Warpspeed

Yes, everything is exactly the same except for the clutch. The GTR also has better spec brakes. The R33 AWD gear ratios are the same in the Rb25s and Rb26s both have 4.11 diffs. The R32 GTS-4 Rb20's came with 4.3 diffs, but all the manual gearboxes are all identical.

Very interesting EJ6. The RB25 block used in the AWD version is different to the "normal" RB25 block. The oil pan rails are quite different, and some of the holes are much larger to take the studs which secure the alloy sump and front diff. So there is the RB25DE, and RB25DET block used on the R33 and R34 rear wheel drive cars, and then there is the RB26DETT, RB25DE, and RB25DET neo blocks as used in all the AWD versions. Your R33 has definitely been modified in some way, and there are two possibilities. The original RB25DE may have been fully rebuilt with all the RB25DET parts, but using the original (AWD) bare block, this is possible, but highly unlikely. The other possibility is that someone has dropped in an R34 Stagea RB25DET neo engine. This engine is different in many ways to the original RB25DET, and is rated for 205Kw, if I remember correctly. There are many detailed changes including variable valve timing on both cams, and the top of the engine looks totally different. It should have "neo straight six" prominently displayed. If it does, you are a very fortunate fellow.

Yes the R34 does come with an RB25DET plus AWD, but it would not come cheap. The best option is to get an R33 n/a GTS-4 and turbo it yourself, a bit of work, but not impossible. Another way would be to fit an RB26DETT to an R33 GTS-4, now that would make a very nice sleeper, and at around half the cost of a GTR as well. If you bought an auto GTS-4 for about $15K, a complete GTR front cut for about $10K, you would have absolutely everything you need, plus you could flog off all the unused bits and recover a few dollars.

Yes thats right. R32 GTS-4 had RB20 turbo engine, and R33 GTS-4 has the RB25 normally aspirated engine only. I have been looking for an R33 GTS-4 manual for over a year, and cannot find one that is for sale, but they do exist. There are quite a few automatics around, if that is what you want.

I would give the electric turbo a big miss. There was a thread on Performance Forums not so long back on this topic, and the sales guy from the company selling those things was torn to shreds. As I recall that particular device was advertised to produce up to 800CFM and up to 3psi boost and it was powered by a 12v electric motor which reqired 20 amps. Now if you grab Corky bells book "supercharged" and turn to page 203, there is a formula for calculating supercharger drive power: Drive horsepower = psi boost x airflow CFM, divided by 229 Now if your electric supercharger can generate 3psi at 800cfm, that would require 3 x 800 / 229 = 10.48 horsepower That is the thermodynamic energy required to compress the air at 100% compressor efficiency. If the compressor wheel is 70% efficient, you need 14.97 BHP actual shaft drive power to turn the wheel. If the electric motor is 80% efficient, it comes to 18.7 horsepower worth of electric power, or 13.96Kw. Now the electric motor on the thing is only 12v at 20A or 0.24Kw. There is not a snowballs chance in hell that an 0.24Kw motor is going to drive a supercharger that requires 13.96 Kw to operate at full rated boost and flow. So it might blow UP TO 800CFM with zero back pressure, and it might produce UP TO 3psi with zero airflow. Some poor bastard is going to put one on his engine and see maybe 0.2 psi boost or something. Not a good investment. To properly design an electric supercharger like that, which will deliver 800 CFM at 3 psi would require 12 volts at 1,163 amps. And that is why it is never going to work. And it is also why any decent supercharger is driven by a big nasty very serious looking belt drive system straight off the crank.

Sounds good eryc. Reading between the lines, it sounds like Whipple have become a bit cheesed off with Sprintex as well, hmmm. Interestingly, all these blowers end up costing about the same these days after factoring in the Oz/US exchange rate. Larger or smaller sizes also cost the same, so dollars are not really going to be a factor in the selection process. Personally I would still prefer the twin screw blower over a roots or centrifugal on an RB engine. But the centrifugals would be more ideal on a push-rod V8 though.

There is nothing in the first post to suggest he is building an RB30 ? So why would any of that be relevant ??

Have to agree completely with Meggala, a set of rb26 pistons is definitely the best way to go, combined with a stock head gasket.

I sent a e-mail to Whipple a while back, asking about alternative pulley sizes, and I received a reply pretty promptly. But I have given up on Spritex. Keep trying Eryc, the smell of money might smoke them out.

Yeah, a 155 Kg St Bernard jumping up onto your Skyline can change its shape quite a bit.

A flat power curve means the torque is decreasing as revs go up, I would rather see a flatter torque curve with the power rising to a peak.

