Warpspeed

If I was going to do something like this, how about a Toyota 1GZ-FE ? V12, 5.0 litres, quad cams, all alloy. It would be like having two RB25DE engines side by side. The engine length would be very similar, so the 4WD sump might come pretty close to fitting with just an adaptor plate. The Toyota V12 is very similar in design and construction to the well known Toyota alloy V8, but with four extra cylinders. It is supposed be a very well built engine, ideal for high Rpm. With a few modifications it would howl like a Ferrari, and make a pretty unique car.

It all depends on what else is done to the car, and what you use the car for. Stored flywheel inertia and some clutch slip is the only way to get ANY manual transmission car moving from complete standstill without stalling. But so very much depends on available engine torque, vehicle weight, and overall gear reduction in first gear. Once you are moving, the flywheel is nothing but extra weight and extra inertia you no longer need. A circuit race car is not normally doing constant starts, so a very light flywheel is usually an advantage. A drag race car with excellent traction will launch harder with a heavy flywheel, but that same flywheel may slow down the rate of acceleration once it has launched. Turbo engines are special, because they usually have minimal torque when off boost, particularly when starting off. If your engine is laggy and has a fairly high boost threshold, a light flywheel is going to make starting off even more difficult than it already is. If you drive the car every day in heavy traffic, a very light flyweel is quite likely going to be a real pain in the arse, especially with a highly modified turbo engine. In flat places like Melbourne, it will not be quite so bad as in hilly Sydney. Starting off facing up hills needs plenty of flywheel.

Agree with all the above. You will need a full R32 GTR front cut for maybe 6-8K to get all the parts you require to do this properly to officially get the engine number changed. It will be much better to sell your GTS-4 and use the cash to buy a genuine GTR. You will then own a 100% road legal car with some resale value. To do the conversion will be a lot of work, cost a lot of money, and possibly create a lot of problems with the law. And it may become just about impossible to sell to someone else later.

Definitely illegal to make any change that alters the original emission characteristics of the engine, and a TO4z is a very obvious modification. Something like a pair of 2530's with the original manifolds and heat shields still in place, you can almost always get away with at a roadside check, because it still LOOKS original.

Turbo cars are funny things, you floor them, and you get that runaway rush of acceleration as the boost builds up that feels really fast. Very highly tuned n/a cars can feel fast too. The cams come on song and the exhaust really howls, and it feels and sounds glorious to thrash up through the gears. But seriously supercharged, and big capacity n/a engines with silent exhausts and an almost flat torque curve, don't feel like that at all. They are not so exciting to drive. They can actually FEEL slow, but the measured over the road performance might tell you otherwise. Handling can be really deceptive too. Some home built hot rod with rock hard suspension that you can power oversteer around every corner, sure may be fun, and you feel like a Formula one driver going around traffic islands sideways at 30Kmh. Wheras something properly designed to be well balanced, and have much higher roadholding capacity may be truly fast but not be anywhere near as exciting to drive. If you want to know for sure, a chassis dyno, drag strip, or race track is the only way to find out. Seat of the pants impression is not always a reliable guide.

Yeah, you must mean those little silver scooters the kids ride on to skool eh ? One leg a pumpin and a look of grim death as they grip those handlebars. But the real tough punk bad ass kids ride skate boards, spray graffiti on public buildings, vandalise bus stops (and probably key Skylines).

Can you imagine rolling up in something like that to an outlaw biker pub on a Saturday afternoon, and parking it in the same row as all the customised Harley choppers ? Then poncing into the bar in your brightly coloured leathers and ordering a flavoured milk ? Why not ask them their opinion of your really cool trendy transport ?

Oh ? And why is that, please explain further.

If you are talking about going to a full Autronic or Motec ECU, that would be excellent. But if it is just some Mickey Mouse piggy back conversion to the standard ECU, forget it.

As a first approximation Rpm to reach full boost is just about inversely proportional to a/r. So if 0.84 = 5,200 Rpm 0.68 would be close to (0.68/0.84 x 5200) = 4,200 Rpm. Of course exhaust back pressure will be a bit higher with the smaller housing, so it will make less power at the same boost, but it will probably not be that much slower on the road, and a hell of lot easier to drive. Go back to where you bought the turbo, and ask them what they can get for you. There are a number of housings available, 0.7 single entry, or 0.68 split pulse may be about the right sort of numbers to ask for. These are the next step down from the 0.81 single entry and 0.84 split pulse that you already have.

You could always buy the smaller turbine housing as a spare part and fit it yourself, it is not a huge job. Then you can decide which you prefer. Nobody can tell you which is best, it is really a matter of personal choice.

If all you want is a T3 0.63 internal wastegate housing, the turbo VL Commadores used these. There should be a million of them out there.

Blitzxtr, what exhaust housing a/r are you using, split pulse or single entry ?

Cubes has it right !! Here are some Nissan RB cam specs to look at: http://www.tomei-p.co.jp/_2003web-catalogu...haft-specs.html Now look at the R33 RB25DE and RB25DET they use absolutely IDENTICAL cams. There is no difference between a 262 cam for a turbo engine and a 262 cam for an n/a engine. Just buy the cams you want and set them up with a variable cam pulley to get whatever valve timing you want.

What is all this nonsense about turbo cams not working in an n/a ???? All the cam does is open and close the valves. You decide what cam duration and lift you want to run in your engine and buy an appropriate cam or cams to suit. There must be HUNDREDS of different cam grinds available. Sure, you need to set it up properly with variable cam pullies, but you have to do that anyway turbo or non turbo.

There are a lot of different models, 2WD, 4WD, and different power levels. And then there is all the optional extra diagnostic instrumentation you can order to go along with with it too.

