Murph

True true. If it wasn't for the tree I wouldn't have a free L20B in the basher sunny.

Oooohh! Damn that looks good! Wonder if he'll get that sort of $ for it?

Nope. Didn't even know one existed. On a unrelated note, I was pretty pissed off when I found that 200B; it looks like it was a pretty neat example before these little shits took in bashing. :mad:

The 810 over here in oz is a 200B. Here's one we found crashed out bush recently. Ended up pulling the L20B and a few other bits out of it.

Just a generalisation. The top fueler only runs in a very specific powerband, so they size the blower to provide the boost they want at that specific rev band. For a street car it's a whole different kettle of fish as you need to operate over a much larger rev and load range. It's a typical characteristic of the rootes blowers that they will drop off in efficiency at higher revs. About the heat produced by the roots, I was trying to say that's a problem when you try to run them at higher speed.

That looks tops alfa! Good work! It's certainly come a long way in the past few years.

Just a heads up. Sorry if this is a repost. Datsun 240K Coupe 99.9% original condition, 2nd owner. White, Body is 100% straight ie not even the slightest dent, has some rust bottom of doors & rear quarters, interior excellent condition, no tears in seats, original console & factory radio! Engine in GC, elec distributor, 3 spd auto. Wont take much time, effort or $$$ to get this car to concours condition, example like this very, very rare these days. Email jamestailly@optusnet.com.au or phone number below. Car Identification: Datsun 240K Price: $2000 ono Location: Narre Warren South Vic Contact: James Email: jamestailly@optusnet.com.au Phone: 03 9705 2556 (hours: Anytime/Leave message)

Hey don't be knocking the Bx10 lineage now champ!

Just read the technobabble article, it seems the water is psuhed by a mechanically driven hydraulic pump, not an electric motor. None the less, why not just directly mechanically drive the compressor? The hydraulic system can only ever add inefficiency. You simply will never get more power out than you put in. The only possible pro that I can see for this system is packaging. I'd say the fact garret dropped the design is a good indication!

Sorry mate, but I have to rip this one up. Hydracharger: There is no such thing as free power. It's like the whole electric supercharger idea, but worse. Why not just spin the turbine with an electric motor, removing several other points of inefficiency. That's pointless anyway, you need some pretty conisderable power to spin the compressor hard enough to make decent boost. For a factory 2L, we're talking something in the ball park of 15kW to spin the turbo. Have you seen how big a 14kW electric motor is? Now you have to start adding up the inefficiencies. The electric motor has considerable losses as does the alternator, niether can turn 100% of the energy going into them, into the form of energy going out. If you added a water pump and piping to that the efficiency of the whole system would plummet. Basically, it'd never work. There is NO FREE POWER. EVER. Do remember the positive displacement supercharger is pushing a larger amount of air per revolution than the engine is swallowing each revolution, hence compressing it. A centrifugal compressor and roots/vane/twin screw superchargers all compress the intake air via different means....but what results is no different, it's compressed air. As for general characteristics for each... Roots: Good bottom end and mid range, lacks top end and not capable of high boost without toasting the air. Centrifugal: Poor bottom end, ok mid range, good top end, probably the most efficient compressor type. Twin screw: good bottom end, mid range and top end. Capable of high boost levels. The only real downside being relativley high outlet temps, nothing intercooling wont fix.....and as Ken has shown, you can get away without it NP. So basically, the twin screw will be making a shite load more power than the centrifugal, right up until the red line where the centrifugal will probably JUST edge it out. Good for dyno queens and that's about it in my opinion. You might as well use a turbo.

This thread was about superchargers on the L-series anyway, so the whole big/little engine/turbo argument is well off topic. PM me with your results....I think we should leave this thread on topic.

Chickenwafer: A centrifugal supercharger isn't the best of both worlds unfortunately. With them, boost pressure is proportional to engine revs. Basically this makes them no better than a NA engine down low, with less mid range than a turbo engine and can only match a turbo or twin screw supercharger on peak power. What's this hydracharger? Never heard of it?

