not ?

It may be adjustable, but it most probably is not going to be as adjustable as you think. Remember, it still has the same spring in there. A typical standard actuator might require 10mm of travel, and it may open at say 9psi and be fully open at 11 psi (for example). Now if you compress the spring an extra 10mm by tweaking the control rod, it might then start to open at 11psi, and be fully open at 13psi. But if you try to go higher you might find that the coils in that spring just go solid. It is not a very long spring you are playing around with. When the supplier sells you an adjustable wastegate actuator, it probably means you can adjust it exactly to the rated pressure, perhaps +/- 20% or something like that (guess ?) You are not going to be able to set the boost anywhere from 5psi to 25psi, no way. You are going to have to use an air bleed system, or a proper boost controller to do that with a five pound actuator, or whatever. I think the best feature of an external wastegate is you can easily change the spring, and/or fit an external pressure regulator that will give you fully adjustable boost. Every external gate I have ever seen comes with a pressure port on both sides of the diaphragm. The manufacturer also will have a wide range of springs available. You cannot do the same with the cheapie on turbo actuator, because the control rod end is open to atmosphere.

Fair enough. Some car mods can be tasteful and look really good, without being over the top. But some guys want the big aluminium FMIC sticking out right the front, huge wheels, eight inch exhaust tip, lowered about a foot, and then cover the outside of the car with rice stickers. Then they get about two defect notices every week and wonder why. Myself I am into sleepers, I get no trouble from cops, vandals or thieves. Have been on zero points now for four years as well. Still give it blast every now and again though, but have a good look around for cops first, hehehe...................

That is correct. The only way to take it apart is to cut it apart. It would be easier to make your own wastegate actuator from scratch, than to try to put a stock one back together again. Not too hard if you have a lathe, to turn up your own housing. But why bother ? Just buy a replacement actuator from Garrett or HKS for whatever boost level you want to run. The last time I bought one it cost $220 about three years ago from AVO in Melbourne.

No, But I see a lot of young guys rice up their cars, then are totally baffled why the cops pick on them. I guess some people are far too stupid see this. Too bad. Stupid people are cop bait. Smart people can have fun in their cars and not get caught. Which are you ?

How about something like: I AM A RICEBOY WANKER COME AND GET ME cops

O/k guys, you want to increase boost with your external gate. If you want to fit a helper spring, and you want 3 more psi, just go through all the same calculations as before, but for 3psi. For the "mythical" gate, that would be 3psi times 10 square inches is 30 pounds extra force, with the same mythical spring height of 1.5 inches. Just add an extra smaller spring inside the existing stock spring with that rated load and height. But there is another and better way to do it. You still need more spring force, but you can do it with AIR PRESSURE on the spring side of the diaphragm. So what you have is a stock original wastegate spring rated for maybe 10psi design boost in your external wastegate. To increase it to 15psi, just feed in a constant 5psi of air pressure on top of the diaphragm on the same side as the spring. The air pressure and spring pressure add together., and the wastegate will not open until 15psi. All external gates have a pressure fitting on the top cover to do exactly this. How you do this is you tap off some boost air pressure (15psi) and feed it through an adjustable pressure regulator so a constant 5psi comes out of the regulator. Plumb that into the top of the external wastegate, and it will then work at i5 psi. If you fit the pressure regulator inside the car, you have adjustable boost. Wind the pressure regulator right down to zero and you get the stock 10psi. Wind it up and boost increases to anything you like. Wind it up to 12 Psi and you get 12 + 10 = 22psi boost for example. Easy.