Warpspeed

Fair enough.

Yes Zahos, now I see your problem. What about fitting a front mount throttle body. This would solve a whole lot of problems.

I have been wondering for a long time where I could get stainless steel mandrel bends in Melbourne, as I wish to make up a set of extractors.

Hi there Ice. I think Zahos has already been to the Pig. They only have straight hose, and we need moulded three inch bends.

I will give it all a bit more thought. See if you can get back to the manufacturer tomorrow.

Well the only concern might be the heat rating on the turbo side. If your intercooler is half decent, heat on the downstream side should not really be a problem though. Because it is an atmospheric induction hose, it probably does not have a pressure rating. It is a bloody tough hose though, it might swell a bit under boost, but so what. For $20 well worth a try I think. Where abouts are you Zahos? I am in the south eastern suburbs. Dandenong is no sweat, but Scoresby is a bit further for me.

Yeah, probably is retail, but even with a trade order it is still going to be a bit expensive. I have just returned from a nice little drive to Dandenong. On the Princes Highway south of Dandenong, there are a lot of trucking places. Finally ended up a place called Truckline at 2-10 Decor Drive, Hallam, ph 97023344. They photocopied a page out of one of their catalogs for me. Now the big rigs usually have a vertical exhaust stack on one side, and an air intake snorkel on the other side, behind the cab. The snorkels uses rubber bends and hump hoses in 3 inch, 3.5, 4, 5, 5.5, 6, 7, and 8 inch sizes. All the variants between 3 inch and 5 inch cost typically $20 to $30 each. I asked the counter guy where they had to come from if they were ordered in, he said Scoresby. The photocopied page that I got says Tubengineers (with a turbo logo), and a phone number 9763-8066. But any truck place could probably get these hoses in the same day. The catalogue describes them as"Äir Inlet-rubberware". Although they are simply plain rubber and not reinforced, the rubber is 7mm thick and pretty stiff. For the low cost, I think it may be worth a try. I bought a 45 degree bend that I have in front of me at the moment for $20.45

I am with you Zahos. It was an interesting exercise to go through though, at least if I ever need the silicone hoses I know where to get them in Melbourne. When I can find some time it may be worth checking Ryco and Dayco, these are two companies that make the moulded hoses in Australia that I can think of off the top of my head. There must also be places arouund somewhere that sell all the truckies accessories, but have no idea where at the moment. Also companies like Kenworth, Caterpillar, probably have some suitable three inch hoses ?

Just got back from H.I.S, they carry almost no stock on the premises, but there are two three inch ninety degree bends in stock warehoused somewhere in Australia at the moment. Anything not in the country takes 8 weeks. They can get 1 metre lengths of 3'' reinforced silicone hose at $190 plus GST. The 3"reinforced silicone bends are very sharp, more an elbow than a bend. $135 plus GST. The stuff I saw looked to be exactly the same as that shown on the Turbonetics USA website, and probably comes from the same original source.

Loudness really has nothing to do with dual/single pipe, it has a lot to do with the type and size of muffler, where it is installed, and any extra resonators placed in the system. As I see it two smaller pipes with smaller diameter mufflers may give better ground clearance, but be heavier and more expensive though. In practical terms it is always easiest to stick with whatever type of original system was on the car in the first place. Just copy it with a slightly larger diameter system. If the original system had a resonator, it was put there to stop droning or exhaust resonance at some particular speed. Copy the original system as exactly as you can, including all the original mounting points, just make it all a slightly larger diameter.

Thanks James. I might just go around to H.I.S. tomorrow and check them out. I have used radiator hose for years on turbo and supercharger installations. The stuff is made to handle heat and pressure, water or air does not seem to matter. Have had hoses blow off due to not being clamped properly, but have never had a single hose burst or rupture. If you need a fairly sharp bend straight after the turbo, a bit of radiator hose in the correct shape is ideal. The only reservation might be that turbos tend to sometimes spit a bit of oil, and the hoses become covered inside with an oil film. But I have never had a hose actually fail on me, and I have run up to 20psi boost.

