I've done some searching and haven't had this answered yet. Please forgive me if it's already been driven into the ground.

Performance wise how do the BECs match up? I can see a distinct handling advantage by virtue of lighter weights, but does the torque penalty override that? My car for instance may weigh a slightly porky 1400 lbs. (635 kg) but that's offset by 200 ft/lbs. of torque (Not sure how you brits measure this. Think not quite twice the stock busa output )

How about track results? Will a Fireblade or Busa keep up with the hotter offerings from Caterham, Donkevoort, et al?

Thanks for any response. Great site you have here.

edit: spelling

[Edited on 8/2/05 by kreb]

In my delightfully simplistic world of Engineering, I'd Phrase the Torque Vs BHP thing like this....

Bike engine = 100ft/Lbs
Car engine = 200ft/Lbs

But..... Bike engine is spinning twice as fast.... Therefore same Horsies.

IT's all a case or Revs and Gearing really.

BEC's tend to scream and wail around a track, (and need to be worked hard), but with a car engine you can happily burble around the roads.... but it just doesn't sound the same

hmm. said it was a simplistic view.

a BEC would show you a clean pair of heals on the track, on a long straight run things may differ, the busa BECS in the RGB get up too close on 150mph at Snetterton but thats about it (standard engines)

on a typical track day you can see the more powerfull cars catching you along the longest straights but they have to brake sooner so you dont see em again till next time around, there are exceptions but your talking "big" money engines. Another example is changing gear mid corner on full power without upsetting the car, difficult to do in a CEC.

$ for $ their in a legue of there own.

Speaking from a Caterham aspect, the guy who won this year's sprint championship, his name's Brodie, was running a Hayabusa powered dedion (heavier than live axle) Caterham - his car was about 435kg I think, and he had a slightly modded engine, c.180bhp. He's a fine driver but I'd still say his car is still very fast as a similar car was almost as quick but driven by a heavier driver - maybe there was 30kg or so all up weight difference.
In my opinion, once you go over the lower weights and start approaching around 500kg, the higher powered car engined cars start getting a big look in. There's a 290bhp Vauxhall engined Caterham that weighs under 500kg and that is VERY fast, although I don't think he ever beat Brodie at a sprint.
Whenever I saw Hayabusa engined cars on a track, I'd guess they were similar speeds to standard R500s - losing out slightly on the fastest tracks, possibly a bit faster on the very tight tracks.
I've heard Fireblade engined Caterhams can be under 400kg but they are not anywhere near as fast as their Hayabusa engined cousins. Infact, I'd say they were pretty mediocre on a fast track where they can't use their weight advantage as much as on a windy track - they basically just lack power. People say they are beautiful to drive, and I'm sure they are - they just seem a bit underpowered.
If you compare Caterhams to other sevenesque cars, I'd say you'd need a very highly developed car indeed to beat the fastest of the standard Caterhams - the R500 EVO (2.0 Metro engine with 250bhp and weighing about 480kg). Donkervort may have got that good Nurburgring time but that was taking 'production car' to the absolute limit of it's interpretation and the normal Donkervorts are not that fast.

So...in a nutshell, if you're doing a BEC and you want it to be fast(i.e. high cornering speed/good acceleration/braking), it MUST be very light to make up for it's power disadvantage over similar yet more powerful car engined cars.

That's very useful information.

How much do the full body kits change matters? I'm a particular fan of the Phoenix.

Also how about the middies? (such as the R1ot)

I ask these questions because I live where sevens are rare and BECs almost unheard of. Team Birkinsport took the regional NASA super unlimited class championship last year, shocking various NASCAR jalopies and the odd turbocharged Viper, but otherwise it's the sevenesque hinterlands here.

welcome Kreb, nice stalker...i like the color, is it gelcoat? where are you located? by mentioning NASCAR and vipers you may be located in the south, thats where i am. im probly going to end up doing a bec with a hayabusa, looking to start this summer most likely. ill let you know how it works out.

Thanks. That's the gelcoat, which I don't mind at all. Unfortunately there are a few minor imperfections which will need to be removed if I really want it detailed.

I'm in Oakland, CA. Within two hours of three great tracks: Infineon (Sears Point), Laguna Seca and Thunderhill. If it wan't so damn expensive to live here, life would be perfect.

Good luck on the Busa. That's sounding better and better to me too.

I would love to visit CA sometime, but i never have had a reason. from everything i have seen it looks like a beutiful place. to give you an idea of the acceleration of a busa powerd seven check out these two sites.
http://www.deman-motorsport.com/index.htm
http://www.super7cars.com/

they both do busa powered cars, the caterham site quotes 0-60 in 3.6 secs with weather equipment and street tires. the other site quotes their car at 3.48 0-60. any way you look at it, thats very quick. this is also with a stock engine presumably, you can allways add a supercharger or turbo. busas can make 500hp on the boost if your pockets deep enough.

