[Diy_efi] Re: LPG vapor injection with gasoline injectors: req fuel

[John Smith1882]

If I don't want to buy an automotive grade gas diffuser, then the MegaSquirt 
I already have must control the fuel. I'll be running MegaSuirt 'n' 
Spark-Extra code with a turbo anti-lag function(if I can figure out why this 
altered verison of 025 is somewhat unstable), so it will handle spark as 
well. It has to be able to richen the mixture on decelleration in order to 
do this.

>Date: Fri, 9 Jun 2006 14:02:25 -0400
>From: "Andy Harvilla" <higrafey at gmail.com>
>Subject: Re: [Diy_efi] LPG vapor injection with gasoline injectors:
>	calculatingfuel requirements
>To: diy_efi at diy-efi.org
>
>John,
>
>Do you have to run the fuel through the ECM?  It might be easier to
>devise a simple vapor carburetor and use the computer for timing, etc.
>-- that's my own route at this point.
>
>Andy


Wait, if I increase pulswidth by 50%, thats 50% more fuel. If I double the 
injectors, thats 100% more fuel....

I know I don't need to fool the MS, but I do need to know what conversions 
are needed in order to tell it what to do. Like I mentioned, I have three 
30lb/hour(315cc/min) Lucas injectors that are low-impedance(4 ohms) and four 
270cc/min(26lb/hr) Denso injectors that are high impedance (12 ohms). With 
those options I can have 90lb/hr(950cc/min) available or 
1100cc/min(104lb/hr) respectively. They are rated for gasoline flow either 
at 100% or 80% DC, not sure. I just need to know how to convert that into 
LP-gas flow.

>Date: Fri, 9 Jun 2006 12:23:06 -0700
>From: "Ken Nelson" <head2wind at gmail.com>
>Subject: Re: [Diy_efi] Re: LPG vapor injection with gasoline
>	injectors:	calculating fuel req.
>
>There are a couple ways to deal here that I would try given you don't want
>to get different injectors:
>Increase injector pulse by 40-50%
>double up the injectors and maintain pulse time, if low impedence: series
>(total Ohms ~6) if high impedence then parallel.
>
>You don't need to "fool" the MS, just tell it what to do.  The size of the
>engine has little to do with fuel.  Desired power output and VE has
>everything to do with choosing the appropriate size of injectors.
>
>You may have freezing problems at 40psi.  Lower will get you less problems
>with this, however you give up flow, not much but even still you would have
>to increase PW of injectors indirectly proportional to fuel pressure if all
>else stays the same.   Once you hit about 90% duty cycle you are at/beyond
>staturation and you will not have any head room to work with if you need
>more fuel