Warpspeed

Not always.... The old design turbos all had a much narrower flow range, so turbo matching was a lot more critical, a little bit too big, and it WOULD be a lag monster. Too small and there would be no top end airflow. What the latest technology turbos have is a vastly wider flow range, as well as less inertia and a higher overall efficiency. So you can now fit a larger turbo and get more airflow without losing anything in response or boost threshold. Or you can downsize slightly and get a massive improvement in response and mid range, without losing anything up top. It may not have much extra horsepower to brag about, but it will make a much faster and easier to drive road car. Don't just think about turbo size, think also about flow range. The latest in turbo technology is always going to beat the older turbo designs in every way.

But it does illustrate the point that a car is not an investment, it will definitely lose value over time and cost heaps to run no matter what happens. Me I drive a clapped out Laser Turbo, but also have many hundreds of thousands of dollars invested. Why ? Because I am retired and don't really want to work anymore. I would rather have the regular investment income than a fast car. When I was your age, I spent every cent I had on messing around with cars, and I never regretted it.

Different people have different ideas about how radical they want to go.... An HKS 2530 will spool about the same as the original turbo, but you can run much higher boost because it does not have the problem of the fragile ceramic turbine wheel. The 2530 is also more efficient at higher pressure ratios, and has higher maximum airflow than the original turbo. The problem is, these 2530 turbos are now getting very old and HKS don't make them anymore. A secondhand one may be worn out or stuffed. But HKS are about to bring out a brand new replacement for the 2530 which is 2006 state of the art technology, called the GT-ZZ. The dealers do not have them yet, but maybe in a month or two, who knows ??? Latest technology with turbos, is like latest technology with computers, always better and advancing very rapidly as time goes on.

The answer really depends on age and financial situation. You are young, no wife, no kids, no mortgage, go for it !!! Later on you may not be able to do it, so have some fun while you can. Later in life you will be able to look back on all the crazy things you did, and got away with. As you get older your ideas change, you slow down, and a really fast car is no longer a priority. But educating your kids, or preparing for retirement may be.

A power FC is the obvious choice. Motec or Autronic would be o/k too, but a lot more work to install, as the FC just plugs straight in. Only thing with the TO4Z with the FC, means you will need to still keep using twin airflow meters feeding into the one turbo. But that is really no problem at all.

Very true and well said. Start off with an aftermarket ECU and THEN decide on further upgrades.

I doubt if Nissan Australia will sell you spare parts cheaper with a bulk buy, but you can always try. Just go into your nearest Nissan spare parts and order a 14411-VC100 replacement turbo for a Nissan Patrol 4WD. This one took two days to come from interstate, but any Nissan dealer can get one in pretty quickly. Some of the more recent small Mercedes diesel delivery vans sold in Australia now use VNT turbos too. I don't know how big these turbos are. The Nissan Patrol VNT is probably still the largest VNT readily available in oZ, except perhaps for Porsche. I don't know how much a new Porsche VNT turbo would cost, probably $6,000+ maybe ? And as Porsche use two of them, they may not be all that big either. But you will also need to figure out a way to control the vanes. The Nissan control actuator looks exactly like a wastegate actuator, but it works entirely backwards. The vanes are held fully open by a spring in the actuator can. Increasing vacuum to the actuator closes the vanes. There is an adjustment screw to set (mechanically) how far the vanes can close at maximum control vacuum. When closed completely the vanes seal right up against each other, and all exhaust flow from the engine is completely blocked. But you can readily set the minimum vane opening position to best suit the engine. It looks a bit like the stop screw on an ordinary throttle body, and works in a similar way on the vane control arm. You will want the vanes fully open all the time except when you want to see some boost pressure during acceleration. The vanes must then very quickly close. The vanes must then gradually open far enough to hold boost at whatever pressure it should be. However you decide to do that, you are going to have to design and build your own vane controller actuator, and figure out a whole control strategy.

These Garret VNT turbos have been around for about twenty years, nothing really new here. They are not really suitable for petrol engines which is why Garret are pushing their GT ball bearing turbos for performance petrol engines, and the VNT turbos only for diesel engines. If these things worked as well as people think they do, companies like HKS would be offering them. I ran a Garret VNT turbo on my Ford Laser for around two years so I can speak from plenty of practical experience. You can order one from any Nissan dealer, part number is 14411-VC100 (charger assy-turbo). Back in 2003 it cost me $1454.55. These variable vane turbos are the standard turbo fitted to the 4.0 litre Nissan Patrol diesel engine in Australia, and that particular engine produces 150Kw, so they are a rather small turbo. Two of these would be required on a larger engine. Porsche seem to have made it work, where nobody else has. No doubt it took a lot of fairly sophisticated engine management and a lot of development. Don't think you can just bolt one on to your Skyline and get the same sort of results without the control system to make it work properly. There is far more to it han just hooking up a standard wastegate actuator to the vane control arm.

