I'm nearing the end of my car-powered mid-engine Mini build (see sig), and I can't help but think about what might be next (if all the stars line up...)

I know just enough about BECs to have some impressions I'd like to get out here and have you comment on them to correct my thinking. The following assumes the drivetrain is mounted mid-engine (not in a Mini this time though.)

1. A bike engine doesn't have enough torque to push a car. I have no proof of this though, and I've never gotten a ride so don't yell at me. (I live in southern California where it's very unlikely I'll ever get a ride in one.) What type of performance can be expected from a injected R1 in a 450kg car?

2. With no flywheel, starting out must be very tricky. Just how annoying is it?

3. The drone of the exhaust must be tiring, is it? Do you wear ear plugs?

4. A $3200 Quaife diff/reverse/center section, while a wonderful all-in-one solution, is very expensive. While I see ways around it, what's the consenses on the unit. Is it really worth it as opposed to the "diff in a can + electric reverse"?

5. Pushing 2-3x the weight, I'd expect the bike engine and especially the tranny won't last long.

6. How long does the clutch last? I realize this depends on a lot of things.

7. I hear the R1 can be used for track days without a dry-sump, while the Hayabusa needs one. True? This is important because the dry-sump is very expensive. While the Haybusa has the advantage of more torque, the R1 is very attractive since it weighs less, costs less, and revs higher.

I'm looking forword to your replies.

Hi Kimini,

Have a look at this website. http://www.zcars.org.uk/

Also, MK Engineering has done one... oh and currently doing a Fiat 500

Answers to what i can:

2. No problems.

3. Depends how far you go and how much you like the sound, you can make them quiet you know but generally yes it can become tiresome after 90 minuts or so.

4. Why have reverse - generally speaking we have had a BEC for over a year and only once found it a problem. Narrow road, oncoming car scenario.

5. Not true... the ratio's are higher so car weight is proportionally reduced to more like 1.5 times the weight.

6. We did 4500 miles with no problems. Clutch is MUCH easier to change. Typically 20 minutes can see a new set of plates/steelies in if you've done it a few times/ no what you're doing.

7. Varied and strong opinions on this one. Engine specific... dry sump's have their own set of problems and are by no means a guarantee on any bike engine. Most commentators recommend Huya/ZX12R to be DS, we haven't - we have used a z-cars chopped sump and baffle kit with no problems so far. (No track days yet though - but the engine it was designed for did plenty of track days)

Have a look at the Z-cars Website... we have Video's on our site to HERE have a look and see what you think!

ATB (S)

If your mini really is 450kg then you should have one quick mini!!!!

The Z cars steel R1 powered mini was about 530kg ish and the guy said it was a little heavy, still went like a rocket though!!!

Have fun and tell us what it's like..... cos i fancy one but with a 2 litre zetec, front engine, rear wheel drive!!

[Edited on 4/9/05 by donut]

he says not in a mini this time!

A 1 litre bike engine has more torque than a 1 litre car engine and there are plenty of 1 litre ordinary cars here in Europe that weigh twice as much as a locost. No problems there.

R1 in a 450kg car = 0-60 MPH in 3.5 to 4 seconds, I'm lead to believe. They are fast. This is largely due to the fact that you can stay in 1st upto 55 maybe where as the lower rev limit of a car engine means that you have to change into 2nd at around 30. Also a locost is about 1/3 of the weight of a normal car which gives about 3x the acceleration.

Pulling away from rest can be a bit tricky the first few times. A bike clutch is designed for hand operation. Your left foot is not as sensitive. Practice. Also, fitting a stiffer clutch spring helps.

Exhaust noise is not a drone, it's a wale! With a proper silencer, it's no louder than some cars.

Who want's to go backwards! Get out and push. A 450kg car is light.

A car and driver is 2x the weight of a bike and rider but the final drive ratio and smaller wheel sizes mean that the load on the engine is more like 1.5x This is just the average load. Peak load is whatever the engine can deliver and is not related to the vehicle. If the engine can dliver 100Nm then 100Nm is sent through the transmission whether the bike and rider weigh 250kg or the car and driver weigh 500kg. Big bike engines are well up to the job.

