Spacers, frames, tensioners. the result is visible! - Toyota Corolla, 1.8 L, 2003

STRETCHES AND FRAMES: STRENGTHENING BONES

Frames today have firmly taken their place among the most popular tuning accessories, and probably not even worth talking about the spacers - this generally applies, almost to the drain section. Sadly, but many put frames and spacers because of beauty, according to the principle it will not be worse ...
Dumb theory.

Those who studied at the university for a technical specialty know firsthand about the subject "Resistance of Materials" or "Strength of Materials". This subject is considered one of the most difficult in high school, thanks to it our army was replenished with more than one platoon of young soldiers. For those who studied in the humanities and whether they simply did not study, we tell you: the strength of materials studies the ability of a material to resist the impact of other bodies on it. In our case, the material is the body, and the other bodies are the road, inertial forces, and other side road objects, including the bodies of other cars. In a coupe, the effect of these factors leads to rather serious consequences for the body, up to the complete unsuitability of the car.

Here's a good example: most household appliances are sold in cardboard boxes with foam inserts around the inner perimeter. Now think, if you just take a cardboard box and start twisting, then you definitely won't have any problems with it, it folds easily and wrinkles. Now we glue the lids with tape, it is still wrinkled, but a fairly large amount of effort must be made. And if you put in the longitudinal spacers made of foam, which firmly rest against the sides, now you can put in a lot of kilogram equipment, even hammer in nails and play football - cardboard that is not durable in appearance will cope with this without problems.

It is the same with a car, but in any, even the most rigid body, deformations occur, even microscopic ones. For another example, let's take, say, a "not new" domestic-made car and raise it on a jack. In 80% of cases, the doors will jam in the openings, which means that the body is deformed! How does this affect the behavior of the car? The main strength characteristic of an automobile body is its torsional rigidity. If the rigidity of the body is not high, then the reactions to the steering turns become "smeared" - the bending of the body and the flexibility of the metal in the areas where the suspension arms are attached cause a mismatch in the operation of the front and rear suspensions. In addition, constant twisting causes the body to age more intensely. The welded seams begin to "open up" slowly, and corrosion creeps into the formed microcracks. Generally, nothing good. The body type also affects the rigidity quite strongly. In this regard, 3-door hatchbacks and coupes in terms of rigidity are much ahead of all others precisely because of the body shape, which provides maximum resistance to bending, but minivans and station wagons are considered the softest.

What are the reasons that prevent designers from maximizing stiffness? The first is weight. The more metal we reinforce, the heavier the car becomes. As a result, we change the "awl for soap". Partly the situation is saved by amplifiers made of lightweight carbon, but another problem arises here - the price. Safety also plays an important role, because the area of ​​the engine compartment should be easily deformed, and therefore be as less rigid as possible. Designers have to compromise and balance these metrics. The torsional stiffness of the body is measured in newton meters per degree (Nm / deg. - the more force (in newtons) is applied, the greater the angle (in degrees) the body is deformed) The higher this value, the less the body is deformed from the applied torsional load
Path and ways to increase rigidity.

There are many options for increasing the rigidity and their choice depends, first of all, on the purpose of the car and the thickness of the owner's wallet. The first is "spacers" or "stretch marks".

The options are just darkness - dozens of varieties and hundreds of modifications. But you can still distinguish the main types: front strut, lower strut, rear strut, you can also add to this group - "kerchiefs" and "rods"
Front strut.

It is a structural element of the front suspension struts.

Front struts are the most common type of body reinforcement, its advantages are obvious - ease of installation, low price, visual appeal and a fairly strong increase in the rigidity of the front of the car. Their purpose is to reduce deformation and movement of the body cups when the vehicle is turning. The installation result depends on the vehicle. If its design is generally balanced, then the result will most likely not be visible. And for others, this device is strongly recommended. For example, for the VAZ "tenth" family. There "walk" not only racks, but the entire front end is deformed! By the way, there is also a special amplifier for it, but more on that later. There is an abundance of front struts on the market now, but only the material and method of attachment are fundamentally different.
Kerchiefs.

