Sweet spot

[Slow progress]

Hi All,

Random question, for British roads what is the gut feeling for sweet spot on power to weight ratio and torque for fun B road driving (safely!).

Take away fwd/rwd/4wd debate, as well as engine type, the more I look myself the more I get drawn to smaller cars with 0-60 between 5 and 7 secs, then it’s down to the torque and shorter gearing. Be interested to see if I’m alone in this.

Cheers,

D

[J1_Jon]

Slow progress said:

Hi All,

Random question, for British roads what is the gut feeling for sweet spot on power to weight ratio and torque for fun B road driving (safely!).

Take away fwd/rwd/4wd debate, as well as engine type, the more I look myself the more I get drawn to smaller cars with 0-60 between 5 and 7 secs, then it’s down to the torque and shorter gearing. Be interested to see if I’m alone in this.

Cheers,

D

No idea about Power to Weight but an XR3i or similar (Astra GTE, Golf GTI) of the same non-turbo era. Even the supercharged MINI ... but if it's wet, a Subaru WRX, every time

Fun <> Fear factor of B-road blasts correlate more to handling (suspension / brakes) than power ...

[georgeyboy12345]

Anywhere between 165 - 295 bhp/tonne

[J1_Jon]

https://www.evo.co.uk/hot-hatchbacks/204689/2022-h...

[Bennet]

Somewhere between 100 and 200hp, and it should make more power the more you rev it, rather than giving you everything from about 1800rpm upward or taking a great lunge forward about one second after you prod the throttle in any gear.

[dibblecorse]

Surely the Yaris GR is the power / weight / handling / size sweetspot for B road blasting ?

[kambites]

For me it's somewhere around the 200bhp per tonne mark, with as little weight and as little vehicle width as reasonably possible, and ideally with the power produced high up the rev range rather than in a slug of low-rev torque.

[CG2020UK]

I think the current gen of hot hatches of 208 GTI, Fiesta ST, VXR, I20N and RS Clio have it all spot on.

Size up the Golf GTI is a brilliant package with the 308 GTI, Focus ST RS Megane and I30N being great as well. Starting to get to big but.

I think handling and suspension is way more important for B road fun.

[samoht]

Slow progress said:

Random question, for British roads what is the gut feeling for sweet spot on power to weight ratio and torque for fun B road driving (safely!).

Take away fwd/rwd/4wd debate, as well as engine type, the more I look myself the more I get drawn to smaller cars with 0-60 between 5 and 7 secs, then it’s down to the torque and shorter gearing. Be interested to see if I’m alone in this.

The desirable power and power:weight depend mostly on the speed range you're driving at - at higher speeds you need more power to achieve the same sense of meaningful acceleration.

The thing is, even the descriptor of "B road" is quite loose when it comes to the speed range. Some B-roads in East Anglia have really tight 90 degree bends around the corners of fields, almost like turning at a T-junction. Other B-roads are wide open with gentle curves where you can carry a lot of speed. So how much power you want is a function of which B-roads you drive.

Having said that, I think 300hp in a 1300kg car is a good starting point, maybe up to 350 or 400hp depending on roads and car.
570hp is definitely more than is required to enjoy a B-road, for me it doesn't make the experience any worse, but equally I don't think it really adds anything over say 400hp in a ~1500kg car.

[MC Bodge]

Not as much as many people appear to believe.

[Leins]

Bennet said:

Somewhere between 100 and 200hp, and it should make more power the more you rev it, rather than giving you everything from about 1800rpm upward or taking a great lunge forward about one second after you prod the throttle in any gear.

This, with weight not much more than a tonne, and size as compact as possible but allowing a comfortable driving position

[911Spanker]

About 200-250bhp, circa 1200Kg, short gear ratios (manual of course), proper steering and RWD.

That rules out just about any car built in the past 10 years.

[gotoPzero]

My 2ps.

