V8 or BEC

[nikpro]

Edd,

have you any experience of the seven type cars?

When you quoted that a high power duratec was an option what power were you thinking of?

What is wrong with the 190bhp of the standard Westfield duratec install?

BHP figures are for pub talk not speed - the difference in performance of a 200bhp and a 250bhp car isn't that big.

Top Gear did an excellent feature with James May & JYS where he shaved 20 seconds of his lap time around Oulton after some driving instruction.

Without any driving instruction I would hazzard a guess you would probably need to double your horsepower figures to gain this much time!

In summary; your decision should be IMHO whether to go for a BEC or a 4cylinder CEC - I would forget a V8 for mainly trackday use. (personally I don't think the V8 ethos sits well with a seven type car - buy a Cobra if you want a V8)

A standard Zetec 1800 or 2 ltr with circa 160hp and a small amount spent on some instruction will see you lapping much faster than a 250bhp duratec with thousands spent on an engine. The same arguement applies for a standard BEC.

Forget HP; it won't make you lap any quicker just give you a bigger pe**s in the pub talk.

[Phil. S]

Forget HP; it won't make you lap any quicker just give you a bigger pe**is in the pub talk.

So more BHP makes your pe**s bigger?! Now that's just going to encourage him  

[V 8]

personally I don't think the V8 ethos sits well with a seven type car - buy a Cobra if you want a V8)

Obviously never driven one

[Bazzer]

Bazzer & ChrisG are right about how the engine torque is usually pretty meaningless on it's own. You need to consider the engine, transmission ratio(s), diff ratio AND tyre diameter together, since the transmission (and diff+Tyre diameter) are a torque vs road speed exchanging device! For a given engine rpm (and engine torque) you can greatly increase the torque applied to the wheels (i.e. improved acceleration) by reducing the rpm of the wheels (compared to that of the engine rpm)  - which reduces the road speed. For any given rpm, the gear ratio of each of transmission gears (and the diff ratio) governs by how much the engine torque is increased at the wheels and by how much the engine rpm is reduced at the wheels (and by inference how much the road speed is reduced/limited too). Double your torque at the wheels by choosing a gear ratio which (in conjunction with your diff ratio and wheel diameter) halves your engine rpm. Edd BEC's have plenty of usable wheel torque!

The torque is the torque, and that's that. You are merely increasing it by lowering the gearing and increasing the revs. No matter what you do, a BEC will not pull from low revs like a V8

Thats more based on the shape of the torque curve rather than the peak numbers though. Torque multiplication is still important though as is the shape of the curve.

I think you would be very surprised just how tractable a Busa engine is low down. I agree the sub litre brigade are not so good low down.

As for on track performance, you have to agree your car is a little different from most V8 sevens. Most SEIGHTS I have seen on track have not been that fast.

Also I think (this is not aimed at you Tommo) there are a lot of optimistic power claims for rover V8 powered cars. I was into TVR a number of years ago and very few of the engines actualy made the power there owners were told they did. The standard head castings seem to be a limiting factor in how much power they can produce.

What would make the Rover V8 engine more attractive in a Seven type car, is a suitable lighter weight gearbox. I know the Engine is actualy quite light, but the gearbox's weigh a ton.

Cheers

Bazzer

[nikpro]

personally I don't think the V8 ethos sits well with a seven type car - buy a Cobra if you want a V8)

Obviously never driven one

I have and it was a lovley car to drive; I just don't think the low reving V8 engine with it's lazy power delivery suits the style of the car - this is an opinion and I realise everybody is different.

To me the seven type car is all about revs and thrashability; the bike engines suit it perfectly.

I went for a CEC because I have a 50% split between road and track and I was more worried about clutch control and durability with the BEC's than the torque.

Two BEC's I'd driven had a very light 'trigger' type clutch that i felt would be a bit of a pain in towns. (I do have the touch of a baby elephant though)

[V 8]

As for on track performance, you have to agree your car is a little different from most V8 sevens. Most SEIGHTS I have seen on track have not been that fast.

Also I think (this is not aimed at you Tommo) there are a lot of optimistic power claims for rover V8 powered cars. I was into TVR a number of years ago and very few of the engines actualy made the power there owners were told they did. The standard head castings seem to be a limiting factor in how much power they can produce.

What would make the Rover V8 engine more attractive in a Seven type car, is a suitable lighter weight gearbox. I know the Engine is actualy quite light, but the gearbox's weigh a ton.

Cheers

Bazzer

Totally agree m8, gearbox weighs a ton, and power can be an optimistic claim. Mine is *supposed* to be 400 hp, we'll see I guess.

My argument is simply that a BEC is by far and away the best economical & technical compromise for road & track. If I was just roading, V8 every time. If I was just tracking, my god the Flymo takes some beating, but you need a big wallet.

Lap record at anglesey and Curb is ian stinton in a V8. Tom held a few in the Flymo aswell.