Most people are happy with a sump baffle in their R1 engine. Some say that overfilling the oil by 250ml is enough. You could do both of course.

Hi I have looked at your site and what a great mini!!!

I had the Zcars R1 mini and it was a great car but !!!!!

It was so loud ear plugs all the time this car had a solid mounted engine and at 6500 rpm there was a resinance that went through the shell and was like a drum it was a real pain

I know the cars now have rubber mounted engines so this will be better

I am also the loony that is doing the fiat 500 speedster with the tuimph triple
engine

I have used the Quaife chain diff @ £600 and no reverse even when I had the mini this was not a problem.

This is not a shopping car and If I did go to the shops I'd open the boot and find a bloody engine in the way.

I feel if you are looking for a fun weekend / trackday car you can't beat a bike engine. As soon as you do your first clutchless sequencial gearchange you are hooked!!!!!!

Just my 2 pence worth or 2 bucks worth!!!

PS is the exchange rate that bad at the moment

Lee

/scratched record mode on

You need to remember that torque at the engine has no relation to acceleration of the car, its torque at the wheels that counts. If you look at it this way, the torque at the wheels produced by a BEC is about the same as an equivalently powered (bhp not torque) car engine car, but with the advantage of less weight and a close ratio sequential gearbox.
A 450kg RWD R1 powered BEC will hit 100mph in 9-10s, plently quick enough!!

Also the weight, as Hellfire mentions, isnt such a difference as first impressions would suggest. Firstly the bikes are designed to be ridden with people on them, ie 180kgs for the bike plus 2 x 80kgs for rider and pillion, plus probably more to cater for heavier people / luggage etc. If you add that lot up you're looking at around 350-400kg designed laden weight. In conjuction with gearing on the BEC thats 50% lower than on the bike, I dont think that a 500kg car with driver puts a huge amount more stress on the engine and gearbox.

As to dry sumping, if fitting in a RWD mini then you'll likely be fitting the engine transversely, same as in the bike. In this scenario, I would say that probably neither engine would need a dry sump. I believe a lot of 'busa powered Radicals dont have dry sumps because when mounted transversely, oil surge is less of an issue, although a lot do partially because a busa engine is a fairly large investment so people are prepared to invest in dry sumps etc to protect the investment.
An R1 certainly shouldnt need a dry sump, just a baffle plate.

Have a look on the US based DSR Forum as they run various 1L bike engines in their cars and have a lot of knowledge on the engines and their weaknesses, which need dry sumping etc.

Chris

Thanks guys, this moves me closer to choosing a bike engine for the next project. While it's still a ways off, it doesn't hurt to start thinking about it now.

Current Nurburgring record for a road legal car is held by a radical SR8, essentially a V8 made from 2 bike engines...

Prior to that it was held by the Donkervoort (see here) which was a car engined 7...

Took one hell of a bike engine to outpace the car engine... gotta love the aerodynamics of the 7 tho..

Very nice!!

id never get through the doors of that thing!

but yeah vey nice

quote:

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Originally posted by G.Man
Took one hell of a bike engine to outpace the car engine... gotta love the aerodynamics of the 7 tho..

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So, at what price do you reckon they'd break even power wise. (Or wouldn't they?)

Not too familiar with the prices of car engines.

I'm the guy who started this thread,

The big difference is torque. With a given bike and car engine both making 160hp, all it means is they'll have the same top speed, nothing more. The car engine though (assuming probably twice the displacement) will have about 50% more torque. Torque is for acceleration and is infinitely more useful day-to-day. Of course if the bike engine produces enough torque to spin the tires, that's enough already!

