spunky
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 posted on 5/5/04 at 10:46 PM |
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Why no auto....
Been meaning to ask this for a while but fear of ridicule has stopped me...
Why are auto boxes never installed into Locosts, or any kit for that matter?
I certainly understand the 'drivers car' concept, no ABS, no servo, no PAS etc, etc.
But surely it simplifies the build and with such demanding cars would allow you to fully concentrate on the driving.
It would also open up the choice of power plants to include some of the bigger capacity 'luxury' cars.
I don't know whether I would want a weekend toy to be auto but since owning an old Jag many years ago I was sold on auto transmission and not
owned a manual for 10 years. And certainly the 3.5 SD1, Rover Sterling and Granada 24v were actually fun for such big cars.
Am I missing a fundamental design reason why it's not done or is it purely preference.
I eagerly await ridicule...
John
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MikeR
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| posted on 5/5/04 at 11:19 PM |
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people like changing gear and having the control of holding the gear (ie the auto box not changing gear mid bend).
If you're really interested I've got an auto box for a crossflow sat in a car waiting for a good home.
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spunky
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| posted on 5/5/04 at 11:26 PM |
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Hi Mike
Thats was one drawback I considered, would make life interesting kicking down 2 gears mid corner in the wet. You can always overide the auto and
select manually.
Thanks for the offer, but I'll see how I get on with a sequential box....
John
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ned
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| posted on 6/5/04 at 07:58 AM |
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the problems as suggested above are not being able to control when the gear is changed. both acceleration, short shifting (in wet) and engine breaking
are effectively impossible in an auto, which on a spirited drive no a locost I believe are part of the fun, enjoyment and attainment of speed,
especially when cornering.
Ned.
beware, I've got yellow skin
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stephen_gusterson
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| posted on 6/5/04 at 09:10 AM |
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F1 cars are auto, so it shouldnr be impossible to make a predictable drivable car.....
some boxes have a sport mode - that effectively short shifts if turned off.
Some auto boxes are heavier and bulkier than the manuals - that could be an issue.
Another point is that many locost owners are performance obsessed - and having a fluid link (torque converter) in the drive chain just loses
perfromance.
The auto could also make the car too lively at the rear. A torue converter does just that - it increases effective torque. This is most noticeable
from take off - my jag xjs was 'on ice' in the wet - just a touch of throttle would break the rear away. If you have ever driven an
average american car, you will find it really easy to chirp the front tyres, due to some part, the high torque applied at take off.
atb
steve
PS - no one has done a diesel locost either - again, down to the performance obsession methinks...
[Edited on 6/5/04 by stephen_gusterson]
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ned
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| posted on 6/5/04 at 09:35 AM |
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but if there was a gearbox suitable for the golf td gti 150bhp engine, i'd give it a go.. bucket loads of torque and more power than a
zetec/duratec.
Ned.
beware, I've got yellow skin
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spunky
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| posted on 6/5/04 at 09:36 AM |
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Steve, good point about the F1 cars.
Certainly an auto box is heavier and less efficient at transmitting the power of the engine to the wheels, having said that, at the traffic light drag
strip with all other things being equal, I'd bet on the auto.
MCN did a piece a few months ago on auto v's manual and concluded that in the acceleration stakes an auto box wins. They even found that some of
the big scooters were out dragging the sports bikes up to road speed limits.
John
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ned
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| posted on 6/5/04 at 09:39 AM |
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silly question, but if some of the big scooters outdrag the sportsbikes, how do they keep the front wheel down as the CoG on a scooter must be higher
than a bike, and if they out accelerate the torque/reaction must be at least equal surely?
Ned.
beware, I've got yellow skin
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spunky
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| posted on 6/5/04 at 09:52 AM |
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Morning Ned.
Short answer is I dunno.
Howerver the COG is lower on a scooter due the the engine being slung just in front of the rear wheel and I the smaller wheels would reduce the
'turning' effect around the rear axle.
The big scoots are also long ugly things, basically overgrown speedflights. I don't know if its been put into production yet, but one of the
Japs was developing a 1000cc scooter..... Why....?
John
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derf
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| posted on 6/5/04 at 11:51 AM |
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The reason us US guys dont fit them is to keep them from being stolen. Automatics are all people know here. the first time my wife had to drive my
car, she came back and asked me why I have 2 brakes, go figure.
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greggors84
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| posted on 6/5/04 at 01:36 PM |
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I recently borrowed a new rover 25 1.6 with auto. All the new rover autos are fitted with semi auto box where u can knock it to the side for sport
mode where it will stay in gear longer, or u can knock it back and forward to change gear when u want.
It seemed quite an electrically controlled box, if i floored it, it would drop a gear (as most autos) but then it would just climb to 3000 rpm and
stay there if i floored it a bit more it would drop another gear and the revs would rise to 4000 but stay there. It was a wierd sound, the engine
being limited to those revs and still seem like it was accelerating.
