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-   -   Building for efficiency instead of performance (http://www.haynes.co.uk/forums/showthread.php?t=7164)

Greenbeast 23rd September 2011 07:49 AM

Building for efficiency instead of performance
 
I'm wondering about the Roadster as a platform for an ultra-efficient petrol car or all electric vehicle.

I currently drive a citroen c1 which can do 70mpg+ (extra-urban).
I was wondering about the possibility of putting one of these engines in the roadster to gain even more mpg.

Thoughts anyone??

Talonmotorsport 23rd September 2011 08:18 AM

I have supplied a few chassis to a training centre who have put 2 very large electric motors running through a type 9 in to a tiger chassis. The only problem is that for every 5 miles of driving you need to carry a 5kg battery which takes 12 hours to charge. Have you considered using a small NA diesel with a turbo? Don't use a turbo diesel just a NA with an added turbo, this means it has smaller injectors so good for economy but burns the fuel more efficiently. You could always get one of those under car mounted speaker sytems so that you can mask the diesel rattle :D

Greenbeast 23rd September 2011 08:24 AM

I've done a bit of research into the electric side of thing, and i may go that way.

What do you think about the ease of fitting a different, much smaller engine in?
I like my little c1, it's quite perky round town and can handle the motorway with ease, fitting it's engine into something that weighs 2/3 as much should improve acceleration but also overall efficiency, no?

twinturbo 23rd September 2011 08:36 AM

I would find an efficient Oil Burner, or try LPG + Petrol.

Electric vehicles just shift where the energy is created, it's often created by power stations that waste fuel as they can't produce on demand efficiently. The Batteries cost a lot to make, transport and to dispose of. Add to that the total in-convenience of having to find a charging point and they realy make little sense.

Even a relativly old VW 1.9TD will probably see into 60-70's if driven conservativly in a roadster. You may have to calculate so gearing ratios to keep the engine at it's optimum.

TT

Greenbeast 23rd September 2011 08:41 AM

I'm comfortable with the downsides of all-electric, i'm weighing up the options.

Where i'm not sure is the donor engine business. I already see 60-70mpg with my current petrol, surely i must be able to easily beat that in a roadster?
What potential pitfalls might i see using a unusual donor engine/drive train?

twinturbo 23rd September 2011 09:24 AM

Gearbox is the usual sticking point, otherwise we would have all sorts of tasty engines in frequent use.

And Complex Imobalised Engine management systems.

TT

Greenbeast 23rd September 2011 09:29 AM

I'm gonna really show my ignorance here but how come you can't just use the original gearbox?

voodoo 23rd September 2011 09:53 AM

Most modern cars have transverse mounted boxes as they are FWD, the roadster has RWD.

Personally I have been looking at the feasability of running a NA diesel on Biofuel, in addition we are working with a local company that has developed a biodegradable alternative to GRP. Strengthwise it is better, costwise it can't get close.

Matt

AshG 23rd September 2011 09:54 AM

personally i think your wasting your time. the roadster has the aerodynamics of a brick. the best way to gain efficiency is to move the car through the air more efficiently.

typically a 2.0 zetec will do between 35-40mpg in something like a focus. have you ever asked yourself why it still only does 35-40mpg in a 7 which is less than half the weight of a focus?

Greenbeast 23rd September 2011 10:22 AM

Voodoo, thanks for that, knew it'd be something obvious.

Ash, good point

brainbug007 23rd September 2011 10:47 AM

Personally I like the sound of using hydrogen. Apparently you can run a petrol engine on it with very little conversions. The tricky bit is getting a tank or some sort of electrolisis process running in a cell that creates enough hydrogen to run the engine from salt water.

brainbug007 23rd September 2011 10:52 AM

Have a read of this, looks cool:) http://www.spiritofmaat.com/archive/...ar/h20car2.htm

flyerncle 23rd September 2011 11:02 AM

Build your own anaerobic digester and run it from the gas it produces,methane as per Top Gear.
It's very simple to do .

Greenbeast 23rd September 2011 11:07 AM

Quote:

Originally Posted by AshG (Post 65441)
personally i think your wasting your time. the roadster has the aerodynamics of a brick. the best way to gain efficiency is to move the car through the air more efficiently.

typically a 2.0 zetec will do between 35-40mpg in something like a focus. have you ever asked yourself why it still only does 35-40mpg in a 7 which is less than half the weight of a focus?

However i just thought perhaps this is because the drivers are tearing round in them rather than driving conservatively? :D

flyerncle 23rd September 2011 12:14 PM

Wait until you have built and conserative goes out the window.;)

Greenbeast 23rd September 2011 12:30 PM

ha ha, yeah i bet

davedew 23rd September 2011 01:20 PM

Quote:

Originally Posted by voodoo (Post 65440)
addition we are working with a local company that has developed a biodegradable alternative to GRP. Strengthwise it is better, costwise it can't get close.

Matt

Does this mean that if you leave it out in the rain, the body will go soggy and fall off!!

robo 23rd September 2011 04:06 PM

The council round here were playing with cng <compressed natural gas>. I dont know what came of it but i know other countries are bigger into it. Takes all night to compress the gas in a car to give you app 300 miles of driving. Ok for normal town stuff but would cause a rep a few problems. And of course no duty on that or filling stations. Hmmm

Thoughts

Bob

tex 23rd September 2011 04:26 PM

Quote:

Originally Posted by AshG (Post 65441)
personally i think your wasting your time. the roadster has the aerodynamics of a brick. the best way to gain efficiency is to move the car through the air more efficiently.

typically a 2.0 zetec will do between 35-40mpg in something like a focus. have you ever asked yourself why it still only does 35-40mpg in a 7 which is less than half the weight of a focus?

beat me to it - if your after an efficient car you wont get it with a 7 type shape - too many sticky out bits.

BUT there are alternatives like the fisher fury type car - basically its a 7 under the skin but slippier cos of body shape

ayjay 23rd September 2011 07:04 PM

I was thinking of a great big elastic band:D :D :D

Greenbeast 23rd September 2011 08:10 PM

Quote:

Originally Posted by tex (Post 65455)
beat me to it - if your after an efficient car you wont get it with a 7 type shape - too many sticky out bits.

BUT there are alternatives like the fisher fury type car - basically its a 7 under the skin but slippier cos of body shape

thanks, i'll look into it

voodoo 24th September 2011 08:00 PM

Quote:

Originally Posted by davedew (Post 65451)
Does this mean that if you leave it out in the rain, the body will go soggy and fall off!!

No, bio-degradable and water soluble are two different things ;)

It is a cellulose resin composite using a hemp based mat and no, you can't smoke it :)

Matt

robo 24th September 2011 09:30 PM

http://westfield-world.com/pics_paulr.html

Bob


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