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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!

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Chassis Heeltoe Explains

About Chassis Braces

Chassis bracing may be the most under-rated and misunderstood modifications available to a vehicle. If the chassis accounts for the frame, steering, and suspension pick-up points; then this assembly must be as rigid as practical to perform at its best. Some compliance in the chassis helps dampen noise, vibration, and harshness (NVH), and it is not possible to completely eliminate flex. However, using strategic pick-up points, aftermarket chassis braces can be very effective at enhancing the feel of steering and suspension systems, greatly improving driver confidence and, as a byproduct, speed.

Strength

Bracing works by resisting the forces of compression and tension. Keeping two points at a fixed distance apart is the goal. With a rigid mounting between them, two points cannot bend toward each other. Judging a brace by its assembly* or how heavy it is may not be giving credit to the actual function of the part.

Materials

Braces are most commonly made out of steel or aluminum. These materials are inexpensive and strong. Aluminum has a lower weight, but fabricating it to be effective does carry a higher cost than a steel part. The most intricate parts of braces are the mounting points. Some manufacturers will, therefore, use steel for the mounting points and aluminum for the joining bar stock, and attach them with bolts. Carbon fiber and titanium are other materials chosen for their lightweight and strength, in the face of their expense.

Construction

Braces made out of one piece, or being a welded-up assembly, are assumed to be stronger than those made of multiple pieces. This statement is a risky one because it is taking design and quality out of the picture. A well-designed brace made with quality materials that bolts together would be preferable to a cheap, flexible brace made to be one-piece. It is generally true that brace which is installed as one piece would be more rigid, but unless the brace is then welded to the chassis itself, this point is largely irrelevant if the brace made is of high quality.

Placement

In general, bars mounted laterally (side-to-side) are effective at reducing twist in the chassis. Twisting movements cause the center points of the frame to move closer together. By fixing these points, the twist is resisted. Also, subframes and uni-bodies are made to accommodate the installation and mounting of other vehicle systems (exhausts, suspension parts, and drivetrain assembly) and closing these open areas “boxes” them in making the entire chassis stronger in that area. Lateral bracing will be felt more in turns where there is a high load.

Longitudinal braces help resist bending in the chassis as the front and rear traverse bumps in the road. The front and rear work together more than most would assume. By simply going over a bump, the chassis will bend, and in these bending moments, there is a numbness that reduces confidence. It’s not as apparent at road-speeds, but at highway or HPDE speeds, confidence is very important. Also, keeping the chassis flat reduces unwanted changes in wheelbase that can make the vehicle hard to set in turns after high-braking zones.

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Chassis Heeltoe Explains

What is the “Chassis?”

When speaking about the vehicle as a whole, the chassis is the first major component that is considered. The frame or unibody is the large structural unit that is the base of the vehicle’s assembly. The wheels, suspension, body, engine, and other vital parts of a vehicle all must attach to a base assembly; referred to collectively as the chassis.

Rolling Chassis

There are differing opinions as to what is included in a rolling chassis. Some sources include an engine and drivetrain nestled within an otherwise bare vehicle frame. Others claim a rolling chassis is more of a complete vehicle without the drivetrain; which is not accurate as a rolling chassis would not necessarily include any coachwork or comfort items. Body-on-frame cars are easier to visualize as a rolling chassis; it’s the vehicle with the body removed. An engine need not be part of the package as long as the suspension arms, dampers, springs, and hubs are there, along with brakes and wheels.

Chassis versus Frame

To state a chassis as “the frame” may be an over-simplification of what a chassis is. The frame is the major component of the chassis; it acts like a skeleton that provides the backbone of the vehicle. To it, suspension arms with spindles, brakes and wheels are attached. As components are added, the frame becomes a chassis. To put it another way, the chassis is the pure functional component assembly without the body on it.

Chassis versus Shell

It becomes difficult to nail down where the chassis stops and the body starts when the vehicle has a uni-body construction. In these chassis configurations, the body shell serves as the frame. As such it is not practical to visualize the frame without the body. With the aid of auxiliary sub-frames that are affixed to the uni-body, suspension arms are attached to the body, to create a rolling chassis. Commonly, people will refer to this chassis as a shell or a rolling shell. While the body is present, the interior usually would not be. Again, the powertrain is “optional.”