Joel. After looking at those two power curves, have to agree the RB30 is going to be heaps stronger at the same maximum boost. But I suspect though that the same rated boost level was only reached at the very top end with the RB25 combination. Fitting the RB30 allowed the turbo(s) to come on boost far sooner and create that massive mid range torque. I would like to bet that some slightly smaller exhaust turbines/housings on the RB25 combination would also have come on boost sooner as well and given a similar if not identical result. Still, it has ended up a mighty impressive engine though, no matter how he finally did it.

My philosophy is to keep the basic engine breathing (volumetric efficiency) as good as possible over as wide an RPM range as possible, and then use supercharger boost to lift the whole torque and power curve to what is required. So if you begin with an RB30DE that has a lot of natural low end off boost torque, but poor top end breathing, a big turbo is going to fix the lack of top end and make a very nice package. On the other hand a normally aspirated six throttle body RB26 is going to lack torque, but breathe very easily to well above 8,000 RPM. A decent positive displacement supercharger is going to lift the torque right up, and you will end up with a far more flexible engine with more low end, and a far extended top end. And it will not be short of power or torque either. The other possibilities are an RB26 turbo, which even stock, is going to lack torque below 4000RPM, and when powered up will be even less flexible. It becomes a narrow power band racing engine. A supercharged RB30DE would be the exact opposite. Bags of low end torque, and completely dead at the top end. It would make the ultimate truck engine. So I think a turbo RB30, or a supercharged RB26 would be the go for the ideal street engine.

It will certainly be an eye opener. Personally I am going the RB26 crank in the RB25 block route. If you remember, you supplied me with the RB26 crank and rods to do it a while back ! But really it all comes down to airflow determining final power, not engine capacity. The difference in the shape of the torque and power curves that a 14mm stroke difference will make, will absolutely astound you.

Ray Halls site has some compressor maps. http://www.turbofast.com.au/FlowTO4B.html Look at the S-3 map, turbos are rated at a pressure ratio of 2.0 (15psi boost) and at the 60% line. Flow is across the bottom, about 35Lb/min I would think for that one.

Hello again Brad. Go to any speed shop or car place, they will have a catalogue for "Mr Gasket Co" the US based hot bits distributor. In that catalogue will be software products developed by Motion Software. There will be Dyno 2000, and I think there is a later Dyno 2002 version as well, but not absolutely sure. My copy of Dyno 2000 cost $160 twelve months ago. There is a website somewhere where you can download a demo program. Well worth a look. On the supplied CD, there is a huge operating manual that you can print out. It discusses engine theory, and how the simulations work, it is an excellent read quite apart from the software itself.

Well your compressor is a TO4 "S" flow, according to the wheel dimensions, and the 0.6a/r cover is pretty standard with that wheel. According to my flow-map rated flow is about 35Lbs/min airflow, or 457cfm, or 305BHP, or 227Kw, depending on how you want to rate it. Your exhaust turbine is also TO4 "O"flow split pulse 0.84a/r, as the guy says, but it apparently has a T3 flange fitted which is pretty unusual. That sized turbo would be about right for a three or four litre sized engine I would think, but it will need an external wastegate.

I think you need to test this on your own car. Just chuck a full jerry can and hose in the boot, and drive it till it stops. The reason being, that a few liters spread over the area of the fuel tank is only a few millimeters of fuel sloshing around. A lot depends on how deep the sender and fuel pickup extend into the tank. So there will be differences between individual cars. I also like to know exactly where the fuel gauge needle ends up when it finally does stop as well.

It would not bring good luck to the bloody cat though..............

Sprintex over in WA used to advertise Whipple in some of the car magazines. I stopped buying magazines a long time ago, so do not know if they are still available from them. Your best bet would be to contact Whipple USA and ask them who their Australian agents are. http://www.whipplesuperchargers.com As to which one, you need to buy Corky Bells book "Supercharged" and do your own calculations. A lot depends on the desired power goal, so there will be more than one possible size you could use. They all cost about the same, so that is not really a factor. It is more a case of getting the very best results for your intended application.

You are right there Geordie. The big horsepower turbo car can turn impressive numbers on the dyno, and be mighty quick down the quarter as well, as long as you seriously thrash it. It makes for a powerful and exciting car, no argument there. But on the street, you might not want to thrash it all the time. So while the guy with the big turbo drops down a gear and 1.....2.....3....then....WOOOOoooossssshhhhh, and he is off. Meanwhile you are about two car lengths in front. The turbo might be quicker to 0-250Kmh, but who cares. You will be quicker to 0-100Kmh, and you will not need to do the big high RPM clutch dump to get there either. There are two reasons for this. First you do not need to shock load the tyres at launch, in fact you do not really need to launch at all. So you will have better traction. The turbo HAS to launch in order to get boost up before it bogs down completely, but furiously spinning wheels do not grip. Second reason, the engine is accelerating in first gear, and the turbo also has to accelerate to catch up. The lower the first gear ratio, and the larger the rotating mass of the turbo the worse this is, the turbo car can never reach anything like rated torque and power in the lower gears. It sure will in top gear though. With a crank driven blower the blower accelerates as fast as the engine in first gear. So although steady state rated dyno horsepower might be a bit less than with a turbo, its all there in every gear. Instantly. So you can easily end up with less power, a slower et, and a quicker car on the street. None of the drag racers understand any of this.

