OK, I constantly see guys complaining and doing the wrong things to improve performance on their Genesis Coupe. There are also a few “generally” practiced theories that do not directly apply to the Genesis Coupe. So here are the basics of how to tune the Genesis Coupe suspension.
-First thing to improve are your driving skills. Any car can be driven “fast” without experiencing understeer or oversteer if you are capable of driving the car at its limit. Most drivers don't have the skill it takes to drive a car at its limit.
-The biggest no no I see people doing is reducing performance in the rear in order to “balance” the cars handling characteristics. Why oh why? The most common mistake is going to a stiff rear sway bar. I will get more into this further into the post.
-Air Pressures, Air Pressures, Air Pressures.
This is the cheapest and a very effective way to control the handling characteristics of your car. How to determine the best air pressures. Every track or diving condition will require slightly different air pressures. Even a couple of psi can make a huge difference. Start with the front tires. Record your cold psi. Chalk the sidewalls of your tires. Drive your car hard. Check the chalk to see how much has been worn off the sidewall. This will tell you how much air to add/remove to keep you contact patch on the tread and not on the sidewall. Record your hot psi. This method can also be used to give you an idea of how much to the adjust compression of your strut and/or spring rates if you are serious. Now that you have the fronts dialed in add or remove psi in the rear tires to control the amount of oversteer you would like in your car.
-Tires
The majority of you buy tires that best fit your wheels rather than buying tires that improve the performance of your car. Stretched tires will make part of the sidewall part of your contact patch. Our car is heavy and it is hard enough to keep the contact patch on the tread with properly sized and fitted tires. Sidewalls that are too small will decrease the consistency of maintaining contact with the road. If you are running 30 series and even 35 series tires, depending on the width, you do not have enough sidewall. One of the things properly sized sidewalls do is help with the compression and rebound. Sidewalls will soak up some of the imperfections in the road which translates into maintaining greater contact with the pavement. Small sidewalls transfer more of those roadway imperfections directly into the suspension and into the body of the car. In other words small sidewalls will make your car bounce more. Buy quality tires that will balance the handling of your car. If you buy cheap tires then you cannot complain about how your car handles. If you buy huge meats for the rear because you want to run 10.5s don’t complain about understeer. Buy tires and wheels for that matter, that are sized to improve the handling characteristics of your car not because they look good. HP always plays a part in traction so it is possible to that those meats are still not enough traction. There are things that can be done that are custom mods to increase rear grip but that involves some work. You can message me on it if you are serious.
-Coilovers/Springs
Springs only, don’t even bother. Waste of money. End of story. I’m not going to say one brand of coilover is better than another. I think you can get increased performance out of all brands of coilovers once they are set up properly. Obviously I have a preferences for Parts Shop Max coilovers because they offer great adjustability, quality, warranty and design. In setting up your coilovers I would start compression at 75% stiff in the front and 25% stiff in the rear and the same for rebound. Adjust as desired in 25% increments. This way you can really feel the change in performance and in what direction the performance is changing, for the worse or better. I would then adjust in smaller increments to really dial in your coils. The reason you will want to be stiffer in the front is because of weight. That’s where all the weight of the car is. The rear you want to set up looser than the front to allow for better traction while turning. You want some flex in the rear to maintain the largest contact patch. To stiff and the inside tire will lift thus reducing the amount of contact with the pavement. I believe most coilovers come with spring rates that are to soft. This is because if they build coilovers 100% for performance everyone would complain about ride quality. I am currently experimenting with 12kg, 10kg, 8kg and 6kg springs so I will have to get back to you guys on what provides the best performance.
-Sway bars
Contrary to popular belief you need a larger front sway and a smaller rear sway to optimize your cars handling. Why stiff in the front? Because you want to keep the front as flat as you can to maintain the largest contact patch. In the rear you actually need some flex to maintain the largest contact patch possible.