Hi Zahos. Yes, straight hose combined with some mandrel bends would be the cheapest and simplest solution. It would also flow very well. Moulded hoses are better though if the installation is really tight, and high flexibility is a prime requirement. AVO had a special a few weeks back on the HKS silicone GTR hose kits. I think the price was reduced to somewhere around $500 ? from the more usual $800 for these kits. I believe the kit consists of four 90 degree bends. Better check with them though. I am using a lot of GTR engine parts in a supercharger installation. As it is not yet fitted to the car, I am not yet at the stage of knowing exactly what the hose routing is going to be. That is why I am extremely interested in anything that you can find out, but am not really ready to go searching myself. I do not yet know exacty what hoses I will need. It must be possible to find a bit of three inch radiator hose with a ninety degree bend that costs less than $200 per bend ! ! !

I cannot see a radiator hose bursting at any sane boost level. There may be three inch moulded hoses made for trucks, busses, earth moving machinery and so on. If you can find them, they would be almost certainly extra heavy duty and be well up to the task. Let me know how you go, because I have a future project requiring three inch moulded hoses, and I am too mean to pay eight hundred dollars for a GTR silicone hose kit. I am also in Melbourne, and I think we should keep in touch. My e-mail is: tlegrip@melbpc.org.au

What about radiator hoses, these come in every shape you could possibly think of up to about two inch. Truck hoses are even bigger. These hoses normally run at high temperatures, and typically 12psi, they work just fine as intercooler hoses.

I believe the GTR pump rating is 4.5 litres/minute. This should in theory at any rate, be enough to feed six 750cc injectors at full duty cycle. (6x750 =4500cc/min)

I thought of a front cut myself, but decided it would be cost less and more convenient to just buy exactly the bits I needed. I really have nowhere to keep it, and selling the surplus bits to recover costs is a real pain. Your situation is different though. o/k Mega, how to supercharge AND turbocharge your engine: I will first describe the simple system, then the problems with this, and the extra complexity required to fix ALL these problems. The basic flowpath is, cold air intake, filter box, airfowmeter, throttle body, turbo compressor, supercharger, intercooler, intake plenum, engine, exhaust turbine/wastegate. The wastegate reference pressure comes direct from the intake plenum. The positive displacement supercharger pulley ratio is set to give boost at maybe half the desired final boost, therefore the turbo controlled by the wastegate sets the final boost figure. The turbo makes up the difference between supercharger boost and desired final boost level. Note that the throttle body must be moved to the intake side of the supercharger. Otherwise with a positive displacement supercharger, if the throttle body is on the outlet the pressure will rise to infinity if you close the throttle at high RPM. At best you will blow off an intercooler hose, at worst explode the intercooler, or break a drive belt. All decent positive displacement supercharger systems are fitted with a bypass around the blower. Every car manufacturer fits one, and so should you, for a road car anyway. One problem with moving the throttle body to the blower inlet is that at part throttle the blower is sucking like crazy against an almost closed throttle plate. The engine will be running at vacuum under steady state constant speed cruise, the vacuum behind the throttle plate will be far higher than manifold vacuum. The blower is actually doing a fair bit of work as a vacuum pump, and draws crankshaft power. It also runs hot, and creates noise, as well as increasing fuel consumption by maybe 10%. The thing to use as a blower bypass is an external turbocharger wastegate. Good ones have a pressure connection on each side of the actuator diaphragm. Fitted with a 3psi (boost) spring, the diaghpram will open the wastgate at a differential pressure of 3psi, equal to about 5 inches Hg vacuum. The wastegate is fitted onto the blower discharge and when open feeds back into the turbo inlet. The wastegate doubles as a blower bypass and turbo blowoff valve,I will return to this later. A second problem arises from moving the throttle body to the blower inlet. All of the pipework after the blower, plus the intercooler add to the plenum volume. The plenum volume now becomes very large, and when you suddenly close the throttle, the engine becomes slow to lose RPM. It feels a bit peculiar actually, as though the engine has a one ton flywheel attatched. This reduction in throttle response really slows down gear changes and spoils the drivability. Stick with me guys, this is where the story gets a bit strange. The fix is to have two throttle bodies one on the blower inlet, and a second one in the original position back on the plenum. Both operate simultaneously, and as I will explain synchronisation is not in the least bit critical. On my car there is provision for an auto kickdown cable, as well as the standard throttle cable. I simply used two throttle cables, one to each throttle body. Simple. A pair of hoses connect the blower bypass wastegate control diagphram directly across the throttle body fitted to the plenum. The vacuum across the plenum throttle body holds the blower bypass open. How it all works: At idle, the idle screw on the plenum throttle body controls the idle speed, and any fast idle features built in also work normally. The idle vacuum holds the blower bypass open, meaning that the blower rotors just circulate air around through the open bypass. The throttle body in front of the blower is just cracked open, how far is not really important because the second throttle body on the plenum controls the airflow. Pressure in the intercooler is atmospheric, or very nearly so (just like a stock turbo engine). Light throttle and gentle acceleration, there will still be greater than 5 inches Hg vacuum and the blower bypass is still held fully open. The blower intake throttle body opens in sync but there is no boost because the bypass remains open. You can drive around like this all day, no boost, keep up with the traffic, and the fuel economy is stock. More throttle opening and the pressure drop across the plenum throttle body falls, allowing the spring to close the blower bypass. The action is very smooth, boost increases as the bypass closes, and off you go under boost. This is unbelievebly smooth in operation, drivability is excellent. At full throttle, boost pressure appears equally on both sides of the blower bypass diaghpram. As it only responds to differential pressure, the increasing boost has no effect on the bypass. Both throttle bodies open together, but if the fully open position does not exactly coincide, it does not really matter. So setting up the two throttle positions is in no way a critical adjustmet. At redline you slam the throttle shut for a gearchange. The blower bypass opens unloading the supercharger, and acting as a turbo blowoff at the same time. The throttle at the blower inlet closes almost fully. There is no boost spike. It all sounds a bit strange I know, but print this out and have a long think about it all. It is the result of eighteen months worth of development time. It works superbly, and is easy and non critical to get going. The only thing to watch is the selection of the spring in the blower bypass wastegate. The spring must be heavy enough so that the wastegate will not be forced off its seat by maximum boost pressure. If it is too heavy the vacuum requird to hold the bypass open will be very high, meaning boost will come in early at very light throttle openings. For maximum fuel economy you want to be able to keep up with the traffic with reasonable throttle openings without hitting boost. You want boost upstream of the plenum throttle body to begin at perhaps 80% throttle, not 20% throttle. Hint. For best control characteristics the blower bypass wastegate should have a large diaphragm area, compared to the area of the poppet valve. This makes spring selection less critical. This post is waaaaaay too long, sorry.