I finally got a ride in a Megabusa and still have mixed feelings. While it accelerated fast enough for me, overall it was rather... what, frantic? Cruising at 60mph means about 5400rpm. I noticed the owner and driver subconsciously reaching for another gear and there wasn't one. Said another way, it wasn't very relaxing, kind of like a Tazmanian Devel, very frantic, high strung, and energetic. That's a great thing for the track but I'm not so sure about living with it on the street.

I realize the bike engine weighs a lot less and has the sweet tranny, but the question is, do those two features outweight the other issues. I guess it'll always be an individual's own personal opinion. As of right now I've swayed back to a car engine.

quote:

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Originally posted by ChrisGamlin

quote:

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Originally posted by G.Man
Took one hell of a bike engine to outpace the car engine... gotta love the aerodynamics of the 7 tho..

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Very nice but the Donkey was hardly a run of the mill car engine was it, supposedly about 400bhp of Audi 1.8T Turbo under the bonnet! Compare the performance of a £1k bike engine with a £1k car engine (need to include buying gearbox etc) and Id say the bike engine'd car will give you better performance for your money.

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quote:

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Originally posted by kb58
I'm the guy who started this thread,

The big difference is torque. With a given bike and car engine both making 160hp, all it means is they'll have the same top speed, nothing more. The car engine though (assuming probably twice the displacement) will have about 50% more torque. Torque is for acceleration and is infinitely more useful day-to-day. Of course if the bike engine produces enough torque to spin the tires, that's enough already!

I finally got a ride in a Megabusa and still have mixed feelings. While it accelerated fast enough for me, overall it was rather... what, frantic? Cruising at 60mph means about 5400rpm. I noticed the owner and driver subconsciously reaching for another gear and there wasn't one. Said another way, it wasn't very relaxing, kind of like a Tazmanian Devel, very frantic, high strung, and energetic. That's a great thing for the track but I'm not so sure about living with it on the street.

I realize the bike engine weighs a lot less and has the sweet tranny, but the question is, do those two features outweight the other issues. I guess it'll always be an individual's own personal opinion. As of right now I've swayed back to a car engine.

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Bike engined cars are a bit frantic but my daily driver is a bit sedate. The vortex is purely for fun. I had a ride in a car with a 2.0i Zetec engine and it was quick but not compelling - I'm the all or nothing type. I have a ride in a hayabusa engined car and thought "I am going to die". That, the cost and the complexity of installation of a good 4 cylinder engine led me down the BEC route. I guess it's not for everyone.

quote:

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Originally posted by kb58
The big difference is torque. With a given bike and car engine both making 160hp, all it means is they'll have the same top speed, nothing more. The car engine though (assuming probably twice the displacement) will have about 50% more torque. Torque is for acceleration and is infinitely more useful day-to-day. Of course if the bike engine produces enough torque to spin the tires, that's enough already!

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quote:

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Originally posted by smart51
I had a ride in a hayabusa engined car and thought "I am going to die".

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quote:

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Originally posted by ChrisGamlin
No offence but that is simply not true! I'll point you towards my previous reply to give the reasons why - basically a torque figure of X at the engine gives absolutely no indication of the amount of acceleration the engine can provide!!!

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quote:

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my driving isnt that bad is it

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quote:

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Originally posted by ChrisGamlin
... a torque figure of X at the engine gives absolutely no indication of the amount of acceleration the engine can provide!!!
[Edited on 14/10/05 by ChrisGamlin]

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quote:

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Originally posted by kb58
I took that into account. A Hayabusa makes 100ft-lb torque at 7000rpm. A Honda K20 makes 150ft-lb at 6000rpm. So comparing "apples to apples", gearing the bike engine down, and torque up, means the Hayabusa makes an effective 7/6 * 100 = 116ft-lb torque at 6000rpm. Yes the bike engine is lighter by roughly 200lbs, or around 20% of the total car weight, but it still doesn't have the equivalent torque/pound as a modern automobile engine.
[Edited on 10/14/05 by kb58]

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Very well if you could gear it low enough, but I suspect if using the standard drivetrain its still going to be geared higher than the ideal required for best performance, ie geared for 130-140mph tops.
Either way, with 240bhp it will be quicker than a busa Im sure.

