Author Topic: Power to Weight Ratios (Read 4823 times)

SteveD CB500F · « **on:** November 30, 2005, 07:27:10 AM »

This was an aside in another thread, but wondered if anyone would like to add to this?

750 = 500lbs and 67bhp = 295bhp/tonne

550 = 400lbs and 50bhp = 275bhp/tonne

500 = 400lbs and 48bhp = 264bhp/tonne

Fireblade (2006) = 165kg (363lbs) and 161bhp = 978bhp/tonne

Please feel free to add other models (350 / 400 / 650) and variants. Did the K's weigh more than the F's?

Bob Wessner · « **Reply #1 on:** November 30, 2005, 09:28:01 AM »

Quote

Did the K's weigh more than the F's?

I would have thought so, but just looked up the specs on an 750 F3 vs K8 and the K8 is lighter 5 lbs.

MetalHead550 · « **Reply #2 on:** November 30, 2005, 12:11:35 PM »

Hey Steve whats the formula? And what the hell is a tonne? English for ton(2kpounds)

?

Gordon · « **Reply #3 on:** November 30, 2005, 12:40:31 PM »

You can find the power to weight ratio by dividing the horsepower by the weight. The higher the number, the more power it has overall.

CB750 = 0.134

CB550 = 0.125

CB500 = 0.120

This is on par with some of the fastest performance cars, but what's interesting is what happens when you figure in the weight of the rider.
With 180 pounds added on:

CB750 = 0.099

CB550 = 0.086

CB500 = 0.083

Hardley any difference between 500 and 550, but much larger difference between 550 and 750.

SteveD CB500F · « **Reply #4 on:** November 30, 2005, 02:03:06 PM »

1 tonne = 1000kg

I can figure the lbs/kgs bit but not the old tons which we haven't used here since I was in primary school (you'd probably call it 1st grade?)

I think Gordon is using the more recent measurement which is a true ratio of kw/kg

The Fireblade I mentioned earlier was 0.758. Compare that with the CB figures!
That is 125kW for 165kg

For the purposes of this calculation I used 1 bhp = 750W or 0.75kW

Gordon · « **Reply #5 on:** December 01, 2005, 08:12:33 AM »

CB400 = 0.099 w/rider = 0.067

CB350 = 0.086 w/rider = 0.058

needswork · « **Reply #6 on:** December 01, 2005, 09:05:54 AM »

H-D XL 883 Sportster

675lbs (dry, claimed by manufacturer) and 45 hp (claimed by an owner) = 0.06 or 150 hp/tonne

H-D doesn't give hp ratings on any of their models except for the V-Rod.

hehe, my car:
'98 Volvo S70 T-5
1427.9 kg and 236 hp = 165.2 hp/tonne

SteveD CB500F · « **Reply #7 on:** December 01, 2005, 09:51:23 AM »

I like the bhp/tonne better too.

My Jag: 1650Kg 240bhp = 145bhp/tonne

needswork · « **Reply #8 on:** December 01, 2005, 09:58:32 AM »

in my HUMBLE opinion though, horsepower is over-rated while torque is under-rated. Torque is the "seat-of-the-pants" feel. Know what I mean?

SteveD CB500F · « **Reply #9 on:** December 01, 2005, 10:02:48 AM »

I do know what you mean. Unfortunately "Honda 4" and "torque" seem to be mutually exclusive !

Seriously - I couldn't tell you what torque figure was available on my bikes. I do know that I rode my neighbours 1450 HD round town in 5th gear and only changed once for a red light!

My Jag is a short-stroke V8 (3.2) and is a bit low on the old torque as well (it's red lined at 7.5k though)

There was an article in Classic & Motorcycle Mechanics a few months ago about diesel bikes apparently they have so much torque that they can out drag a modern crotch rocket up to 60 or 70 (which is probably all you ever need for zooming around town)

needswork · « **Reply #10 on:** December 01, 2005, 10:10:43 AM »

"Unfortunately "Honda 4" and "torque" seem to be mutually exclusive"

Yeah, that's (sadly) true, my 550 is rated something like 27 ft/lb. I drove a friend HD (1300 cc?) and it had great torque.

Deisel bikes! I never knew such a thing existed. The torque would be great but I probably couldn't get past the rattly noise and smell. $:-\$

dusterdude · « **Reply #11 on:** December 01, 2005, 03:55:31 PM »

yep,torque is what moves ya

gaijin · « **Reply #12 on:** December 01, 2005, 07:14:48 PM »

Yeah, diesel bikes are pretty cool. My buddy has a nice motard that he converted to run on biodiesel as well as normal diesel. Runs like a champ.

I remember hearing something about a new diesel sportbike prototype, wonder if google can find it..

Bob Wessner · « **Reply #13 on:** December 02, 2005, 02:11:51 AM »

Here's one, pretty impressive numbers.

http://thekneeslider.com/archives/2005/02/25/thunder-star-1200-diesel-by-star-twin/

SteveD CB500F · « **Reply #14 on:** December 02, 2005, 03:44:56 AM »

165 ft lbs of torque (let alone 250!) sounds like serious 30-70 mph acceleration.

Compare with 27 ft lbs on the 550 and 33(?) for the 750

needswork · « **Reply #15 on:** December 02, 2005, 06:08:49 AM »

hehe, pull yer arms off.

Jim Shea · « **Reply #16 on:** December 02, 2005, 08:51:50 AM »

Torque, shmorque. My bike pulls in 5th from 30-40 mph no problem..

dusterdude · « **Reply #17 on:** December 02, 2005, 09:13:13 AM »

damn jim,dont be afraid to speak your mind

Jim Shea · « **Reply #18 on:** December 02, 2005, 10:32:11 AM »

I do speak my mind, trouble is I am normally thinking bollocks, so that's what I end up talking!

dusterdude · « **Reply #19 on:** December 02, 2005, 10:49:44 AM »

uh huh

Jim Shea · « **Reply #20 on:** December 02, 2005, 11:21:24 AM »

Mark,
You have the dubious honour of receiving my 500th post, does that make me an old timer now??
Jim.

dusterdude · « **Reply #21 on:** December 02, 2005, 12:25:03 PM »

yea,ur and old timer.....lol and thank you for the honor

MetalHead550 · « **Reply #22 on:** December 02, 2005, 12:50:06 PM »

Anybody read that article in Bobs link about the V8 they made by grafting two hyabusa engines together? Using it in cars, makes 375hp and revs over 10k! Crazy stuff, it must sound glorious to hear a v8 reving that high. Which reminds me, I saw an old in-line 4 Excelsior that a guy had made into an 8 cylinder at a swap meet in Iowa this past summer. Talk about cool, mabey I can find a link.

dusterdude · « **Reply #23 on:** December 02, 2005, 01:45:03 PM »

id like to see the link about the busa

Einyodeler · « **Reply #24 on:** December 02, 2005, 02:26:11 PM »

Whoa!!!

http://www.autoexpress.co.uk/evo/driven/53640/radical_sr8.html

http://www.jalopnik.com/cars/custom-carshot-rods/tuners/the-hayabusapowered-ultima-twinengined-insanity-machine-029819.php

http://www.zcars.org.uk/ultima/conversion.htm

Check out the videos of the busa powered Minis on the last link....gotta love it!!

News:

Author Topic: Power to Weight Ratios (Read 4823 times)

MetalHead550

gaijin

Jim Shea

Jim Shea

Jim Shea

MetalHead550