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I'm a bit concerned...
David Jenkins - 23/6/04 at 08:06 AM

...by the large numbers of drivers who seem to be stuffing their bike-engined Locosts into the scenery! There have been quite a number recently, but no-one's reported lately that they've put a car-engined car into the hedge.

Is it just the phenomenal acceleration in a light car, or is there a fundamental design issue that's making them very hard to drive? For example, tyres that are too wide for the light-weight car? Or is it purely inexperience?

If the insurance companies latch onto this trend there'll be a "premium adjustment" in the coming months for the bike engined cars...



David

[Edited on 23/6/04 by David Jenkins]

Terrapin_racing - 23/6/04 at 08:38 AM

A number of incidences I have read about were due to the drivers unfamiliarity with the power curve of the bike engine - now fitted to there car. One guy was happily accelerating around a bend when the motor came on cam and he did a pirouette act writing the front end off!
This was his first run in the car

ned - 23/6/04 at 08:42 AM

i'd tend ot agree with terrapin man..

a bike engine is revvy and the engine accelerates quickly thorugh the rev band. most of hte accidents i've come accross have been people getting it round half way round or out of a bend.

most people know what to expect from a car engine, the engine doesn't accelerate as quickly normally but has more torque and possibly a better torque/power curve than a bike engine. so perhaps a combination of experience and engine type would be my guess...

Ned.

Terrapin_racing - 23/6/04 at 08:48 AM

Makes me ask the question - how many bike engined builders have ever had a bike? I know loads of guys (but generally in motorsport) who have bike motored cars but hae never ridden a bike!
Maybe thats why a few come off so badly at first??

locoboy - 23/6/04 at 10:40 AM

as a first time bec builder I too am a bit concerned by this I think the recent reports should serve as a warning that these cars are probably as far removed as can be from a normal car driving experience and should be shown the respect they deserve.

I for one will be taking it steady in my CBR 1000 car ...............well round the bends anyway

Isnt it the case that those most recently to stuff it in the scenery are people who have bought the cars not built them? Maybe there is a bit of car self preservation in every builder which limits the number of risks they take..............................there is after all a lot of blood sweat and tears involved in each and every home built car out there.

ned - 23/6/04 at 11:00 AM

col, i believe you're right. i also heard that insurance is cheaper if you built the car yourself, you're less likely to bend it as you know how much effort was put into making it! its the people that buy cars other people have made that end up bending them quite quick it would appear.

those that bend cars they made themselves are probably more likely to fix them themselves too and not let on to an insurance company if they can get away with it! whereas those thaat just bought the cars wouldnb't know where to start, so settle with the insurance company instead.

Ned.

spunky - 23/6/04 at 11:23 AM

My insurance policy is for parts cost only in the event of a claim, no lobour costs are covered.

Has anyone had a BEC on a rolling road.
I'm very interested to know what the rearwheel torque figure is. The diff and smaller weels will all act as torque multipliers. I have a feeling the figures could be surprising. Maybe some of the racer members know the maths involved...

John

Jasper - 23/6/04 at 11:24 AM

I would agree, you have to treat these cars with a lot of respect, I was driving home in the wet last Sunday, and just putting the pedal half way down on a straight lit the back wheels up.

It's more like driving a true race car - progressive acceleration out of a corner, always break in a straight line, be smooth and flowing when driving.

Though I would also add these cars do - on the whole - break away at the back end quite predictably. I think what happens to most people mid bend is lift off overstear, go in a little bit strong, get scared, lift of the accelerator too fast, and the back end comes round. This is far less predictable and snappy than regular oversteer.

I would suggest that EVERYBODY who has never driven a seven (esp BEC) or the like b4 goes on a track trainig day b4 going on the road, it really gives you a good bit of practice in handling the car.

And I also don't think that many people realise just how quick these cars are. I was following Hicost down a piece of straight, dry dual carriageway on Sunday, we came out of a roundabout and he completely floored it (I could here the dump valve through ear-plugs, crash helmet, and my exhaust!). I went for it too and he couldn't shake me off, that's +400bhp cossie against 140bhp ZX9 - BTW he came up with some lame excuse abou the roof slowing him down

And yes, I would also agree that if you built it, you get use to it and you tend to drive it slowly at first incase anything falls off!

locoboy - 23/6/04 at 11:24 AM

agreed, i guess the moral of the story is build it and dont bend it!

pbura - 23/6/04 at 12:17 PM

I wonder if BECs could use a bit more roll stiffness in front to induce a little initial understeer at the limit. Not like a plowing Detroit monster, but just enough to allow the driver to make a decision whether to back off or to intentionally break the back loose.

