Downside of Bike Engines and now car engines

[nickaddison]

Oh yes and my old exhaust tested at 109db, the new one at 99db at 8,000

 

Blue Light 05 DVD available NOW!

[STEVE GILBERT]

Nick

 

The Fireblade Shop. Do a Google, they are located in Sible Headingham near Haverhill.

Barry is the owner.

Its where all the new engines came from in the first place!

 

 

 

See My Caterham Fireblade Here.

 

Edited by - STEVE GILBERT on 23 Oct 2005 18:00:07

[metal mickey]

So, to recap.

Advantages of bec's are:

they are light (compared to Vx's )

they are cheap (compared to tuned Vx's )

you get a sequential gearbox thrown in.

Disadvantages are:

they are noisy (I know a man that can fix that 😬)

No reverse as standard - fit a reverser,job done.

Tiresome on long journeys - wear headphones.

Made your mind up yet Dave?

 

[Jason Plato]

whats the most popular / effective reverse solution presently ?

[metal mickey]

there are three ways to obtain a reverse.

Electric motor, reverse box inline in the prop or a diff incorporating a reverse mechanism. I'm very impressed with the last option as a 2.89 lsd can be fitted and that obviously raises the overall ratios. I haven't calculated the effect of that yet on engine revs and the cost is quite high at 3K. There is an inline reverser that can be speced with an overdrive input but is reported to be very noisy-something the manufacturers are looking into.

[Mike Molloy]

My Blackbird weighed in at just over 460kg on Metal Mickey's scales. That was with half a tank of fuel, so I guess around 450kg basic wet weight. (Roadsport cage, JPE screen, foam driver's seat only.)

That makes it about 75kg less than my old 1.6K Academy car, but still a fair bit heavier than a LA Fireblade.

The question is, what difference does it make?

Which direction leads to Nirvana?

Reduce weight and add lightness (a la BEC), or (for example) 300bhp Duratec bulk herbs?

I dunno, and I'm not a good enough driver to make comparisons. Would have thought the former is more in keeping with Mr Chapman, but I wouldn't say no to another 50bhp either...

[Jason Plato]

Mike , does your satisfaction lay with a tuned Busha then ?

 

Dave

[dannylt]

Having come from a 250bhp tuned 'busa (SR3) to a 250bhp Duratec I can honestly say I'm having much more fun now. The Caterham is obviously far slower, but tyre shredding torque is far more entertaining that outright speed IMHO. Opinions will obviously differ :-)

 

On the road there's no competition - the SR3 was absolutely awful, pose factor aside.

 

[metal mickey]

Danny, what spec are the 250hp Busa ? Interesting that you now have more fun - how do you explain that ? What would the 7 be like with the 250hp Busa in it?

[dannylt]

The Powertec Hayabusa is 1500cc (stroker crank), bespoke cams, porting and throttle bodies plus many detail things to make more reliable - mainly in the clutch and gearbox area. I don't know of one without a dry sump either. The revlimit is 10,500 instead of 11,500 for the 1300 but it has much more midrange.

 

I think it depends on how you prefer you driving - either neat and grippy and fast, or plenty of adjustable and entertaining oversteer on demand. The Radical is much too fast for track days, so the Caterham is far more fun (though still pretty quick!).

 

[Mike Molloy]

A Busa (no 'h' Dave! ) lump would be nice, but the problem is cost. IMHO the engine is essentially a disposable component. If it goes bang I'd just buy another from a breaker for 1K - 1.3K. Hayabusa engines command 3 times that. I believe the guy on "Kit Car Crisis" paid 6K for a blueprinted Hayabusa with dry sump (no tuning allowed for the RGB series).

Getting modest BHP increases from a bike engine seems to be a hideously expensive business.

How much does a Powertec 1500 cost anyhow? More than a full house Duratec I suspect...

I'd be interested to hear from Brodie as he is a man who has had the chance to compare Duratec V. Busa in some detail.