Not everyone lives in your happy little world of larger capacity engines that can make big power AND still have a responsive turbo. I think you really need to go drive a 2L with a larger than stock turbo, then come back and comment. I'm quite aware the R31 didn't have an ideal setup, but I can guarantee you it was pretty near on 2 seconds. Unlike your large capacity engine, at that load condition the R31 wasn't producing anywhere near the exhaust flow required to spool the turbo. As before, go drive a 2L with a larger than stock turbo. It's not like they're uncommon. Would you agree power output will change with boost pressure? Yes. Good. Say you're balancing it around the corner like you said. Say you squeeze the throttle open another 15%, does boost instantly change with and proportionally follow throttle position? No. Maybe close on your engine, but refer to response No. 1. You see, that's what you get out of an NA or supercharged car, that's what I personally want. Is this an admission?

Regarding my blanket statements about turbos, I did say that the examples were at the extreme end, but never the less, the same principles still apply (to a lesser extent). As for the preoccupation with throttle response, I like it. It's totally irrelevant who you think needs it. I like it so I will choose engine configurations accordingly. The car in the two second example was a RB20 NICS powered R31, using an HT18. Not a colossal turbo on the compressor side, but the exhaust side certainly is for a 2L. As per my example, 80kph, 2nd gear, floor it and it'd take around 2 seconds before it'd make decent boost. And no, it didn't run out of rev range.....before the turbo would spool it'd barely accelerate, it is a low comp 2L pushing 1500kg after all. The second car in question and one I've driven in anger on many occasions is an R32 with an ITS turbo, not sure on the model but is said to be good for ~260rwkw. Better response than the R31 had, but still a pain in anything twisty. That extra .8L of a liter you have makes a BIG difference. You should line yourself up a drive of a small capacity, large turboed car some time and you'll see exactly what I'm talking about. This statement makes it quite obvious you're not quite grasping what Ken and I are talking about. Ken summed it up perfectly with:

I've driven plenty bloke. Like I said my example is toward the laggier end of the scale, but never the less still applies. Sure some may be happy with how a turbo cars drives, I am not. That's my opinion and I am entitled to it.

I have to sort of disagree. To get a 1:1 ratio you're needing a pretty damn huge turbo. Certainly not something that'd be typically considered streetable. Do remember in the vid of zacs 1600 that we simply can't say acurately what the exhaust pressure was due to the fluctuations (100-200kPa). Even if you take the average of that you have a greater than 1:1 ratio. Ignore that point....I had confused ken with what I meant. Totally disagree on this one. Firstly we should be clear on some terminology. When I'm refering to lag, I'm not talking about the the motor needing to be above a given rpm for the turbo to boost, I'm talking about how long it take to go from nothing to full boost when the engine is already at high enough rpm to spool the turbo. For example take an average turbo car driving down the road at 80kph, 2nd gear, 5000 rpm just holding that speed, turbo wont be boosting. Now floor it. How long does it take for the turbo to start making useable boost? That's lag! With pansy little turbos eg my mates VG30DETT, we're talking maybe 0.5 sec or so....not much. But when you're talking large turbos, we're talking seconds. Two good examples are two mates RB20 powered skylines, both with different large turbos. Both of them will take around 2seconds to start making useable boost. That sort of lag shits me to tears. Sure the cars are fun being silly fast and all, but they're almost useless when it comes to the corners, because it simply wont make the power you want when you want it. Example 1: Brake hard for the corner, even get hard on the power very early in the corner and it still wont make good power until you're out the other side. Example 2: We were out in the middle of nowhere and decided to pull a donut.....drop it in 2nd, rev out to the limiter almost imediately, so back of the accelerator to get it off the limiter, foot down again, oh look its dropped off boost, then bogs down before it can build boost again. Basically the same happens in corners. Sure it's an extreme example this car having a rather large turbo and all.....but the same happens with pretty much any turbo setup. Having come from the 260Z where I am some what spoilt for throttle response, any amount of lag shits me to tears, even the tiny little bit in my mates Z32 tt. Holy sh*t. That was a bigger spiel that I meant to write! Cherio

Yeah I think I had seen that one Ken.....sounds cool. What is your estimated power level with the current setup?