In some of the serious financial forums that I frequent, poo stand for "price of oil". Quite funny to hear someone say poo us up a dollar forty today because of middle east tensions, hehehe. On the same forum if you said FMIC, none of them would have a clue what you were talking about.

Very true. The best way is to properly duct the intercooler air into the radiator, so that all the air pulled through the radiator by the ducted cooling fan first absolutely must go through the intercooler. Idling, I can place my hand over the front of the intercooler and feel the air being drawn in. I see too many intercoolers just stuck out in front, with no thought at all about how it is supposed to work at low vehicle speeds, or when idling in traffic.

Agree with you about the end thrust coming from pressure differentials. Full boost pressure will be behind the compressor wheel, but the front is only open to roughly atmospheric pressure. So boost is trying to pull the compressor wheel forward. The bigger the wheel, and the higher the boost pressure, the more thrust load is placed on the shaft. A similar thing happens at the hot end. Turbine inlet pressure gets behind the turbine wheel and tries to pull the wheel out of the back of the turbo. There can be a fairly high positive pressure behind both wheels, but depending on what the turbo and engine are doing, the forces may be highly unequal. That can be particularly true for some really wild hybrid turbos that have highly unequal pressure and wheel sizes.

Inlet temps always will go sky high idling in traffic, no matter what you do. All the pipework under the bonnet heats up to perhaps around 80C, as it gets all the hot air straight off the radiator fan, exhaust manifold, etc. As the engine is only idling the cold air coming out of the intercooler gets pretty hot when it passes along the inlet pipework, plenum, and inlet runners. So expect to see inlet temps of maybe around 50C. I run an Autronic ECU that displays inlet temperatue after the throttle body, so I can see exactly what is happening. But as soon as I hit the throttle, and get some significant airflow, that cold air goes straight down those hot pipes without picking up any significant extra temperature. The temperature comes down from around 50C to perhaps 4C above ambient within a couple of seconds.

It all depends on how far below the detonation threshold you are running your engine. If the engine is being tuned on a dyno well below full throttle, and if you keep advancing the ignition, the power will rise up to a peak, stay constant over a small range of ignition timing and then fall away without seeing any detonation at all. Hopefully, even at full throttle and full flat out boost, the engine power will peak well before any detonation occurs. If you keep advancing it further, it probably will detonate, but that is certainly not the optimum position to set the ignition timing. But then the engine might be a horribly overboosted heap of crap, running with no intercooler on cheap unleaded fuel. It will probably then start to detonate fairly early with power still increasing. Only then might you use the dubious tuning technique of running it right up to detonation and backing it off 0.01 degrees. If your engine is like that, good luck to you. It will blow up for sure, and probably fairly soon. There are two very firm facts to keep in mind. Detonation destroys engines, and your engine will make more power when properly set up with correct ignition timing, than it will overboosted, with the timing backed off to stop the resulting detonation. The other fact is, for best turbo response and fastest spooling, you need the highest possible exhaust gas temperature. Hot exhaust gas expands and drives the turbine, cold exhaust gas cannot do that quite so well. If you want high exhaust gas temperatures, you run LEAN mixtures, and ignition as far RETARDED as you possibly can without actually losing engine power. The turbo will absolutely love it while it is trying to spool. Those 12:1 maximum power air fuel ratios, and that super advanced ignition may be the hot tip around the pub on Saturday night, and an excellent way to tune so you end up having a lag monster. If you want your car to run really sharp, and be fast and responsive, those hot tuning tips will not get you there. Anyone that thinks engine tuning is all really simple and basic, has a very great deal to learn. Also anyone that says they can just look at a standard fuel or ignition table and decide how to "improve it" without exensive dyno testing with proper instrumentation are just kidding themselves.

You say the turbo is oil cooled, then it most certainly is an older sleeve bearing unit. I have never seen a ball bearing turbo that was not water cooled. The reason being that ball bearing turbos require far less oil flow, and the reduced oil flow just cannot pull out enough heat all by itself.

True, but failure could result in a severely damaged engine. No that is not how you adjust ignition timing. You advance timing until there is no further increase in torque on the dyno, then just back it off so it is right on the edge of dropping off. In other words you run the minimum amout of timing for best power. Your method is to use the absolute maximum timing the engine can possibly stand, just below detonation. That is both foolish and dangerous. What you say is true, but you absolutely MUST set the correct air fuel ratios before adjusting ignition timing. Air fuel ratios will definitely change burn rate and require different ignition timing. You suggest setting the ignition timing first, which is totally wrong. You say it is not hard, but you have a power FC with the plug in control module. He has just a bare standard ECU with no keyboard or screen readout. Try adjusting your FC without the hand controller, and then tell me how easy THAT would be.

Forget it Matt. You will never be able to figure out where in many different maps the engine is actually operating. And even if you knew where all the maps were, and what variables each map applied to, there is still no way to intelligently change the data. Suppose you begin with the airflow meter signal, that is modified by air temperature, which is modified by engine Rpm, which is modified by water temperature, which is modified by rate of engine acceleration/deceleration, which is modifed by throttle position. There may be six or more maps, and the location on each map is constantly changing. So maybe your engine pops and bangs under light throttle acceleration at 3,200 Rpm, but only on a very cold day. What would you change to fix that ??? There will be many hidden maps with no way of knowing which is which, or if the values stored there should be increased or decreased, or even where on all six maps the engine is actually operating. There will be thousands of stored numbers with no clue as to what any of them do. Just changing things around blindly will get you absolutely nowhere.

With FMIC you will definitely gain because of the denser air. Ever notice how much better your turbo car runs on those cold crisp frosty nights ? With FMIC you will lose response due to increased pipe volumes. So what actually happens depends on the particular circumstances. My own car lost nothing in boost threshold or response with a big FMIC, but it now goes much better on really hot days, or after heat soaking in heavy traffic.