AS paulr33 says, if you dyno your car in January at 2pm on a scorcing hot day in Darwin, it certainly will increase the power reading. But if you do it in August at midnight in Hobart where it is well below freezing the power reading will be reduced from what it really is.

That all assumes the standard fuel pressure regulator can still control the fuel rail pressure with a much more powerful fuel pump fitted. But what if the regulator and return line to the tank are now too small to cope with the vastly extra fuel volume that must be bypassed ? Suppose the fuel rail pressure is now much higher than it was before, would not the engine run rich ? Best measure fuel rail pressure and see if it is what it is supposed to be before making any quick judgments.

Sure old people have accidents, but far less than young males in the 18-25 age group. The sort of accidents old people mostly have are usually at fairly low speeds, and while the damage might sometimes be spectacular, or even funny, usually nobody gets hurt. Big difference between granny reversing into a fire hydrant and flooding some poor bastards garage, and some young punk doing 200+Kmh and wrapping it around a steel pole and killing himself and three of his mates. So some hopeless old fart crushing a supremarket trolley in a carpark, is not going to be front page news. But if some young dude launches a GTR off a freeway ramp into the roof of an occupied house, it probably would make the six o'clock news.

That will definitely be your problem then. Just realise that your whole exhaust system and muffler is probably now full of black oily residue. Expect to still see some smoke for a day or two at full throttle. That will quickly go away. So don't get a fright when you see some more smoke first time you drive the car !!

Stocky has nailed it, spot on. With a turbo, you need to look at total exhaust back pressure as well as boost pressure. If the engine is suffering severe constipation from a very restrictive turbine and exhaust system, it is just not going to flow a lot of air, or make a lot of power. Too many guys only look at the compressor end of the turbo. It is the exhauust side where all the hidden power is lurking. We all know that a larger free flow exhaust system makes a big difference with any factory turbo car. Fitting a slightly larger a/r turbine housing does too. All without changing anything at all on the compressor side. Obviously you can get to the stage where the compressor ends up being too small for the job, but when you replace a small factory turbo with a larger aftermarket turbo, it is the reduction of back pressure on the exhaust side that really picks up most of the flow (and power). The only real problem with this, is that boost threshold and lag get worse. You can keep going after more and more power, with a larger and larger turbo, and the car becomes harder to drive and more peaky. More powerful, yes, but at some stage it just becomes far too impractical for a daily driver. I think we all end up doing this at some stage. Hakai, if you can get a good price for your car, do it. A GTR has many advantages, including street legality (trouble from cops), and resale value.

Hakai, o/k let's look at the options. You don't want to go the RB25/RB26 or RB30 route because it has all been done before. Fair enough, although it would be fairely straightforward and give a known good result. Sydneykid has a point, in that a proven turbo package on your RB20 could be made to give excellent results, but again it has all been done before. Turning to supercharging, neither of the Toyota superchargers are really large enough to make a conversion worthwhile. The 4AGZE is rated at 150Kw and the IGGZE is rated at 160 factory Kw. Putting one of these blowers on your engine will get you nowhere. Sure it will have more low end torque, but the top end power will be rather dissapointing. Fitting one of these will be a LOT of work, it will certainly be unique, but I am sure you are never going to be entirely happy with the final result after all that work. A centrifugal supercharger will be easiest to fit, but the engie will be vey peaky, far more peaky than with a turbo. The Skyline is not a light weight car, and the RB20 is not a huge engine. It will feel slow except right at the extreme top end. Centrifugal blowers work best with large capacity engines with very poor top end breathing, I would very strongly recommend you not fit a centrifugal supercharger. Your best bet is either an Eaton or a screw supercharger. If you are on a very tight budget, get a secondhand Eaton. These are not wonderful, but are very good value. If you want the best, buy an Opcon or a Whipple screw blower. It will be expensive, but the results will be extremely good. If I was doing what you are doing, I would first fit an RB25DET and gearbox, and get it all going in the car standard, with a Power FC computer. I would then either upgrade the turbo, or fit a screw blower to it as I could afford to do so. Another avenue would be to sell your car and buy an R32 GTR, and start with that. More expensive, but a much better basis to begin from. By the time you have upgraded everything to handle the extra power, an R32 GTR will look like a real bargain.

