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Author: Subject: BEC / CEC Performance Crossover Point
scootz

posted on 24/11/15 at 06:59 PM Reply With Quote
BEC / CEC Performance Crossover Point

(Very!) broadly speaking, where do folks think the performance crossover point is between BEC and CEC.

For a point of comparison take 2 notional cars that share similar chassis, suspension, steering, and braking components, but different drivetrains.

BEC
11.5k RPM limit
420kg
170hp
80ft-lbs

CEC
7.5k RPM limit
520kg
190bhp
160ft/lbs

The circuit has a good mix of straights and twists.

Which one do you choose and why... ???





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phelpsa

posted on 24/11/15 at 07:25 PM Reply With Quote
Bike engine, sequential box, weight is king. You'll need a lot more than 20bhp more to make up the 100kg deficit on the track.

In sprinting there are three types of powertrain that seem reasonably well matched across circuits. Breathed on CBR1000RR engine, 190bhp, 420kg. Breathed on busa engine, 220bhp, 450kg. Breathed on duratec + sequential, 270bhp, 520kg.

EDIT: bare in mind that's on slicks.

[Edited on 24-11-15 by phelpsa]

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adithorp

posted on 24/11/15 at 07:27 PM Reply With Quote
That's not going to be a contest... well not a fair one. At 100kg lighter the BEC will stop and corner quicker and at 440bhp/ton the cec would need another 45bhp to get near it on acceleration.
Mines 500-550kg with me and 170@ the wheels. CECs seem to need to be over 250bhp to stay with me and in the end their brakes and tyres will fade before mine.





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INDY BIRD

posted on 24/11/15 at 07:29 PM Reply With Quote
Well im in the lucky position where i have had both so can with confidence that they both have = and - points,

driven a few trackdays with bec an cec, and my cars being a with rover k series 185 bhp and a with zx10r 170 bhp,

The cec took over on the straights and would keep pulling when the bec would start to laps around 110 mph,

out of the corners the BEC was quicker to get the power down for sure, and under braking even with the extra weight i could brake later in the cec especially using the gears to slow down and not touch the brakes etc,

Overall i was quicker in the CEC on a lap, but there is not a lot in it, but the cec gave me more confidence than the BEC for some reason especially when the car got out of shape with the extra torque etc,

Thats not to say i dont like BEC i love them and i think most will steer towards them on track for good reason, and they are very quick, aslong as you do get the weight to 420 kg otherwise the cec will be all over the BEC like a rash,

summary

Straights CEC
Out of corners BEC
Top Speed CEC
Bracking CEC
corner speed BEC

Hmmm there pretty even really but ill wait for someone else to throw there hat in on this

Oh and i have been on track in the CEC and pushed BEC all the way and got past them, and they where busa zx9 and a R! just my opinion though,

[Edited on 24/11/15 by INDY BIRD]

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daniel mason

posted on 24/11/15 at 07:32 PM Reply With Quote
Of the 2 you've stated the bike powered car should be much much quicker!
I've regularly sprinted with the wscc guys and terry everall and tim nunn are faster than all but a couple of the CEC cars, and at some places faster (like 3 sisters)
Both have been in the 65's at Blyton park from a standing start (which was the same as I could manage in a radical!
But there's a few in higher powered cars like Adrian Clinton Watkins with the duratec race engine, the Bunn hodder Car with the blown type r motor, John Hoyle in the 2.1 c20 xe (ask Jeff w how fast he is) wh regularly beat the bec's at places like Blyton a and Anglesey.
Its a difficult one to answer and like you say it's driver dependant. The average driver would probably go quicker In the CEC but get someone like Tim nunn in a bike powered car and they are truly unbelievable!

[Edited on 24/11/15 by daniel mason]

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scootz

posted on 24/11/15 at 07:32 PM Reply With Quote
Cheers guys - just the sort of input I was hoping for.





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INDY BIRD

posted on 24/11/15 at 07:34 PM Reply With Quote
Agree with above average driver (like me ) its more a confidence thing i suppose and what suits your driving style as well,

And the proper sprint guys and racers will probably get the best out of the BEC for sure,

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daniel mason

posted on 24/11/15 at 07:44 PM Reply With Quote
Hi Shaun I was in no way insinuating you were an average driver, and was writing my original reply before I read any other responses so sorry if it came across that way.
What I was meaning is you really need to be 'on it ' in a bike powered car to get the best from it. A bit like this from 3 years ago
https://m.youtube.com/watch?v=k6nEykLHN0M

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INDY BIRD

posted on 24/11/15 at 08:12 PM Reply With Quote
No apology needed I am an average driver and it was with a smiley face, and i agree you need to be on it with a bec all the time to get the best from them, cec is a bit more forgiving for people like me a wanaby stig

hence the reason im going cec now is uppose it suits me better thats all,

thanks any way daniel but apology not required

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danny keenan

posted on 24/11/15 at 08:27 PM Reply With Quote
I think these video is a good comparison of BEC vs CEC.
My car is the black and yellow MK and the other three are 295bhp caterhams.