An ordinary spacer works exclusively in compression, but you can make it work in torsion, for this the cup is additionally reinforced with one more element - kerchiefs (special thick steel plates). As a result, the strut also begins to work in torsion. With gussets, you can also strengthen the places of the wheel arches, suspension struts and stiffening ribs of the entire body, in most cases, for this you will have to disassemble almost the floor of the car, at least the entire interior for sure, therefore this technique is used mainly on racing cars.
Barbells.

In addition, the so-called "rods" can be attributed to the additional element of the front struts. The rod is a special movable mount that connects the engine and the strut, besides this there are rods that connect the engine with other "strong" elements. This element works mainly during engine braking and abrupt starts, the effect is a decrease in the displacement of the power unit under extreme loads, a decrease in car drift during a sharp start, a decrease in the movement of the gearshift lever handle, and, of course, an increase in the overall rigidity of the body. The disadvantages of using rods include an increase in the noise level in the vehicle interior
Lower strut

The lower strut reduces movement of the front suspension arm bracket, reducing stress in the arm bracket and side member floor connector. Taking part of the load on itself, the lower strut removes the body parts from the high stress zone. As a result, improved handling, stability, increased body life. Installation is quite time consuming.
Rear strut.

Reduces the movement of the rear mounting cups, increases the overall torsional rigidity of the body. Result: improved handling, stability. The main thing to consider: the rear strut is effective only if it is fixed to the power elements of the body, and not to intermediate elements (seat mounting brackets, for example) The rear strut is also quite easy to install and dismantle, but there are also negative aspects: firstly, this is extra space in the cargo compartment, and secondly, there are pitfalls, the rear strut can increase understeer, especially if the rear of the car is reinforced with some other elements. If the car has a stock suspension, it is better to abandon the reinforcement of the rear or reinforce it with only one reinforcing element.

In addition to struts, there are many ways to strengthen the body - an increase in welds, reinforced subframes, anti-roll bars and cross members, various reinforcing elements in places with weak rigidity, developed for a specific model and, of course, frames.
Enlargement of welds and welded elements.

Increase in welding seams. The fact is that the body on the conveyor is welded by spot welding, i.e. there are gaps between the welding points. Naturally, the denser these points are, the more rigid the structure. However, their increase is hindered by technological problems in production and the complexity of their implementation without special tools. But this problem can be easily fixed by a qualified welder with decent equipment. The main thing is not to run into an unskilled welder and not to violate the physics of the body. It is also common to weld new additional iron elements into weak parts of the body.
Stabilizers and crossbars.

These units are also present in stock and have a bunch of properties that affect handling, comfort, so usually factory cars have intermediate ones, so to speak, not too soft, not too hard. There are two options for improving them - strengthening and replacing. Side effects - increased noise, sensitivity to unevenness and all the same positive properties: handling and stiffness. It is strongly not recommended to install stabilizers, cross-members in tandem with the rear strut are especially special on the stock suspension.
Stretchers.

Subframes are in many ways similar to stabilizers and crossbars, the only difference is in globality, for some versions of the subframe, serious modifications of the entire front end of the car will be needed - overcooking and cutting, glasses and even shock absorbers are being altered, and in appearance such works are not very friendly. But the effect! You can completely change the geometry of the suspension, improve stabilization by increasing the castor, increase the track and, as a result, stability and handling. Stiffness, of course, will also increase.
Details on order.

In addition to all of the above, there are parts that reinforce the body of a particular car in its weak points. This topic is quite relevant for the Vaz of the 10th family, their body is very weak, and therefore literally every centimeter can be strengthened.
Safety cage.

The frame, in a racing car, performs not only its direct functions of protecting the pilot, but also superbly strengthens the body. It is obligatory for use in any racing car, the only difference is in its complexity (although the obligation appeared not so long ago in 1994, before that the installation of the frame was a purely personal matter). The frame is a combination of rigidly connected steel (steel with a ultimate tensile strength of at least 45 kg / sq. Mm) cold-drawn seamless pipes, for example, 30HGSA. By type, frames can be roughly divided into two categories: homologated and non-homologated. The former you can install in your car and you can be admitted to official competitions. However, it is very complex and presents certain difficulties, which we will discuss below. The second type is "civil" frames, simpler and naturally cheaper.