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Chassis Heeltoe Explains

Wheel Hub Spacers & Hub Adapters (w/ Video Content)

Why you want wheel hub spacers

Heeltoe has done the homework and found that there are three main reasons why you would want wheel spacers:

  • Looks
  • Handling
  • Brake Clearance

If you are trying to fit different bolt-pattern wheels on your car, you might be needing Hub Adapters instead, which we’ll explain a little further down.

That stance!

Bumping out the wheels on a car to widen the track is a great way to make the stance appear more aggressive. Car manufacturers leave ample room for wheels and tires to move and articulate to avoid rubbing in extreme situations, but this clearance can result in a “sunken-in” look to the wheels as they often sit far inside the fender arches with a fist-full of unsightly fender-gap; hardly a flattering stance for a dialed-in Heeltoe ride.

Getting the tire snuggled up to the fenders makes a car look a little lower and meaner. When sized properly, wheel spacers will complement the look of factory or aftermarket wheel and tire combos without much worry about rubbing. Of course, there is a tasteful limit to how far you push out the wheels, so act in moderation if you want to stay classy.

Flatter in the turns

Back in the 90s, Pontiac had a “Wider is Better” campaign promoting the wide-track design of their Grand Prix model. Contrary to the name, the Grand Prix is no “grand prize” of performance engineering, but the concept is true. A wider track–the distance between the left and right wheels, measured from the centerline of the wheel–will tend to improve the roll-resistance of the chassis. A little wider stance can help the car feel flatter and more stable in turns.

Brake clearance

Another main reason a car would need wheel spacers is to provide more space for aftermarket brake upgrades. Big Brake Kits sold by Heeltoe, or BBKs, often feature 4-, 6-, or more caliper pistons; a performance benefit with a side effect of to get much fatter than standard calipers. The additional size of aftermarket brakes oftentimes leaves little or no clearance to the backside of the wheel. Wheel spacers move the wheel away from the hub which makes for a more comfortable fit of larger brake calipers behind even a standard wheel.

So, how do they work?

This video helps you understand a little more about how these bolt-on spacers work.

You may have seen different kinds of wheel spacers and here we are explaining how the “bolt-on” kind work. Viable spacers below 10mm (0.4″) in thickness do not have studs in them and require extended studs to be installed to allow for enough thread engagement for the lug nut after the wheel is installed. There is no major rule of thumb for how thick is safe to go on a standard wheel spacer, but 5mm (0.2″) is the max that we would ever go, assuming you have even enough thread on the studs to begin with. If in doubt consult a technician.

Get Fitted

Getting the right size spacer for your needs is all about taking a simple measurement with a tape measure or ruler.

If you are trying to move the tire closer to the fender, measure the distance from the sidewall or tread blocks to the edge of the fender to approximate the width you need. Keep in mind that the tire will camber-in away from the fender as you drive so you may have a little more room than you think.

If you are trying to make clearance for brake calipers, the measuring can be a little more tricky. Ideally, you will have the brakes installed on the car’s hub & knuckle, and then put the wheel on over them. The risk here is that if there is contact between the spokes and the caliper, you can scratch the caliper, so first cover the caliper with blue painter’s tape. Then, add washers to the wheel studs to stand the wheel away from the hub until there is sufficient clearance to the calipers to spin the wheel without hitting the caliper, being sure you sung the wheel down onto the washers to get a true idea of the spacing needed.

Wheel spacers are available in fixed widths, so once you know how much space you approximately need, round out to the next size. Below are the most common widths of spacers you will find in millimeters with the approximate English unit conversions. For the most part, spacers of 15mm thick or greater will have studs in them already, where smaller ones will need longer studs installed in the hub, which, depending on the kit you get, may or may not be included.

Avail with Studs in Spacer? mm Size Approx Inch Size
w/o studs in spacer3mm1/8″
5mm3/16″
8mm5/16″
10mm25/64″
w/ or w/o studs in spacer15mm19/32″
w/ studs in spacer20mm3/4
25mm1″
30mm1-3/16″

There are more sizes than the above available, many with or without hub ring options. This chart just gives you an idea of how spacers are sized out. The difference between “rubbing” and “not rubbing” is as small as 1-2mm (1/16″) so don’t be afraid to get close but definitely round-up.

