Technique: what you need to know about torque steer

Posted on 16-08-2015 at 23:08 by mauritsh – 52 Comments”

One of the cars has quite bothered by, the other car, not at all: torque steer. What is it, why do we have a brother dead, and how can you prevent this?

What is torque steer?

Torque steer is a phenomenon that almost exclusively occur in model year cars with an engine transverse in the front. Now we are not talking about a small spaardieseltje or something like that, because it occurs just with cars, with quite a few bhp’s and Nm’s.

Actually, it comes down to that the cars that have to deal with torque steer under heavy acceleration to one particular side. Not fine, because if you have a car a to z’n tail kicks, do you want that ” ie does what you want.

How is it caused?

Well, we know that, due to the hard action. Look for a better understanding of the story that is to come to the picture below. Small sidenote: we assume that the car is properly aligned and the tire pressure and such cases both sides are equal.

This is a rather schematic representation of a model year car with the engine transverse in the front. Logical consequence of this layout is that the transmission on one side of the block. In this case, the automatic transmission, so rather close to the are as follows:*. There is then a differential under. From the differential, the drive shafts, each of the front wheels of the driving. Nothing new, not exciting.

Or is it? One of the consequences of this layout is that the two drive shafts are unequal in length. The are as follows: * is driven by a shorter axis, the rechtervoorwiel by a longer shaft. Here comes the monkey out of the sleeve.

For one reason or another, has mother nature chose to use more torque to the wheel with the shorter drive shaft. At quite a pounding so it is this wheel that is harder to accelerate than the other wheel. Logical result: the car pulls to the side of the wheel that has less torque gained, in this case, so to the right. A good toef gas et voilà: torque steer is there.

Now you will also understand why the phenomenon hardly occurs with rear-wheel drive cars. This type of car generally has the differential lock between the rear wheels, so that the drive shafts (and therefore the traction forces) per wheel are equal.

Note: there are more things that torque steer can cause, but we pick the most important for this story to get out.

Possible solutions

One of the ways to torque steer to eliminate the “manipulation” of the length of the drive shafts. We say consciously to manipulate, because it is not works the same as simply aligning the lengths of these axes.

In brief, it boils down to is that a connector an end to the inequality between left and right. This intermediate shaft is separately mounted and is not moving with the right wheel. The shaft that eventually the right front wheel drives is just as long as the instance on the left, so torque steer for a large part of the neck is rotated. Look at the figure below for a schematic representation.

In addition, this solution allows the entire front suspension be adjusted to ensure that both driven wheels have the same amount of torque given with a solid dot gas. It’s a bit far for you now to discuss what results with toe-in and toe-out can be achieved, but with the tweaking of both cases is the tight feeling in the wheel, indeed, be solved.

For those of you who are interested in what toe-in (or toe out) exactly means: check the picture below, further, Google is your friend. Note that this Formula-racer so does not suffer from torque steer, because drive to the rear wheels.

In addition, for example, Fiat in the past, cars built on the ‘short side’ of a hollow shaft is used, and on the other hand, is a solid shaft. By means of this trick is the torsional stiffness of both axes somewhat aligned, so torque steer, most often, will be fixed.

In addition to adjustments to the axles themselves, use a variety of manufacturers sperdifferentiëlen to the problem in the bud. Please note: fine tuning is required, because otherwise such a solution is not the issue, only worsen. Ford, for example, on the Fiesta ST, and in the most recent Focus RS torque vectoring system, which, as it were, the operation of a differential lock simulates.

Also fits Ford (a well-known builder of cars that have to contend with torque steer) on the pure stuff as the Focus RS500 their acclaimed Revoknuckle-suspension due to unwanted effects to brush away. Also Opel solved the problem by modifications to the suspension of the Astra OPC.

Summary

A powerful motor, across the front of a car with front wheel drive is mounted, under heavy loads for plucking movements in the steering wheel and in the worst case, to a car that the scheduled job is different. The problem is often (but not always) caused by drive shafts of unequal lengths, and can in various ways be eliminated. This article gives only a very concise description of the phenomenon, we have tried in each case the most basic things to name.

Comments, additions and/or tips? Comments!