Know's:

-SC14's off a Toyota 1G-GZE work well on L4 engines and are reasonably easy to adapt, using the A/C mountings.
-SC14's have a 125mm pully on them, and with a 175mm crank pulley, that'll get the SC spinning to 9800RPM at 7,000 engine RPM. That's below the 10k rule of thumb limit.
-Plugging the numbers in, an SC14 will be pumping 30.6lbs/min of air @ 9800RPM (assuming a 90% pump efficiency, note: that is not compressor efficiency which will be down around 50%.) Thus at the manifold you'd expect around 14-15PSi of boost, which while on the high side for a blower, with good intercooling, fuel mapping and E85 shouldn't be a problem.

-An L18 with an open 45cc head, 87mm Flat-top pistons, 1mm HG and 0mm deck height has a compression ratio of 10:1
-An L4 EFI inlet manifold is hard to find (but I've got one.)
-An intercooler from a 7MGTE or XR6 turbo both have inlets and outlets on the same side, and would probably fit in the nose of a 180b, and be a good (+cheap) choice. XR6 intercoolers are on sale now for $30
-E85 (or E-Flex from pump fuel from Caltex or United) has awesome anti-knock characteristics.
-The Works 72 cam I've just bought should work well given a limit of 7100RPM.
-Supercharges are good in that it's very hard to get tempted and just wind up the boost that little bit more. Thus the temptation to fiddle with it once set up is removed
-supercharged vehicles with BOV's at full noise sound amazing (throttle plate between SC and inlet manifold, not pre CS as in many factory applications.

Assumptions

Plugging the numbers in gives: 206kW at the crank, or somewhere around 160/170 very instant / very torque'e RWkW. Which going from word on the street in the 4AGZE circles is about the best you can expect form an SC14. And I think that'd be a whole lot of laughs in a 180b and more then enough on 205/50R15's. Be good at the tack/hill sprint/club car etc... and as mentioned never tempted to wind it up just that little bit, because that would push parts past the safe zone of operation and the effort to do so on an SC setup.

Unknown's
-Best way to get direct fire ignition / sequential injection on an L4, I'm thinking an EDIS 36/1 crank pulley with a home signal from a modified distributer, but I'm coming up short? Obviously running wasted spark/batch fire with a crank only trigger would be a far easier/simpler option.
-Whether this actually would work and is a good idea. Compression too high / too much boost?
-Will a standard fibre head gasket be up to the job (assuming good tune, faced head, faced block, ARP studs.) Or will a MLS one be required.
-Injector requirement, 550cc or larger?
-Exhaust size, 2.5" be a good size?
-Has anyone thought to do this before.
-Costs: I'm thinking ~$7,000 including an engine rebuild and an ECU.

This is speculative at the moment but I had to post it up to get peoples feelings and see whether or not this would be a viable route to go. Other options would no doubt be cheaper CA/SR/3SGE Beams/FC20... but the 180b I've bought has the original motor and well it'd be nice to keep it in there if I ever get serious about modifying it beyond the Twin solex's/cam, extractors and exhaust I've already got. Turbo would be cool but I'd not want over 200RWkW for a streeter that I and the girl will be doing club events in. It just seems like a more interesting alternative.

Look forward to reading your opinions

Regards
Jordan

P.S: attached is a spreadsheet I've been working on for far too long. you may or may not find it of use/interest. but it's been helpful to me in working through Ideas on my TA22 race car.

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Past rides: 86 Hilux, 3x ke55 rollas's (2coupes,) 2x ST185 GT4's, RA28, TA22, KE10, P610 datto, RT40 corona x3, RT132, MX13.

Current Rolling stock: 2000 model ST215 Caldina, CAA22 celica (race,) RT40 corona (cruiser)