There are four possibilities here, and I have had all of them at one time or another. 1/ There is just too much oil pouring into the turbo because the oil restrictor at the inlet fitting is missing. There absolutely MUST be a pin hole restrictor, usually 1.0mm to 1.5mm in size to restrict flow when using any BB turbo. 2/ The oil just cannot get out of the turbo because something is wrong with the oil drain pipe. Pressure builds up inside the turbo, and it will force it's way out past both seals, even with a perfect turbo. 3/ If the bearings have a lot of radial play (the turbo is stuffed), then the oil seals are just not going to be able keep the oil in. 4/ There is massive pressure buildup in the engine sump due to blowby past the rings. The engine will be VERY oily and this should be fairly obvious too. I would go for number one. Remove the oil inlet fitting from the turbo and have a real close look at it. There will be a very small hole. If the oil pipe just runs straight into the top of the turbo with a big hole, then that is your problem. Less likely, but remove and inspect the whole turbo oil drain line and fittings. You absolutely must be able to roll at least a 10mm ball bearing all the way down that pipe. If you cannot, find out why and fix it. Stuffed turbo bearings will be very obvious, and need no further comment. Really bad engine blowby and sump pressure buildup should be pretty obvious too.

Wow, I have read some pretty strange way out off the wall theories in this thread. First thing, cylinder temperature is not going to effect air fuel mixture, how can it ? If the same amount of air, and the same amount of fuel go in past the intake valve, how does cylinder (or head) wall temperature effect the mixture ? It most certainly will lower the DETONATION threshold for the hot running cylinder, but that is quite a different thing to running lean. Perhaps someone could explain to me how temperature effects either airflow or fuel flow ? Next myth. The electric fuel pump pumps almost a constant volume of fuel (at least if it a decent pump it will). This flows through the fuel rail. In the GTR it goes in at the back, and out at the front through the pressure regulator. Fuel flow through the rail will be pretty constant, and even if there was significant pressure drop along the length of the rail, cylinder six would always receive the HIGHEST pressure. It should be cylinder number one that runs lean if the fuel rail was the problem. The real culprit is the plenum. At standard power levels and airflow the stock GTR plenum works fine. Nissan have carefully designed the runners and placed steps and ridges inside the plenum to get equal airflows over the whole operating range of THE STANDARD ENGINE. As soon as you start significantly increasing air velocity, the whole design goes to hell, because it was never designed to work at that power level. What you really need is a more suitable plenum. Fix the plenum, and the air fuel ratios should even up. The Trust plenums offer little if any power advantage, but I am told the flat out airflow distribution is somewhat better. Cylinder six may still detonate first because it runs hotter, but that is not an air fuel ratio related problem. The original post on this thread is only concerned with even air fuel ratios, not detonation, that is another quite different problem altogether.

Messing around mixing factory cams is just not worth the effort. All of these cams are emissions cams and almost identical in specification. Either leave the standard cams alone, or get some proper aftermarket cams.

I would say ..... it depends. My car used to absolutely fly on those cold humid winter nights, but in 38 degree mid summer heat, and after long periods of idling in city traffic it would be an absolute slug. That was with the crappy factory intercooler. After fitting a GTR front mount it was much more consistent. Did it increase power, probably not much in winter, but in mid summer it made a hell of a big difference. There are too many conflicting factors to know for sure exactly what a FMIC is going to do for you. Maybe nothing, maybe a lot, it depends.... A pretty good guide is, does your car go harder with a stone cold engine ? If it does, then a more efficient intercooler is exactly what you need. If it goes better when the engine is fully warmed up, whatever you have now is working fine.

Not that funny really. They are worried about exhaust fumes getting back into the car if you run with a back window open. So in a passenger car, you cannot usually bring the exhaust out in front of a back wheel, but in a ute you could. Same with a truck, side exhaust anywhere behind the cab is fine, or a vertical stack is o/k but it must be behind the last widow that can be opened. There are also rules about not having the exhaust pipe projecting out beyond rear bumper. It is all fairly obvious stuff.

