Power to weight vs power and weight

Power to weight vs power and weight

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Norfolkandchance

Original Poster:

2,015 posts

200 months

Monday 19th January 2015
quotequote all
Hi,

I realise that there is no answer to this and that it will vary from circuit to circuit, lots of other factors like grip, traction, wind resistance etc will have a big impact but...

Imagine you have 2 cars. One weighs 750kg and has 150bhp, the other 1250kg and has 250bhp. They both have 200bhp/tonne. They have about the same amount of drag.

So, assuming traction wasn't an issue they should both accelerate at the same rate, except that drag will have an impact so the heavy car would be quite a lot faster in a straight line, espcially at the end of long straights. But it would have to brake and turn all that extra mass.

Would the light car have a hope? What about at Mallory Park or similar?

Your thoughs / expirience please

How do you think they would compare?

Norfolkandchance

Original Poster:

2,015 posts

200 months

Monday 19th January 2015
quotequote all
BertBert said:
why would the heavier car be faster down the straight with the same power to weight ratio?
Bert
Because it would be better able to overcome the aerodynamic drag.

Norfolkandchance

Original Poster:

2,015 posts

200 months

Tuesday 20th January 2015
quotequote all
Thansk for the replies. What I was really asking was...

The more powerful car will be faster on the straights and the lighter car will be able to brake later and corner faster. Would being lighter by 500kgs be enough extra braking and cornering performance to counter the 100bhp advantage of the more powerful car?

To me 100bhp seems like a lot!

I guess the Lotus Cortina / Ford Galaxy battles of the 60's or the mk2 Jag / Austin A40 suggest that at times there will be a balance between a lighter car and a heavier but more powerful car. I also take on board the passing on the straights, blocking in the corners argument. I remember exactly this happening when lighter 400cc GP bikes were allowed in with full fat 500s in the 90's. The light bikes were fairly competitive in qualifying but didn't get to use their cornereing advantage in the race.