The power of negative thinking
Volkswagen DRIVER - July '07
"A straightforward suspension tweak totally transforms the Mk 5 GTIs handling in tight corners.
SINCE WE FIRST reviewed it, in the December 2004 issue, we've driven just about every single permutation of the new GTI: Two- and four- door, manual and DSG, with 17- and 18- inch rims, in just about every colour and configuration, not to mention several examples of the Edition 30 and quite a few highly modified examples too, both on the road and on the track.
There's no doubt whatsoever that it is an exceptional car; not necessarily the most powerful, fastest, or most stylish of modern hot hatches, but undeniable the best all- rounder for the modern driving environment. It's as comfortable and competent crawling along the Kensington high street, in the rush hour, as it is storming at full- throttle through the Craner curves at Donington, in the wet
But there's one aspect, which we've had reservations about; not enough to warrant outright criticism, but anyone who has driven the standard GTI hared will know that it is less than pin point perfect when it comes to right turns. With its excellent steering response, it turns in well enough, but try to hold it right in to the corner on a tight off- camber bend and it'll just drift out. Even on the 18s, with lower profile tyres, it still doesn't have the ultimate ability to hook right in and hang on there, hugging the kerb right round to the exit point.
It's inevitable really; any chassis designer engineering a modern day car, no matter how sporting its aspirations, has to consider ultimate safety first. No matter that the car has sophisticated electronic handling aids, it has to be designed so that it communicates clearly to even a novice driver. And, since not everyone can afford a new GTI will necessarily have the razor sharp skills of a racing driver, understeer is the default when it comes to handling.
Understeer is where the front end of the car starts to run wide; as it does so the instinctive reaction of any driver is to ease of the throttle, reducing the speed and diminishing the risk. It's oversteer, when the rear-end swing around, inducing a panic attack in the average driver. Which has to be avoided, and the only solution is to engineer machinery for the mass market to produce understeer, which is all very well for most everyday situations, but for the enthusiastic driver it takes the edge off the handling, enough to result in dissatisfaction. You may never need to overtake on the inside of a bend in normal road use but the ability to hold a tight line is paramount to accurate controlled driving in any situation, and essential for anyone interested in taking their car out on track.
So, what can be done to sharpen up the handling of the Mk 5 GTI? The answer is to increase the amount of negative camber in the static position, to help improve the tyre contact with the road surface when cornering hard. Although the front tyres are perfectly upright when driving in a straight line, as the car steers and rolls into a cornering situation the suspension movement naturally exerts sideways forces, pushing the tyre onto the its outer edge, resulting in positive camber and reducing contact, increasing the slip angle and causing understeer. If the basic setting is negative, through, then as the car turns and rolls - the tyres will essentially become upright, offering greater grip when cornering.
But to achieve negative camber on the Mk 5 golf you have to be able to move the lower ball joints further outwards, and there is no adjustment to play with, as the boltholes, which are used to secure the ball joints aren't elongated as they are on the Mk 4 Golf.
The answer is to modify the wishbones themselves, and this is what the engineers at Morego have done with their aptly named power grip suspension kit. They simply cut off the ends of the wishbones and weld extension piece on. It's not a particularly sophisticated modification, more the kind of thing you'd find on a racecar, but it's very effective, producing around 1.75° of negative camber- enough to make a difference to the handling, but without incurring any adverse effects on straight-line stability at speed.
Having spent most of the morning behind the wheel of a standard GTI, we recently drove Morego's demonstrator a 250bhp GTI DSG, taking a particular interest in it's handling, and the extra front end grip is very impressive, almost making the car feel as it is on sticky race rubber rather than ordinary road tyres.
Even though the demo car was fitted with standard 17- inch rims and a set of fairly ordinary tyres, it was able to hang on like a limpet. We spent a happy couple of hours driving the car near Morego's premises in Brackley, where there are several roundabouts on the A43 ring road to play with, and traffic permitting the GTI would simply steer around faster and faster with every lap. There's no longer any hint of understeer; indeed the car feels perfectly neutral up to the point at which the tyres ultimately start to lose grip or the back end begins to run wide.
One of the potential dangers with negative camber is that the car can begin to feel a bit twitchy at high speed in a straight line, but a couple of lengths of the A43 towards silverstone soon dismissed this as a doubt, and a spirited exploration of some of the choppy local country roads showed that it was just as well controlled over rough surfaces as the standard car.
Tyre wear? Well, yes, if all your driving is at high speeds on the motorway then you might find the inner edges starting to feather first, but remember that the point of negative camber conversions is to keep the tyres upright when cornering, rather than roll them onto the edges. For most cars especially those driven as a GTI should be the negative camber conversion will actually produce a more even distribution of tyre wear across the tread surface.
Highly recommended, then, this powergrip kit is the first modification we'd make to a Mk 5 GTI, even before re mapping the ECU or fitting a free flow exhaust. It costs £495, which includes modifying the wishbones on an exchange basis, as well as a full fitting service and re- adjustment of the tracking. It's barely visible to the naked eye, and doesn't reduce the 0 60 time or raise the exhaust note, but for the enthusiastic driver we reckon this is probably one of the most satisfying modifications you can make to your Mk 5 Golf."