Minimum bhp/tonne for a family hatchback

[Welshbeef]

The question about is 300 bhp/tonne the most god ever need on the public road got me thinking what about on the other side of the range a family hatchback.

What would the minimum bhp / tonne required to propel four adults and keep up with the flow of traffic.
I've driven a super mini city thing which had c70bhp/tonne which had enough for two adults but going up an incline literally turning off the air con made a notable difference.

I'm guessing but I'd imagine 100bhp/tonne would be the number to cope withte requirement to pull four adults along.


Note when I say bhp per tonne I mean on a car with no passengers.

[Benbay001]

Just for keeping with the flow of traffic? My 83bhp/ton is quite adequate, if not more than is needed.

[davepoth]

70bhp/tonne will do 5 up on the motorway at illegal speeds, it needs a bit of stirring though.

[Welshbeef]

Benbay001 said:

Just for keeping with the flow of traffic? My 83bhp/ton is quite adequate, if not more than is needed.

Could you carry four adults and still keep up with the flow of traffic?

[andy-xr]

An average rep mobile is what, 90bhp/ton? Something like a 130hp diesel averaging about a ton and a half?

[Chicarito]

A Passat Bluemotion or similar seems to manage on somewhere around 65bhp / tonne and still manages warp speed 5 in the outside lane of the M1.

[Benbay001]

Welshbeef said:

Could you carry four adults and still keep up with the flow of traffic?

Almost certainly. Id like to say 45mph overtakes are a piece of cake, even 4 up. But i would be lying, a bit more go would be nice.
But for keeping with the flow of traffic its fine.
I would imagine a diesel would be even better, or a turbo petrol, due to the power delivery.
If you feel you aint going fast enough, drop a gear.
Most cars near where i live are similarly powered.

[maxdb]

Comfortably I would aim for around 150bhp +. Motorway driving around 110bhp should do it. I have no trouble in my Citroen C1 with a whopping 68 bhp tho - it's just crap at taking bends at high speed

[vladcjelli]

maxdb said:

Comfortably I would aim for around 150bhp +

Per ton? Are you sure you've read that right?

Check this list, and make sure you're singing from the same hymn sheet.

I reckon about 70hp per ton is more than adequate for daily grind style pootling.

[maxdb]

Yeah I missed that bit :$ I was just going by general car weight. Per ton i would say around 80bhp per ton would be adequete on the M.ways.

[va1o]

75

[Benbay001]

va1o said:

75

.26
To be precise.

[bga]

Welshbeef said:

Benbay001 said:

Just for keeping with the flow of traffic? My 83bhp/ton is quite adequate, if not more than is needed.

Could you carry four adults and still keep up with the flow of traffic?

My Octavia has something in the region of 75 bhp/ton. 4 up it easily keeps up with traffic on all types of road.
Acceleration isn't great but there is more than enough power to make more than adequate progress.

[paranoid airbag]

I seem to get along with 75hp in a car just shy of a tonne with fuel and just me... 5 up, it really struggled though, I nearly had to drop into first on a couple of hills, but then at that point it's maybe 60hp/tonne.

[kambites]

I do occasionally find the OH's Punto annoyingly slow, usually when it wont maintain 70 on a hill on the motorway or I have to join a dual carriageway via a short uphill slip road. Especially if it has more than just the two of us in it.

I'd say 60-70bhp/tonne is adequate but 100 is vastly more pleasant. When we replace the Punto, it will be something with over 100.

[jagnet]

My caddy van gets by with about 50bhp/ton empty, which it never is, so day to day it'll be around 45bhp/ton. Whilst it's not at the top of the list for a hoon, I've never struggled to keep up with traffic. Overtakes need plenty of planning, but are still possible.

I can't say I've found myself leading a queue of traffic on open roads, and only on long climbs on multi lane roads do you really feel the lack of bhp.

I'd suggest that you could easily get away with lower still and remain usable, given that the average family hatchback is treated as a method to get from A to B with minimum excitement, nor does it seem particularly keen on the concept of overtaking. I wouldn't want to own one myself though.

[FreiWild]

Same with our Caddy maxi, 100 hp, 1800kg ~55hp/ton. and you can still keep up with the flow of traffic comfortably and get to speeds you wouldn't be allowed to travel at in the UK.

[Welshbeef]

Remember it's bhp per tonne excluding passengers.

I do think it needs to be 75bhp/tonne in a golf sized car - 100bhp/tonne is notably better but frankly I'd say you'd struggle to overtake with four adults.


Should torque per tonne also be important for this discussion or is just plain bhp/tonne the key?

[surveyor]

83 bhp/ton in an Espace loaded up with 5 + luggage was ample.

[kambites]

Welshbeef said:

Should torque per tonne also be important for this discussion or is just plain bhp/tonne the key?

Depends on whether you know what the gearbox is for, I guess.