The box was fine for cruising and motorway driving. Using the manual change made it a bit more fun, but the torque converter made it feel like i had
my foot half pressing the clutch down. Its a very indirect feel and one i wouldnt want in a sports car. Im sure autos in bigger sportier cars are alot
better, but if you had one in a locost im sure it would be more lo tech than the rover one.
After 2 weeks of driving it i couldnt wait to get back to my fiesta and change the gears myself!
Chris
The Magnificent 7!
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MikeR
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| posted on 6/5/04 at 01:53 PM |
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hate to differ ...... well ok, i don't.
Westfield did a diesel, called it the weisel. high mpg and pretty quick acceleration - only problem was a heavy and underpowered (by todays standards)
ford 1.8 turbo diesel in my view.
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stephen_gusterson
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| posted on 6/5/04 at 02:20 PM |
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the 'constantly slipping clutch' is a typical effect of an auto.
later boxes have a 'lock' feature that locks the torque converter after a certain amount of revs. American cars have the feature to lower
emissions.
atb
stev
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JoelP
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| posted on 6/5/04 at 02:46 PM |
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feel free to correct me, but i was quite sure that F1 cars arent true auto. i thought it was preprogrammed where to change gear on the track, when to
leave it in gear etc, with override buttons onboard. and others are only auto one way, and you downshift manually.
not sure how it is this season, think autos are banned now arent they?
ps i used to drive an omega 3ltr auto, was very boring, even dangerous. dropping gears on roundabouts, and impossible to hold/control slides without
locking it in gears, which is crappy anyway. when i make a locost MPV i may do auto though.
[Edited on 6/5/04 by JoelP]
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stephen_gusterson
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| posted on 6/5/04 at 03:07 PM |
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" i used to drive an omega "
thats the problem in a nutshell, isnt it? regardless of box...
atb
steve
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britishtrident
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| posted on 6/5/04 at 03:10 PM |
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Just about the only slush boxes suitable for a book sized Locost are the ancient BW 35 and 45 or if you go all germanic and BMW donor the ZF ---
the Ford C4 and C5 boxes are so unreliable they aren't worth a considering. The model 35 was offered most british medium car of the 60s/70s
right up to the series 1 4.2 XJ6 and also auto versions of the MK2 Cortina and MK1 escort, it was ultra reliable in cars under 2 litres (not so
behind a Rover V8 or Jag engine) but it had lousy ratios for sporting use. The 45 was mainly used by Chrysler UK and BL had 4 speeds but worse
ratios.
But go up to Rover V8 size and an auto box becomes a better proposition the GM box in later SD1 models was a good box.
With most epicyclic autoboxes the chassis would need to be altered to accomodate the gearbox sump.
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Noodle
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| posted on 6/5/04 at 03:29 PM |
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quote:
Originally posted by stephen_gusterson
" i used to drive an omega "
thats the problem in a nutshell, isnt it? regardless of box...
atb
steve
Git.
Your sort make me sick
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JoelP
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| posted on 6/5/04 at 03:29 PM |
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quote:
Originally posted by stephen_gusterson
" i used to drive an omega "
thats the problem in a nutshell, isnt it? regardless of box...
atb
steve
1996, heated back seats, less the £2k. find a similar car like that though?
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stephen_gusterson
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| posted on 6/5/04 at 03:40 PM |
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I used to like the princess / ambassador, but that would get similarly slagged.
We have a guy here at work who has an omega. Its his second as a company car, and hes gutted that its just gone obsolete cos he was just about to
order a third.
He recons he uses it cos he needs to get old people in the back and it has a lot of room.
Strange, most people want a snazzy car to entice younger ladies in the back
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gjn200
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| posted on 6/5/04 at 03:46 PM |
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quote:
Originally posted by JoelP
feel free to correct me, but i was quite sure that F1 cars arent true auto. i thought it was preprogrammed where to change gear on the track, when to
leave it in gear etc, with override buttons onboard. and others are only auto one way, and you downshift manually.
not sure how it is this season, think autos
I think f1 uses normal gear box but the changing is done hydraulically. A 7 gear auto box would be about 4 feet long!! Oh,and how could an engine blow
lock up the rear wheels?
<- Me!
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NS Dev
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| posted on 6/5/04 at 04:51 PM |
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A few interesting points!
Last first, a 7 speed auto would definitely NOT be 4 feet long!! I saw the GM prototype 7 speed at Strasbourg transmission plant!! (we supply parts
for these 'boxes to GM) They will be in cars in the near future!!! They fit in the same casing as the pre-production 6 speed auto, which in turn
uses a very slightly modded 5 speed auto casing!
Next, whilst I do not like auto boxes because of the fact that they basically "waste" a large proportion of engine power during convertor
slip periods, I have to admire the new generation "infinitely variable transmissions"
Whether you like the idea or not, these are the future. (so much so I have bought shares in the leading development company!)