David Jenkins - 23/6/04 at 12:39 PM

Would narrower front wheels have a similar effect?

DJ

greggors84 - 23/6/04 at 01:22 PM

Wouldnt you want less roll stiffness at the front to induce understeer?

pbura - 23/6/04 at 02:48 PM

quote:
Originally posted by greggors84
Wouldnt you want less roll stiffness at the front to induce understeer?


I believe that the problem may be that the BECs have less weight at the front than a book car, making the rear want to break away sooner than the front. To compensate, less grip would be wanted at the front (or more at the rear).

David J has made an excellent point in that this could be done with the tires: they could be narrower (or the backs wider), more tire pressure could be used, or a less grippy compound.

The other way would be to increase roll stiffness at the front. This puts more load on the outside tire so it doesn't grip as well.

It seems sort of a waste to give up cornering power at the front, so probably the best course would be to make sure everything has been done to maximize rear grip first. Second choice (IMO!) would be to alter roll stiffness because this would reduce the overall roll angle of the car, giving a little more help to the rear.

David Jenkins - 24/6/04 at 07:08 AM

I was giving this some thought last night, as I was sitting on my (delayed ) train...

How many people building ANY Locost has had much experience in driving rear-wheel-drive cars? Being an old fart I had a driving license for 7 or 8 years before I drove a FWD car (apart from the odd trip in a mini), so all my 'foundation skills' were learnt in an assortment of RWD cars. The last commonly available RWD car with no driver aids was probably the Sierra (I'm excluding the BMWs, as they've never been 'cars for the masses' and use gadgetry to keep you on the road).

There are certain RWD skills you just HAVE to learn if you want to commit your life to a fast corner, such as getting the speed right before you turn in, not upsetting the balance of the car in the middle of the corner (e.g. by lifting off, braking or changing gear), and powering smoothly through the turn. FWD cars have a totally different technique - when I did a day out at Silverstone I found it difficult to change gear mid-turn in a Pug 306 GTi...it went against all my previous experience!

I wonder how many of these bike-engined accidents are caused by lack of RWD experience combined with the 'coming on cam' surge that you get with these engines.

Maybe there isn't a basic design flaw with the BEC cars after all - just a need for new drivers to build up their RWD skills before they hit the pedal hard.

Just a thought - a.k.a. 'ramblings' - better get ready for work now...

David

theconrodkid - 24/6/04 at 08:47 AM

think you should do a bit of karting,that teaches you how to get out of trouble,i had a couple of BMW 3 series,had to treat them with respect in the wet

Jasper - 24/6/04 at 08:53 AM

David - nail on the head time, that's why I went and had tuition and did track days b4 I started larging it on the road. I'd never had a RWD car before - or at least not one that I drove fast. Totally different driving experience - my wife will also agree with this, totalled my 525 BMW (diesel estate) in the wet on a bend 4 months after passing her test and only ever driving FWD.

I think the BEC's just accentuate and existing problem - loads of power, lightweight car, RWD.

Mk-Ninja - 24/6/04 at 09:16 AM

Must admit Im driving mine very cautiously at present not knowing where the limits are, and I have driven loads of RWD cars in the past.
Im looking forward to a couple of track days and I guess it would help if one of them was a bit damp to get a feel without loads of grip.

Gordon

David Jenkins - 24/6/04 at 09:48 AM

quote:
Originally posted by theconrodkid
think you should do a bit of karting,that teaches you how to get out of trouble


That makes a lot of sense.

I'd love to have a go - but there's only the commercial 'works outing' type places near where I live. Don't know if they would let me just go and drive around for an hour without being involved in a group. I don't want to race - just play silly beggars for a while!

Might give them a ring, though...

