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Chassis

Progress Group CSII/CSIII Spring Rate Guide

Progress Group coilovers are configurable with a variety of spring options for all different sorts of use profiles. Here is a blog to help understand what the different spring rate selections will do for you!

ALWAYS CONSIDER the following:
* Primary vehicle use
* Secondary vehicle use
* Weather and road conditions
* Driver skill & experience

CONSIDER…
For the sake of comparison, typical OEM spring rates for these applications are approximately 220#/in front, and 110#/in rear. With the numerous Civic & Integra applications, there is a range of spring rates, and these C.S. (Competition Series) systems are significant-to-dramatic upgrades from your OEM damper and spring calibrations.

SHOP: Once you’ve decided on a spring rate choice for your car, shop Progress Group CSII & CSIII Coilovers on Heeltoeauto.com

CSII Non-Adjustable Damping

D-SERIES/Single cam applications

350/250: Best ride for a daily driver. Great for commuting. The front may bottom out if set up too low.

350/350: A good compromise, less understeer & more fun. A modest concession to ride quality. This may be choppy for some drivers with short wheelbase models; Civic Hatch and CRX.

350/450 or 350/550: Offers minimal understeer, quick turn-in, less roll, fast & fun, with the 55 rears being even better for a good for drag launch. Rides rough on bumpy or poor roads.

B&K-SERIES/Twin cam applications

450/350: Best ride for a daily driver. Fun and well-mannered. Modest understeer. Recommended for street/performance & daily drivers.

450/450: Good compromise, less understeer, less roll & more grip.

450/550: Minimal understeer, awesome handling, quick steering response, good for drag launch. Rides rough on bumpy or poor roads.

550/550: Good for track cars equipped with a front end spoiler or splitter. Also for street cars running super-wide wheels & tires and low ride heights. At this point, you should know you are signing up for a huge compromise in ride quality. Very stiff!

Here is MORE DETAILS about these combinations:

** STREET-PERFORMANCE
FRONT HEAVY setups (350/250, 450/350 etc.)
Good for Daily Drivers (DD), poor weather and road conditions because these setups do not upset the ride on the highway and during cornering. The softer rear suspension tracks nicely and rides better because it is more compliant. These calibrations ride well on uneven road conditions if set up at a reasonable ride height around 1.0 in.to 1.5 in. less than OEM (12.5 in.). Expect a dramatic improvement in handling capability and steering response. These setups will still have some mild understeer, less than OEM but still easy and forgiving to drive every day and in all weather conditions. This is the choice for sport-tuned Daily Drivers.

** STREET-SPORT
SQUARE setups (350/350, 450/450 etc.)
These setups are a compromise between ride quality and all-out handling. Some impact on ride quality makes for less understeer and faster vehicle response. The stiffer front springs also help prevent bottoming out. This combination is plenty stiff, and NOT recommended for true daily drivers (TDD) on poor roads, or drivers rolling a lot of commuter miles. Good for ‘fun cars’ driven by more experienced drivers.

** AUTOCROSS-TRACK & DRAG SPECIFIC
REAR HEAVY setups (350/450, 450/550 etc.)
Much more aggressive. This calibration has more grip, and is intended for use with ‘performance/track’ alignment settings and sticky tires. If ride quality is a major concern, don’t go here because the stiffer rear springs make for an uncomfortable (and choppy) highway ride. This is a more balanced and LESS FORGIVING setup intended for enthusiast TRACK days and AUTOCROSS events. These combinations will also launch well for mild drag applications on DOT tires. Expect a HUGE improvement in handling capability. This would also be a great low-budget setup for new (road racing) drivers going to a (track) DRIVING SCHOOL or TRACK events.
Faster chassis response, less forgiving, and MAX GRIP in most cornering situations. The chassis balance will be very close to ideal, having minimal understeer with ‘track-oriented’ alignment settings and good UHP tires. This is a BIG compromise in ride quality and will require more DRIVING SKILL to drive at the limit (on the track please!) NOT RECOMMENDED for wet/snow/poor weather and road conditions.

ALWAYS CONSIDER the following:
* Primary vehicle use
* Secondary vehicle use
* Weather and road conditions
* Driver skill & experience

CONSIDER…
For the sake of comparison, typical OEM spring rates for these applications are approximately 220#/in front, and 110#/in rear. With the numerous Civic & Integra applications, there is a range of spring rates, and these CS-II systems are significant upgrades from your OEM damper and spring calibrations.

CSIII Adjustable Damping

The above infor for the CSII mostly applies to the CSIII, although there is some additional capability with the CSIII that allows for higher rates than the CSII. Here are some notes for the CSIII’s expanded range.

550/450 – 550/550: Very stiff front and softer rear for poor roads and bumpy race tracks. Good for track cars equipped with a front end spoiler or aero-splitter. Also for street cars running super-wide wheels & tires and low ride heights. At this point, you should know you are signing up for a huge compromise in ride quality. Very stiff!

550/650 – 550/800 – 650/650 – 650/800: These setups are aggressive for track-only applications on smoother tracks with race tires or UHP shaved tires. At this point you should have some track experience and have some idea about what you are getting into. Call in and we can discuss these track-only setups and select one that best suits your application and specifics.

