Aren't you all just SICK of these questions...?!

[stavroskebab]

Ok, so I've finally decided that perhaps a car-engined 7 is a better idea for me than a BEC. THEN I discover that a BEC can offer a far superior 0-60 time than a car engine of FAR GREATER BHP! How does this work then?
Am I a fool to ignore the obvious performance superiority of a BEC?! Brain overheating got to goooooooo.......

[Mutant Rat]

Usually a combination of:
1) Light weight
2) Very short gearing (ie. flat out, screaming at 12,000 revs at 110 mph).
3) Ultra-sticky 'track day' tyres.
4) Bullshit.

I'm not saying that properly built BEC's aren't capable of very quick acceleration, but it's easy for anyone to bung a Fireblade engine into their Locost and claim a 3.5 second 0-60 time. Talk is cheap...

[Jon Ison]

Heres part of this years RGB race report from Brands Hatch, RGB been road going bike engined cars, regs include

1) Road legal tryes
2) Engines straight out of bike with no mods
3) Capable of passing an MOT, 50% of the RGB cars are used on the road too.

And heres the clip form the report, make your own mind up as too how quick they are.

Before the RGBs went out the Roadsports Championship had their qualifying session. The Roadsports Championship is an eclectic mix of sports cars, including Nobles, Porsches, a Morgan +8, a TVR Tuscan etc. At the front of the grid the cars will be costing well in excess of £50,000, and yet the pole winner (Noble) wouldn’t have made the top three in RGB! Furthermore, the third quickest Roadsports runner in a Noble M12 would have qualified fifteenth in RGB!



This does illustrate just how quick the RGB cars are, and whilst no one will ever say motorsport is cheap, the RGB Championship does represent incredibly quick and competitive racing for the money.

[Mutant Rat]

I think this mainly proves how quick and competitive kit cars are. Hardly a fair comparison, though - and I think I'm in a reasonable position to take a balanced view on this, since I own both an ex-750MC Kit Car Championship racer (Sylva Phoenix) and a fast 'production' road car (TVR Griffith 500).

Sure, 400-500 kgs of lightweight spaceframe will lap a circuit quickly, but would you like to go touring to the South of France and back in it? Will it cruise comfortably on a motorway, or hit 170mph on an Autobahn? Will it provide adequate comfort and facilities to use all year round, including the trips to Tescos and the evenings out with your girlfriend in a her party dress, make-up and a £100 hairdo?

If you must make a comparison, at least make it like-for-like: bike engine kitcar vs. car engine kitcar.

Qualifying times for a couple of recent race meetings (selected because qualifying hopefully presents more consistent times than race conditions, with traffic etc.):

Cadwell Park 6th June
Car engined kitcars:
Fastest qualifying lap 1:07.94 @ 78.48mph
RGB kitcars
Fastest qualifying lap 1:05.78 @ 81.5 mph
Roadsports:
Fastest qualifying lap 1:09.16 @ 77.09 mph
(Porsche 993)

Donington May 14/15th
Car engined kitcars:
Fastest qualifying lap 1:22.06@ 85.87 mph
RGB kitcars
Fastest qualifying lap 1:17.44 @ 90.99 mph
Roadsports:
Fastest qualifying lap 1:17.67 @ 90.72 mph
(Noble )

I wouldn't dispute that BEC's are quick, but there isn't the night-and-day difference that some BEC enthusiasts would have you believe. And there is a price to pay, in the form of the need for manic revs and stupidly short gearing to exploit the performance. It can be a bit embarrassing when that diesel hot hatch that you blasted past on the slip road cruises effortlessly past you half a mile later as you bounce off your rev limiter at 110mph!

>> Edited by Mutant Rat on Sunday 21st August 22:25

[andygtt]

bike engines develope the power using revs so do not have huge torque that spins the wheels and instead go very fast.

[Jon Ison]

Been too le-mans two up, camping gear the works in a BEC, its horses for corses, I was fine with it,others may not be, geard for 132 in top on limiter wich puts it 7k ish revs at road legal speeds, there not for everyone, live n let live eh ?

The times you posted above makes your argument in 4 above fall down though, and lets go £ for £ too how much does it cost to get 350bhp/ton in a car engined kit ? oh not forgeting the 6 speed suquentional box too that you get for free, how much is a 6 speed sequentional gear set from quife (scuse speeling)


I will be the 1st too admit over 120-130 BECS hit a brick wall, but for road use I think been capable of 130 and sub 4 secs to 60 is quick enough.


horses for courses, BECS are quick, under estimate them at your peril on A & B roads.