David

[Edited on 24/6/04 by David Jenkins]

Alez - 24/6/04 at 09:58 AM

This is the formula that made me crash:

RWD +
big BPH / ton +
inexperience_with_ (RWD + big BPH / ton)

No more, no less. Everytime I drove the car I was feeling so safe and able of controlling the situation (sideways roundabouts LOOKED like fun ) that I'd push limits slowly but steadily. I had never driven something so powerful yet so stable and noble. What I had yet to learn is that when you lose your front end in one of these you cannot back up, it's just game over!

The reason why people crash these and not car engined Locosts is because of the huge BPH / ton factor, not many car engined cars you can compare to around, there are many more BECs than turbo Cosworths around!

To sum up, after my "experience" I TOTALLY agree with Jasper and also I must admit I'm a complete dumbass!


[Edited on 24/6/04 by Alez]

David Jenkins - 24/6/04 at 10:07 AM

quote:
Originally posted by Alez
To sum up, after my "experience" I TOTALLY agree with Jasper and also I must admit I'm a complete dumbass!


Alez, you'd better get some practice and training before you get too excited by the new car...

David

[Edited on 24/6/04 by David Jenkins]

[Edited on 24/6/04 by David Jenkins]

blueshift - 24/6/04 at 01:13 PM

I keep nearly crashing my mx5, good practise for not crashing the locost when it's finished.. I hope.

not going to be a BEC but 220lbft from the v8 will demand enough respect.

David Jenkins - 24/6/04 at 04:02 PM

quote:
Originally posted by Syd Bridge
Has anyone considered that with a lightweight bec, the tyres need to be a good deal narrower than a heavier auto engined car?


Never mind BECs! I've fitted Yoko 185/70 x 13" partly because I think they suit the car, but also because that's what Caterham use on their cheapest models - and whatever you think of Caterhams in many other respects, they do handle amazingly well!

I also expect them to be a lot more forgiving when making stupid mistakes - to let go more progressively than big fat sticky tyres.

(That's what I hope, anyway...)

David

pbura - 25/6/04 at 03:01 AM

quote:
Originally posted by Syd Bridge
Trust the seppo brain bank...


Geez, Syd, keep going on like this, and no one will know that you can be a very nice guy!!

OK, next time you're out hobnobbing with the goober-smoochers, why don't you pose this question to your idols:

"Car 1 has a 650/650 front to rear weight distribution, and Car 2's is 450/650. How should Car 2 be set up differently than Car 1?"

They may mutter in their salads about Newton, but chances are they'll come up with bigger tires in the back and/or a heavier anti-roll bar in the front.

And WTF's wrong about that?

spunky - 25/6/04 at 08:53 AM

Syd.
Not wishing to 'blow feathers up yer arse'
to use a roughneck phrase. But I watch your posts with interest and have to say that you and a selection of other members do appear to post from genuine knowledge/exerience.
So a question....
Am I asking for trouble...
Mid engine with a front axle weight of 220Kg. 195/60/ tyres on 14" rims.
Softly sprung with softish damping.
Weight distribution 60/40 back to front without driver?

Just curious on your take before I push the car into a Lincolnshire dyke...

John

gys - 25/6/04 at 08:56 AM

quote:
Originally posted by Syd Bridge
Also, if the builders on this site spoke to the tyre manufacturers and asked for their recommendations, you would be surprised at what came back. The widths suggested would be far narrower than most are currently running.

You obviously did, and what did they recommend you? Based on a car with...

pbura - 25/6/04 at 12:52 PM

Syd,

You've missed the mark with your speculation about my sexual orientation, Syd Father of four children and stepfather of two more, and I don't even belong to a club where I could shower-peek Not that there's anything wrong with that

I'd rather have a discussion than a slagging match anyway. For the record, I don't make any pretension of expertise in car design; I've just been reading and thinking. and trying to relate to my own (limited) experience. So that's where I'm coming from. I'm entirely open to learning.

When I said "bigger tires on the rear", I meant comparatively bigger, same as Mr. Jenkins, whom you've not yet called a wanker, or questioned his masculinity Tire selection would be the #1 consideration, BTW, though it wasn't my first thought. I don't advocate big, low-profile tires on a 7, either, mainly because of weight and aqua-planing, so I don't know where you got that facet of your argument.

I also agree with you that springing should be lighter on a lighter car.

