HP vs. Weight: Help me settle a debate

[tigerblade]

Assume stock SV650 vs. stock RC51, neither has been lightened.  The RC has the HP advantage for sure, but the SV has the weight advantage.  On a track with only a few straights like MAM, how many seconds per lap faster would you expect the RC to be?

[Eddie#200]

.001 ;D ;D

[tigerblade]

That would definitely prove my point!   ;D

[MightyDuc Racing]

There was a fast rider on an SV this weekend at Jennigns running in the HW classes (maybe HW SS?) for track time and probably overall points.  He was pretty much at the back of the pack.  This is a well-built SV.  There were several large twins in front of him.  At least one was an RC51, I think.  This SV is a regional and national champ from last year.  Jennings is definitely NOT a hp track.  Hope this helps.

[Nate R]

Well, what are fast SVs running at BHF compared to RC51s?   Is someone saying that the SV will be almost as fast because of teh lower weight!? It's all about the ratio there.

Well, what times did Ed Key get last year on a good day? And Rick Bruer? Anyone?

Something like 1:18s comes to mind, with an RC running what, a 1:16?

These are vague guesses/memories, so don't use my info, Tigerblade, unless someone else can confirm it.

[Baltobuell]

 I've heard 7lbs = 1hp but I think that applies more to drag racing.

[Nate R]

That depends on teh weight and HP of the bike. On a bike with 330 lbs and 180 HP, taking off 7 lbs is BETTER than adding 1 HP, and on a 500 lb bike with 50 HP, I'm sure it's the other way around. I think the 7 lbs thing is too general.

[Xian_13]

Okay, now that we are desktop racing...
if all things are equal, and you only focus on the HP/WT ratio you would need to have the same rider on the all bikes to compare.

But that will never be the case, however lets take a look at it

Mighty Duc's Bike is 295#s and has 92ish RWHP
If am geared up and sit on that bike, the bike and I will weight 440# (yeah I am one skinny little F*** I know ;D)
HP/WT = .20909

Now you take a guy that is 180#s and has 15#s of gear, put him on a bike that Weights 365# (rough guess of a Gixxer 600).
If the gixxer has 110 RWHP the HP/WT = .1964

on paper the Duc, with me as a rider would be a clear advantage, however Road racing is more skill driven and equipment driven then HP driven (at the club level).

I hear SVs can make 100 RWHP when built, but I don't know about the RC51. I really doubt the power of an RC51 is less then 120.. but thats a guess.
SV @ 365# w/100HP HP/WT = .2739
RC51 @465# w/120HP HP/WT = .2580

(Stock)SV @ 365# w/65HP HP/WT = .1780

as far as wt=1 hp, the weight of motorcycle and rider breaks down to 5#s is equal to one HP.
So when you are sitting down to dinner tonight reaching for that 2nd helping... just think what 20# of gut eqauls out on the race track! (BTW that would be roughly 4HP)

[Xian_13]

Well I figured I should add more to what I wrote....

When talking Horse power, people often over look the fact that HP ratings, are only Peak HP.
In the real world, we don't have the bikes at Peak power all the time. At this point it, what makes a big differance is power is, in the range of RMP you use it.

When racing, HP only come into play while 100% in the trottle, lets not over look Braking and Corner Speed.

Braking... (laws of kenitics) Things in motion tend to stay in motion. The more mass you have to stop, the more energy must be used.To prove this, hop on your street, do a few hard brake checks... then add a passanger, rinse and repeat.

Corner Speed...
In drag racing, racers start from a dead stop. If you look from Corner exiting to next corner racing to be a drag strip, the advantage will be to the racer that is going fast to begin with...

In my opinion... I would rather be @ BHF on an SV then an RC51, unless you are a Honda rep. and you are going to give me a RC51 ;D

[Super Dave]

Stock for stock....

I'd bet the RC51 would do better in lap times at MAM.  In stock form, suspension wise, neither is the greatest.  So, the RC has 120HP vs the SV's 70 or so.  By how much, it would probably be close.

HP doesn't make for substantially faster lap times.  If it did, a racer that has two bikes would go substantially faster on his higher HP bike.  Fact is, Larry Denning doesn't go much faster on his R1 than he does on his R6.  

Lightnin Larry...where are you?

[HandleThis66]

so how does this weight to hp equation really work?  now it's mah understanding of the generalization... 7lbs=1hp.  but i've been advised that is a generalization, and it differs from byke to byke depending on the compression, and torque.  so how much hp advantage do i really have @ 105lbs, which is mah projected max weight...for 105x7=15 hp lost total on mah body.  i still need to figure in the weight of tha gear, but i want a # for max weight so i have tha most advantages possible for mah slow a$$.  just inquiring on tha subject... sweets - rhiannon :-*

[HandleThis66]

and that is on an f-2, if it even matters... :-/