[Edited on 8/2/05 by sean951]

Kreb,

I like your Stalker. Any chance of posting some decent (big) pictures of it.

Jon

yes, i would like to see some also

The pheonix and cars like it (eg: fisher fury) don't weigh a lot more than a seven. Therefore they don't loose out on handling, if at all. Their big advantage is the considerably better aerodynamics they offer as you start to get to about 80mph and above. In comparison a seven as the aerodynamics of a brick and struggle to get past 120mph or so. Therefore the top speed of a pheonix is a lot higher. Wish I could afford one!


Andy

from the 750mc site :-

RGB Caterham
Brands:- 51.76 52.19
Donnington:- 1.18.42 1.17.16
Mallory:- 49.4 49.96
Snetterton:- 1.15.68 1.15.78

RGB = Road legal bike engined car (standard bike engine max 180bhp)

Caterham = Mega £££$$$$££££


pound for pound not bad performence from a BEC.


Oh, nearly forgot, the minimum weight for a RGB that set the times above is 580kgs, so its no lightweight, take it down to 400kgs n watch it go.

[Edited on 9/2/05 by Jon Ison]

Thanks for the info. Here's a gallery with some pics of my car. There's also some fun renderings of a full body kit that a friend and I are working on.

http://www.smm.com/gallery/Berkeley-Choate-24?page=1




[Edited on 9/2/05 by kreb]

very nice bodywork.personaly i have allways wanted to see a full bodied seven coupe version. but i know the cost of windows and windscreen overcomplicates things, and adds $$$$$. i think i prefer the single oval opening at the front of the car as apposed to the tripple in the renderings. even if it is a bit played out(miata/elan). great work though, theres some good people on this list when you get around to making the bodywork. check out the midi section and seek out sgraber.

i hope you dont mind, i played around with one of your renders. this was quick, so dont pass jugdment. i was thinking something like this though, with a double bubble roof, for head clearance. and maybe some removable roof pannels like the new tvr.

You bloody butcher! How dare you touch my precious.... Just kidding

Yeah, the double bubble is a good look - like the Viper coupe.

The grille is just for fun - too close to the Nissan thing really.

As currently rendered, I'm sure that the thing will have front lift problems. We're going to design a bolt on "cowcatcher" skirt for high speed Applications.

Back to an earlier question: how do the mid-engined BECs stack up with the front-engine BECs? I'd think that they have the most potential of the variants, as the rearward weight bias would pay acceleration and braking dividends. - Not to mention weight, aerodynamics and polar moment?

edit: The Fischer Menace looks quite promising as middies go

[Edited on 9/2/05 by kreb]

I'd say a sub 450kg 130bhp BEC is about as quick as the average 550kg 170-180bhp Car Engine'd Caterfield, slightly quicker in the corners and under braking, maybe a smidge slower on the longer of the straights.
As Nick implied, its torque at the wheels that counts not at the engine, and because a BEC can rev much higher it can be geared lower, hence multiplying the engine torque more than a car engine'd transmission can manage (unless you want it to top out at 75mph!).
The mid engine'd cars will reap the same benefits as any other mid engine'd car, although the benefits when compared to a Caterfield probably isnt quite as marked as the weight distibution of a front engined car is very good anyway. The RGB series mentioned above has a weight penalty for mid engines, 50kgs I think (John, can you confirm?), so gives an idea of the potential gain if built to the same regs.

Pardon the bonehead questions, but when it comes to turboing a BEC, how will the engines hold up? On the surface I'd think that a bike would be perfect for a turbo from the perspective that you weren't really expecting any power for the first several thousand RPMs anyway, so lag wouldn't be nearly the issue that it would on a lower reving engine (think almost any car motor)

OTOH, I'd think that a bike engine is already pretty highly stressed. If you take say an R-1 engine and want to take it up to 250 HP are you going to destroy the thing unless you rebuild the internals? I guess the proper question is how much power will the stock internals handle on the common donors -Hayabusa, R-1, fireblade and CBR?

Thanks again!

(I haven't screwed with bikes since my old Maico in the early 80s.)

450bhp busa engines are not uncommon and reliable.

turbo bec?

http://www.situne.no/index.php?id=1014

imho a good 1.8/2ltr cec will beat a fireblade car, but a hyabusa can only be beaten by a good tuned 2ltr cec.

in our race series a 240bhp vauxhall 2ltr 16v car can beat a standard radical prosport and sr3 with hyabusa engines. A 250bhp powertec hyabusa had a run on a vauxhall 2ltr at rockingham but it blew up and they replced it with a standard one after that..

Ned.

[Edited on 10/3/05 by ned]