How does a flex fuel vehicle accomodate E85?

I presume with larger injectors. And help from ECU.

If so then how does it deal with very small PW when using E10 at idle or low load?

VAFPR will help but PW under 1.5 msec may be an issue?

 

just to give u a very basic idea the ecm has a methanol sensor located in the fuel line or tank to know wether the car is running gas or e-85 some ecms like the megasquirt can actually calculate the required fueling based on actual methanol content as read by the sensor as some e85 could be mor elike e70-e90 etc or if u have gas in the tank say 2 gallons then put 5 gallons of e85 in the tank

id belive the oems just se the sensor to detect the ethanol content to a percentage and use it to switch between 2 diffrent ve and ignition tables

typically when going from gas to e-85 there is a 30% fueling change

now at idle if the pulse width is 1.7ms on gas + 30% would mean 2.2ms on e85 roughly

again roughly

most ppl use a 30% factor to start when switching from gas to e85 but ive seen reports of the percentage actually being much lower

 

Not 100% sure but they do have larger injectors and various sensors to determine the fuel type on the fly. Believe its a fuel composition sensor and readouts from o2 sensors, it can adjust from there

 

Factory flex fuel vehicles have an additional sensor near the catalytic converter that tells the ECM when E85 is being used, in which is then immediately adjusted for in the tune...

 

I forgot that the PW at idle needs to be larger with E85. I was thinking it was the same as E10. My question was how to do a work around a very low PW at idle.

Does a E85 vehicle use an injector 30% larger? I presume so.

So if I built a HP motor to run E85 I would use a much larger injector to fuel on top end vs reg fuel.

 

more then likley u would run a low -z peak and hold type injector
these can have a much smaller minimum pulse width with these then the stock high z type injectors

my prescision 65# low -z injectors will work down to a .6ms pulse width

yup u would size ur injector based on the flow requiremnts needed for ur hp level on e85 since the injector needs to be bigger with e85

if u sized it by gas numbers it would be to small on e85

 

OK. I forgot of the low vs high injectors.