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Two questions we are asked frequently by our followers are:” Is it worth spending more money on coilovers for my track car?” and “What is the difference between cheap, mid-range and expensive coilovers?” They are two very good questions as prices in the coilover market can vary from £200 for a set, up to £3000 for a set and much more. One aspect of pricing differences could be due to coilover brand alone based on good marketing plans, manufacturer links and many more reasons. Therefore, to make this article all about what the physical differences and benefits are between differently priced coilovers we decided to focus upon one single brand that offer a range of coilovers all at different prices and investigated the differences between each set. The brand we chose to focus upon is GAZ Shocks based in the UK.
The Coilover Range
Below is a list of the coilover range currently on offer by GAZ alongside the average price for each kit. They are arranged in order from cheapest to most expensive on the average price per kit. These prices will fluctuate between models slightly. We will work through each kit in the next section to discover where the price differences come from.
- GAZ GHA Kit
The average price of this kit is £525.60 + VAT but can vary between models. This is the entry level set of coilovers that GAZ offer and is the cheapest of their range. Within this category there are different options such as GAZ GT, GS, GP and GAI which are all variations within the GAZ GHA kits.
- GAZ Gold Pro Kit
The average price of these kits is £622.90. These coilovers fall into the mid-range offering from GAZ and are possibly their most popular option holding high regard within the track day communities.
- GAZ Gold Kit
The average price for these kits is £965.31 + VAT. These coilovers are aimed at motorsport and are a step above the GAZ Gold Pro coilover range.
- Gaz Monotube Kit
The average price for these kits £1260 +VAT. The monotube dampers are a different design to the above coilover kits and have a more complex assembly which we will explain in more detail shortly.
- GAZ DA Kit
The average price for these kits is £1365.31 +VAT. The GAZ DA kits are similar to the GAZ Gold kit but have additional features that increase their performance potential which we will get to shortly.
What Causes The Kits To Have Different Prices?
Now it’s time to answer some important questions. What are the physical reasons why the coilover kits have different pricing? What is the difference between a mid-range set of coilovers and a high end set? What am I actually getting for my money and will I feel the benefit when I drive my car?
- GAZ GHA Kit
GAZ GHA kits require the use of some donor parts from the car. This reduces component machining costs and allows the overall price of the kits to be lower. They also do not have bump or ride height adjustment making them quite a basic coilover that will lower your car and stiffen your spring rates to reduce roll and bump. They do have rebound adjustment via an 8mm hex nut on top of the piston rod which rotates to alter the tension on the shim stack inside the damper. Using an 8mm hex nut is a cheaper form of adjustment as it is directly attached to the piston and is relatively simple to manufacture helping to reduce costs. The bodies are manufactured from steel making them heavier than other options in the range too. The GHA kits are limited to 450lbs on top adjustable struts which is enough for most cars running road tyres or track day tyres but is a limiting factor due to the strength of the materials being used. The GHA kits also have softer valving than other kits in the range to make them more complaint on roads, making the car more comfortable.
- GAZ Gold Pro Kit
GAZ Gold Pro kits are manufactured from aluminium and are anodised. Straight away these will cost more than the GHA kits as the material is more expensive and is more resistant to corrosion giving them longer life and preventing the adjustment from seizing up. The material also gives the added benefit of being lighter weight for track use. These coilover kits also offer bump and rebound adjustment and have ride height adjustment on the spring base. In order to provide the adjustment of bump and rebound, valves need to be placed inside the dampers to help control the oil flow through the piston. The extra components, machining time and materials are where the additional cost is created over the GHA kits.
- GAZ Gold Kit
The GAZ Gold kit is a more serious coilover designed to handle the high demands of racing and serious track use. They come with a larger diameter body which is able to house more oil than the above options. This helps to keep oil temperatures down due to the increased volume dissipating heat more efficiently. They are also fitted with a larger alloy gland to displace the oil when the piston rod is being extended which is then fed through a bleed hole to the control mechanism on the side of the strut. The control then dictates how easily the oil flows through the assembly, changing the bump and rebound ratio accordingly. This system is more complex and requires more intricate components than the system above, increasing their costs.
They also have a stronger piston fitted which is made from a higher grade material and has a larger diameter. This means that they are able to handle a stiffer spring rate more consistently which is a must for hard track and race use. These coilovers can also be provided with adjustable top mounts giving the capability to adjust the camber and/or caster using the top mounts too. The GAZ Gold coilovers can handle up to 1000lbs out on circuit which is close to what dedicated track cars use that run full slicks making them able to handle the demands of the race circuit more reliably than other options. These coilovers also offer ride height adjustment as well as bump and rebound adjustment. External reservoirs can be fitted to these coilovers at an additional cost too meaning that the attachment point is machined and then fitted with a blanking plug. The extra capacity of oil, stronger body, stronger piston, complex internal valving, level of adjustment and additional features is why these coilovers cost more than the above options.
- Gaz Mono-tube Kit
A mono-tube damper has most of its components machined in the UK to a very tight tolerance to ensure consistent reliable performance. Customers are able to specify the exact damping and rebound valving that they want for these dampers as each one is custom made at the factory. The mono-tube damper contains many intricate components compared to the other dampers in the range. It has a high pressure cylinder, a seal and rod guide assembly, piston rod with main piston, upper and lower shim stacks and a floating piston with a viton seal and a bronze loaded slide ring. Each one of these components is carefully manufactured and assembled.
