Biofuel - conversions for TVR's?
Discussion
I am willing to be flamed for this, but in the spirit of intelligent debate, a practical query - Could our respective TVR P&J's ever be converted economically/reasonably to Biofuel/E85? I have read some positive comments on the prototype Lotus Exige 265E, but am interested in whether this has any application to our cars. Specifically
- has anyone out there done it or considered it?
- what ramifications are there for the engine (greater wear? significant new parts?)
- practically, would using E85 (or comparable) result in a measurable loss of performance (don't think so), sounds (less sure on this) or simple TVR "character".
- any other practical issues you forsee (ie - realistic cost of conversion? lack of UK E85 fuelling stations is one I am aware of).
The Lotus website - http://www.grouplotus.com/engineering/green_techno... - demonstrates that their prototype was initially a standard spec Exige, modified then for E85 use. V interesting, although am not sure the Speed Six is a prime candidate for this conversion!
- has anyone out there done it or considered it?
- what ramifications are there for the engine (greater wear? significant new parts?)
- practically, would using E85 (or comparable) result in a measurable loss of performance (don't think so), sounds (less sure on this) or simple TVR "character".
- any other practical issues you forsee (ie - realistic cost of conversion? lack of UK E85 fuelling stations is one I am aware of).
The Lotus website - http://www.grouplotus.com/engineering/green_techno... - demonstrates that their prototype was initially a standard spec Exige, modified then for E85 use. V interesting, although am not sure the Speed Six is a prime candidate for this conversion!
I think the biggest concern is the fuel lines, both rubber and metal as ethanol absorbs water (forget the technical term for these compounds) and forms a mild acid which will corrode the lines. The need to be replaced with ones that can take the stuff.
Not sure about engine internals. I would guess that the head gaskets may need replacing, possibly the valves and rings.
I have thought about it as well, but don't have the time to explore it right now.
Not sure about engine internals. I would guess that the head gaskets may need replacing, possibly the valves and rings.
I have thought about it as well, but don't have the time to explore it right now.
Just this morning I was thinking about this in an entirely different context (involving Jag V12s in particular) - if you re-engineer an engine anyway (including aftermarket management), would it be feasible to jack up the compression ratio in order to optimise it for running E85+, then provide some sort of limp-home programme with alternative ignition and fuel mapping and limited performance in case one needs to use straight petrol, or a lower ethanol/petrol mix?
900T-R said:
Just this morning I was thinking about this in an entirely different context (involving Jag V12s in particular) - if you re-engineer an engine anyway (including aftermarket management), would it be feasible to jack up the compression ratio in order to optimise it for running E85+, then provide some sort of limp-home programme with alternative ignition and fuel mapping and limited performance in case one needs to use straight petrol, or a lower ethanol/petrol mix.
In an ideal world you'd want variable compression ratio (something [only?] Mercedes-Benz is reported to have achieved). Running E85 at gasoline compression ratios just makes the fuel consumption bad because it's inefficient. Running gasoline at E85 compression ratios risks detonation and catastrophic failure. Driving would be pretty horrible in an E85-optimised car running on pump gas with weird AFR/timing - too horrible and too risky IMHO.
bosscerbera said:
Running gasoline at E85 compression ratios risks detonation and catastrophic failure. Driving would be pretty horrible in an E85-optimised car running on pump gas with weird AFR/timing - too horrible and too risky IMHO.
D*mn. Back to the drawing board then. Thought it might be acceptable as a limp-home solution when combined with knock-sensing circuitry. Oh well.It's possible to do the limp home mode. You can detect the spcific gravity of the fuel in use and modify the base injector pulsewidth appropriately. A lambda of 1 is stoichiometric for both fuels, so there's no change in ECU hardware needed.
Of course this means you will have a compression ratio that is not ideal for either fuel, but super unleaded will run happily in 12:1 compression engines, although it'll not be nice at peak load...
BTW I have my Griff just about equipped for E85, all I lack is a source where I live
Of course this means you will have a compression ratio that is not ideal for either fuel, but super unleaded will run happily in 12:1 compression engines, although it'll not be nice at peak load...
BTW I have my Griff just about equipped for E85, all I lack is a source where I live
dinkel said:
It's not only the compression rate - racers use E85-ish stuff - but also the use of different materials. Ally / magnesium and E85 don't mix that well . . . Back to good old steel mills then.
In Sweden this stuff is already used right?
The material problems were mentioned earlier in the thread. E85 is used in lots of places, in big farming states in the USA dual-fuel vehicles are pretty common. The E85 is sufficiently cheaper than gasoline for the loss of efficiency when running on E85 at gasoline compressions to still make economic sense. In Sweden this stuff is already used right?
The broader issue is using up food crops for inefficient use as a vehicle fuel.
dinkel said:
It's not only the compression rate - racers use E85-ish stuff - but also the use of different materials. Ally / magnesium and E85 don't mix that well . . .
All 'bi-fuel' cars on the market so far have standard (alloy or alloy/cast iron) engines. Only difference is in the fuel system (rubber/plastic parts). If the valve seats are hardened sufficiently to work with LPG, they will cope with E85, too.dinkel said:
In Sweden this stuff is already used right?
There's a few thousand cars at least (Ford Focii, Volvos and Saabs) in The Netherlands with E85-capability, too. Apart from a few cars in governmental duties (Rotterdam compensates their communal services for the extra fuel costs caused by E85 usage), none of them will see any E85 though, as long as a litre is 1.95 euro due to the same fuel taxes being levied on it as on a litre of petrol...bosscerbera said:
for the loss of efficiency when running on E85 at gasoline compressions...
At the moment, I'd say E85 (or E100) makes the most sense with forced induction as a means of variable overall (rather than just static) compression?bosscerbera said:
The broader issue is using up food crops for inefficient use as a vehicle fuel.
In fairness, the ecologic potential of biofuels will only be realised with the second generation fuels which IIRC are generally cellulose-based. As with every major development, though, you need to start somewhere, build an infrastructure, iron out the bugs even before it all becomes economically viable.If biofuels offer a genuine opportunity for the internal combustion engine we know and love to stay with us for a while longer, I'm all for them.
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