Just found these figures for the S2000......

6-Speed Manual
Final Drive 4.10:1
1st Gear Ratio 3.12:1
2nd Gear Ratio 2.05:1
3rd Gear Ratio 1.48:1
4th Gear Ratio 1.16:1
5th Gear Ratio 0.97:1
6th Gear Ratio 0.81:1

Plumbing those into the gearcalc spreadsheet, even on 185/50-13" it tops out in 6th at 171mph, 5th tops out at 143mph and 4th at 120mph .
Are you going for a low Sierra diff or using the S2K one?

I'd maybe consider looking for one even lower (say a 4.6 Sierra if they do such a ratio?), that would bring it down to just over 150mph in top, and with usual Locaterfield "aerodynamics" you'll need much more than 240bhp to get over 150mph let alone 170!

If I put in the original S2000 tyre size (225/50-16" ) then it says that it will theoretically top out at 175, but actual top speed probably limited by aero rather than gearing , 175mph is about right considering 175mph/9000rpm = ~19mph/1000rpm in top - for a production car you wouldnt have top gear any lower otherwise it would be useless for motorway cruising etc.

Not sure where your gear cal gets 200mph from tho

[Edited on 14/10/05 by ChrisGamlin]

quote:

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Originally posted by chris mason
something's not right there, the supposedly top speed of the s2000 in stock form is just under 150mph
gear calc show's it has over 200mph.

hmmmmmmm

Chris

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Secondary reduction sounds like the engine doesnt directly drive the clutch but instead is geared off it in much the same way as a bike engine.

Ignore the figures Ive posted above as I accidentally left the 4.6 diff in, so your 200mph is probably about right if using a 4.1 diff and not including this secondary reduction. If including that 1.16 reduction, it appears to be geared for 170mph with stock tyres and diff, so similar to what I said above really, about 19mph per 1000rpm in top.

quote:

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Originally posted by ChrisGamlin

quote:

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Originally posted by kb58
I took that into account. A Hayabusa makes 100ft-lb torque at 7000rpm. A Honda K20 makes 150ft-lb at 6000rpm. So comparing "apples to apples", gearing the bike engine down, and torque up, means the Hayabusa makes an effective 7/6 * 100 = 116ft-lb torque at 6000rpm. Yes the bike engine is lighter by roughly 200lbs, or around 20% of the total car weight, but it still doesn't have the equivalent torque/pound as a modern automobile engine.
[Edited on 10/14/05 by kb58]

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What you havent taken into account is that the busa revs to 11k whereas the K20A only revs to around 8k(?). If you add that into the equation the bike's high rev limit allows you to gear it much lower and still achieve the same top speed, say 11mph/1000rpm in top to achieve 120mph compared to say 15mph/1000rpm for the K20A (although Im not sure the stock box would get you anywhere near that figure, probably nearer 20mph/1000).

Basically you need to look at torque at the wheels and ignore the engine torque. The lower gearing on the bike that is facilitated by the higher revving engine means the engine torque is multiplied up more in the BEC than the car engine, so the resulting torque at the wheels figures for both engines are very similar, but the BEC has the weight advantage still. In other words, if the bike and car were the same weight, they'd perform about the same.

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quote:

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Originally posted by chris mason
by using the secondary reduction as per the primary reduction on a bike it now brings out the top speed of the stock s2000 to just over 180mph at approx 21mph per 1000rpm in top gear, now saying that the car will only rev to 7500 in top gear that wouldn't be too far off,

rpm in top gear always seems strange as some cars bounce of the rev limiter and some don't make it too it.

Chris

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Originally posted by G.Man

The Bikes BHP is a ficticious figure due to the over-rev it manages, look at the torque curve at those rpm's and that gives you an idea of the impact a hill will have on that top speed... massive...

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quote:

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Originally posted by G.Man

The Bikes BHP is a ficticious figure due to the over-rev it manages, look at the torque curve at those rpm's and that gives you an idea of the impact a hill will have on that top speed... massive...