[stavroskebab]

Cheers guys.... some food for thought. Actually, all this confusion started when I took a lot at the tech specs for the Westfields on parkers.co.uk. This was my first chance to see independant stats comparing bike and car engined cars times in relation to their BHP. A 126BHP Megablade out sprinting a 200BHP V8? Eh?

[wob]

stavroskebab said:

Cheers guys.... some food for thought. Actually, all this confusion started when I took a lot at the tech specs for the Westfields on parkers.co.uk. This was my first chance to see independant stats comparing bike and car engined cars times in relation to their BHP. A 126BHP Megablade out sprinting a 200BHP V8? Eh?

See the above regarding gearing etc, plus the simple fact that a bike engine (& integrated gearbox) weighs a hell of a lot less than a V8 plus gearbox. There's a lot more to it than BHP...

Add to that the fact that many BEC builders are religious about low weight - take mine, it has no bodywork, seats, or, er, engine... erm that's actually because it's just been a rolling chassis for the past couple of years whilst I did another degree- I'll get me coat...

[dern]

Having been in a passenger in a zetec westy (justin's) and a carb'd blade powered car (can't remember what it was now - like a full curvy bodied 7) and owned a 1700 xflow westfield the bec felt *substantially quicker than either of the cecs and that blade engine is particularly powerful.

I'm building an r1 powered car.

Mark

[Mutant Rat]

Jon Ison said:

Been too le-mans two up, camping gear the works in a BEC, its horses for corses, I was fine with it,others may not be, geard for 132 in top on limiter wich puts it 7k ish revs at road legal speeds, there not for everyone, live n let live eh ?

I'm all in favour of live-and-let-live! The problem is that all fanatics, be they BEC enthusiasts, Environmentalists, or religious types, are so stong in their belief that they can overlook glaring shortcomings at times...not helpful for someone like Stavros, wanting a balanced, impartial view.

Jon Ison said:

The times you posted above makes your argument in 4 above fall down though

My argument was that the difference in acceleration between a BEC and a car engined kit isn't quite as dramatic as the fanatics would have you believe. By my rough reckoning, on the basis of the figures I gave, a BEC will lap a circuit about 3% faster than an equivalent car engined kit. Assuming, logically, that part of this advantage will come from better handling (lighter weight), part from better braking (lighter weight again) then acceleration is only responsible for a small part of a 3% overall increase in performance. These are real, unarguable figures, not subjective hype, and it's difficult to see an earthshattering advantage.

BECs can feel much faster, when in reality they are perhaps only a little faster, because of the manic fury of the engine noise. Your senses are being tricked, in just the same way that sitting close to the ground in an open car will feel much faster than sitting in sound-insulated comfort in a Bentley Continental GT.

Jon Ison said:

...and lets go £ for £ too how much does it cost to get 350bhp/ton in a car engined kit ?

Sorry, I don't buy the 'BEC kits are cheaper than car engine kits argument'. It falls down in the same way that all cheap racing Formulae fall down...as soon as they catch on, people who have the cash available will start spending it in a quest for the last tiny performance advantage. It all tends to even out in the end.

For the record, my Sylva has circa a mere 320 bhp per ton and whilst probably not capable of being a front runner these days (Crossflow engine!) still shouldn't embarass itself in a 750 Club race. I paid £4K for it, race ready. Even doggy looking Locosts seem to be asking £6K upwards with a Fireblade engine?

Jon Ison said:

oh not forgeting the 6 speed suquentional box too that you get for free, how much is a 6 speed sequentional gear set from quife (scuse speeling)

Again, you have to recognise that there is a downside as wall as an upside. Sequentials are great on a circuit, or for manic 10/10ths thrashing down country lanes, but any dog box is clonky and chattery at low speed and requires more concentration to make sure you are in the right gear at the right time - no switching straight from 6th to 2nd, when you suddenly find that the corner is a lot sharper than you thought it was or that you are right on top of a T-junction that you thought was a hundred yards further on! Not to mention the fact that the 'free' 6-speed probably won't be so appealing if you are doing reasonable annual mileage and are having to rebuild it every couple of years 'cos you've knocked the dogs off!

Regardless of whether they are sequential or not, I don't run dog boxes on road cars for a reason - not because they are too expensive, but because they are a pain in the arse!

Jon Ison said:

I will be the 1st too admit over 120-130 BECS hit a brick wall, but for road use I think been capable of 130 and sub 4 secs to 60 is quick enough. horses for courses, BECS are quick, under estimate them at your peril on A & B roads.

