Does BIG BHP mean fast road car??

fai17 · December 21, 2005

As above.....What do yous think??

st3ph3n · December 21, 2005

It certainly helps the cause Peter, but it's not the be all and end all.

Usability, tractability, power delivery, power to weight ratio, handling, grip, aerodynamics. Everything matters.

Of course different cars are better suited to different roads too! A fast car on a motorway doesn't always make a good car on a B road. And a good car on a B road might run out of gears/puff on a motorway.

imprezapete · December 21, 2005

Depends how you mean Pete, your question is open to very broad subject.

johns · December 21, 2005

Up to a certain point, more power does mean a faster road car given the same driver and conditions.

However, beyond a certain point, Imprezas with big power become more difficult to drive quickly, with all the power coming in at the top end of the rev range. There can also be problems in using all the available power due to traction, speed limits etc. In some cases, you may be limited by how early you can apply full throttle coming out of corners. In lesser powered cars, some corners may be safely taken at full throttle , but in higher powered cars you would be off into the scenery.

It must also be said that 90% of a cars speed on the road will come down to driver ability and local road knowledge. A good driver will in most cases be faster overall in a medium powered car than an average/poor driver in a very powerful car. I dare say that a very well driven 106 or even a works van for example could keep up with most of us on most roads in typical conditions (ie keeping to speed limits, safe overtaking only). This obviously wouldn't be the case if the road was a serious of long straights where the extra power could be used to full advantage.

John

RS Grant · December 21, 2005

I would say that a good torque spread is very important to make quick progress on the road.... specially down a tight twisty back road where you need something to launch you out the bends, so I would be happier having a higher torque figure than BHP figure to be honest. I would say that high BHP engines are more suited to the track where you'll be at 10/10ths all the time, hence keeping the car in the magical top 2-3k revs constantly.

Cheers,

Grant

Gumball · December 21, 2005

a balance of both peter as Grant said is what you want.

High bhp- steams along in straight lines, like the straight at KH for instance.

high torque- very very quick off the mark and will give you aggressive power after slowing down for a bend.

a good balance of both is a good idea.

torque steer is a problem sometimes though if you have too much.

WRC cars for instance are limited top speed and have a not too high BHP figure, but something like 500lbft through the gears !!!!!!!!!

RA Dunk · December 21, 2005

<< but something like 500lbft through the gears !!!!!!!!! >>

got me "DROOLING" that has!

coulty · December 21, 2005

always said it is down to torque for a quick car didn't i chris

Stuart

Gumball · December 21, 2005

you sure did Stuart. im glad you gave me that advice !! it meant when i went to Andy F i knew what to do and have got a quick car now

paddy247 · December 21, 2005

Power without torque is nothing.

B.H.P = work rate

TOURQUE= turning force

I think lol

wilky · December 22, 2005

Torque gets you off the line or on the charge again, its Bhp that keeps you going,

Callum W

Carl Davey · December 22, 2005

My perception has always been greater bhp for top speed but greater torque for winning 'races'. Power to weight ratio also plays a surprisingly big part as i have found lately.

I am enjoying having the use of two cars at the moment. The first is my run-around Cavalier Turbo which has 204bhp with marginally more torque, 4wd and weighs somewhere near the classic Imprezas 1250kg - doesn't have the chassis though! The second is my girlfriends Clio 172 Cup which has (they say) 172bhp with torque nearer 150lb/ft, Fwd and weighs about the same as a baked bean tin.

Point to point the Clio is brilliant fun and puts a huge smile on your face, i honestly doubt i could keep up with myself driving the Clio if i were driving behind in my last Classic Impreza in 300bhp guise. It is ridiculously fast although being NA doesn't *feel* as quick as the Cavalier which will steam past the Clio at 140mph. In total honesty though the short gearing and torque steer make the Clio a pest to drive for any length of time.

It all comes back to what John says about the power being useable, driver ability and road knowledge. A greater spread of torque will make the car easier to drive fast as this will help dig a driver with less road knowledge out of the hole of not being able to keep the car quite on the boil. To answer your question in my opinion big BHP will make for a fast road car in a straightline. Any other circumstances require the input of so many variables it is nigh on impossible to answer.

terminator · December 22, 2005

Depends on who is driving.

johnnyr6 · December 22, 2005

driver input counts for a lot, roads are a good leveler, it's easier to keep up with quicker cars on the road than on track or dragstrip. Just look at the runs we do, A wide variety of scoobs all with differing mods and power sticking together.

fai17 · December 22, 2005

Thanks m8...just wondering

Anymore input to this matter so i can learn some more info.

=Robbo= · December 22, 2005

BHP is a peak figure and pretty meaningless. Torque through the rev range, big brakes and good handling = fast road car. IMO.

Robbo.

ally-b · December 22, 2005

My Dad ,

...who used to race (hill-climb)T-series MGs , A-7s etc , always said ...

... if you want to go faster - get better brakes !!!

and... weight is a handicap ... if she wants YOU to drive faster , tell her to get oot

In other words ...

Power/weight and torque make the most difference , in the real world

speed limits apply so , acceleration and "oomph" count more than flat-oot welly ,

'speshly in the bendy-bits . (Scotland)

I hope that nonsense helps

PS : Just noticed ...I'm just repeating what Robbo said

AlanG · December 22, 2005

As everyone else says.

Having a peak figure doesn't mean a great deal when used on the road.

For a good. powerful road car, they like to look at the "area under the curve" on a dyno graph so to speak i.e. say you produce 300Ib ft of torque. Over how many rpm do you have this 300Ib ft of torque?

This was one of the things with my project in that the aim was to produce a high torque over as wide an rpm span as i could get.

fai17 · December 22, 2005

<< As everyone else says.

Having a peak figure doesn't mean a great deal when used on the road.

For a good. powerful road car, they like to look at the "area under the curve" on a dyno graph so to speak i.e. say you produce 300Ib ft of torque. Over how many rpm do you have this 300Ib ft of torque?

This was one of the things with my project in that the aim was to produce a high torque over as wide an rpm span as i could get. >>

What are your figures again AlanG???

AlanG · December 23, 2005

With regard to "area under the curve" Peter.

I had 400Ib ft from 3800rpm - 6300rpm,

450Ib ft from 3900rpm - 6000rpm

and 500Ib ft from 4000rpm - 5500rpm.

That's in 3rd gear though. Boost comes in earlier in the higher gears, so figures for "area under the curve" should be over a greater rpm.

RS Grant · December 23, 2005

Jesus christ.... Thats impressive!!

Cheers,

Grant

fai17 · December 23, 2005

Thats scary m8.

When are you taking me out for a pax lap on Knockhill

I'll bring spare underwears too.

AlanG · December 23, 2005

I'm sure there will be a Knockhill day i can take you out Peter.

I'll try and keep it on the tarmac this time though, but if not, bring spare underwear just in case!!