Baz, I've seen you drive. Get in the Flymo & we'll probobly see what it can really do, instead of in the hands of an old fart like me!!  

Nick, Sorry m8, just don't agree.....JMHOT

[JeffC]

So more BHP makes your pe**s bigger?!

Mine is *supposed* to be 400 hp

horse alert

remind me not to stand beside you again in the netty              

[Bazzer]

My argument is simply that a BEC is by far and away the best economical & technical compromise for road & track. If I was just roading, V8 every time. If I was just tracking, my god the Flymo takes some beating, but you need a big wallet.

Yup I agree that BEC's are not the best for the road. I know some people really like them on the road. I just think the only thing its good for is going fast and you can't really do that on the road. So you have to put up with all the noise and vibration and not are not able to exploit its performance.

The other thing is that BEC's feel faster than the actualy are. I have been in some CEC's that are as fast as my Busa, but they don't feel it.

A Car engined 7 can be much more relaxing and you can enjoy the feel of it without feeling its laughing at you for going so slow.

I used to think that 7's did not make good road cars, but after test driving a lot "normal" sports cars this year I changed my mind. None of them came close in the feedback and driver apeal. Never driven a Elise though only passengered. So maybe that would be nearer the mark.

I know this is going to be really contentious on this here but if I could have all the money I have spent on my car back to by another one. I would probably go for a Duratech powered Caterham (narrow not fat) with a sequential box.

Cheers

Bazzer

[dern]

Also I think (this is not aimed at you Tommo) there are a lot of optimistic power claims for rover V8 powered cars. I was into TVR a number of years ago and very few of the engines actualy made the power there owners were told they did. The standard head castings seem to be a limiting factor in how much power they can produce.

There's a world of difference between the figures dreamed up by tvr and what a proper engine builder will give you.

The only disadvantage a v8 has as far as I can tell is the relative slowness of the gearchange and possibly a bit of weight although I didn't find any of the weight issues a problem on my first trackday (the weight of the gearbox is pretty central anyway) and I didn't have any problems keeping up with a blackbird engined caterham once I'd learned how to drive on track.

Can't see how you can say one is better than the other... I think most people are just justifying their own choice. In some circumstances a v8 will beat a bec and in some a 4-pot will win but it mainly comes down to the driver unless it's a drag race.

The factors are the rev range, the torque, the noise and all the rest. All you have to do is drive a few and see which of those characteristics suit you best. I love the noise and the torque of a v8 coupled with the sense of occasion but am building a bec for 90% track work purely because the gearchange is better suited and the engine costs are relatively disposable.

All this talk of v8s not being able to go around corners and becs not having any torque is just a load of hot air when it comes down to it. If v8s couldn't turn corners then I wouldn't have passed all those elises on my track day (easily out cornered them) and if becs had no torque then no one would have bothered with them.

Regards,

Mark

PS. If anyone wants to come for a ride in my car and after the event describes the engine as 'lazy' I'll buy them lunch  

[Bazzer]

Agree totaly about TVR's figures. But I also know of people who had spent a lot of money having them tuned and still not making what the tuner claimed.

A 300BHP+ rover v8 is not as simple as a minor cleanup of heads and a cam change. Even the best engines the BHP/Litre is low so  you need capacity to get good power from them.

I am not saying it can't be done its just not cheap.

I also agree its about what puts the grin on your face. Rover V8 engines are fantastic engines. Really good torque spread and sound great.

But there is no getting away from the fact that a V8 car is going to be 100Kg-150Kg heavier than a light weight BEC. This will have a big effect on the wear an tear of the car on track.

You can make a V8 stop and go well on track, the flymo is a great example of this. But If you put a similar development into a BEC you get somthing like NickA's Busa. How does that compare to the V8 cars in the speed series ?

After running a Rover powered TVR on track for 2 years the difference in running cost is huge compared to the Busa. Thats without crashing the TVR at Castle Coombe :-)

I did however consider converting my broken 5L TVR into a SEIGHT but I decided for what I wanted it for the Busa would make more sense.

Bazzer

[V 8]

horse alert

No....just an old nag

Anyway, I'm taking the Busa Abuser to Harywood to play. WHO'S BRINGING THE BEER ON SAT NITE??

[adamnreeves]

Nothing constructive to say but V8/CEC or BEC is a likely topic for a new posting record!

[Barry Ashcroft]

horse alert

I must be hung like a shire horse then    

If only

Can't be arsed to get involved with the why's and where four's just to say that my car is awesome      

[V 8]

Mines more awesome na na na na na    

[Edd]

Good to see some healthy banter going on!!!

I'm not after a car to brag bhp about in the pub, if i was i'd import a drag skyline with 1000bhp and be done with it.

I'm after a car that is right for me, so best thing i'm going to do is go and test drive a megabusa and seight at the factory and see which suits me the best. I'm hoping it's the BEC one as i will be more into track days and quite fancy a pro shifter  

I've driven a couple of westfields and one caterham before, but not one with a duratec or bec or v8 i'm afraid!!