Sure, BECs are quick, no-one would deny that. But I spend a fair bit of my time these days sitting on motorways at a three figure cruising speed, on my way to somewhere more interesting. A car engined Seven/spyder isn't ideal, but at least it's tolerable. The TVR is much slower than either a BEC or a car engined Seven on the B-roads, but is relaxed enough to make a 250 mile round trip to the Cotswolds and back up through the Malverns something to look forward to (I can even hear and walk properly afterwards, too!). Alternating between 10K revs on the clear bits and clonking up and down a sequential dog box in the congestion past Birmingham on the M42 sounds an awful lot like my idea of hell...

BECs are great for track use and focused, 50 mile sprints down country lanes early on a Sunday morning, but the performance advantage isn't substantial enough to outweigh the disadvantages in a lot of other situations.

But we've drifted way off topic...

stavroskebab said:

am I a fool to ignore the obvious performance superiority of a BEC?

I'd say no...you aren't a fool, because the performance advantage isn't quite as obvious and dramatic as the hype makes out (circa 3% on the track, judging by current racing lap times, probably less in real-world road use) and has to be weighed against some disadvantages that might be pretty significant, depending upon the use you have in mind for your car.

As Jon says, it's horses for courses...depends how much of your time you plan to spend running the Grand National!

[busa_rush]

Mutant Rat said:

Sure, 400-500 kgs of lightweight spaceframe will lap a circuit quickly, but would you like to go touring to the South of France and back in it? Will it cruise comfortably on a motorway, or hit 170mph on an Autobahn? Will it provide adequate comfort and facilities to use all year round, including the trips to Tescos and the evenings out with your girlfriend in a her party dress, make-up and a £100 hairdo?

No one car will do all those things well, a BEC is simply the best, most focused design to achieve cheap, high speed action with geat handling, fantastic acceleration and that raw, race car feeling. For that they are unbeatable. The rest depends on how much you like your speed.

Cruising isn't a sports car thing, it's a cruising car thing and a good cruising car by definition won't be a good track car, just buy the car that suits your most frequent activity. Mine is acceleration - that gives me a real buzz and I don't care if the Golf TDi finally gets past me half a mile later, he's only got radio 2 to entertain him, I've got 11,000 rpm of a manic screaming Suzuki work of art to keep me ammused

[theconrodkid]

i had the honour of being passenger with jon ison on a trip to le mans,i have been round donny in another BEC,the bec,s are certanly faster round the track and on the run to le mans was no more tiring than my car engined 7.
if it wasnt for the lack of reverse i would definatley have a bike engine.
best thing is to have a go in both types and make your own mind up.

[Mutant Rat]

busa_rush said:

Mutant Rat said: Sure, 400-500 kgs of lightweight spaceframe will lap a circuit quickly, but would you like to go touring to the South of France and back in it? Will it cruise comfortably on a motorway, or hit 170mph on an Autobahn? Will it provide adequate comfort and facilities to use all year round, including the trips to Tescos and the evenings out with your girlfriend in a her party dress, make-up and a £100 hairdo? No one car will do all those things well

On the contrary...check the lap times on the 750 MC races again! A Porsche 911 or Noble M400 will give very similar acceleration and lap times to a BEC kit, yet be fairly civilised and practical on the road and have a much higher top speed. Modern Lamborghini's and Ferraris will, too, and the latest generation of TVR's won't be far behind.

You'll just have to pay a little extra!

Of course, if we are talking about performance:£££, the things we're discussing have way too many wheels...if any of our biker friends stumble across this thread, they'll be wetting themselves!

[Jon Ison]

Can i throw a huge spanner in the works.......

given the right road a bike wont get near a BEC proven fact.

given the right road a BEC wont get near a bike, proven fact.

Most bikers ive come across dont wet themselves, they often pull up and want a closer look, you play, they play, pull up, banter..... respect.

look, BECs are fun cars, no good for shopping, no good for rainy days ect..... cruising @ 130+, we know all these things, but what they do do well is nip up n down A+B roads pretty bloody quickly, I dont see anyone preaching there a great daily runabout, but come on, where for £5k or less can you buy such summer fun and performance, we havent all got unlimited budgets, for nothing beats on a summers day standing on the brakes, knocking it down 4 gears and pulling out the other side like a train too 3 figure speeds leaving almost anything in your wake, ok after this its game over, Ferrari, Newark, back lanes, blew him too bits, dual carridgeway, waved him by, he was coming by anyway.....

Now then, why where bike engines banned from a 1700cc kit car class, running the same weight ?? was it beacuase jo bloggs 1700cc £5k screaming x flow was been put too shame by a £500 bike engine ? (zx9 just gone on ebay for £250) or was it some other reason ??


come on man, give me your TVR anyday in winter, but leave it in tha garage in summer and get a real car............