For my extra 50bhp I was thinking about a spot of NOS... It's only for overtaking pesky Radicals on trackdays after all! 😬

[DSL]

I would take any claim of 250 bhp for a tuned 1500cc busa with a very large pinch of salt, they factor in a large percentage boost for theoretical ram air effect & even if that were the case, one of the more respected tuning house's who have just done my tuned busa motor will tell you that level of power is just not realastic.

[dannylt]

Maybe 250 is optimistic, but it's not far off. I can only just outdrag SR3's from 60-100. I can't remember what the standard engine costs (Radical get crated factory engines in huge piles) - around 4 to 5k? Then 4k for the 1500 conversion, plus 2k dry sump, plus 1k for injection (a must for a hassle free life IMHO!). Roughly, and I'm sure their prices have gone up!

 

A shot of nitrous might help you get past... until the next braking area and corner! :-)

 

[DSL]

From what I can gather alot of the advantage comes from the minimal power losses through the transmission & ultra rapid gearchanges.

 

Not to mention the lack of weight to persuade to change direction / braking zones etc.

[dannylt]

The gear changes are definitely quicker, but the weight is roughly the same, at 530kg claimed. The advantage is simply downforce and monster grip!

 

[DSL]

I was referring to the relative differences of a bike engine as opposed to car engine installed in a Caterham *thumbup*, as a minimum I would of thought a busa install to be at least 40-45kg lighter than a duratec engined car & gearbox combo.

[dannylt]

Oh right - sorry! With slicks I doubt there would be much in it, or at least, down to the driver.

[Jason Plato]

Brodies Busa was weighed at oulton Park weighbridge and was 45 kg lighter than my K series Caterham .Duratec is heavier again.

 

I guess at least 35Kg of that loss is over the front axle as all the dedion and diff is pretty much the same.

 

Edited by - Dave Jackson on 25 Oct 2005 08:12:20

[dannylt]

My Duratec weighs around 520kg, what I meant was that I think the torque makes up for the weight difference.

[DSL]

Yep probabaly does in a straight line, but rapid direction changes will alway's favour a lighter engine *thumbup*

[dannylt]

The torque really makes a big difference on corner exit again though. If anyone has a 250bhp 'busa Caterham I'll be very interested to join them on a track day though!

[Davey Bee]

Mike, looks like it will be down to the final cost. However I'd need an engine that gave very good power/weight. The only reason that I'm considering this is to improve handling. I love the power and torque of my Vx 😬 😬

 

TRY 5S

Buzzin' Bee It's never too late for a happy childhood *cool*

 

 

 

 

[Mike Molloy]

Just my 2p worth regarding the "bike engines have no torque" argument...

 

According to the Caterham brochure the Blackbird has a peak torque figure of "only" 92 lb-ft.

Looking at a dyno curve for one of these engines reveals it generates >90% of peak torque from 6K - 10K rpm.

The blackbird 6th gear ratio is 1.64:1, compared with the Caterham 6-speeder top ratio of 1:1.

So, assuming diff ratio and wheel/tyre sizes are the same, the Blackbird gives the same "seat-of-the-pants" shove as a car engine with > 92*0.9*1.64 = 136 lb-ft from 3600 to 6100rpm.

 

How does that compare with a K series?

Is it roughly similar to a R300? (Peak power in the 160 - 170 bhp bracket.)

[DSL]

And a busa has more of everything *thumbup*

[Violet Elizabeth]

Including weight 😳 At least another 20kg for the 1300 over 1000cc bike engines such as R1 and GSXR1000. Plus the dry sump. Plus you really need a chunkier axle.

 

You can't compare diff ratios, even in BECs, as the Busa is reving lower than some other bike engines, needs a 3.14 diff compared to the 3.38 running in the Blackbird, 3.27 in the Blade, and 3.62 (?) in R500.

 

If we don't mess with the engines that much, then I am firmly of the opinion that the bhp/tonne of a 1000cc engine + live axle such as the R1 will match that of a Busa/de dion setup. And it will be cheaper too.