Cut to the chase most tuners say around 30% extra fuel is needed when using e85 over gasoline. So assuming your just on your stock engine (or basic bolts) but had the desire to run e85. In this example we'll use the b18a in my little crx.

B18a comes stock with 240cc injectors
30% additional fuel would equate to new 312cc injectors

So would simply swapping in some 310cc injectors(tad off) put out the necessary fuel to satisfy a near 1 lambda ratio for the e85? of coarse it is only a neighorhood number, but on the cheap shadetree mechanic style would the duration of a 312cc injector pulse give out 30% more fuel than a 240 as the comuter is still sending the pretimed pulse.

I know of one fairly built engine running stock GSR ecu with 400cc injectors on e85 and it seems to run well, but that skews my math horrible and im not sure if the extra fuel is my bad math, misconception in cc in relation to fuel volume, or the built engine needing the extra fuel, just not sure.

Other option would be an adjustable FPR. Again assuming WOT fpr around 42psi 30% increase makes 54psi. Would the 30% increase in WOT fuel pressure put the needed 30% extra fuel in to compensate for e85?

Yes these are bandaid solutions compared to real tuning, yes timing would suffer, yes it would not be precise... I have just had this notion stuck in my head and need some more experienced thoughts on it.

Thanks HT

 

might need to get a bigger fuel pressure reg too but ya that would would. just like a turbo, spit more fuel to counter the extra air.

 

would bumping the injector size up this little be enough to drop the fuel line pressure when at wot while all injectors are feeding off?

thanks

 

Yes those are bandaid solutions compared to real tuning, yes timing would suffer, yes it would not be precise... you have just had this notion stuck in your head and need some more experienced thoughts on it. You also have a noticable avatar.