BEC going mainstream?
adithorp - 3/10/14 at 12:56 PM
Just spotted
THIS CONCEPT over on pistonheads.
Surely it'll never catch on. Everyone knows they have no torque, self destructing gearboxes and clutches, are noisey, uncomfortable, can't
be driven for more than ten mins on the road and only suitable for the track...
jossey - 3/10/14 at 01:17 PM
I thought it was 8 minutes... Lol
Speaking of which... Doesn't the Lexus lfa have a twin bike engine by Yamaha?
[Edited on 3/10/14 by jossey]
40inches - 3/10/14 at 01:22 PM
quote:
Originally posted by adithorp
Just spotted
THIS CONCEPT over on pistonheads.
Surely it'll never catch on. Everyone knows they have no torque, self destructing gearboxes and clutches, are noisey, uncomfortable, can't
be driven for more than ten mins on the road and only suitable for the track...
A bike engine in a car!!!!!! Who ever heard of such a thing, would be totally useless on a run to the Alps and back
loggyboy - 3/10/14 at 01:32 PM
I cant believe those performance figures based on a car with 200bhp and 99ft/lb.
JAG - 3/10/14 at 02:29 PM
The main weakness of bike engines is the clutch and gearbox...
...both of which VW has replaced with a 7 speed DSG - so only half the bike power-train really 
ashg - 3/10/14 at 02:33 PM
the biggest shame is how ugly it is.
Sam_68 - 3/10/14 at 02:58 PM
quote:
Originally posted by JAG
The main weakness of bike engines is the clutch and gearbox...
...both of which VW has replaced with a 7 speed DSG - so only half the bike power-train really
And the other, for some of us, is how annoyingly frenetic and highly-stressed they sound, in road use, due to the short gearing of the
typical bike box, and the need to rev the nuts off them to get to the power.
The V-twin Ducati at 11K rpm is only firing the same number of times per minute as a 4-pot at 5,500rpm, so it overcomes that problem too... same
reason as I selected the Aprilia V-twin for the ultra-light design I'm working on.
Nothing wrong with the engineering behind bike engines, so long as it is applied appropriately instead of being cobbled into some half-arsed
Heath Robinson application that it was never suited to.
Fuel consumption figures are noticeable by their absence in the publicity material for the XL1 Sport, so no indication of what the 265 section tyres
do to the rolling resistance, or the flared arches and ducts do to the CdA, but it's still nice to know what might be achievable by production
hybrid technology a few years from now?
PAUL FISHER - 3/10/14 at 04:03 PM
At 890kgs with only 99 ftlbs of torque, put a driver and a passenger in it with a full tank of fuel and you could be over 1100kgs, I can't see it
being very quick then
Sam_68 - 3/10/14 at 04:29 PM
quote:
Originally posted by PAUL FISHER
At 890kgs with only 99 ftlbs of torque, put a driver and a passenger in it with a full tank of fuel and you could be over 1100kgs, I can't see it
being very quick then
Actually, you're right... I only skim-read the original article and jumped to the conclusion that it was still a hybrid and so could benefit from
the electric 'boost' to pad out the torque curve.
Reading the actual VW press release more thoroughly, there's no mention of any retention of the XL1's hybrid technology, so basically what
we have here is just a fat, albeit aerodynamically efficient, BEC.
Interestingly, according to the press release, and even with the less frenetic character of the V-twin, Volkswagen has seen fit to equip the car with
'...a newly developed step-down transmission to reduce engine speeds by a factor of 1.86'.
On reflection, and apart from weighing over twice (!) as much, the concept doesn't sound a million miles away from another
low-drag, lightweight, high performance coupe that was built back in the 1960's:
I know which I'd rather have...
So much for progress?
snapper - 3/10/14 at 11:00 PM
My though was... 168mph & 5.7 0 to 60
Perhaps they should gear it lower for 140 mph and a sub 5.0 to 60
Sam_68 - 4/10/14 at 07:34 AM
quote:
Originally posted by snapper
My though was... 168mph & 5.7 0 to 60
Perhaps they should gear it lower for 140 mph and a sub 5.0 to 60
That wouldn't have played to the car's strengths, though?
For a BEC, it's plain overweight, so whilst you could use the normal trick of short gearing to mask the lack of torque, you'd never get
really dramatic acceleration figures... whereas if the aerodynamics come anywhere even close to the original XL1's, there is the potential
(which they have obviously exploited) for an attention-grabbing top speed figure.
As it is, I suspect that the calculated 0-60 figure of 5.7 that is quoted will be much to do with careful choice of ratios on the 7-speed box,
coupled to the very fast changes that are achievable with DSG and that;
a) The car will struggle to match them in reality and;
b) Lowering the overall (final drive) ratio wouldn't help much, because the lower intermediate ratios will have been carefully selected to
optimise 0-60 already.
....they're actually doing pretty well to get a 'computed' time of 5.7 out of something that heavy, with so little torque.
russbost - 4/10/14 at 12:37 PM
A typical bike engine/transmission has a reduction gearing of around 1.5/1,6 before the gearbox, so effectively multiplying that 99ft/lb up to over
150ft/lb, without knowing what they've done with the DSG gearbox & whether it still has the reduction gearing it's impossible to judge.
Also having a 7 speed gearbox could make quite a difference, particularly if they've kept the low gears low & tightly spaced, but then made
everything from 3rd upwards (1st & 2nd will give the low 0 -60 time) more widely spaced you could have a very tall 7th to keep revs down for
motorway cruising.
I can't see any reference to whether it's still hybrid or not it says the sport is "similar" to the XL1, if it retains the hybrid
motor that's a further 27bhp with lots of instantaneous torque so it all seems feasable - albeit a little pointless