It sounds like we have similar interests ! I have been turbocharging, supercharging, and twincharging engines for thirty years (I am an old bugger). It is the engineering that interests me, figuring things out, and trying new ideas. You mentioned the GTS-4 gearbox. As far as I know these are identical to the GTR, at least with the RB25. I think the RB20 version has different ratios though. My plan is to put RB26 crank, rods, and pistons into the RB25 block, I already have these parts. I can keep the same engine number and avoid any hastles with the cops that way. I also already have the GTR six throttle body inlet manifold and GTR intercooler. I do not want to buy a GTR, even though I could afford one (just). The 33GTS-4 has everything I want at half the price, and without the big wheels, wings, and badges that attract the wrong attention. The 33GTS-4 looks like a family car, not a hotrod, this is absolutely perfect for a sleeper. Cheers, Tony.

Used to work for a private company in Victoria, where the guy that owned the company had a lot of company cars, Porsches, a Ferrari Boxer, stuff like that. He got booked by a speed camera doing around three times the speed limit in the Ferrari. When he got the fine through the mail he told them it was a company car, and that he could not say for sure who was actually driving it at the time (it was him obviously). They said no worries mate, just pay the fine, and hand in the plates for twelve months. He did not care, lost no points, and had other transport. This might not work for everyone though.

The idea of adding a supercharger is to get low end boost, so forget the centrifugal. I used a Toyota roots blower from a 1GGZE plus a TO3 from a VG30 fitted with a 0.82 exhaust housing. The wastegate setting was 18psi, and an intercooler was used as well. The blower drive ratio was 1.5:1 on a 1.6 litre engine, and the blower gave around 9psi by itself, the turbo did the rest. I had full boost from 2000RPM to redline, the thing pulled like a train at any speed, there was absolutely no turbo lag either. The thing is, that when you stomp on it the blower produces instantaneous boost, and the sudden large increase in exhaust flow really kicks the turbo into boost quickly as well. Set the desired boost with the wastegate, then play around with the blower pulleys and turbine exhaust A/R to get the effect you want. The blower gives low end grunt, the turbo top end airflow, you can set it up to have more of one or the other, or both! You can have all the advantages of either method together, with none of the disadvantages. Absolutely fantastic ! ! ! It is a lot of work fabricating parts though. If you can do it all yourself no worries. If you have to pay a workshop to make the bits and sort it all out, then the expense would be HUGE.

