Cheeky performance claim?

[Peter Carmichael]

http://www.blackbirdmotorsport.co.uk/Hayabusa.htm

 

I wonder if they would care to verify a 9.8 second standing quarter alongside mr Edmands?

 

Peterid=teal>

253 BHP K-seriesteeth.gif, no gearboxbum.gifid=red>

[Andrew Walker]

They should enter it in the next Curborourgh Sprint.

[edmandsd]

Yeah right !

 

To do this quarter mile time you would need to do 0 - 60 mph in under 2 seconds and 0 - 100 mph in under 5 seconds. Terminal speed would need to be about 140 mph.

 

 

It's nonsense like this that leads people to think bike engined kit cars are unbeatable at every motorsport discipline.

 

I had to laugh (out loud) when a chap came up to me after I'd just run a 10.6 second quarter mile at the weekend to say I should put a Hyabusa lump in it to go faster !!

 

 

Edited by - edmandsd on 6 Jun 2002 16:26:52

[dino ferrana]

Sounds unlikely with a car that probably weighs a similar amount to Daves with a lot less power?

[edmandsd]

I like the front arches and downforce mod to the bottom of the nosecone though !

 

I would guess a Hyabusa powered Caterham would run a standing quarter mile in low 12's (maybe high 11's) at around 110 mph.

[Laurence Wilson]

The arches are a good idea, though I'm not personally convinced by their aesthetics!

 

Cheers! teeth.gifid=orange>

Laurence 'LOZ' Wilsonid=purple>

[dino ferrana]

There was an article in a paper ages ago with someone taking a Caterham to a wind tunnel with Mr. Coates. They added long drop front wings (lower than those shown) with vents in the top. I can't remember the other mods but I think they made a reasonable difference!

[ian crocker]

This claim has been debated loads of times in various forums. The bike-engined brigade always refuse to believe it is rubbish as most people have no appreciation of what the different quarter mile times really signify.

 

Anyway, that particular timing was done by Motorcycle News. They measured out a quarter mile (God knows how they did it - 400 paces ?) and then put a chalk mark on the ground. They then used a hand-held stopwatch to time the car.

 

Ian

[robmar]

nice an accurate then blush.gif

 

rob

[murph7355]

It does only say they "saw" the standing quarter in 9.8secs.

 

Maybe they simply stood someone 1/4 mile away and it took 9.8s for the myopic driver to spot them?

 

Perhaps the shovel on the front was to whip him over the bonnet as the driver hit him?

[Graham Perry]

I think Duncan Cowpers Turbo Huyabusa Dax at 360 BHP would give nearly every other seven a run for its money, when he gets it sorted. What little I have seen of it so far indicates that it will be fast.(FTD at the sprint I saw it at) Its not that light but he reckoned on 750BHP / tonne when I asked him. Best of it, is that he is running on low boost. The engine was tested on the dyno at over 400 BHP on a higher setting. He's talking about making it road legal, so my proposed move to the local class 8 sprint class, that he will occupy has been postponed (Many £k's on new engine saved as well) !

[Nifty]

I saw a W*******d with wings racing alongside Jason Krebs at Snetterton a few months back. He certainly seemed to gain from the down force around parts of the circuit....though Jason skinned him in the end teeth.gif

[Morls]

The engine would do a quarter in 9.8 in the bike, and 180mph or so, all for about £8000 new.

 

Mad.

 

Mark

[ian crocker]

Graham, I don't think Duncan's car would perform very well on list 1A tyres. I've seen another on list 1As and it just gets wheelspin in every gear as it comes on boost. Spend the money - you know you want to!

 

Ian

[Gary G]

Nifty, it sure was ugly though!!

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BTW, sent you an e:mail thanking you for the CD. The e:mail address I used looks a bit odd, so don't be concerned that it's a virus or anything.

 

 

 

C7 GAR id=red>

 

[Nifty]

Has it arrived already Gary?

That was quick if it has!!

 

We'll have to start a new thread just to post up quotes..some classic sketches.

 

Nifty.

[Graham Perry]

Ian, I agree. I think he will have to use 1b's and go into another class. I won't be troubling you in class 8 for some time yet though.

[edmandsd]

Duncan Cowpar's old 4WD Cossie Turbo car ran 0 - 60 in 3.1 secs and 0 - 100 in 7.6 secs with an 11.2 sec 1/4 mile time.

 

I know the new 2wd Hyabusa turbo car's still in it's development stage but I did see it run at North weald a while back recording low 12 second quarters at 122 mph. More to come i'm sure in terms of time and speed.

 

I've never fancied a 2wd turbo car for 1/4 mile drag racing though - Doesn't really suit the discipline in my opinion. Wayne Saunders 7 second Probe/Focus was an exception I suppose..........and not just because it used a BDTE engine !