* FRONT HEAVY setups (350/250, 450/350 etc.)
Good for Daily Drivers (DD), poor weather and road conditions because these setups do not upset the ride on the highway and during cornering. The softer rear suspension tracks nicely and rides better because it is more softer & more compliant. These calibrations ride well on uneven road conditions if set up at a reasonable ride height around 1.0 in. to 1.5 in. less than OEM (12.5 in.). Expect a DRAMATIC improvement in handling capability and steering response. These setups will still have some mild understeer, less than OEM but still easy and forgiving to drive every day and in all weather conditions. This is the choice for sport-tuned Daily Drivers.

* STREET-SPORT ‘SQUARE’ SETUPS (350/350, 450/450 etc.)
These setups are a compromise between ride quality and all-out handling. With some impact on ride quality, you will have less understeer (more neutral balance) and faster vehicle response. The stiffer front springs also help prevent bottoming out. This combination is plenty stiff, and NOT recommended for true daily drivers (TDD?) on poor roads, or drivers rolling a lot of commuter miles. Good for ‘fun cars’ driven by more experienced drivers.

* AUTOCROSS-TRACK & DRAG SPECIFIC
REAR HEAVY setups (550/650, 550/800 etc.)
Much more aggressive. This calibration has more grip, and is intended for use with ‘performance/track’ alignment settings and sticky tires. If ride quality is a major concern, DO NOT go here because the stiffer rear springs make for an uncomfortable (and choppy) highway ride. This is a more balanced and LESS FORGIVING setup intended for enthusiast TRACK days and AUTOCROSS events. These combinations will also launch well for mild drag applications on DOT tires. Expect a HUGE improvement in handling capability. This would also be a great low-budget setup for new (road racing) drivers going to a (track) DRIVING SCHOOL or TRACK events. Faster chassis response, less forgiving, and MAX GRIP in most cornering situations. The chassis balance will be very close to ideal, having minimal understeer with ‘track-oriented’ alignment settings and good UHP tires. This is a BIG compromise in ride quality and will require more DRIVING SKILL to drive at the limit (on the track please!) NOT RECOMMENDED for wet/snow/poor weather and road conditions.

Check out this cool CSIII Unboxing Video on our YouTube Channel!

Categories
Chassis You Can Do It! DIYs

How to tune your adjustable coilover damper kit for the street.

There are a lot of folks out there, bless their souls, who have bought into the craze of coilover suspensions without having full knowledge of what they are getting into.

This article is a shot-gun approach at dialing in your favorite coilover kit for the street. Aimed at our core market, front- & all-wheel drive Honda and Acura cars, primarily driven on the street. This is a really general methodology, but it works. People often get mixed up because the changes they make in the front or rear impact the other end of the car, and you keep chasing your tail. With this approach you get the front all dialed in on what is important there, and you can tackle how the rear reacts afterward.

Front

The first thing you would do is set the preload back to zero and then move the damper adjustment knob in the front at least midway in its range, if not more stiff or almost full stiff. This will give the input control and sharpness of steering and handling you probably want. Less “bounce” per-say or “float” in the front end is desired. Those feelings give a certain distrust in the handling of the car and your ability to control it. Moving this stiffer should not adversely affect the ride at all although there will be more harshness through the steering wheel, firewall, and floorboard. It may seem that the car is transmitting more from the road, and this is a good thing. Dial it back to give more NVH isolation if needed, but keep it firm. You should not need any more preload here, but if the front end seems to feel like it bottoms out at all you can add preload about 1/4″ at a time until it feels a little better.

Rear

The ride quality and ultimate balance of the car is largely dictated by the rear setup. Here I recommend people make the damping as stiff as they can without feeling too much discomfort. Start in the middle and move softer if you need more comfort over bumps (you won’t be able to make it perfect over all bumps, you are going to have to find a compromise) or firmer if the ride is not uncomfortable. The firmer you make it the better the car is going to feel in a corner but will ride worse and worse. Ultimately you want to find where you are unable to accept the ride and dial it back a bit. In general, you want as much stroke in the back as you can get because this will allow a good ride and add grip, but want body movement controlled enough that it doesn’t feel like it is wallowing about. Preloading too much here, or putting stiff springs, is great for swinging the tail around an auto-x course, but makes the ride like garbage. Don’t preload the rear if you can help it, but again if the suspension seems to cycle too much even on firmer settings, add preload incrementally.

Spring rates and preload.

The only real reason to change rates is if you are exceeding the cornering load limits the kit was designed around. Springs are spec’d to hold the car up and to resist forces in cornering. A car with lighter weight will need lighter springs, and heavier cars need heavier springs. Also, a car cornering at .8g will not need a firm a spring as a car cornering 1g. I think a lot of people think that works in reverse…take an .8g car and add heavier springs to make it corner like a 1g car. Maybe this is true to a certain extent, but more important are the tires, tire pressure, road surface, and other grip related factors. Those all add grip. Firmer springs without more grip will cause the car to slide easier.

Wider tires mean more grip meaning harder cornering loads requiring firmer springs. Increasing the rates will allow the car to cope with harder cornering loads, but will dramatically impact the ride. This is especially true if the dampers are not tuned to accommodate these changes. Many adjustable suspension kits are designed around a single spring rate and allow some latitude up and down in spring rates but don’t mistake this as truly stiffening or softening the suspension.

Then there is preload, which is largely misunderstood. Changing the spring preload does not change the spring rate, but can lead to the effect of a firmer feeling suspension. Really what it does is it increases the load needed to compress the spring initially. Once the spring starts compressing it will feel normal but a larger input is needed to do that. This is particularly helpful bu increasing the amount of force needed to bottom out the suspension.

We hope that gives you enough information to get started on dialing in your suspension! By all means reach on out to us if you need more specific advice!