The bastards get you three ways: 1/ Income tax. Originally levied by government to finance wars, it is now just mass plunder and a rip off. 2/ Interest payments. We have been brainwashed to believe that everyone MUST borrow just to have any sort of a life at all. So the banks reap the interest from you, but only if you let them. 3/ Inflation. The amount of money in circulation is gradually increased in such a way that your savings are eroded. The bastard banks can print a fifty dollar note for a couple of cents, and use it to buy fifty dollars worth of real assets for themselves. The crooks (Federal Reserve Bank) will tell you they are raising interest rates to dampen the economy which is becoming overheated. Or lower interest rates to stimulate the economy. It is like a vampire saying we are now sucking more of your blood because you are becoming too healthy, and we want as much blood as we can get without actually killing you. Or you are becoming very sick, so we will reduce our blood sucking and let you recover a bit, before we increase it again later. Is it any wonder that a great many people work all their lives to pay off loans, and taxation, only to retire into poverty on the old age pension. If the first step to financial independence is saving, the second step is understanding how the bank money fraud works. It will truly shock you what you will find out.

I have had this problem myself, several things you can do. If its only one cat, get rid of it.......................... If you are a cat lover, do not read my previous sentence. Get a cat of your own. A big mean nasty tom cat. It will be boss cat, and keep other cats away. Give your cat a nice warm place to sleep, and it will not show any interest in your car at all. A really bright light shining down on your car will discourage cats from sleeping there. It shines in their eyes, and they cannot lay on your nice warm bonnet and look around.

Yeah its possible............. First thing though, if you have an intercooler core thats say 75% efficient, that means it will remove 75% of the heat that the turbo put into it in the first place. Now if you double the size of the core, or use two inter-coolers in series, the second core is going to give you 75% of that 25% you missed out on through the first core. So both combined give you 75% + 18.75% or 93.75% If you add a third core, this will give you 75% of the 6.25% the first two missed out on, so efficiency goes up to 93.75 + 4.69% to 98.43% You cannot get to 100% ever, maybe 99.9% but never 100%. BUT, the pressure drop goes up by a factor of three. So the third core removes stuff all heat, but adds to the pressure drop. The interesting thing though as you compress a gas it becomes hotter, we all know that. And when you allow the pressure to drop through expansion, it falls in temperature. So part of the temperature reduction through any intercooler is caused by pressure drop across the cooler core. This is the Joule Thompson effect. (look it up on Google) So as you keep increasing the pressure drop by adding more restriction it IS possible to lower the temperature below ambient. But you would not want to do this because you are also decreasing the density by adding more restriction and lowering the pressure.

Difficult to say, but here are my figures from my computer simulation. Stock RB25DE 10:1 compression, valve timing (non VVT) 15/54 54/15, these are both 248 cams as used on early non VVT engines. Torque at 3,000 RPM 171 ft/lb Max torque 181 ft/lb flat between 3,500 and 4,000 RPM Max power 173 BHP at 6,000 RPM (129Kw) Rear wheel kilowatts (82%) 106 Kw I know this is a bit low, but that is how it came out. There are things I cannot enter such as intake runner length and exact exhaust details and so on. RB25DE miller modified engine, 10 psi boost, roots blower with average intercooler (80% efficiency). Compression ratio 10:1, inlet valve timing 20/72 (272 duration). Exhaust valve timing 54/15 (248 duration). Torque at 3,000 RPM 299 ft/lb Max torque 315 ft/lb flat between 4,000 and 4,500 RPM Max power 354 BHP at 7,000 RPM (264Kw) Power at rear wheels (82%) 216Kw RB25 modified with RB26 pistons, 10 psi boost with roots blower and average intercooler (80% efficiency). Compression ratio 8.5:1, inlet valve timing 15/54 (248 duration). Exhaust valve timing 72/20 (272 duration). Torque at 3,000 RPM 314 ft/lb Max torque 316 ft/lb flat between 3,500 and 4,500 RPM Max power 348 BHP at 7,500 RPM (260Kw) Power at rear wheels 213Kw So either way it is going to double your power.