By the type of installation, two types can also be distinguished - welded and collapsible. The former are welded directly into the body structure, i.e. it will be impossible to extract it from there without a grinder. In the second case, only the hinges are welded into the body, and the pipes themselves are bolted to them. In this case, the rigidity is slightly lower, but it is possible to remove the frame. I note that almost all the cars of the USSR circuit racing championships in the 70-80s had a removable frame. Pipes (or arcs) in the frame can be divided into main and safety pipes. There are "mixed" options, for example, where the main frame is welded in, and the arc near the seats is removed. You can make the frame yourself (naturally non-homologated and possibly extremely dangerous, not safe), or you can purchase a ready-made kit. The main side effect of the frame is weight. The average frame weighs about 40 kg, which is quite a lot. In addition to this, the deterioration of visibility and embarkation and disembarkation, as well as only non-elastic multi-point belts can be used as belts. So in everyday use this thing will cause certain difficulties, well, and the most important problem is the difficulty of obtaining a technical inspection, if you have a frame installed, you will not have to go through the bottom of an instance. The frames have a rather complex structure and various gadgets, such as pipe windings, which protect the rider from injuries that the frame can cause during an accident. In civilian tuning, frames are often used for beauty, for example, in Germany, for example, they are on almost every second tuning car. If you participate in races, the question of the frame is solved by itself, but before installing it in a civilian car, you need to think a hundred times, in addition to impairing visibility and physical inconvenience, the safety cage can play the role of a safety cage. If in racing the frame can save from a terrible accident while preserving living space, then in life it can kill. Frameworks allow you to avoid some traumatic factors in favor of others. living space is preserved, but the installation of the frame eliminates the airbags, and inelastic multi-point belts expose the pilot in accidents to significant overloads that may well kill (for example, rupture of internal organs), but the frame reinforces the body as much as no other element, the same WRC cars there is nothing more than a frame on which body panels are mounted and these facts make you think. If in racing the frame can save from a terrible accident while preserving living space, then in life it can kill. Frameworks allow you to avoid some traumatic factors in favor of others. living space is preserved, but the installation of the frame eliminates the airbags, and inelastic multi-point belts expose the pilot in accidents to significant overloads that may well kill (for example, rupture of internal organs), but the frame reinforces the body as much as no other element, the same WRC cars there is nothing more than a frame on which body panels are mounted and these facts make you think. If in racing the frame can save you from a terrible accident while preserving living space, then in life it can kill. Frameworks allow you to avoid some traumatic factors in favor of others. living space is preserved, but the installation of the frame eliminates the airbags, and inelastic multi-point belts expose the pilot in accidents to significant overloads that can very well kill (for example, rupture of internal organs), but the frame strengthens the body as much as no other element, the same WRC cars there is nothing more than a frame on which body panels are mounted and these facts make you think.
The power unit is rigidly connected to the body.

Even in motorsport, such a method of increasing the rigidity of the body is widely used, such as the inclusion of units in its power structure, for example, an engine, a gearbox and a final drive. This means that they are all rigidly connected to the body, which also greatly increases the rigidity. For example, similar solutions are found in almost all "formulas", incl. our Formulas "1600" and "Rus". In general, the progenitor of this idea was the legendary Colin Champman, the founding father of the Lotus firm, who first brought the idea to life on the Lotus 25 Formula 1.
Folk ways.

There are also popular methods, for example: the holes of the sills and side members are filled with polyurethane foam. The way is cheap and angry. In the pluses, there is a slight increase in rigidity, in the minuses - the lack of ventilation and, as a result, increased corrosive activity. Also, when these parts are replaced by welding, there is a risk of fire.

PS The rigidity of the body is also noticeably influenced by how the power unit is installed. Therefore, the difference in results is higher for cars of the classic layout - there the torsional stiffness is increased by the front suspension beam. But in front-wheel-drive cars with a transverse engine and McPherson-type front suspension, a noticeable increase can be given ... by the back of the rear seat! For example, in "eights" and "nines" the back seat increases the body rigidity by about 1000 Nm / deg due to the fact that the back is solid and rigid, and on the long-suffering tenth family the back is separate and this 1000 Nm evaporates. Therefore, VAZ recommends that owners drive as little as possible with the rear seat folded down - the body is at the same time weakened and resists twisting load worse.