Well,

Definitely decided on a supercharged / injected L18 for my 180B SSS.

Now comes the question on what supercharger to use. Having looked around, and received some great advice on this forum, I thought I'd look further than the Toyota SC14 blower.

Another two types that seem to be available for a bit more cash than the SC14 are Eaton M45 or M62 and Mazda Eunos s/c. The Mazda one is a twin screw, similar to the Opcon that Baz seems to rave about. The closest comparison seems to be to a Lysholm LYS1200 in size. Eaton seems to be similar to SC14, but supposedly more efficient.

So, first question. Does anyone have experience with these superchargers ?

Second question. What size do I need ? Is it better to run a small supercharger at higher revs, or a bigger one slowly to produce the desired level of boost ? Is there a lower limit of efficiency so that the larger one won't work well at low engine revs , especially seeing as I want response rather than all-out horsepower ? And finally, any thoughts on the Eunos blower ? Its designed for a 2.3l V6, and I believe this motor runs a reaonably high level of boost, so is it going to be too big for 1.8l ?

_________________
1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Dave,

I've only messed a little with the SC14. Yes an Eaton (and any twin-screw supercharger) will be more efficient than a SC14 (and any rootes type supercharger). My SC14 made 5psi on my L28 with a larger than stock (from the 1GGZE of course) pulley. Would go quite nicely on an L18 with intercooling and EFI.

What size you need is dependent on how much boost you want to run. Get some basic volumetric efficiency figures for the different types of blowers and your L18 and work it out (or just ignore VE alltogether):

An SC14 moves 1400cc of air in one revolution. L18 ingests 1800cc per two revolutions = 900cc per revolution.

If you want 10psi boost that is: 10+14.7/14.7 ( 1.68 ) * 900 = 1512cc per revolution required.

1512/1400 = 1.08:1 drive ratio required.

This is, as I said, ignoring volumetric efficiencies (SC14 won't produce exactly 1400cc per revolution, nor will an L18 ingest exactly 900cc per revolution). My gut and basic verification figures from my L28 setup (ie, off the top of my head basically) indicate that the SC14 is less efficient than the L, hence the ratio leans a bit that way (so might be 1.15 or 1.2:1 in the previous example).

Hope this helps a little.

Got any more info on the Eunos S/C. Is it a roots/twin screw/centrifugal(hehe)? It does sound a little too big for a mild setup if you ask me. So i say: do it!

Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

Dave,

Thanks for the reply.

The Eunos one is a twin screw, off the Miller cycle engine. This runs (so I believe) fairly high boost to make the Miller cycle stuff work, so I ended up writing this one off as too big for my needs. For other applications like an L6, it might be a good alternative.

In the time since I posted this thread, I've got hold of a book on supercharging - "Supercharged" by Corky Bell. This explains a great deal. I've also lashed out and bought a brand new Eaton M45 supercharger , so hopefully this will turn out to be suitable.

There seems to be a plethora of these available on ebay.co.uk for next-to-nothing, as they are fitted to some models of the new Mini. There is also, apparently, a "Works" uprade available over there which involves driving your brand new Mini to a tuning place who rip the old supercharger off, install the new one, plus other bits and pieces, and give you your upgraded mini back, plus a virtually new supercharger in a box in the boot. I paid 102 pounds for it (bit over $250 .

Postage is a bit expensive, but it all worked out to be the same price as buying an SC14 from a jap importer here.

Anyway, thanks for the response. Looks like I'm taken my first step down the supercharger path. No turning back now, unless you see a "Brand New Supercharegr from Mini Cooper" ad on eBay or in the Ozdat classifieds over the next few months.

_________________
1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

Any idea oh physical sizes Dave? Seems to be a major downside to them to me. They have to be big so you don't have to spin them hard (positive displacement I am talking)


Dave

_________________
USA Daily: 2014 Nissan GT-R, very minor modifications for the track
USA Project: 1978 280Z, minor suspension upgrades, VK56DE conversion in progress. SOLD
AUS Race Car: 1973 240Z, L28ET, Autronic, GT35R. SOLD
AUS Project: 1972 1600, 3200km old S15 SR20DET, ground up rebuild. SOLD

They have a displacement of 45 cubic inches (0.75 litres).

Initially, they struck me as being too small (hence my initial post), but the Eaton web site lists them as suitable for 2 - 3l engines. They were fitted as factory equipment to the new mini, up to the 2.3l 4 cyl mercedes "kompressor" motors. I found many references to them being used successfully on Mazda MX5 1.8 litre, and BMW Z3 1.9 litre engines. I may have thought differently if I wanted high boost, but thats not what I'nm really after. Just hope I don't change my mind once its running, as the M45 doesn't leave a great deal of headroom for increasing this.