I would choose BEC all the time

https://m.youtube.com/watch?v=iWGTNzYinqk

Thanks Danny

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Andy D

posted on 24/11/15 at 08:53 PM Reply With Quote
quote:
Originally posted by danny keenan
I think these video is a good comparison of BEC vs CEC.
My car is the black and yellow MK and the other three are 295bhp caterhams.

I would choose BEC all the time

https://m.youtube.com/watch?v=iWGTNzYinqk

Thanks Danny


Car engine cars have stronger wishbones Danny?

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danny keenan

posted on 24/11/15 at 09:02 PM Reply With Quote
Andy just slowed for a lap to make sure everything was ok.i finished the race in 4th in front of the white Catherham which hit me
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INDY BIRD

posted on 24/11/15 at 09:02 PM Reply With Quote
Yeah Danny is one of the drivers that can for sure get the best out of the BEC, peddles it pretty well against some big bhp cars
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jeffw

posted on 24/11/15 at 09:09 PM Reply With Quote
At somewhere like Goodwood or Combe I'm big number of secs down the road from any of the BECs.

This is quite a good comparison




Start them together....!

Swings and roundabouts !

[Edited on 24/11/15 by jeffw]






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Andy D

posted on 24/11/15 at 09:10 PM Reply With Quote
quote:
Originally posted by danny keenan
Andy just slowed for a lap to make sure everything was ok.i finished the race in 4th in front of the white Catherham which hit me


Well done mate!
Although this is getting a bit off topic..
This is pretty nippy! I saw 158mph at one point, and he's definitely not "on it"
2.3 V6 bec?

https://www.youtube.com/watch?v=UiHZrm9_Y9w&feature=youtu.be



[Edited on 24/11/15 by Andy D]

[Edited on 24/11/15 by Andy D]

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adithorp

posted on 25/11/15 at 12:06 AM Reply With Quote
quote:
Originally posted by jeffw
At somewhere like Goodwood or Combe I'm big number of secs down the road from any of the BECs....



...Swings and roundabouts !

[Edited on 24/11/15 by jeffw]


But your car doesn't have just 20bhp more than the BEC as in the original Q.





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jeffw

posted on 25/11/15 at 06:10 AM Reply With Quote
Which was the point Adi....you need a lot more than 20HP to be infront of a BEC






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scutter

posted on 25/11/15 at 10:27 AM Reply With Quote
Nice discussion, could I add to it?

At what point do BEC's become too light? Assuming they have no aero package, has anyone experianced that they cannot push the tyres into the surface well enough.

This shouldn't effect me, not with a 3.0 V6 up front, just curious.

Regards Dan.





The less I worked, the more i liked it.

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jeffw

posted on 25/11/15 at 11:25 AM Reply With Quote
There are not many BECs under 400Kg (like there are very few CEC under 500Kg) so I doubt that it would be an issue. There are BEC engined single seaters which are under 300Kg but they have aero.






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mark chandler

posted on 25/11/15 at 05:22 PM Reply With Quote
How can they be to light unless you have negative aero?

Going around a bend the heavier the car the more force the tyres have to contend with so the more grip you need, weight works against you here.

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Sam_68

posted on 25/11/15 at 05:51 PM Reply With Quote
quote:
Originally posted by mark chandler
How can they be to light unless you have negative aero?


Damping limitations and sprung:unsprung weight ratio start to tell, in short.

Even with the lightest wheels, hubs and tyres, it's difficult to reduce unsprung corner weight below a certain point, and the inertia of that unsprung weight starts to become very difficult to control when you hit a bump, when there isn't so much inertia from the sprung weight to react it against.

As Jeff suggests, most race tracks are smooth enough for it not to be too much of an issue, even at the achievable minimum weights of BECs, but road use is a very different matter.

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scootz

posted on 26/11/15 at 11:10 AM Reply With Quote
quote:
Originally posted by Neville Jones
What are you contemplating now, Scott?



Ah, just wondering...