-Types of set ups
First you need to understand that at slower speeds like in autocross you will experience a greater degree of understeer and at higher speeds like in road racing you will experience a greater degree of oversteer. So understanding your end goal is important. I do not believe decreasing the performance of the rear in order to balance the car is the correct way to address a problem but I realize there is a limit to how much you can improve the handling of the front of the car. Personally, I would just add more air pressure to the rear than add a stiffer rear sway. I only recommend a stiffer rear sway for lower powered drift cars.
-Alignment
The optimum performance set up will cause a lot of tire wear on a DD so you need to decide what settings are worth the extra tire wear. You will not be able to dial in to much front camber. I have run as much as -3 up front and I think the front of the car would perform even better at -3.5. The reason is because of the McPherson front suspension design. There is so much positive camber gain under compression that you just can’t run to much negative camber. In the rear I believe running anything more than -1 is a waste. All you are doing is decreasing the contact patch in the rear. Toe out in the front about a 1/16” total. A little toe out will help your car turn in better and add high speed stability. In the rear I like zero because it’s a rwd. Our cars come with quite a lot of caster stock. I believe this is to improve the steering wheel return that is slowed by the dual knuckle design which does help with high speed straight driving stability but at a price. Reducing caster will help increase the size of the contact patch of the front wheels while turning. Basically as you increase your steering angle the more the car will rise. Park you car and turn the wheels and watch the front of your car go higher. That’ why I have reduced my caster.
-Ride Height and Weight transfer
Balancing the car significantly effects the handling performance of the car. I never weighed the car stock but I did have to raise the front when I had my car corner balanced just to get to a 55/45 front to rear weight ratio. I would say 99% of you including those of you who are at stock height have to much weight on the front. For all of you that are lowered. I will tell you right now 98% of you are to low. Our cars suspension geometry does not allow you to lower the car very much at all without increasing all the negative effects like body roll and positive camber gain. The lower you go the further away your roll center will be from your cars center of gravity. The effect of this is more body roll. This is a reason why so many of you love stiff sway bars. They reduce the increased amount of body roll you tuned into your car by slamming it. This is another example of reducing the performance of one aspect to make your car “feel” like it handles better.
There are plenty more things I can add like figuring out a way to keep the suspension travel in the optimum range which results in the reduced change in suspension geometry but that requires custom modification which I plan to dig into once I finish up with my spring rate testing.
-First thing to improve are your driving skills. Any car can be driven “fast” without experiencing understeer or oversteer if you are capable of driving the car at its limit. Most drivers don't have the skill it takes to drive a car at its limit.
-The biggest no no I see people doing is reducing performance in the rear in order to “balance” the cars handling characteristics. Why oh why? The most common mistake is going to a stiff rear sway bar. I will get more into this further into the post.
-Air Pressures, Air Pressures, Air Pressures.
This is the cheapest and a very effective way to control the handling characteristics of your car. How to determine the best air pressures. Every track or diving condition will require slightly different air pressures. Even a couple of psi can make a huge difference. Start with the front tires. Record your cold psi. Chalk the sidewalls of your tires. Drive your car hard. Check the chalk to see how much has been worn off the sidewall. This will tell you how much air to add/remove to keep you contact patch on the tread and not on the sidewall. Record your hot psi. This method can also be used to give you an idea of how much to the adjust compression of your strut and/or spring rates if you are serious. Now that you have the fronts dialed in add or remove psi in the rear tires to control the amount of oversteer you would like in your car.
-Tires
The majority of you buy tires that best fit your wheels rather than buying tires that improve the performance of your car. Stretched tires will make part of the sidewall part of your contact patch. Our car is heavy and it is hard enough to keep the contact patch on the tread with properly sized and fitted tires. Sidewalls that are too small will decrease the consistency of maintaining contact with the road. If you are running 30 series and even 35 series tires, depending on the width, you do not have enough sidewall. One of the things properly sized sidewalls do is help with the compression and rebound. Sidewalls will soak up some of the imperfections in the road which translates into maintaining greater contact with the pavement. Small sidewalls transfer more of those roadway imperfections directly into the suspension and into the body of the car. In other words small sidewalls will make your car bounce more. Buy quality tires that will balance the handling of your car. If you buy cheap tires then you cannot complain about how your car handles. If you buy huge meats for the rear because you want to run 10.5s don’t complain about understeer. Buy tires and wheels for that matter, that are sized to improve the handling characteristics of your car not because they look good. HP always plays a part in traction so it is possible to that those meats are still not enough traction. There are things that can be done that are custom mods to increase rear grip but that involves some work. You can message me on it if you are serious.