Really don't know why you stick at anti-roll bars, Syd. Seems like a legitimate next step in balancing a car (if a next step is needed). Could you explain why not? BTW, I acknowledge that ARBs are going to act like a road spring on a one-wheel bump, so should be used sparingly.

I may have misjudged the front/rear weight distribution of a BEC, but it was just for discussion purposes. What are the correct figures?

Pete

P.S. I have a busy day and weekend coming up, so may not be able to trade barbs until Monday.

David Jenkins - 25/6/04 at 01:06 PM

quote:
Originally posted by pbura
When I said "bigger tires on the rear", I meant comparatively bigger, same as Mr. Jenkins, whom you've not yet called a wanker, or questioned his masculinity


What I wear or do in my spare time is entirely my own concern... and anyway, it was a misunderstanding, anyone could have made the same mistake, I thought the curtains were closed...

David

pbura - 25/6/04 at 01:15 PM

quote:
Originally posted by David Jenkins
quote:
Originally posted by pbura
... I meant comparatively bigger, same as Mr. Jenkins...


... I thought the curtains were closed...


I have an alibi!!!!!!

Peteff - 25/6/04 at 01:18 PM

I run 165/65x13's on standard Sierra 5.5"x13" rims. They look a bit narrow on the rear and don't fill the arches but they are new tyres and I'm too mean to replace them. They still grip well and if they do let go I can catch it before it gets too far out of hand. I would put a lot down to tyres and rims designed for heavy cars being used inappropriately and breaking away earlier due to the lighter weight. Stickier tyres would be the obvious answer to my thinking.

JoelP - 25/6/04 at 01:57 PM

jeez, reading this thread you would think my car's going to be like a spinning top! it has the worst of everything suggested so far: 14s with smallish tyres at the front, standard sierra steels at the back (to be replaced with the 14s when 2 pairs or original tyres are worn out), too stiff at the front, too soft at the back, too much camber at the back, an almost rear weight bias, and a clown at the wheel! and no LSD...

this is going to be more fun than i'd anticipated!!

mackie - 25/6/04 at 02:50 PM

I plan to treat our car with plenty of respect, especially with all that torque.
I think we plan to make it a softly sprung as possible and the will be running it on Sierra 14in alloys with 195/60 tyres front and rear. I think we may end up needing bigger tyres at the rear as suggested above.
Having read a little bit about suspension design we shall probably try and engineer a little toe in on the rear too.

ned - 28/6/04 at 08:57 AM

mackie,
i was thinking of adding some toe in on the rear on mine too, just a couple of spacers on the dedinon ears or something

Ned.

Mark Allanson - 28/6/04 at 07:46 PM

I came to Locosting after a long line of Bertone X19's, I still love the cars, I just got fed up with welding the damn thing every weekend.

I used to run 10mm of toe in at the rear (5-9mm as standard), it gave really balanced and predictable handling, oversteer so progressive I didn't even pause the converation with my passenger when the back stated to move.

The tyres were 165 70 13's, I did try 185 60 14's, but this ruined the car, made it dead and uninteresting, also made the back end a bit snappy.

gjn200 - 28/6/04 at 10:16 PM

quote:
Originally posted by Mark Allanson


I used to run 10mm of toe in at the rear (5-9mm as standard), it gave really balanced and predictable handling, oversteer so progressive I didn't even pause the converation with my passenger when the back stated to move.

The tyres were 165 70 13's, I did try 185 60 14's, but this ruined the car, made it dead and uninteresting, also made the back end a bit snappy.


Maybe, but you had the power of a wet fart

Mark Allanson - 29/6/04 at 06:19 AM

The first one had the standard 85BHP, the last had a Lancia HPE 2.0 fitted, it used to 'fart' on everything!

type r1 - 9/7/04 at 06:37 PM

dudes,

quote:
Originally posted by Terrapin_racing
A number of incidences I have read about were due to the drivers unfamiliarity with the power curve of the bike engine - now fitted to there car. One guy was happily accelerating around a bend when the motor came on cam and he did a pirouette act writing the front end off!
This was his first run in the car


is mr. terrapin referring to me?

if he is, allow me to set the record straight. (no offence taken and none meant).

first of all, i was not driving the car for the first time, it was the fourth time in this particular bec. i had already spent 5 - 6 hours driving this car, in various conditions and at various speeds. it is not the first bec i have driven, either, as i have also driven a fireblade-engined indy.