The only logic I can see as to why the smaller displacement supercharger works is that the Eaton is more efficient, and also tolerates being spun to higher revs than the Toyota ones. After doing all the calcs in the book I've bought (similar to what you've provided), it seems the Eaton M45 will give me just under 10 psi on a pulley ratio of about 1.9:1. This is maybe a bit more boost than I was looking for, so I might be able to reduce the ratio to get a bit less boost. A 1.9:1 ratio still allows me to rev the L18 to 7500 rpm, which shouldn't be neccessary too often with the low-down torque that I'll achieve. Thats the plan anyway.

I plan on making a water-to-air intercooler that will bolt directly to the outlet port of the supercharger, so hopefully the additional heat generated by spinning the supercharger fairly hard won't be too much of a detriment.

I stand to be corrected on any of this. It's still all theoretical, with a bit of heresay from various websites and books thrown in . There isn't a great deal of info around when compared to turbo's.

Anyway, here's the Eaton website with specs on all their stuff.


http://www.automotive.eaton.com/product ... argers.asp

_________________
1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

hows the supercharger project going ?
I have been considering one for my L16.

I've been meaning to post my progress in the members rides section, but haven't got around to it yet

A lot of work has been done on the body, but no actual spanner work on the mechanicals.

I have however pretty well got my plans set in stone now, and have gathered most of the bits I need to build the motor.

As alluded to above, blower is an Eaton M45 off a Mini Cooper S. I picked one up from eBay.co.uk for the princely sum of 101 pounds (about $250). It is off a 2004 model mini, and has supposedly done 12 miles . Driven off the showroom floor, straight to the John Cooper Works garage where it had a JCW "kit" fitted (new head, new blower, new exhaust, plus a few other bits). All the replaced bits are given back to the cutomer, after which heaps find their way to eBay and sell very cheaply.

A blower pulley I got from Datsport is a pretty good fit, even though it was designed for a Toyota SC14 blower. By my calculations, it will give 15psi boost, and the blower will hit its redline of about 17,000rpm as the L18 hits 7,000 rpm. The mini guys seem to think its safe to go over 17,000 occaisionally, there are plenty of overdrive pulley kits for the mini. Boost plans have increased from a planned 10 to 15psi already Incidentally, the Eaton M45 should work even better on an L16. It will provide more boost, or same boost at lower blower revs. I have considered an L16 engine for the 180B instead of the L18 for this reason.

My ideas of making a water-to-air intercooler have changed, mainly because I picked up a Subaru jobby for $200. Cheap, supposedly pretty good, and able to be installed without cutting up the front of the car.

I have acquired an SR20 fuel rail, SR20DET injectors and an SR20 manifold for the fuel side of things. The current plan is to cut the injector bosses out of the manifold and adapt them onto (probably) a custom inlet manifold, or (possibly) a webber manifold. SR20 fuel rail will be modded to suit new manifold.

Engine management will be provided by a Haltech E6X ecu (group buy on DatNet ). This was going to be a megasquirt, but my lack of knowledge of electrical things, plus a lack of knowledge of efi convinced me to get a (hopefully) easier to install and tune commercial ecu.

Ignition is still being decided upon. I've got a CA18 CAS which I was going to adapt in place of the distributor, but may also go with a Haltech hall efect sensor. This can provide wasted spark ignition via two coils. Or I may go an electronic dizzy arrangement. As you can tell, ignition is still being investigated

Engine will be rebuilt, using an already ported A87 head I have lying around. It will be ported some more and and fitted with a fairly mild cam and oversized valves. Pistons will be hypertec standard compression ones from Datsport, giving 8.5 to 1. Head will have some work done on the combustion chamber, mainly unshrouding the valves both for better flow, and may reduce compression a bit ?. Another option is to use a U67 head, which will also give lower compression. As you can tell, 8.5 to 1 is giving me a bit of concern. Will it be too high with 15 psi boost ? I don't know The rest of the engine will be built to pretty normal modifed Datsun specs. Shot peened and polished rods, nitrided crank, etc, etc. I've also been looking at cryogenic treatment of some engine bits, anyone used / heard of anyone use this ?

Water injection will also be fitted, which should help with detonation.