[Mutant Rat]

Jon Ison said:

Now then, why where bike engines banned from a 1700cc kit car class, running the same weight ?? was it beacuase jo bloggs 1700cc £5k screaming x flow was been put too shame by a £500 bike engine ? (zx9 just gone on ebay for £250) or was it some other reason ?? come on man, give me your TVR anyday in winter, but leave it in tha garage in summer and get a real car............

Since when was there any weight limit in the 750 Club championship?

And, yet again, you're comparing like-with-not-even-slightly similar.

Tell you what, I'll admit the absolute superiority of BECs if you can lap any British circuit of your choice faster in a bike engined car than I can in my Crossflow engined one...just one condition - the bike engine has to have been designed in the same year that the Crossflow was!

Anyone know where Jon can get hold of a second-hand Norton Commando?

Incedentally...you really wouldn't want to drive a TVR in winter. You're better off sticking to something with a bit less torque. Seriously.

[Jon Ison]

so there's no minimum weight limit including driver in 750mc club racing class's ???


like for like ????

kit car = kit car ?????


130bhp xflow = 130 bhp bike engine ????

both cars same weight with driver ??? pretty much like for like too me ???


don't remember claiming all conquering superiority, remind me ???



>> Edited by Jon Ison on Monday 22 August 22:55

[Mutant Rat]

Jon Ison said:

so there's no minimum weight limit including driver in 750mc club racing class's ??? like for like ???? kit car = kit car ????? 130bhp xflow = 130 bhp bike engine ???? both cars same weight with driver ??? pretty much like for like too me ??? don't remember claiming all conquering superiority, remind me ???

There didn't used to be a weight limit in the kit car championship. Have they introduced one these days, then? Sorry...haven't been on the scene for a while, other than as a spectator.

Kit car = kit car
1960's engine vs 1960's engine, or failing that, same level of engine technology...2 valves per cylinder, pushrod single cam, all cast iron, if you want to match the Crossflow.

Let's be honest, the Crossflow hasn't been considered competitive in motorsport since the early 1980's, so it's hardly fair to be using it as a benchmark against current bike engine technology, now, is it? It was only used in the kit car championship because the rules originally banned anything with more than 2 valves per cylinder!

>> Edited by Mutant Rat on Monday 22 August 23:10

[Jon Ison]

yup, there is a minimum weight limit, (including driver)

yup the x flow is dated, but i was thinking more 130 bhp x flow v 130 bhp bike engine in the same car weighing the same minimum weight.

bike engines where banned from kit car series that used the K series too.

Now i must go and check my car weighs 480kgs before Silverstone this weekend, yup I'm a fat ba@@##d and weigh in at 100kgs.

And yup, go and check the results, only 3 starts this year with 2 dnf's and a 10th at Mallory if i remember correctly, but when you fund it all yourself out of the old sky rocket you have too do it for fun alone with zero glory, 1st season back after writing last one off at Cadwell 3 years ago


Truce ??? horses and course and all that.......

[Jon Ison]

I assume you would prefer this type of bodywork though, not so damage ???

[Mutant Rat]

Jon Ison said:

yup, there is a minimum weight limit, (including driver) yup the x flow is dated, but i was thinking more 130 bhp x flow v 130 bhp bike engine in the same car weighing the same minimum weight. bike engines where banned from kit car series that used the K series too. Now i must go and check my car weighs 480kgs before Silverstone this weekend, yup I'm a fat ba@@##d and weigh in at 100kgs. And yup, go and check the results, only 3 starts this year with 2 dnf's and a 10th at Mallory if i remember correctly, but when you fund it all yourself out of the old sky rocket you have too do it for fun alone with zero glory, 1st season back after writing last one off at Cadwell 3 years ago Truce ??? horses and course and all that....... /[pic]www.locostbuilders.co.uk/upload/resizeofdscf0127.jpg [pic/] >> Edited by Jon Ison on Monday 22 August 23:27

Just checked the regs...looks as if I'd be forced to go the RGB route anyway! RGB is a minimum weight including driver, whereas car engined is a minimum weight plus driver. Like you, I'm a 15 stone fat ba@@##d these days, so my only hope would be an ultra-light RGB and hope that some of these seven stone weaklings have to carry a bit of ballast!

130bhp Crossflow vs. a 130bhp bike engine in identical chassis and running identical weights would be an interesting excercise.

Leaving aside driver skill, my money would be on the Crossflow if there were no gearbox restrictions, but that's because the match would be unfairly biased against the bike engine. 130 brake is quite modest for a Crossflow, so the temptation would be to build an 1800cc engine tuned for high torque. Without the weight advantage, I think the BEC might struggle...but then fair's fair cuts both ways - I don't think it would be right to handicap the BEC by taking away its natural advantage of lower weight.

Truce, indeed!

Livened up the kit car forum a little, this evening, anyway!

Good luck for Silverstone!