Spacer or Adapter

Spacers and Adapters are fundamentally the same thing, with one important difference. The difference between a spacer and an adapter is that a spacer moves the factory wheel out with the same bolt pattern. An adapter will act as a spacer but also change the bolt pattern, allowing you to use a 5×100 wheel on a 5×114 hub, for example. So if you have a 5×100 set of wheels that you truly love, you can put them on your 5×114 hub, provided you have room at your fenders for the extra 15mm-minimum spacing you’ll see.

Hub Centering

Hub-centricity is another frequent concern with wheel spacers. The wheel of the car has an inside bore designed to fit over the snout of the wheel hub. Some wheel spacers and adapters are very nicely designed and incorporate a hub centering feature. However, this design feature does increase the cost and also limits the supply of the exact, right spacer for you right when you need it. Plus you need to know the hub bore on you car as well as the bore diameter of your wheels, and in a wheel-fitting pinch, you probably don’t know this.

It’s often claimed that without hub centering rings to fit a mismatched wheel and hub size, a vibration will be present while driving. Heeltoe’s experience has disproved this claim without exception. While having a hub centering ring is ideal for the most support of the wheel on the hub, lug nut seat design will perfectly center the wheel on the hub and prevent any vibration. As always, even and proper torquing of the wheels is critical.

Billet or cast alloy?

Most spacers are machined from billet aluminum. You should always make sure you get good quality spacers because the studs need to be OE quality or better and the spacers themselves need to be strong. This stuff holds the wheel onto the car and having one break would be a catastrophe. Spending a little more money on quality or well-known brands is generally recommended. Some spacers that don’t have studs are made of cast aluminum, which is perfectly fine, as long as they aren’t too cheap and don’t deform with the wheel torqued down.

In Conclusion

The real reason you want spacers or adapters boils down to a personal need. You either put brakes on that won’t fit the wheels you have, or you put wheels on and they don’t look perfect against your fenders, or you want to improve the look and handling of the car a little without changing the wheels for different ones. Whatever the reason we hope you know a little more about how to select a spacer for your needs and always know that #HTinyourcorner!

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Chassis Heeltoe Explains

BC Racing BR Series, Swift & Extreme-Low Unboxing & Product Lap

Heeltoe Automotive offers the complete line of BC Racing Coil-over damper kits, including all the custom options you want to get the perfect set for your car!

Swift springs are offered to improve the quality and consistency of the ride. Custom spring rates can be selected at no extra charge, and include appropriate damper valving changes. The Extreme-Low option gives you a shorter damper to allow for the lowest drop possible (for those looking to lower 3.5″ or more).

Check out this video from Heeltoe showing you more of the features of the BC Racing coilover kits, in living color!

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Chassis

Product Announcement: Medieval-Pro Torsion Bars Now Available

The torsion bar front end of a Honda Civic/CRX from 84-87 or Acura Integra from 86-89 is one of the more widely misunderstood components on these unique Honda models. But what generally isn’t misunderstood is that you want larger ones if your car has any sporting pretense.

The torsion bars are these cars’ front springs, supporting each corner of the car. They function as front springs but¬†work a lot like sway bars. In these Hondas, splined bars connect a free-floating front control arm to the subframe via an adjustable “torsion tube.” Stock bars are around 17-19mm in diameter. The size relates directly to how “stiff” the suspension is.

For many years, a company in Los Angeles called Upgrade Motoring produced torsion bars, which Heeltoe had sold under our in-house label “Medieval-Pro.” However, in 2016, the supply of these bars began to fade. The pricing continued to rise and customers were unable to afford them any longer. In January 2017, Upgrade Motoring announced they could no longer produce torsion bars.

This sad day came just around the time that Heeltoe has decided to combat the rising prices by producing bars through another manufacturer. One was found and the second generation of Medieval-Pro Torsion bars are here!

Currently, Heeltoe offers bars in 24, 27, and 30 mm diameters, in CRX lengths. New circlips and snap rings are included.