No you don't need an engineers certificate for exhaust modifications, for two reasons. It is not related to safety, and exhaust components are regarded as expendable (like tyres, spark plugs, batteries and so on). But whatever you do, it must still conform to certain legal requirements. There must be a functioning catalytic converter located in the original position, and noise must be within the legal limit. Ground and body clearance must be sufficient, it must not leak, and the exhaust exit must be located behind the last window that can be opened. Apart from that you can do pretty much whatever you like. How much is entirely up to how much you want to spend.

It is really an impossible question, but here are my thoughts: Depreciation, highly variable, what you pay for the car initially, as to what it is worth when you finally dispose of it. Registration and fuel, probably about the only things you can be fairly certain about. Maintenance, up to you really. Do you want to keep it in excellent condition, or let it run down. Do you do all the maintenance yourself or pay for labor ? Repairs, again highly variable, maybe none, maybe HUGE if you are unlucky and buy a lemon, or can you do your own repairs ? Insurance, how much risk are you prepared to take on yourself, and how much risk are you prepared to pay to have insured ? Highly variable. Only YOU can answer these questions yourself. Nobody else can.

I have done a bit of work with Miller cycle engines, both computer simulations, and in car. Agree, that the benefits of the Miller cycle can only be gained with a positive displacement supercharger, it will definitely not work properly with a turbo. The whole idea is to move most the work of the compression stroke away from the piston, and do it instead with a much more efficient rotating supercharger. You can then apply massive amounts of intercooling and end up with a far lower charge temperature at the end of the final compression stroke. The secret of the Miller cycle is also in the very high expansion ratio that can be obtained with a relatively late exhaust valve opening point. But to get all that extra efficiency, the exhaust valve MUST open into a low exhaust back pressure. With a turbo, that simply is not going to happen. If exhaust back pressure is say, twice boost pressure, it is just not going to work properly. I suspect it will be very gutless off boost, laggy, and the fuel savings you expect from this are just not going to happen. An RB25DE would make a wonderful Miller engine, fit a screw supercharger, a large front mount intercooler, and a much longer duration inlet cam. I would expect it would go rather well, and maintain the original normally aspirated fuel economy with heaps more power. To get the best out of it, a power FC would be required and probably a set of DET injectors. When fuel goes to $2.00+ per litre, low compression turbo engines are going to become fairly expensive to run. You could get similar performance from a Miller, with far better part throttle economy. No lag with a supercharger either !!

Here is a list of all the various Nissan factory cams. The differences are only slight between all of them, they all have to pass strict emissions, hence there is not a lot that can be done by the factory. http://www.tomei-p.co.jp/_2003web-catalogu...haft-specs.html Replacing a cam with another that has only five degrees more duration and maybe an extra millimeter of lift will hardly make any noticeable difference. Going from 240 to 262 degrees is the sort of worthwhile improvement you need. Cannot answer for sure about the oil pump drive, but I believe after R32, the later ones are now all the same.

The problem with this is that every little bit of extra power becomes harder and harder to get, and much more expensive if you stay normally aspirated. Much better to fit a turbo to begin with, unless you have a particular reason not to.

RB26 crank rods and pistons will drop straight into an RB25 block. Compression ratio will be 8.5:1, same as it would be in a GTR. The combustion chamber volumes are the same. All the factory RB emissions cams have very similar timing (between 240 and 248 duration) with almost zero valve overlap. There is no real point messing around swapping factory cams around. Either leave the cams stock RB25DE, or get some proper aftermarket cams. The HKS2530 will give a very strong mid range and be very responsive, especially with the diff you have, but the turbo is a bit small for flat out power. It will be very responsive and torquey driving around the suburbs, I think you will be quite pleased with the result. Oil pumps vary in volume only because of the extra oil volume required for the turbos at idle. Even an RB25DE pump would work fine in a GTR at normal operating Rpm. But if the idle speed was set very low, the oil light may probably come on. At perhaps 2,000 Rpm or above ANY oil pump is going to give full rated pressure. The RB25DE pump will probably work fine with one ball bearing turbo, but idle pressure may be very slightly less than it would be with an RB25DET pump, or an RB26DETT pump. The ball bearing turbos require less oil flow than the older sleeve bearing turbos. Try it with the original pump, or get an RB25DET pump, anything else is overkill. Oil squirters are good, but fitting them to a block that did not already have them is going to be a very expensive bit of machining work. I would either try to find an RB25DET block or a GTR block that already has them fitted, it would probably be a lot cheaper. Or I would not bother with the oil squirters.