A mono-tube damper body is the cylinder in which the piston and rod moves in and out. The pistons in these units have valve ports machined in both faces with various flow characteristics. These faces have precision ground shims on both sides in varying diameters and thicknesses. They are assembled in a tapered stack to alter the damping forces. Under the main piston is the floating piston, this has a viton seal and PTFE slide ring fitted. This is to seal a high pressure nitrogen gas charge. The floating piston moves up and down as the piston rod travels in and out of the shock absorber. Above the floating piston this is filled with a high viscosity damper fluid, all air is expelled and the rod guide & seal assembly fitted so the fluid cannot aerate or foam as it is under high pressure. This maintains very consistent damping under extreme conditions. These dampers work in any position, inverted, horizontal or any angle required. A mono-tube strut insert works in the same way but the outside of the main cylinder is ground and hard chrome plated. It is fitted inverted inside the strut tube which is bored to take PTFE bushes for the inserts to slide up and down. Units built in this way are very strong and take higher side loadings.
Each damper is tested on the damper dyno before sale like all the other dampers in the range but the mono-tube dampers are much more accurate. The difference in price from the GAZ Gold coilovers is due to a few things here: the additional components; the very tight machining tolerances which takes up a lot more machining time and requires extra processes; all the valving is made individually for application rather than batch runs being produced and the materials used inside and outside of the damper are more expensive.
- GAZ DA Kit
The double adjustable dampers are a lot more complex internally than the above options (excluding the monotube kit) and they contain a lot more intricate machined parts that are made on site in the UK. They can be manufactured from either steel or aluminium depending on the customers’ requirements and offer bump, rebound and ride height adjustment. These coilovers come with external reservoirs fitted and twin adjustment on the rear dampers. The external reservoirs are one of the main reasons why this kit costs the most due to the extra manufacturing and assembly costs when producing them. They include their own floating piston which separates the nitrogen from the oil helping to keep the oil pressurised. The extra capacity of oil required to fill the external reservoir keeps overall damper oil temperature down which helps to maintain a consistent level of damping when out on circuit which is very important for hard circuit use where other dampers could start getting hot and reacting differently to track conditions than earlier in the race which can change the way that the car handles and ultimately slow the driver down.
Why Are “Budget Coilovers” or “EBay Coilovers” So Cheap and Do They Work?
If you have ever looked for coilovers to install to your car then you have most likely come across some very cheap kits around the £100 – £250 mark. A lot of these coilover kits can be found on EBay hence the connotation “EBay coilovers”, but why are they so cheap? One of the main reasons for the price difference is that they are often manufactured in the Far East in bulk. This means a few things: the first is that the ride is often very harsh due to the “one for all” valving used in the damper, the spring rates are often much the same at the very stiff and harsh end of the spectrum making the car often too bumpy to perform well on circuit. Also, the vast majority of coilover companies will dyno test each damper before it is shipped and will be sent with the dyno print out to show that each damper is within the approved tolerance for sale. The budget coilovers are most likely not dyno tested with the only chance being the odd one from a mass run of them being tested every now and then. This means that very inconsistent dampers could be together in one box, giving unequal damping to each wheel which is going to be detrimental to performance.
The materials used are also often basic giving way to seizure and corrosion which often takes place in only a couple of years from experience. It is very important for a particular car to have its own designed spring rate and it is very important that that spring rate comes with matching valving in the damper so that the package can perform effectively. This is not the case with budget coilovers and they can lead to slower lap times than stock suspension due to the fact that they are too harsh of a ride and can lead to the car being bounced around causing the tyre to leave contact with the ground.
The summary for budget coilovers is that if you are only bothered about getting your car low and stiff then they might be an option for you. However, if you intend on getting your car lower, stiffer and faster on circuit then steer well clear of them and choose a company that can provide dyno print outs and matches their valving to the spring rates installed.
How Important Is Damper Valving?
In short damper valving is very important. The shock absorber must be able to control the spring correctly. If the valving is too harsh with a soft spring installed then over damping can occur where the damper will stay compressed for too long during bump conditions as the valving is too strong for the spring to overcome, keeping the spring compressed too long. This can make the bumps feel much larger but can lead to a situation where the damper can bottom out over consecutive bumps. This happens when the car hits a bump and before it is able to re-extend it hits another bump, compressing it further and so on until it bottoms out and loses all damping capabilities.
Another situation that can occur is under damping where the valving is too soft compared to the stiffer spring. This scenario will feel very unstable at high speeds and is unsafe to drive as well. The feeling with an under-damped car is that the spring will extend too quickly causing the car to begin bouncing on the spring as the damper is incapable to control its movements effectively. It is for these reasons why it is best to avoid typical “budget” coilovers and opt for an established company that takes time to install the correct valving for the installed spring rate and operating conditions as oppose to the “one for all” valving that is often used in budget coilovers.
Key Features of a Good Track Day Coilover
If you are serious about getting some good coilovers for your track day then there are some features that you are definitely going to want as part of your coilover kit to make your car handle much better and to help you improve out on circuit. The required features are:
- Adjustable Bump and Rebound Damping
Having adjustable bump and rebound damping will help you firm things up when you get to the circuit. Your corner entry and exit handling behaviour can also be fine-tuned using these settings as well as how the car handles bumps and elevations in the circuit.
- Adjustable Ride Height
Having adjustable ride height is important as it allows you to lower the centre of gravity of the car. It also allows certain aspects of geometry to be altered such as roll centre heights. The main benefit of adjustable ride height though is that it allows the corner balancing to be optimised to provide even loading side to side and to tune the cross weight of the car to make it perform better out on circuit.
Another good additional feature that you can add on to your coilover is adjustable top mounts. These are not as fundamental as ride height and adjustable damping but they will allow you to alter your camber and caster in most cases, providing a lot of adjustment to get the tyre working effectively out on circuit to decrease those lap times.