Gearbox will be CA18DET, provided my $50 "broken" box I bought off nissansilvia.com is economical to repair. Having a mate who owns a gearbox and diff repair shop will help here

Diff is also still undecided. My current preference is R160 Subaru LSD, or maybe try to stuff short-nose R200 internals into a longnose case that I've got lying around. Again, gearbox / diff mate will come in handy.

Well, thats about it.

I wont be starting on mechanical mods till the body is completely straight and rust free, all primered ready for paint. Then I'll be doing the mechanical work before stripping it down again for painting and final re-assembly.

OK, I'm scared now. Didn't seem like TOO much work till I put it all down on paper

I'll try to post progress in the member's ride section this weekend.

_________________
1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

stick with the L18 - they still rev quite freely. the L16s and FI are a great match, but only if you keep them on boost (not hard with a supercharger, but there's always "that" situation where you'll need it).

all cryogenics is good for is eliminating minute movements in the engine internal under high load / high speed that cause things to rub a little more than they should which in turn hurts power. that said, most engines see a further 500rpm up top (and subsequent power increase with it) due to the more stable and stronger nature of the moving pieces. if you're really chasing the extra 8.67hp that will give you, then yeah - go for it.

but cryotreating bearings and rings will increase their life and reliability at sustained high rpm for very little cost - as well as brake rotors, drum linings etc etc.

i've done a ton of research into this and these are my conclusions about cryogenics and are quite open to debate.

another alternative is to use molybdenum in your oil - it puts a very thin (like half a thou) coating on all moving parts and sets like stone when mixed with hot alkaline products - like warm engine oil!!!

8.5:1 + 1bar of boost with good tuning (maybe WI?) and a W2A intercooler should be fine - i plan to run 10.0:1 CR and 10 psi in an L18 with just WI and a closed chamber head. the A87 has better squish properties than the U67, and better squish = better burn = more reliable power (no power/torque discussions over this please - you all know what i mean). also closed chamber heads reduce swirl - and i think good NA swirl + FI = detonation. you should let the inlet pressure move all your charge into the chamber and the pressure should distribute it evenly without the head trying to swirl it all up again. that's why non-xflow heads respond so well to even small amounts of boost.

again, only my opinion and open to debate.

the bigger the charger, the easier it can cope with higher boost levels without frying the bejeezus out if the air. bigger charger = cooler boost at the same boost level with half the rpm as a smaller charger working twice as hard.......... i think - it's late as i write this. you know what i mean.

anyways, food for thought. would love to hear Baz's thoughts on this.

_________________
frankenstein projects R us.

The Republic of Western Australia -
Propping up the Nation's Economy since 1901.

with the head why not just bolt a L20B head on ?
bigger everything & less compression.
or in my case a L18 head on my L16.

has anybody got any idea what HP these things would output with the supercharger bolted on ?

Yeah, sort of my logic on using an L16.

Smaller motor, won't need to drive the blower as hard to achieve same boost as on the bigger motor.
I don't want to drop the compression TOO much, plus I already have a good, modified A87. Jury is still out on which head to use - I haven't actually sat down to work out the exact cr's I'll get with each head. Plus I could always use different dished pistons to adjust cr, depending on the chosen head.
Ask me again in 12 months I haven't really got a specific figure that I'm aiming for. My thoughts are that I won't need as much outright horsepower to achieve the same performance, due to the better spread of torque that the blower will (hopefully) supply. That's my theory anyway.

_________________
1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

my reasoning for it

_________________
frankenstein projects R us.

The Republic of Western Australia -
Propping up the Nation's Economy since 1901.

what about a commodore v6 blower ? to big ?

I believe these are Eaton M90. This has twice the displacement of the M45 I'm using.

The only problem I can see using one is dropping off the bottom of the "efficiency" scale of the supercharger due to having to run it at lower rpm.

_________________
1970 ex Group A Rally P510
1971 P510
1972 180B SSS
1965 SP310 Fairlady
1966 SP311 Fairlady

if its twice as big wouldnt you get as much "air" at half the rpm.....or am i missing the point entirely ?

\

sorry - half the rpm of the supercharger - not the engine.

should have been clearer there.

it's like having a smaller engine spinning at 5000 rpm and a bigger engine idling - which will have the cooler exhaust gas...?

they're not the same principle, but it helps explain how supercharger RPM relates to boost temperature. the big one spinning slower and cooler will make the same boost as the small one spinning faster and hotter.

same boost - 2 different inlet temps and 2 different power levels.

_________________
frankenstein projects R us.

The Republic of Western Australia -
Propping up the Nation's Economy since 1901.