secondly, i was not accelerating around a bend. i was overtaking two cars (tin tops) that had just negotiated a 90 degree bend and which had slowed down to about 30 mph. i was driving in a straight line, no faster than 45 - 50 mph. there had been a couple of showers during my journey and the road was a little wet. i was not accelerating furiously, as i did not need to. overtaking two slowly moving vehicles on a mile long piece of straight road, with perfect visibility and with no other cars coming in the opposite direction, did not demand an overly zelous right foot.

i did not leave the road at a huge velocity, and if the field next to the road had been flat, the incident would have been no more severe than an excursion in to the kitty litter at a race track.

unfortunately, i happened to be driving past a field that had a ten foot dyke, running along the edge of the road. it was driving the car into the dyke that caused the damage to the front end.

i had a look at the road surface afterwards, as i couldn't figure out why the car had spun at all. i noticed that most of the tar had been worn away and i was basically driving on wet stone chippings that were protruding from the surface.

the other thing to remember is that the car had 17" rims with ultra low profile tyres, with very little give in the tyre wall, designed for a car weighing between 1000 and 1800 kg.

take a look at a toyo proxes t1-s and you will see that they are rated for a maximum weight of 450 kg each corner.

as the car i was driving was 480 kg total, you can see that they were an entirely unsuitable choice of tyre and wheel.

you need a higher tyre wall, 50 percent minimum, as the car is so light the tyres never reach operating temperatures, and a much softer compound, to enable the tyres to have any amount of adhesion.

the insurance assessor actually said that the tyres were unsuited to a car as light as this. he has seen kit cars running on 8 year old tyres that are hardly worn. the compound has completely gone off and the tyres are a great danger to the driver.

my advice is to use the softest compound you can afford, avon acb10s, yokohama a032r, yokohama a042r, and such like.

ultimately, of course i accept responsibility for the accident, but i do not believe that i was being reckless or immature (i'm 43 with 2 big teenage children), or that it was purely because of my inexperience. there were contributing factors that made what happened a lot easier to happen than it might, otherwise have been.

don't foget, this car had an lsd as well. all well and good under perfect operating conditions, but extremely unforgiving in the previously described scenario.

so, drive carefully peeps.

thanks again for all your well wishes.

i am more-or-less recovered from my injuries, just a slightly niggly rib and a that's about it.

take care,

kindest regards,

dom.

[Edited on 9/7/04 by type r1]

Jasper - 9/7/04 at 06:51 PM

Not sure that I agree that Toyo Proxy's don't reach temperature. I run 195/50/15's and often check how warm they are when I get home from a drive, and they are nearly always nice and warm and sticky.

A would agree that stickier is best of course, but you could be in as much trouble running the soft cut slicks like the Avons and Yoko's when it starts to rain and they can't shift the water out.

If they ain't hot enough, you ain't driving hard enough

BTW - Toyo have brought out a new range of sticky road legal tyres at a good price for the large wheel sizes.

Aloupol - 9/7/04 at 07:24 PM

quote:
Originally posted by type r1
is mr. terrapin referring to me?


No, with all these differences it must be somone else ;-)

David Jenkins - 9/7/04 at 09:12 PM

quote:
Originally posted by type r1
unfortunately, i happened to be driving past a field that had a ten foot dyke, running along the edge of the road. it was driving the car into the dyke that caused the damage to the front end.


I'd guess from your location that this was on the fens somewhere... I've driven past these ditches many times, between Ely and Bury St Edmunds - and often thought that I would NOT want to drive into one of them!

For anyone who's never seen them, imagine a nice flat country road with quite a severe camber. A foot or so after the tarmac runs out the grass curves down into a 10 foot deep ditch, often with 6 foot of icy water at the bottom. No crash barriers, walls, posts or anything like that.

Several times year people drive off the road and don't get found for a day or so....

David

[Edited on 9/7/04 by David Jenkins]

Terrapin_racing - 12/7/04 at 02:47 PM

Never heard of you Dom??

type r1 - 12/7/04 at 10:31 PM

mr terrapin,

cool.

who are you talking about, then?

dom.

Terrapin_racing - 13/7/04 at 09:41 AM

Better not say after your reaction ...