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As for the £250 challenge, I raise you a £50 pinto..

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Are we talking about hills or mountains, being up some fairly steep hills in mine and they don;t seem to make much differance; even with a heavy chassis.

Andy

I'll run the numbers end to end this weekend and we'll both see what's what.

I need to locate gear ratios for both the Hayabusa and RSX-S K20... shouldn't be hard to find.

quote:

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Originally posted by ChrisGamlin

What you havent taken into account is that the busa revs to 11k whereas the K20A only revs to around 8k(?). If you add that into the equation the bike's high rev limit allows you to gear it much lower and still achieve the same top speed, say 11mph/1000rpm in top to achieve 120mph compared to say 15mph/1000rpm for the K20A (although Im not sure the stock box would get you anywhere near that figure, probably nearer 20mph/1000).

Basically you need to look at torque at the wheels and ignore the engine torque. The lower gearing on the bike that is facilitated by the higher revving engine means the engine torque is multiplied up more in the BEC than the car engine, so the resulting torque at the wheels figures for both engines are very similar, but the BEC has the weight advantage still. In other words, if the bike and car were the same weight, they'd perform about the same.

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Andy, Im sure you realise but for the benefit of others, thats cos it makes absolutely no difference.
Once again its the torque at the wheels that determines how little speed you loose up a hill, and once again a high revving, low torque bike engine with a low ratio gearbox will perform just as well as a torquemonster that revs to half the RPM with twice the torque.

Off to bed, my head hurts

Oh no...

Not another "mine's bigger than yours" argument! We'll be up with the Cateringvan crowd soon!

These arguments are all pointless - a seven with a Morris 1000 engine is probably faster than the average tintop, and a lot more fun!

If you want a screaming engine that's a thrill a minute (but a PITA for a long journey) then get a bike engine - otherwise pick your favourite car engine.

Each to their own thing...

David

[Edited on 14/10/05 by David Jenkins]

Here's the busa ones....

Primary Reduction - 1.596
1st - 2.613
2nd - 1.936
3rd - 1.529
4th - 1.284
5th - 1.134
6th - 1.040

revs to about 10,800rpm

Its personal choice, I for one wouldn't be swayed from a BEC for a fun road and track car, as for hills ?????

Slack hill on way too Matlock, some will know it.......
my 900cc blade and 1100cc bird as yet too be beaten up it showing outrageous speed at the top and leaving Subaru's and the like in its wake, its steep, its long, the engine just pulls n pulls......and that's without much of a run at it as those that know the hill will know its 40mph run up too it and a regular mobile camera spot in the 40 limit, you'd think they would cotton on and wait at the top.......

I think youve missed the point David, I cant speak for anyone else but Im not arguing which is better, just making sure that when people make a decision on what they think will perform best for them, they do it using the correct calculations and figures!

Chris Head/wall banger for you to use...

The "torque vs BHP" argument crops up wherever there are petrolheads & motormouths & are usually circular with the odd misconception...
The answer lies in good old 'o' level GCE physics,
power = force * velocity
or
power = mass * acceleration * velocity

There's no gearing factor in that equation. And it says that at a given speed the acceleration is determined by mass and the power available. Period.
The common misconception is due to the "peaky" nature of "power tuned" race engines, a less powerful engine with a wider torque spread can be faster because a) there's no doldrums where the next gear up is off the cam already and b) you spend less time messing with gears instead of accelerating. So folk say "torque is more important than power". Which is daft.
cheers me dears
Bob

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Originally posted by _Aero_

quote:

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Originally posted by G.Man

The Bikes BHP is a ficticious figure due to the over-rev it manages, look at the torque curve at those rpm's and that gives you an idea of the impact a hill will have on that top speed... massive...

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So when Hellfire shows the dyno'd 152.5bhp at the wheels on a bike quoting almost 200bhp at flywheel (with ramair which there's hasn't) this equates to say a 15% loss in transmission and resulting in a healthy 170+bhp at the flywheel. I think he may have something to say about your superfluous adjectives...

