Right folks can some of you clever tuners tell me, what's the most important for a fast road car, bhp, or torque, or both??

Reason i'm asking alot of people never seem to mention torque figures it's always about there bhp, but surely torque is as important to making a quick car, for instance, the WRC cars of today are what? probably around 300bhp but have HUGE amounts of torque, now compare the rally cars from the 80`s they had 400-450+ bhp, and yet i've seen a video clip recently showing a now WRC car against a Quattro with more bhp but there was hardly anything in it. Ok, i know technology has come on in 20yrs or so, brakes/ suspension etc are better, cars are lighter i guess, so i'd be interseted in your thoughts on this..

 

well m8 if u think about it its torque that puts your car flying not the bhp what good is bhp without it its useless compare jap imprezaz to those of the uk japanese cars are running masses of bhp thats what they aim for but back here in the uk its torque aswell as bhp the uk tuners i would say have a better edge on the tunning side cheers scoobzie

 

 

For a turbo road car, the quickest boost transition and turbo spoolup possible, the longest torque curve that starts at the lowest practical revs.

An EVO probably, once you strip the Euro emmisions tat off of it , or a Diesel....

<runs for flame proof bunker>

 

Yep......except for the part about the EVO!!

I recall Andy talking about a 2.5 set up with a MD321H turbo the other day, with 400bhp+ but the spool characteristics of a TD04

Er, one of those please!!

 

I think the only reason wrc cars dont run massive bhp is because of the restricter they have to run in the turbo,so they go for torque instead.Pull the restricter and map accordingly and they produce big bhp and torque.JAY

 

They're both important, a nice big fat chunk of torque low down gets you moving off the line, and a nice big power figure at the top end keeps you moving, if you look at any power and torque curve from a dyno you get your torque peak, and then as it decays the power creeps up.

 

And don't forget that gearboxes can act as torque multipliers. A high revving car with high bhp and relatively low peak engine torque can produce high wheel torque provided the right gearing is selected. Problem is, many people don't know how or care to or are too lazy to drive these sorts of cars properly - eg high revving Hondas

 

The killer really, is flexibility. There's not an instant transition from puttering around peacefully to instant thumping torque and acceleration...

Lots of things can help. Variable cams, VNT turbos, fly-by-wire and probably even Petrol direct injection.

The last one's part of the key to flexibility, as if you can lean out the cruise AFRs enough, the engine's already running a surfeit (sp) of air. All it needs then is enough fuel to make it expand more. Because of the greater volumes of inlet air, the turbo's more awake to start with. Dunno if that'll ever happen properly, given the requirements for closed loop, fast idle and emissions.

J.

 

A fast car needs both. As mentioned above, gearing works as a torque multiplier so in other words you can do without a lot of torque with correct gearing. Nothing will make up for a lack of power though - a low powered car will always be gutless whatever you do with the gearing.

You might wonder about the new generation of 'sporty' diesels, but you need to look at these in perspective and realise these are not the smoky old Peugeot minicabs of old, but turbodiesels. OK their torque looks huge compared to their power outputs leading people to think they are fast because they have loads of torque. No, they are fast because they are turbocharged so make good power as well. Most 2 litre turbodiesels are making an easy 150bhp nowadays. 15 years ago, 150bhp or thereabouts out of a 2.0 normally aspirated petrol engine was pretty big news e.g. Clio Williams. In 2007, 75bhp/litre is lazy.

 

As above, both.

IIRC, 400bhp was Andy's lazy setting. Full on it was approx 480bhp, 520ft lb.

Anyway, Scoobs usually have both in plentiful supply.

 

Torque is the thing to have so long as the torque curve is long - the same as with power. Its the area under the curves that makes for a rapid car not peak figures. They are only useful in the pub.

 

I agree with Dynamic, there is only Torque, a long flat torque curve is what you want.

 

That sounds interesting

 

I think the real answer depends how you drive as well, what is a just small enough turbo for one driver is far to big for another.....

I like my 'full boost at 1400rpm' myself, but yes it does run out of puff past 5,250 but a near enough flat 200lbft+ from 2000 to 4,500 is a very nice drive!

Simon