I have actually had a dual system fitted to my 4WD laser at one stage of its development. It is the quickest combination I have ever had. It was only removed because the supercharger eventually became noisy from internal wear, and was probably not far from spitting the dummy. I also wanted to try something a bit different. My next attempt was to fit a variable vane turbo, as these are supposed to have really good low speed boost characteristics and fast response. This is still on the car at the moment. The supercharger/turbo combination just eats it. Still not satisfied, my current project is a supercharged 33GTS-4, although I am still looking for a suitable car in Melbourne. I may import one though if I still cannot find one by Christmas. Trust me guys, the supercharger/turbo combination on a road car is an absollute killer. The only down side is cost and fitting it all into the available space. I could talk for hours on this subject, but the Skyline may finally end up this way as well, time will tell.

Would not know the official figures for your engine, but a lot depends on how you actually measure it, for example engine hot or cold? At full throttle, or just turn the key? How fast is the engine going to crank, is your battery o/k? All plugs out, or only the one you are measuring, this effects cranking speed a fair bit. I would measure each cylinder and if they are all almost all the same, do not worry about it, whatever the actual readings turn out to be. For a variety of reasons there is no direct relationship between compression ratio and the measured cranking pressure. Things like valve timing, engine temperature, and cranking speed have a large effect. Also your compression gauge may be way out if it is a cheapie. If every pot is similar that is all you realy need to know. If one or more pots are far less than the rest, then try to figure out why and fix it.

Why drain the system? I have had this problem, the fluid gets low and foams up with millions of microscopic air bubbles that get pumped around the system. The hydraulic fluid becomes mostly air and the power steering stops working, and the pump kicking up an ungodly whine when you turn the steering wheel off centre. Just top up the fluid to the full mark. Now this is not ging to fix the problem immediatley because the foam is still being pumped around the system. But gradually over a couple of days the system will bleed itself and the noise will go away. Top up the fluid again, and you will be back in buisiness.

I was only kidding Cereal.................really. One viable fuel alternative is Compressed Natural Gas (CNG). This is not the same as LPG (butane/propane). It is the gas that comes out of your gas pipe at home compressed and stored, still as a gas at very high pressure. The authorities do not like CNG because you can compress it yourself at home with suitable equipment, and they cannot tax it. Also the insurance companies are not too thrilled about the potential for fires and explosions occuring in home garages all over the place. There is information on the net on this subject, and there was a company in NZ that manufactured all the bits you need to compress the gas and convert an engine. I think this company went out of buisiness a year or two ago however. I was really interested in this subject a couple of years ago, at that time Sydney Council were running a pilot program, and some of the diesel busses were converted to CNG back then. If petrol prices go out of control, it may be a way to get around it, and give the finger to both the oil companies and the government. If it becomes popular it will almost certainly be made illegal though. Do a search on the net, there is probably more information around now then there was a couple of years back. From the engineering perspective, as a fuel the calorific value and octane are important. I cannot give figures off the top of my head, but the information should be available somewhere. The gas itself is so cheap it is almost free, however the catch is that because the required storage pressure is very high, the electrical power required to drive the compressor is not so cheap. Happy motoring Tony.

Jeeeez Cereal don't let the yanks know there is oil under the Timor sea, they will come over and bomb the crap out of us.

Hi Joel. Originally I was thinking only to get a standard weight steel flywheel that would take a bit of a rev without exploding. However, rev210 and yourself have now got me thinking a bit about flywheel weight. With 4WD turbo cars the BIG problem is getting the car moving from a standstill, with a larger than stock turbo and decent cams, this only becomes worse. Launching the car at a million revs is a bit hard on the driveline ! I do not think a squirt of nitrous is really a practical solution on an everyday streetcar, although it certainly does work. I am planning something a bit different. A supercharged GTS-4, designed to have a large amount of torque over a wide rev range. A light flywheel is going to make a lot of difference in first gear, and I will not have to launch the car. I agree with what you say about rev matching and faster engine response. The GTR six throttle body setup is also a step in the right direction for fast throttle response as well. Hmmmmmmmmm interesting.