173BHP from 1000cc

In news:bvp4q3$rra$ snipped-for-privacy@kermit.esat.net, JK decided to enlighten our sheltered souls with a rant as follows

Hmm, the race Fireblades that I sometimes work on are about that kinda power.. not bad...

Although my ol' Sapphire Cossie was 528 bhp out of 1993cc...

Unless my friend that you tune for the BSB... u aint getting that sorta figure from a blade !!

In news:bvp634$s8a$ snipped-for-privacy@kermit.esat.net, JK decided to enlighten our sheltered souls with a rant as follows

indeed we do... PR Racing in Liverpool

(yep, that lot at the back of the grid)

Ohhhhh the Paul Jones team..... yeah...watched the season...interesting.... you guys ever going to come over & race in Ireland ? Will keep an eye out over the 04 season... Cheers....& nice to see a bike guy in here.

Cheers, JK

Because car engines don't have enough valve area per CC. In other words the they don't have such a large bore/stroke ratio. The capacity is pretty much immaterial in determining horsepower. All that matters is air flow which follows from valve area. I don't know what valve sizes that engine has but if you follow the calculations on my website you can work out what the ultimate potential of your engine is. 180 to 200 bhp is quite achieveable from most of the 1 litre bike engines with good cylinder head development.

Dave Baker - Puma Race Engines

season...interesting....

Plenty of bike people (and an odd trike person) on here as regular posters and many, many more as lurkers.

JB Guzzi1000SP Trike, Guzzi850T3, FJ1100, GPZ900R, ZZR250R......

Per Eklund's Saab 9-3 was 750 bhp from 1985cc...

In news:bvp7d6$sqp$ snipped-for-privacy@kermit.esat.net, JK decided to enlighten our sheltered souls with a rant as follows

Ahem! It's Gordon "great at starts, crap at winning" Blackley nowadays..

tis planned for some point, we were meant to be there last season.. but we're only a tiny budget (£150k) team.

Ta, although to be honest, I do most of the car work for PR.. They're great with bikes, not so good with 4 wheels. I do help out at the BSB meets though, when I'm not doing my proper job.

Also, I think a little thing called revs comes into it too. Aren't bike engines designed to yield high power but at much higher revs than a car engine, at the expense of low down torque? Try putting 4 people and their luggage, 0.5 tonne of steel bodywork around a bike engine, and /then/ try pulling away at 10mph in top gear ;-)) Oh, and doing that for months on end for an owner who (a) doesn't know where the oil goes and (b) has a layer of dust on his service book.

Of course "in my day" bike engines needed rebuilds every 16k-20k miles too.

They're all just engines at the end of the day, regardless of what metalwork is around them - many Japanese car engines blur the edges between the two extremes don't they? Certainly in terms of revs attainable, and excellent harmonic balancing etc.

-- Ken Davidson DocDelete

To get high revs, you need a short stroke otherwise piston speeds become unmanagable. Shortening your stroke means enlargening your bore for the same displacement, which gives more room for valves in the cylinder and therefore a larger valve area and more power.

For a normally aspirated petrol engine, the engine has to suck its air in so to get more air in you have to make the intake less restrictive which means bigger valves. You can cheat and turbo / super charge the engine, in which case valve area isn't such a big problem anymore.

-- James

New Mazda RX8 has 250 BHP from a 1.3L.

Yes, but this is a rotary 'Wankel' engine. The capacity is not comparable with a piston engine, also the engine is not very fuel efficient.

I wish my 899cc, 39bhp, engine could do something like that :-D

Johannes H Andersen ( snipped-for-privacy@sizefitter.com) wrote: : Pete M wrote: : > Although my ol' Sapphire Cossie was 528 bhp out of 1993cc...

: Per Eklund's Saab 9-3 was 750 bhp from 1985cc...

Both use turbos ... the GSXR doesn't.

Blair.

You mean for road use? The car would be undriveable and probably unreliable. How many big powerful bikes more than a couple of years old are there on the roads?

Lots. In fact, I know of more 5 or so year old (and more) sports bikes than I know of new ones.......

There's many reasons why this can't be done for car engines, including:

• Most car drivers are too lazy to check the oil etc. - a high revving engine needs lots of attention
• How many car drivers would want a car that needs servicing every 4k miles?
• A car needs a much heavier flywheel than a bike - which affects the way you need the power produced - you need more low-down pull in a car than on a bike.

I'm sure there's loads more reasons, but I can't think of them all at the moment.

However, if the bore is much different from the stroke, then surface heat losses may reduce power. The minimum surface area for a given cylinder volume is when bore = stroke.

The limiting factor for turbo/super charged engines is the cooling requirements.

It's all relative to the rev range. You wouldn't gear a 100bhp

Didn't help running a CB125S (single sohc) though the red at 9,500rpm and back out at 11,000rpm in to the green on the other side. Tacho and speed was marked up to 12,000rpm=80mph, so I took it there. It didn't actually die or come to any real harm the choke just vibrated on and strangled it.

-- Peter Hill Spamtrap reply domain as per NNTP-Posting-Host in header Can of worms - what every fisherman wants. Can of worms - what every PC owner gets!

You have less transmission losses with a bike.

It is a race engine. What cars are you comparing it with? F1?

Bikes have a less coefficient of drag to a car, hence the greater top speed per engine size.

The power to weight ratio means that bikes have an advantage in speed, but not necessarily comfort.