explain hp/ per litre

[redsprinter]

can anyony explain to me what hp/ltr means ? i sorta get it but don't .

[af300e]

Yup, easy. Take for instance, the suzuki rgv250. This is a 250cc two stroke road bike. Produces around 50hp.

1 litre divided by 250cc (or ml) = 4

4 x 50hp = 200hp per litre

Now that's a figure to be pround of!

Or the new R1

1 litre at 185hp. or 185hp/L If you could get a 4age to that sort of power vs displacement it would be making 296hp or over 220Kw.

[Konakid]

Thats it, basically a means of showing true engine efficiency, more relevant in Naturally aspirated cars however.

i.e Honda S2000, 2L 4cylinder making 176Kw has a high Hp per Litre

Also known as Kw per litre.

[yoshimitsu9]

<div class='quotetop'>QUOTE (KonaKid @ Apr 3 2008, 02:46 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=512392)</div>
Thats it, basically a means of showing true engine efficiency, more relevant in Naturally aspirated cars however.

i.e Honda S2000, 2L 4cylinder making 176Kw has a high Hp per Litre

Also known as Kw per litre.[/b]

hondas philosphy= 100hp per litre

[Group A]

<div class='quotetop'>QUOTE (yoshimitsu9 @ Apr 3 2008, 04:55 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=512484)</div>
hondas philosphy= 100hp per litre[/b]
A general rule of thumb in club motorsport is that if you can get 100hp/litre, you're doing well.

Forumla 1 cars have over 750hp from 2.4 litres, that's pretty impressive.

[Sprinterboy]

Club car budget vs F1 Team budget.... I know which one i'd prefer.

[redsprinter]

so ive got 140rwkw on a 4agte ...

correct me if I'm wrong i only make 87.5kw/ltr ???

1 litre divided by 1.6cc (or ml) = 0.625

0.625 x 140kw = 87.5hp per litre

[narchi]

no its actually from the engine usually.

say u have 160hp motor from a 1.6
That is 100hp/L.
Just divide the diplacement by the HP.
320HP from a 1.6l is 200hp/L and so on.

[Intense]

13b Renesis = 177kw from 1.3 litres, 182 hp / litre

[4door]

with forced induction it is more potential.

for an NA engine to make 100hp per liter is good.

i like the honda philosophy, is to make 100hp per liter or more, i wish more manurfactures would follow this.

[driftke70]

for future reference, when something has a / or says per such as hp per L or hp/L it means divide.

so pretty much if you have 140kw, around 185hp DIVIDED by 1.6
so around 115 hp per L

[Hokey]

M3 has highest hp/L for factory motor doesn't it? weld two 20v's together for a fun high hp/l motor :D

[Anthony]

rgv is cheating about as much as the renesis. both figures should be halved for fair comparison to the proper engines. :P

[Intense]

<div class='quotetop'>QUOTE (Anthony @ Apr 11 2008, 11:05 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=516705)</div>
rgv is cheating about as much as the renesis. both figures should be halved for fair comparison to the inferiour engines. :P[/b]


Fixed

[Benno]

I think Ant was getting at the fact that chook cookers and oil burners have double the amount of power stokes per revolution as their otto cycle counterparts

[driftke70]

13b is effectively a 2.6 4

[hugh]

Heres something interesting...In 1934 MG made a car The "Q" series. 747cc capable of 133MPH!! Supercharged, running 2.5 atmospheres, which for people who don't know, that is about 2.2bar or around 33psi!!! still holds some records to this day. It had 110kw engine for 747cc, giving it around 150kw/L, which by todays standards are amazing, this was in 1934. Only ever made 8, I know someone that has 2 of them...It held the record of hp/L for a long time, but I don't know what is now, maybe M3 as someone has pointed out earlier...

[Anthony]

I think M3 is a contender for Naturally aspirated specific power, not forced induction like your MG. I don't think there are any factory M3's getting 150kW per litre :)

[floody31]

<div class='quotetop'>QUOTE (hugh @ Apr 13 2008, 07:24 PM) <{POST_SNAPBACK}> (index.php?act=findpost&pid=517373)</div>
Heres something interesting...In 1934 MG made a car The "Q" series. 747cc capable of 133MPH!! Supercharged, running 2.5 atmospheres, which for people who don't know, that is about 2.2bar or around 33psi!!! still holds some records to this day. It had 110kw engine for 747cc, giving it around 150kw/L, which by todays standards are amazing, this was in 1934. Only ever made 8, I know someone that has 2 of them...It held the record of hp/L for a long time, but I don't know what is now, maybe M3 as someone has pointed out earlier...[/b]

In 1951 BRM debuted their 1.5 Litre, supercharged, V16.... 72psi boost, 612hp. Fangio's car did 189mph at Albi circuit.

Anyway this could go on forever with forced induction cars but the BRM is pretty amazing. Everybody needs to hear the sound clip of it, it is spine tingling.

http://youtube.com/watch?v=Tk8qPlOKB0I


As for hp/ litre, I think currently the motorcycle manufacturers have everyone in the shade. Kawasaki's old ZX-12R made 185hp at the crankshaft or 154hp/litre in regular production, and has been seen close to 200 with exhaust/remap/cams at the rear wheel. Reasonable effort for 1.2 litres. Obviously not as good as 180 from 1 litre like the R1 of course!

[redsprinter]

what makes a bike engine so effiecent compared to a car engine?

[floody31]

They don't have to comply with quite as stringent noise and emissions regulations; and generally you see the best per litre efficiencies at lower capacities, my theory on that is its mostly due to the minimal size and weight of internal components in smaller motors, plus smaller relative sizes of support systems.
Thus higher revs, higher gas velocities, easier to size fuel systems, exhausts appropriately etc within constraints of both size and budget.
In general, the bigger the engine is the hp/litre thing becomes a game of diminishing returns.

[redsprinter]

and i guess the torque figure goes out the window right ?

[AE86AL]

Motorcycles don't weigh as much as cars and don't carry as much load so the internal parts can be engineered on the leaner side.

Bikes are generally not produced as daily transport for the masses so the engine can be built with perfomance far more present in mind than longevity.

Car manufacturers CAN build wicked engines to match bike performance but they wouldn't last long enough to be viable.