<100bhp/tonne = normal cars, "slow".
100 - 150bhp/tonne = adequate for normal driving.
150 - 200bhp/tonne = fast enough 90% of the time but could use more power for real fun.
200 - 250bhp/tonne = fast, more than enough in most cases. Always feels enough.
250-300bhp/tonne = getting pretty serious. Might be too much in some situations.
>300bhp/tonne = rapid, be careful! Likely not able to use it all on the roads.

In which case 200-250bhp/tonne.

Also see

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[FMOB]

Surely sweetspot y = mx-5 is the answer.

[Bobupndown]

B Road + Mk1 Mini, 850cc, 37bhp.
Fun doesn't have to be fast.

[AmyRichardson]

gotoPzero said:

My 2ps.

<100bhp/tonne = normal cars, "slow".
100 - 150bhp/tonne = adequate for normal driving.
150 - 200bhp/tonne = fast enough 90% of the time but could use more power for real fun.
200 - 250bhp/tonne = fast, more than enough in most cases. Always feels enough.
250-300bhp/tonne = getting pretty serious. Might be too much in some situations.
>300bhp/tonne = rapid, be careful! Likely not able to use it all on the roads.

In which case 200-250bhp/tonne.

Also see

https://www.pistonheads.com/gassing/topic.asp?h=0&...

I've never driven north of ~270hp/t, so can't really comment on the heady realm of 300+hp/t.

That said, I can't see that any amount of power is problematic as long as the delivery is immediate, linear and predictable. A boosty 100hp engine hooked to a terrible throttle map is more of a liability than a really obvious, analogue 500hp one.

Again, it's circumstances, there are scenarios (no traffic and wide, well surfaced and well sight roads) where anything short of Saturn V-grade thrust won't lead to stimulus overload. Folk who've been in, e.g., 620 Caterhams talk about that being on the edge of sensory overload, so maybe there's a hard limit for the individual as well.l!

[gotoPzero]

When I say trouble, I mean of the blue flashing light kind

[valiant]

MC Bodge said:

Not as much as many people appear to believe.

Yep

Handling is far more important. Booting it on a straight line gets boring quickly, learning how to carry what little speed you have some lovely flowing bends is a glorious sensation.

[Mr-B]

FMOB said:

Surely sweetspot y = mx-5 is the answer.

Yeah this.

I have a ND and a GR86, perfectly adequate for fun.

I see cars like Macs and Ferrari's with 7/800bhp and I think it must be so frustrating to use them on roads, you are not using 20% of what is available (unless it is for a full 3 seconds). I had a squeaky bum moment last summer when I thought I got snapped by a camera van (I hadn't fortunately) and that was with a pathetic 160bhp at my disposal not 5 times that!

[Mr Tidy]

Slow progress said:

Hi All,

Random question, for British roads what is the gut feeling for sweet spot on power to weight ratio and torque for fun B road driving (safely!).

Take away fwd/rwd/4wd debate, as well as engine type, the more I look myself the more I get drawn to smaller cars with 0-60 between 5 and 7 secs, then it’s down to the torque and shorter gearing. Be interested to see if I’m alone in this.

Cheers,

D

That's an interesting question.

For most of 2019 I had two BMWs with the same engine.

A 2005 E90 330i, 258bhp at 6,600 rpm, max torque at 2,500rpm, claimed 6.3 seconds 0-62 and unladen weight of 1,450kg.

And a 2006 E86 Z4 3.0Si Coupe, 265bhp at 6,600 rpm, max torque at 2,750rpm, claimed 5.7 seconds 0-62 and unladen weight of 1,395kg.

But they felt totally different on a B road blast. The Z4 encouraged me to get involved, the 330i just felt ponderous by comparison so maybe the type of car is a big factor too.

I replaced the Z4 with a Z4M Coupe in 2020 (343bhp @ 7,900 rpm and 5.0 seconds 0-62) and while I love it, getting into blue light territory is just too easy!