[Graham Perry]

How about a BDT in a seven, Anyone ever done it ? Presumably it would fit in an SV provided you could get a gearbox or diff to take the BHP & Torque

[EFA]

A couple of points:

 

There is a point in Sprinting where 100bhp is quite insignificant compared to aerodynamics, vehicle mass and sheer grip. Thats why Paul Ransons Pilbeam is rather faster than any Seven with a similar VX engine.

 

There is also a point where power is meaningless, and torque is everything. This is the point at which the energy lost to aerodymamic drag starts to equal the torque developed by the engine. Sadly Torque is the one thing bike engines lack. I am sure that 250bhp of VX or K power in a Radical would permit top end acceleration far greater than that presently available.

 

Cars also have more wight, but importantly much more aerodynamic drag than bikes. This is the main reason BEC's have top speeds far short of their two wheeled cousins.

 

As DE says anyone who believes a BEC can do a sub 10 qtr is only kidding themself.

 

DUncans tiems wwerre quick because his 4wd systme gave exceptional 60ft times.

 

 

 

 

 

Fat Arn

Visit the K2 RUM siteid=red>

See the Lotus Seven Club 4 Counties Area Website hereid=green>

 

 

Edited by - Fat Arnie on 8 Jun 2002 23:13:20

[Morls]

I stand ready to be proven wrong, but...

 

With my (limited) understanding of the forces that balance at top speed I don't think the following is theoretically correct:

 

"There is also a point where power is meaningless, and torque is everything. This is the point at which the energy lost to aerodymamic drag starts to equal the torque developed by the engine."

 

My understanding is that (assuming ideal gearing), top speed is where the rising drag curve crosses the falling thrust curve (Plotted against a base of speed).

 

The thrust at the back wheel would surely be the same for any properly geared (so peak power occurs at top speed) engine making 200hp, irrespective of the ratio of torque/revs needed to create this power.

 

I cannot see how the diff would know the difference between a prop turning at 6000rpm transmitting 200bhp from a bike engine or a prop turning at 6000rpm transmitting 200bhp from a car engine. The speed of, and torque generated in, the prop must be identical given the fixed relationship between rotational velocity, torque and power.

 

In practice I would agree though that engines with a high torque and linear power delivery are easier to get smooth thrust curves for, without the 12 speed gearboxes that small capacity racebikes of the 60s had.

 

Mark

[Peter Carmichael]

If your BEC makes decent POWER at 80% of maximum revs and has a close gearbox, then it isn't a loack of torque that is the issue.

 

Power to weight is the key to acceleration.

At speed, it is (engine power - drag power) to weight.

 

Car engines tend to be bigger. For equivalent power to weights, car engines are more powerful. When you take off equivalent drag power, there is proportionally more left of the car engine's power than the bike engines so it keeps accelerating to a higher top speed.

 

A 200 bhp bike engine will be slightly peakier than a 200bhp 2.0 litre VX XE. However at 80% of revs, it will only be a percentage point or two down on the car engineand the weigth will still be significantly less.

 

250bhp bike engines are much rarer than 250bhp car engines and are likelier to be peakier still, but still only by a few percentage points at 80% of revs.

 

Peterid=teal>

253 BHP K-seriesteeth.gif, no gearboxbum.gifid=red>

[Simos]

[twopenneth]

 

Power/torque point is at the other end of the scale i.e. when you first start to move. Once moving power is the key ingredient because the torque can be effectively multiplied by gearing.

 

Torque is a bigger ingredient in getting you off the line because the low speed doesn't allow you to take proper advantage of gearing. This is significant in sprinting, though in a race you'll make it back elsewhere.

 

High reving engines (as opposed to big lumps) also lose out in windage because they have to accelerate all their bits through a larger rev range. Given a fixed speed interval to gear into this will give greater losses than the larger engine even though they're both rated at an equivalent power at a constant speed. The differences however are small if the lump is also turning 9,500 rpm !

 

[/twopenneth]

[Barbara Swift]

None of this technical stuff I'll leave that to you lot - Peter you have mail. smile.gif

 

Barbara.

[Morls]

Simos,

 

I was busy nodding my head in agreement but then thought....'ang on...that (long rev range means longer to spin up to power) theory ain't always right.

 

Thinking of bikes, the revvy ones always feel like they have less flywheel inertia and respond much quicker than the not revvy ones.

 

Or, more noticably bike vs car... a blipped throttle on the bike will have it up to 12K and back in no time.

 

Or R500 vs beplenumed K, surely the pricey one gets to 9K before the quiet one gets to 7K.

 

I suppose, for a given power output, (in bike vs car) the revvy engine is likely to be of smaller capacity & hence be made of smaller bits with less reciprocating mass and therefore capable of accelerating quicker.

 

I see Arnie's point about car engines being good for top speed, but not due to torque, just power... Has anyone actually seen a normally aspirated bike engine making the power of a top K or VX (or BD?).

 

 

Mark