Astute readers will know that some Civics actually come with a shorter torsion bar than the CRX does and that the Integra bars are nearly 1″ longer. Due to current production and demand limitations, Heeltoe is only producing CRX-length bars at this time. The good news is, any of these cars can use the CRX bars. If you have Civic tubes, the CRX bars will stick out the back slightly, which is not a functional problem. You will need CRX torsion tubes if you have an Integra, which can be found at junk yards and the like. For evidence, find this link:¬†Integra Torsion Bar Installation

Keep in mind, the change in length from an Integra or Civic bar will also change the wheel rate. To make sure you are selecting the right bar for your application, find our Honda Torsion Bar Wheel Rate Guide here.

Shop For Medieval-Pro Torsion Bars Here: Medieval-Pro Torsion Bars

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Chassis Heeltoe Explains

Koni Sport Yellow Shock & Their “Height Adjustable” Nature: Don’t Put Too Much Stock In That…

Koni Sport/Yellow shocks provide a broad damping adjustment range and will accommodate a broad range of springs.

In many applications, Koni Sport, or “Yellow,” shocks, also feature numerous snap-ring lands, or grooves, in the bodies which allow for movement of the spring perches to different positions. Moving the perches up has the effect of raising the car, and moving them down lowers the car. So, naturally, many people consider the Koni Sport damper as a “height adjustable” part. I think even Koni promotes it this way. So it must be!

We at Heeltoe use a lot of caution when calling Koni Yellows “height adjustable.”

Most people don’t realize that the awesome Euro-tuned Koni damper is also rather IKEA-like from an external standpoint (just look at the instructions…sheesh!). The perches can be moved to varying degrees but a cautious observer notices that the fronts (for the 3rd gen TL application as an example) have two height settings and the rear has three (!).

If Koni made these dampers to be height adjustable why would they not allow the same range of adjustment on both the front and rear? And more than that, the rear ring-land spacing is not always evenly spaced.

Why?

The reason being, in our estimation, that the Koni Sports are broadly used across varying applications and this adjustment is needed to accommodate different installations. The adjustable valving allows them to use the same front dampers on these Honda and Acura cars:
2g TL, 3g TL, 2g CL, 6g Accord, 7g Accord, 1g TSX.*

The rears are more focused as fitting the 3g TL, 7g Accord, and 1g TSX with the earlier cars having a different part. Likewise, the rear dampers are supplied with spacers to allow them to fit the different rear hub carrier dimensions (because TL/Accord is wider than TSX).
Don’t forget Accords come in all combinations of I4/V6 and 2dr/4dr.

The different height levels of the Konis are there because these dampers can be adapted to various pre-load levels to compensate for the loads these different cars have on them. When installing Konis on all these cars you will note that the standard dampers’ spring perch heights moves. So to set a car at “stock height” you pick the perch height that corresponds with the stock damper.¬†

So why not call that a “feature,” MrHeeltoe?

Simply because not everyone is going to derive benefit from moving these perches in the same way. Say you install the dampers to the stock levels on your car and decided to lower the front and rear because the spacing of the perch settings allow you to.

Then you go blab to your buddy about Konis being height adjustable, then he gets them for his car and finds that the combination of perch settings he has to work with doesn’t allow a level height change.

It might be semantic but here at Heeltoe, we try selling parts as responsibly as we can. A misunderstanding in a forum bout has no accountable party. But we must be accountable to our customers for every sale and strive for the happiest customer.

So when we sell Koni shocks we tell people to pair them with the lowering spring that best meets their lowering needs. And if they really need height adjustment, they would be better off getting a threaded body coilover kit.

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Chassis Heeltoe Explains You Can Do It! DIYs

Spoon Rigid Collar Bushing Reuse: Are They One Time Use?

The Spoon Rigid Collar Bushings are great pieces for ensuring subframe-to-chassis alignment is correct. If you are not familiar with these awesome bushings, please see a very informative video in this post explaining what they are and how they work.

Here is what the Spoon Rigid Collar Bushing kit looks like:

In a nutshell, the Spoon Rigid Collar Bushings slide over the bolt and deform to fill the tolerance to the bolt hole.