I will try and explain!! old CVT's used belts, either rubber (DAF Variomatic) or Steel Segment Push Belt (various manufacturers)
Torotrak are the leading developer of a new transmission based on a purely mechanical toroidal variator unit coupled with a differential shunt.
Basically if you think about an epicyclic gearbox (car diff. or sturmey archer bike hub), you get the different speeds by locking or unlocking either
the Annulus gear, sun gears or planet carrier. A differential shunt uses this effect by using carefully sized gears and driving one compononent
directly from the engine permanently connected, the second component through a variable speed gearbox, and connecting the third component to the
wheels. If you think it through and have the right sized gears, at a certain RPM of the engine, the permanent engine input will exactly cancel out the
input from the variator and give a "geared neutral" i.e. the car is stationary. Any increase in the variable speed gearbox output will
cause the car to move off. Any reduction in output will give reverse.
By coupling this "differential shunt" to a electro-hydraulically controlled infinitely variable "gearbox" (which has no torque
convertor or fluid drive, it is mechanical drive and extremely efficient, basically the same efficiency as a manual gearbox) you get infinitely
variable forward gears with the efficiency of a manual gearbox, together with geared neutral which does away with the need for a clutch, and geared
reverse.
The beauty of it all is that you can then combine the gearbox with the engine into a hybrid power unit, and you accellerator just sets the deman for
speed of the vehicle. In very simple terms, if you accellerate slowly and gradually to a cruising speed, the variatot would maintain a highish ratio
and keep the engine revs low and around the engine's peak torque band. If you booted it flat out from a standing start, the transmission would
allow the engine to achieve max power rpm and then load the engine without pulling the revs down by more than a preset level. (just like dialling in
the load on an electrical engine dyno) This would give the fastest acceleration possible, much quicker than a manual 'box could ever
achieve!!
The possibilities are endless. Torotrak has a patented system to fit to off road vehicles where you switch over to another driving mode (called Total
Off-Road Control) and take your feet of the pedals. You dial in the desired speed on control on the dash and the vehicle drives at that speed! Uphill,
downhill, makes no odds, using the computer control of the engine and gearbox together, uphill is easy, but downhill the computer can back off the
gearbox ratio to slow down the vehicle, right to a standstill, even driving with some reverse effort if wheels lock up! It can then engage reverse on
the same dash control and reverse back up the hill with no gearchange of loss of the flow of power.
ABSOLUTELY AMAZING is the only way to describe it!!
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britishtrident
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| posted on 6/5/04 at 06:31 PM |
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Which reminds me Austin fitted a fully variable belt less transmision in the 1920s ! --- of course it only lasted about 5 minutes in the hands of Joe
public.
I love automatics on cars with really big engines but find anything with a fully variable ratio system totally horrible to drive.
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NS Dev
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| posted on 6/5/04 at 06:41 PM |
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I thought that until I drove one (prototype) with non-belt type transmission and electronic control, then I was sold on the idea! Full engine braking
on lift off (more so than with manual) faster accelleration than a manual with no "slip", the whole experience just felt like driving a
very lightweight car where you get the feeling of the car instantly speeding up and slowing down in time with your right foot, with none of the usual
elastic feeling you get with even manual gearboxes. Just wear earplugs and don't look at the revcounter and it just feels like a bigger engined
car with no gears and direct drive!! Performance with this type of transmission on a big v8 engine is shattering!!
Sensitivity of the "throttle pedal" (which of course it isn't any more, just a faster/slower pedal!) is exponential from any given
point, i.e. at any point in the pedal's travel, a slight movement gives fine control i.e. good mid-corner control, and large sudden movement
gives huge response (great powerslides and fun!!!)
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Noodle
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| posted on 6/5/04 at 07:56 PM |
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quote:
Originally posted by stephen_gusterson
I used to like the princess / ambassador, but that would get similarly slagged.
We have a guy here at work who has an omega. Its his second as a company car, and hes gutted that its just gone obsolete cos he was just about to
order a third.
He recons he uses it cos he needs to get old people in the back and it has a lot of room.
Strange, most people want a snazzy car to entice younger ladies in the back
Cheap, rear-drive and huge in estate form. Great for a family motor. Does doughnuts in the snow with family on board. Ho hum.
Tell your old mate that the new one's out in 2006 and it's rear-drive too. (I think it's a Holden platform this time, rather than
the other way round)
They're doing a Corvette V8 version. And quite right too, although I don't suppose that's going to snap much geriatric knicker
elastic. Ugh. 
Cheers,
Neil.
[Edited on 6/5/04 by Noodle]
Your sort make me sick
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britishtrident
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| posted on 6/5/04 at 08:31 PM |
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quote:
Originally posted by JoelP
1996, heated back seats, less the £2k. find a similar car like that though?
And how many will need to be spent to keep it running -- Omegas are prone to expensive EMS faults and the rest.
1k will find a nice 96 Rover 620 or 623 --- ultra reliable, that will sail through MOTs year after year without spending a penny until the body rots.
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