Alcohol - EFI

[Jemison Richard]

Hey Bud, 

I remember when Stromberg's were king.  However, I never personally ran any
of them.  Does sound like we're pretty close to being contemporaries, ha!

Thanks for quantifying this stuff.  You keep good notes!  The mechanical
fuel injection I have worked with, Hilborn and Pete Jackson.  Ah, they were
simple.  A pocket full of pills and you were on your way, ha!  Then Isky
(Ed) came up with the micrometer pill (really precise but some were prone to
vibration problems).  Mechanical injection and chrome rings were the way to
go at one time.......long, long ago......

One small point (and I think someone quantified this on this list recently),
some may wonder why to mess with alky if it takes a lot more to get the job
done!  Higher octane hence higher compression is possible.

Rick


> -----Original Message-----
> From:	Fran and Bud [SMTP:quest100 at gte.net]
> Sent:	Tuesday, December 01, 1998 2:56 PM
> To:	diy_efi at efi332.eng.ohio-state.edu
> Subject:	Alcohol - EFI
> 
> A few old time data points on running Alky (methanol) that may help to
> provide a frame of reference for Alcohol/EFI efforts:
> 
> Stromberg 97 carbs: (Ask your Grandpa!)
> gasoline jets = .045 to .048 dia. -vs- methanol jets = .076 to .090*dia.
> Flow characteristic of Str. 97's was to richen with increased air flow
> thru
> venturi consequently
> the smaller jet sizes correspond to dual carb setups while 3 and 4 carb
> setups required the larger jets.  At any rate the alcohol jet area was
> typically 3.5 to 4 times the gasoline jet area. 
> 
> Mechanical (constant flow) FI: (Ask your Dad)
> gasoline nozzles = .020 to .024 dia. -vs- methanol nozzles = .030 to
> .035**dia.  (292 - 327 SBC)
> This was at 30-40 psi fuel pressure.  If both jets were flowing gasoline
> the
> .02? nozzle could flow about 27 to 30 #/hr and the .03? nozzle would flow
> about 75 to 85 #/hr. (each nozzle).
> The excess fuel was bypassed from the nozzle supply back to the tank thru
> a
> bypass check valve and pill (orifice).
> 
> Note:  Not only were the jets or nozzles changed to larger sizes but all
> of
> the flow paths had to be increased in size also - lines, passages, dump
> tubes, needle valves, etc. and these old engines were struggling to get 1
> HP/cu.in.
> 
> Other Considerations:
> Optimum air/fuel ratio for gasoline = 14.7 /1 & for methanol = 6.5 /1
> also latent heat of vap. = 3+ times as high for methanol as for gasoline
> resulting in significant extra cooling of intake charge = more dense air =
> need for more fuel.
> 
> Seat of the pants estimate for a 350 SBC which at 35 to 45 psi would run
> 24#/hr EFI injectors might lead you to believe that 80#to 90#/hr EFI
> injectors would be needed for alcohol. Smaller if the pressure was raised
> to
> 60 - 70 psi .  This kind of injector is $$$/each. (Indy/F1)
> 
> You will also have to either make sure that all soft goods/sealing
> compounds/etc. will not be affected by the methanol (dissolve/swell/etc.)
> or
> change them out to materials that are compatible - including the internals
> of the lines/pump/regulator/injectors.  Have heard that Rochester
> injectors
> will accept alcohol but dont know for sure and dont think Rochester makes
> high enough flow rate injectors - but you could go to two
> injectors/runner. 
> 
> Please feel free to disagree with any or all of this - thats how we will
> all
> come to understand the EFI world a little bit or a little better.
> 
> Regards, Bud