villn808
Well-Known Member
ur thinking injector delta pressure
Don’t know what I’m thinking lol. Winging it.
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ur thinking injector delta pressure
That makes more sence, sort of. 1000HP on 98 octane petrol = 700-800 hp on 108 octane E85 due to the lower energy density of alcohol if fuel volume was kept the same.the 1000hp would be on petrol so less on e85 but they wouldn't use any lower the twin 340lph pumps so u should get 7-800rwh out of it on e85, flow is based on pressure also so if u increase the fuel line size u also have to keep that increased volume at the same pressure which lowers flow, -6 or -8 line is plenty even factory feed line is enough
They're referring to the volume of fuel available and what that would equate to in terms of the fuel supply requirements of an NA engine vs an FI engine. FI requires a greater volume of fuel. So the point I think Villn808 was that trying to make was, that the volume those pumps can deliver would theoretically be sufficient for 1000rwhp NA, but far less for FI. Bur, I'm happy to stand corrected.That makes more sence, sort of. 1000HP on 98 octane petrol = 700-800 hp on 108 octane E85 due to the lower energy density of alcohol if fuel volume was kept the same.
But isn't that the beauty of E85 capable V8's with their fuel flex sensor. The ECU would recognise the E85 and change spark advance and increase injection rate so the same (or a little more) engine power is produced. Even if supercharged, the same would hold true because the flow rate of the pump/lines/injectors MUST meet combustion requirements else detonation and destruction occurs.
So it seems even on a flex fuel vehicle, practicality dictates 1000hp on petrol still = 1000hp on e85. NA or supercharged wont make a big difference. So what am i missing?
I will try to give you a basic understanding of F/I fuel systemsThat makes more sence, sort of. 1000HP on 98 octane petrol = 700-800 hp on 108 octane E85 due to the lower energy density of alcohol if fuel volume was kept the same.
But isn't that the beauty of E85 capable V8's with their fuel flex sensor. The ECU would recognise the E85 and change spark advance and increase injection rate so the same (or a little more) engine power is produced. Even if supercharged, the same would hold true because the flow rate of the pump/lines/injectors MUST meet combustion requirements else detonation and destruction occurs.
So it seems even on a flex fuel vehicle, practicality dictates 1000hp on petrol still = 1000hp on e85. NA or supercharged wont make a big difference. So what am i missing?
no cant keep fuel volume the same u have to think of fuels by there stoich value not octane rating, ethanol needs about 34% more volume for same stoich value, everyone uses the same volume to petrol as then ethanol is leaner so of course its not going to make the same power so to get the same EQratio u would have to run petrol at AFR of 22:1 im sure petrol wouldnt be good there either, at the same stoich value (EQratio) ethanol makes more power then petrol it just needs the flow to keep up, u can use the fuel pump calculators to see the difference needed, also need to account for BSFC, AFR and if regulator is referenced to boost or not as mentioned it offsets the delta pressure needed otherwise u can run out of injector flow offsetThat makes more sence, sort of. 1000HP on 98 octane petrol = 700-800 hp on 108 octane E85 due to the lower energy density of alcohol if fuel volume was kept the same.
But isn't that the beauty of E85 capable V8's with their fuel flex sensor. The ECU would recognise the E85 and change spark advance and increase injection rate so the same (or a little more) engine power is produced. Even if supercharged, the same would hold true because the flow rate of the pump/lines/injectors MUST meet combustion requirements else detonation and destruction occurs.
So it seems even on a flex fuel vehicle, practicality dictates 1000hp on petrol still = 1000hp on e85. NA or supercharged wont make a big difference. So what am i missing?
Thanks guys.
Much as I suspected though it’s still a little unclear how a/f ratio is used to cool a vehicle with catalytic converters which I thought required an average a/f ration closer to the ideal 14.7 So all fuel types would/should aim for that But who are we kidding, modded cars that produce lots of HP don’t meet pollution requirements so can dump more fuel into the engine to keep things safe and cool as long as the pump can keep up And their lies the rub...
Guess my confusion was that I didn’t pick up that @villn808’s comment was in relation to manufacturers spec (being written by sales people) based on 98RON fuel whereas he was wanting to run E85. So his comment was related to some downgrade for E85 and further again for super/turbo charged uses (in a non complying car ) to reverse engineer a HP figure to flow rate to HP figure for another fuel
Would be much easier is specs were detailed.... with pumps it should be a graph of fuel flow rate against fuel pressure and then the buyer can work out more clearly whether it would meet their flow needs for whatever fuel and boost they care to use. It would be much better way but I guess a graph is not as catchy as 1000HP (Said in a deep booming voice)
I blame it all on sales people
thats where most get stuck AFR is only usable if u stick to the one fuel type, stoich "lambda 1.0" with any fuel type is the point where the injected amount of fuel and air are all burnt in petrol its 14.68:1 straight ethanol 9:1 (e85 9.7:1) at that point they both burn with the same result for emissions just ethanol itself burns cleaner so its better for environment, when u go into power enrichment that stoich value is multiplied as u need extra cooling to make power just ethanol cools better as it vaporises when ignited and petrol only atomises which dosnt draw out as much heat, ethanol has a lower stoich value only because it carries more oxygen which is partly why it makes more power if u can inject more oxygen in attached to fuel with the intake charge then u can make more powerMuch as I suspected though it’s still a little unclear how a/f ratio is used to cool a vehicle with catalytic converters which I thought required an average a/f ration closer to the ideal 14.7 So all fuel types would/should aim for that But who are we kidding, modded cars that produce lots of HP don’t meet pollution requirements so can dump more fuel into the engine to keep things safe and cool as long as the pump can keep up And their lies the rub...