Minimum HP requirement

[superchow]

Hey All,

I was cruising down a suburban road heading to work wondering how much power I would need in my car to keep the current speed (50 mph). It got me thinking about what other peoples' needs in a car would be. I know my father in would not consider anything under 160 hp.

Here people idolize Metros and the such, which must have around 60-80 hp.

I suppose I should really be talking about torque - which is why maybe the Prius doesn't "feel" slow when accelerating from a stop, and my Civic feels taxed when loaded with passengers and luggage.

What are your Friday afternoon ponderings on this matter?

[Daox]

You can use this nifty calculator Darin put together to calculate your HP requirement at speed. You can access it from clicking "tools" at the top of the page.

Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com


Horsepower requirements for cruising are pretty small.

[superchow]

Yes, I realize that. But what would one personally find acceptable in terms of "excess" or "passing" power? Sorry for the confusion.

[IndyIan]

Interesting question, "passing power" is quite often why people don't like to get smaller engined cars. I still pass people in my 127hp Tracker but it takes some planning and technique. The tailgate, pull over, and then nail it method doesn't work well with it.

[tasdrouille]

At the speed I drive on highways I have roughly 55 to 65 hp available in 5th. When I want to pass I just mash it and it goooeeesss (relatively speaking...). So imho in a passenger car 60 hp right where you need it is plenty.

[MadisonMPG]

Geo's have 55 or 49hp, assuming you mean the 3cycl. I would think you could get by with 40hp or so at 55mph. Assuming it had a Cd of .32 or so, and was smallish.

[MetroMPG]

Answer depends on weight & aerodynamics! (And to a certain extent the environment you drive in.)

The previous generation Smart Fortwo CDI (Canadian / Euro market) has 40 horsepower - and a worse (from the conventional perspective) power to weight ratio than a Geo Metro 3 cylinder car. I'd drive one!

Somewhat related thread:

What 0-60 acceleration would you accept for good fuel economy?

-

[superchow]

Thanks for the feedback. So I am not alone - power compensates for lack of skill/inattention. Heh, makes me want to make a bumper sticker that goes something like this:

"Hybrids - Helping to get good mileage despite their drivers." Present company not included of course...

The world would be a much different place if power was inversely proportional to vehicle weight. Maybe then manufacturers would be more likely to build lightweight cars and trucks.

... but I digress.

[robchalmers]

My polo has a stonking 60hp, and it can out-gun 2 litre+ cars off the lights and due to the gearing @70 you massage the gas it will pick up effortlessly and shoot round passin 80+ quicker than most of the bigger cars I've driven in the states (v6 malibu/fusion/trailblazer/cobalt etc). alot of people mention power/weight ratio but personally for useability I prefer to look at torque/weight as a measur and maybe take a sneak at the gear spacing stats too!

[superchow]

Originally Posted by robchalmers

My polo has a stonking 60hp, and it can out-gun 2 litre+ cars off the lights and due to the gearing @70 you massage the gas it will pick up effortlessly and shoot round passin 80+ quicker than most of the bigger cars I've driven in the states (v6 malibu/fusion/trailblazer/cobalt etc). alot of people mention power/weight ratio but personally for useability I prefer to look at torque/weight as a measur and maybe take a sneak at the gear spacing stats too!

I agree with the "diesel power". My parents still drive their 93 Passat TDI with 90 hp and it always is eager to pull. A torque/weight comparison would be interesting. Especially when looking from a performance and fuel economy point of view. TDI - FTW!