No A/C on mine, so all good there....but I can see why it's a problem if you're making a kit. Yeah sorry, I probably wasn't clear. I meant an external bypass when I was talking about dumping to atmosphere. Aside from bypass valve location, the two systems would work in the same way. What's the bypass valve actuator attached to? Is it one line into it or two? With the wastegate setup you have one line to either side of the diaphram. One attaches to the blower outlet and the other to the inlet manifold. The result of this is that the bypass valve position will be pretty much inversely proportional to the throttle position. So, no or low boost at low throttle, medium boost at medium throttle, and full boost as soon as you floor it. Good point about the acceleration enrichment. I suppose that'll be a hassle to deal with at the time. I'd be very interested to see how it compares with the eaton. Looking at the charts the eaton M90 seems to be on par with the whipple 2300 (?). I'll be interested to see how the new setup turns out....I might just be ordering a manifold from ya. Will do! They're the sort of boost levels I'm looking at running....so will be interested to see how it goes with the bigger blower. Thanks again Ken.

Fair enough. I was thinking of going the remote mount option as I wanted to stick with a stock inlet manifold. I've done a quick dummy up and you're right, there are a few things over there that have to be moved....but nothing that's too difficult. I can't see any reason why I couldn't just dump to atmosphere instead of back to the inlet side of the SC? There are a few blokes over here in oz running this exact setup without any hassles. One catch here is you'd have to have to use MAP sensed engine managment, but that'd be a given for what I have planned. With your internal bypass setup, does the bypass open/close at one given throttle position, i.e. it's open or closer, or does it vary, so that it's fully open with the throttle closed, and gradually closes as you open the throttle? If it work in the later way, then it's operating exactly the same as the wastegate setup (and can be plumbed back into the inlet of course). I'll be vrey interested to see what you come up with here. I've got a rough idea what you're thinking....exactly the sort of thing water-air is perfect for. I'd set on the whipple idea based on the experience of a few people over here. One guy in particular has used them on three difference road and race cars over the years and has been VERY impressed. Back on the throttle response of a remote mount SC setup, the way I'd planned to do it (and the way the other guys here have), the throttle body remains in the stock location on the inlet manifold, so should still have pretty good throttle response? Thanks for your input Ken, it's interesting to see another angle on it all. Justin

Thanks for the info Ken. That built in bypass effectively works in exactly the same way as the method using the wastegate that I had mentioned. It would be pretty handy to have it built into the supercharger though. Two positives of the wastegate idea are firstly that by using and adjustable wastegate you could change the rate at which the bypass will open/close with pedal position to suit your driving style/cars use. Secondly you can dump the air from the bypass to atmosphere and avoid recirculating it. Not sure that by recirculating the air it'd really heat up enough to have to worry about it. Both small issues really......the better packaging of the internal bypass would be more important to most. It'd think water injection should see some pretty decent benefits in your setup. I'll be following progress on your car with great interest as realistically, I wont be getting started on my planned setup for about a year or so. With regards to redesigning the manifold to fit under a stock bonnet and to allow intercooling options, why not mount the SC on the other side of the engine? With a remote mounted oil filter kit (cheap) there's plenty of room over there, still allowing access to the spark plugs. It'll also greatly simplify inlet piping to and from the intercooler. While on the topic of intercoolers, what's your plan there? Air-air or water-air? I'm thinking water to air using one of the PWR barrel coolers... Keeps the packaging of the whole setup quite simple. http://www.absoluteradiator.com/images/Liquid-to-airKit.jpg Justin P.S. Any thoughts, agree/disagree with any of that, just say. I'm still learning with the whole SC thing.

Very nice Ken! Out of interest, what's the supercharger you used (with an internal bypass valve)? My copy of that edition of sportz mag should be somewhere between the US and here.....I don't want to wait till I get it to find out though!

I should auction my mates RB20 piston....at least it REALLY looks like it's damaged.

That ol ute's pretty cool. I recon that'd look tops with a good tidy up.

I vote no, on several counts. 1. I don't think they'd suit the car, but that's just my opinion. 2. Blue light = bad idea. This comes down to the basics of how your eyes operate. I can't remember the exact reasoning off the top of my head, but basicaly your eyes will take longer to readjust to the low light conditions when driving at night after looking at the blue light. Now red is a better option as it's picked up by a different type of "sensor" in the eye that can quickly adjust to the varying light levels (if someone wants to correct any of that or give a more technical description, feel free). 3. Big white faces lit up with bright blue lights = extra bad idea.