-Coilovers/Springs
Springs only, don’t even bother. Waste of money. End of story. I’m not going to say one brand of coilover is better than another. I think you can get increased performance out of all brands of coilovers once they are set up properly. Obviously I have a preferences for Parts Shop Max coilovers because they offer great adjustability, quality, warranty and design. In setting up your coilovers I would start compression at 75% stiff in the front and 25% stiff in the rear and the same for rebound. Adjust as desired in 25% increments. This way you can really feel the change in performance and in what direction the performance is changing, for the worse or better. I would then adjust in smaller increments to really dial in your coils. The reason you will want to be stiffer in the front is because of weight. That’s where all the weight of the car is. The rear you want to set up looser than the front to allow for better traction while turning. You want some flex in the rear to maintain the largest contact patch. To stiff and the inside tire will lift thus reducing the amount of contact with the pavement. I believe most coilovers come with spring rates that are to soft. This is because if they build coilovers 100% for performance everyone would complain about ride quality. I am currently experimenting with 12kg, 10kg, 8kg and 6kg springs so I will have to get back to you guys on what provides the best performance.
-Sway bars
Contrary to popular belief you need a larger front sway and a smaller rear sway to optimize your cars handling. Why stiff in the front? Because you want to keep the front as flat as you can to maintain the largest contact patch. In the rear you actually need some flex to maintain the largest contact patch possible.
-Types of set ups
First you need to understand that at slower speeds like in autocross you will experience a greater degree of understeer and at higher speeds like in road racing you will experience a greater degree of oversteer. So understanding your end goal is important. I do not believe decreasing the performance of the rear in order to balance the car is the correct way to address a problem but I realize there is a limit to how much you can improve the handling of the front of the car. Personally, I would just add more air pressure to the rear than add a stiffer rear sway. I only recommend a stiffer rear sway for lower powered drift cars.
-Alignment
The optimum performance set up will cause a lot of tire wear on a DD so you need to decide what settings are worth the extra tire wear. You will not be able to dial in to much front camber. I have run as much as -3 up front and I think the front of the car would perform even better at -3.5. The reason is because of the McPherson front suspension design. There is so much positive camber gain under compression that you just can’t run to much negative camber. In the rear I believe running anything more than -1 is a waste. All you are doing is decreasing the contact patch in the rear. Toe out in the front about a 1/16” total. A little toe out will help your car turn in better and add high speed stability. In the rear I like zero because it’s a rwd. Our cars come with quite a lot of caster stock. I believe this is to improve the steering wheel return that is slowed by the dual knuckle design which does help with high speed straight driving stability but at a price. Reducing caster will help increase the size of the contact patch of the front wheels while turning. Basically as you increase your steering angle the more the car will rise. Park you car and turn the wheels and watch the front of your car go higher. That’ why I have reduced my caster.
-Ride Height and Weight transfer
Balancing the car significantly effects the handling performance of the car. I never weighed the car stock but I did have to raise the front when I had my car corner balanced just to get to a 55/45 front to rear weight ratio. I would say 99% of you including those of you who are at stock height have to much weight on the front. For all of you that are lowered. I will tell you right now 98% of you are to low. Our cars suspension geometry does not allow you to lower the car very much at all without increasing all the negative effects like body roll and positive camber gain. The lower you go the further away your roll center will be from your cars center of gravity. The effect of this is more body roll. This is a reason why so many of you love stiff sway bars. They reduce the increased amount of body roll you tuned into your car by slamming it. This is another example of reducing the performance of one aspect to make your car “feel” like it handles better.
There are plenty more things I can add like figuring out a way to keep the suspension travel in the optimum range which results in the reduced change in suspension geometry but that requires custom modification which I plan to dig into once I finish up with my spring rate testing.