I think it sounds like a heap of fun without a massive expenditure.
I looked at doing something similar with a mate who had a 280ZX on dual fuel. Not a brilliant setup, but changing to a dedicated complex mixer LPG system and adding an SC14 would have made it quite sweet, and all on a student-friendly budget.
The ignition can be done with a Megasquirt computer, 36/1 wheel on the crank pulley (I had one laser cut to bolt on the the harmonic balancer of my L20B), EL Falcon ABS sensor (variable reluctor type) and 4 x Chevy LS2 coils. Use high quality shielded cable for the signal to the computer. It's a wasted spark system but has a huge spark and it's possible to use a knock sensor with this system, too.
The Megasquirt can also run your injectors, although I have a Gas Research LPG carby on my car. I may one day convert to vapour gas injection or use the Megasquirt to run water injection (like an Aquamist).
I don't know if the 10:1 static compression ratio is too high with the E85 and boost but good water injection could make it useable.
As long as you don't get detonation your head gasket should be OK. A metal gasket is a bit like forged pistons- more tolerant of imperfect tuning.
2.5" exhaust size is plenty with a turbo and 2 straight through mufflers but with a supercharger you may need more muffling to make it legal.
The 72 degree cam you mention may not work as well as you want. Usually with forced induction cam overlap is minimised by increasing the lobe separation by a couple of degrees. A custom cam ground by a really experienced grinder is probably ideal, but I'd try a standard one first and then if change it later if I wasn't happy with it.

Good luck! And please keep us informed.

My current project (and has been my current project for many years ) is a supercharged L18 in a 180B SSS. I'm doing it for much the same reasons as yourself, just seems like an interesting project.

My plan is to use an Eaton M45 blower off a Mini, flat top forged pistons, open chambered head, custom inlet manifold, Subaru water-to-air intercooler plus water injection, graft a CA18 CAS on instead of the standard dizzy (or even mounted on the front of the rocker cover and driven from the cam sprocket), LS1 coils, CA18 injectors, bypass valave (rather than a BOV) from a mini cooper and a Haltech ecu. The idea of using CA18 fuel and ignition is that I can (hopefully) use a basic CA18 program on the Haltech to get it running easily (I know very little about electrickery to make engines run though). I plan on having the throttle after the supercharger as well. I made up a custom crank pulley to suit the ribbed-belt on the M45 blower.

You're planning on running higher boost than I am (although I started my project before E85 became available....), I worked mine out at around 9psi.

You sound like you're well on your way down the correct track - I'd love to see something like this up and running. Mine is realistically still years off.

Gratuitous blower shots, blower has done under 100k's, bracket is home-made :

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

72 cams work well in supercharged L series.
Upper rev limit 8000.

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A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Static compression at 10.1 with 15 psi = effective compression at 20.2, maybe a little high even for e85.

From memory SC14 L20B 1.14 step up: 13 psi with 8:1 comp great on E10.
come to think of it may be 1.14 was 9 psi & 1.270 was 13 psi.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Any Idea what kind of power that tidy little set up was making?

Regards
Jordan

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Past rides: 86 Hilux, 3x ke55 rollas's (2coupes,) 2x ST185 GT4's, RA28, TA22, KE10, P610 datto, RT40 corona x3, RT132, MX13.

Current Rolling stock: 2000 model ST215 Caldina, CAA22 celica (race,) RT40 corona (cruiser)

Am I the only one that likes cat videos?

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When the sign says "don't feed the bears", man you better not feed the bears.

Any info/pics of your LPG setup on here mate?

Cheers

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SSS 180B

Never on a dyno.
But sufficient to see off 4.2 ,injected, ported, cammed, V8

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

[quote="SSSBEE"][quote="180BSSSt"] I have a Gas Research LPG carby on my car.[/quote]

Any info/pics of your LPG setup on here mate?

Cheers [/quote]

None on here but I'll find one for you.

Thanks mate.

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SSS 180B

As you can see the Gas Resrearch carby is on an adaptor I made to go on the front of the log-type plenum. This was mainly to lower it so it would clear the bonnet but also added plenum volume. The convertor is nice and close and its supply line runs through the box section next to the top of the strut tower. The turbo is all hidden under two layers of heatshield. Air filter is just below the front bumper. Yes, it has an intercooler but it can't be seen from outside the car.

That's awesome mate, What is gas research carby do you use?

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SSS 180B

The smallest- 350cfm. With a blow-through setup you size the carb as you would for an atmo motor of that capacity. That way it's fine on boost or off. Just remember that with a blow-through LPG setup you need a "balance line", a hose between the carby (1/2" is a good size) and the top of the convertor (there's usually a vent with mesh over it. Pull that out and tap a thread for a hose fitting). This means that the convertor (think of it like a float bowl for a petrol carby) "sees" the same pressure as the mixer and correct air/fuel ratios can be maintained.

I don't think we're completely off topic here as LPG is an alternative to running E85 and works very well with forced induction. Gas carb or mixer setups are unbeatable on a small budget and there's LPG vapour injection available for more money. I don't know of a good commercially available programmable liquid gas injection system (I've wanted one for years) but that's the ideal LPG system.