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Yup, I'm convinced. It doesn't matter what rpm an engine runs at, it only matters what power it generates, at any rpm.

Running the numbers through CarTest was very enlightening. I created two "Super-7" cars.

Car1: Hayabusa, 160hp, 100ft-lb torque, 1200lb test weight, 40% on front tires. Geared so top speed was 140mph.

Car2. Honda K20C, 200hp, 140ft-lb torque, 1400lb test weight, 60% on front tires, geared so top speed was also 140mph.

Here's where the big difference hit me... shift time. In the CEC I left it at the default of 0.4 seconds, but with the BEC I cut it to 0.2 seconds. That made all the difference.

End result, the BEC, thanks to the fast shift time, reached 1/4 mile in 12.8 seconds, with the CEC trailing at 13.1.

Very interesting.

But you can always spend £3000 on an elite sequential box for the CEC

quote:

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Originally posted by Bob C

The answer lies in good old 'o' level GCE physics,
power = force * velocity
or
power = mass * acceleration * velocity

There's no gearing factor in that equation. And it says that at a given speed the acceleration is determined by mass and the power available. Period.

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smart makes an excellent point...

The car will have a different torque spread and wide ratio box, whereas the bike engine will use more revs and a closer ratio box so that you can keep it on the boil....

Was the same with my 250 kart... we got 60bhp out of the honda CR250 and revved them to 12,000 rpm, much more than any crosser would...

but all the power was from 9000-11,000 with about 1k of over rev...

Boy was that exciting to drive, but drop out of the rev band and you were dead in the water...

Same applies to the bike motor really, below 4-5k they are nasty, above that all hell breaks loose, and its the noise and delivery that makes it so exciting...

you cant compare very well,

and when you compare you need to let it be on 1 point only.....

also its all about priorities, Sound, Clutch
Cornering,PETROL CONSUMPTION....

Also from 1 figure you cant say nothing....

sow peak BHP isn't use full, max rpm isn't usefull..

we will need 2 Dyno Figures to be able to see and compare 2 engines....

what if you have an engine that has torque but only deliver it between 2000 and 3000Rpm.. and out of that zone it has 50% less..? wouldn't be very usefull?

also when you switch to next gear..you fall down in revs... and thats the point where i think an Bike Engine picks faster up.....

at the end its all about F=MxA...
@ any engine speed used on the test

the avarage value of the 2 will make one faster as the other...

also we need to consider the acceleration of the engine speed it self!

how much time does it take for an car engine to rev to 6000? and howmuch for an bike to 6000? or to 12.000?

i think its clear an CEC for the ROAD..and an BEC for competition...

i personally think BEC are much more graggile than CEC not only because the engine wich it fits of the CEC it should be able to make 200.000miles...

how much you give an BEC??

Tks

A bike engine has a close ratio box compared to a car engine...

The rev range is greater but in relation to what that does to the performance its much of a muchness...

The real score is the weight loss that makes the torque requirement that much less so the bike engine results in a much more exciting delivery in most cases...

Okay, my cossie would have been more than a match, and actually worked out cheaper than a zx12r with dry sump, goodrich hoses and aeroquip fittings, but when you look at the cheaper r1 or blade engines the picture is far less clear cut...

there will always be fans of both, and fans of either...

I'm not so sure 330bhp of cosworth would be "more than a match"

As always its a pointless exercise because it entirely depends on the circuit, certainly along the straights it would p1ss all over a BEC but in the corners would lose out like any other heavier car, and would lose out even more in areas where you need delicate throttle control, the main reason why you need more power in a turbo engined track car than a N/A to get the same lap time.

Somewhere fast like Spa or Thruxton it would beat a BEC over a lap, but somewhere like Anglesey or Cadwell my money would be on the BEC.

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Originally posted by Jon Ison
I'm not so sure 330bhp of cosworth would be "more than a match"

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