I've had an early 90's Caterham for some time now.

Raceline Zetec on Jenveys and Omex (200-ish bhp)
BGH Box
SPC Tracsport live-axle with Tran-x slipper and discs
Nitron Dampers
Alloy calipers

Thing is, I also have one of Andy Bates excellent 2008> Fireblade packages that's now surplus to requirements. He's marketing it for me, but I've been having (VERY!) tenuous thoughts about maybe putting it in the Cat and saving Andy some hassle.

I recall that the James Whiting Fireblade Cats had live-axles and could shift pretty rapidly with only 130bhp and 410kg. I can imagine that a newer 170bhp Blade engine (lighter still) would move the game on further.

I think JW still offers the driveline packages (Blade prop / reverse box, etc.) for around the 1.4k mark. I'd see good money back on the Zetec / BGH package, but I'm not sure I could live with a BEC for the days when I just want to pootle into work with my 7.

Like I said, very tenuous thoughts - the driving experience would have to be CONSIDERABLY improved to significantly move my interest in doing this further along.

I get that the Blade engines are the dogs-danglies on the race-track, but would they maintain that performance advantage when let loose on our pot-holed, greasy B-roads.





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sdh2903

posted on 26/11/15 at 12:12 PM Reply With Quote
quote:


I get that the Blade engines are the dogs-danglies on the race-track, but would they maintain that performance advantage when let loose on our pot-holed, greasy B-roads.


For that statement alone I would be sticking with the CEC setup.

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40inches

posted on 26/11/15 at 12:36 PM Reply With Quote
quote:
Originally posted by scootz
quote:
Originally posted by Neville Jones
What are you contemplating now, Scott?



Ah, just wondering...

I've had an early 90's Caterham for some time now.

Raceline Zetec on Jenveys and Omex (200-ish bhp)
BGH Box
SPC Tracsport live-axle with Tran-x slipper and discs
Nitron Dampers
Alloy calipers

Thing is, I also have one of Andy Bates excellent 2008> Fireblade packages that's now surplus to requirements. He's marketing it for me, but I've been having (VERY!) tenuous thoughts about maybe putting it in the Cat and saving Andy some hassle.

I recall that the James Whiting Fireblade Cats had live-axles and could shift pretty rapidly with only 130bhp and 410kg. I can imagine that a newer 170bhp Blade engine (lighter still) would move the game on further.

I think JW still offers the driveline packages (Blade prop / reverse box, etc.) for around the 1.4k mark. I'd see good money back on the Zetec / BGH package, but I'm not sure I could live with a BEC for the days when I just want to pootle into work with my 7.

Like I said, very tenuous thoughts - the driving experience would have to be CONSIDERABLY improved to significantly move my interest in doing this further along.

I get that the Blade engines are the dogs-danglies on the race-track, but would they maintain that performance advantage when let loose on our pot-holed, greasy B-roads.


I did 3000+ miles in my BEC, the only down side was hill starts, but you get used to that.
I found it very civilised, with fantastic sound track http://www.locostbuilders.co.uk/forum/23/viewthread.php?tid=194307

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femster87

posted on 26/11/15 at 01:05 PM Reply With Quote
quote:
Originally posted by scootz
quote:
Originally posted by Neville Jones
What are you contemplating now, Scott?



Ah, just wondering...

I've had an early 90's Caterham for some time now.

Raceline Zetec on Jenveys and Omex (200-ish bhp)
BGH Box
SPC Tracsport live-axle with Tran-x slipper and discs
Nitron Dampers
Alloy calipers

Thing is, I also have one of Andy Bates excellent 2008> Fireblade packages that's now surplus to requirements. He's marketing it for me, but I've been having (VERY!) tenuous thoughts about maybe putting it in the Cat and saving Andy some hassle.

I recall that the James Whiting Fireblade Cats had live-axles and could shift pretty rapidly with only 130bhp and 410kg. I can imagine that a newer 170bhp Blade engine (lighter still) would move the game on further.

I think JW still offers the driveline packages (Blade prop / reverse box, etc.) for around the 1.4k mark. I'd see good money back on the Zetec / BGH package, but I'm not sure I could live with a BEC for the days when I just want to pootle into work with my 7.

Like I said, very tenuous thoughts - the driving experience would have to be CONSIDERABLY improved to significantly move my interest in doing this further along.

I get that the Blade engines are the dogs-danglies on the race-track, but would they maintain that performance advantage when let loose on our pot-holed, greasy B-roads.


Send me your Zetec Setup ( for a good price though)

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