Subframe bolt hole diameter versus bolt diameter.

The irregular mating surface between the subframe and chassis is made more rigid which really does dramatically improve the chassis feel.

Spoon Rigid Collars Bushings deform to fill tolerance between the subframe, chassis, and bolts.

The question of the day is, once these rigid collars are installed and deformed, do they need to be replaced if the subframe comes out again?

Heeltoe’s answer is no, these are¬†not¬†one-time use bushings. We have in our own shop #HTSpecTSX removed the subframe twice after initial installation, with plenty of driving stints in between removals. Our observation was that while the bolts are decidedly more finicky to remove and replace after the bushings are in, and that subframe re-installation alignment is more challenging because the bushings are in place, the¬†re-installation of the subframe had gone without issue.

Indeed the additional effort needed to remove and install the subframe, while not excessive by any means, proved that the collars worked and did their job.

No degradation of the effect of the bushings was noted after repeated removal and reassembly.

That being said, we would NOT recommend attempting to remove deformed bushings from one car to install them on another, even of the same model. Once a Spoon Rigid Collar Bushing set is deformed on a specific chassis and subframe we feel this “mates” these items all together and that attempts to move used bushings from one car to another would be an unsuccessful job.

On a final note, Heeltoe DOES recommend that the suspension alignment be adjusted after subframe removal, even with the bushings in place.

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Chassis Electronics Heeltoe Explains

Tein’s EDFC: What Is It, Why Get It, & How To Order It!

TEIN (rhyms like “vein”) is one of the foremost suspension suppliers for the aftermarket industry. With a wide array of coilover damper choices to suit all kinds of cars in all kinds of uses, there is almost a Tein kit for anyone. But one of their most innovative items is the¬† EDFC , or Electronic Dampening Force Controller. This simple electronic controller and motor package is designed to make adjusting your TEIN suspension kit’s ride and handling settings as simple as, well, doing nothing! We’ll explain…

What is the EDFC and why would you want it?

The EDFC is a kit that can be used with various TEIN suspension kits (most any kit which has the adjustable knob on the top to allow for you to adjust the firmness of the suspension) to adjust the firmness from inside the car using a cool electronic controller.

“Wow how cool!” most people exclaim upon hearing this. But the next comment is usually “but I don’t change my settings much. If i just ‘set it and forget it’ why would I get this?” Here is Heeltoe’s take on it…

Yes, many people will set their suspension firmness once and then leave it alone. So if you don’t see the inherent value here, we understand. But consider that the reason they are not changing it around is that doing so is a pain in the ass. If it were as easy as pushing a little button, we think more people would adjust their suspension settings more often to suit their mood and needs at the time. Not all roads are created equal, nor are all cars or drivers. The EDFC allows people to take control over how their car is riding and handling over different surfaces and will allow them to get better overall value out of their suspension investment.

The Stuff You Need

First, you need a Tein suspension kit which is EDFC compatible. We try to list the EDFC parts needed under compatible TEIN damper kits, but if you are not sure if yours is or not, please contact us for help

Second, you need an EDFC controller kit. As of this writing, the options are the EDFC II, EDFC Active, and EDFC Active Pro.

  • EDFC II: A 1/4 DIN unit that allows adjustment of the front and rear suspension firmness from the driver’s seat with a push of a button. Change settings in 16 or 32 increments for fine damper control with up to 3 memory settings.
  • EDFC Active: With the use of an optional GPS sensor, this more modern unit will actively adjust firmer or softer based on the vehicle speed and acceleration. Plus, easier to install with partial wireless connectivity.
  • EDFC Active Pro: The full capability of this kit allows the driver to program the suspension to adjust each corner of the car individually to suit different g-loads, accelerating, decelerating, or cornering. It also will target varying speeds as well as offering auxiliary inputs

Third, you need an EDFC motor kit. There are various motor kits available and they are always selected based on the damper-shaft size. We try to list the EDFC parts needed under compatible TEIN damper kits, but if you are not sure what motor kit you need, please contact us for help.

There’s some Optional Stuff

The one main optional thing everyone would think about is the Anti-Tangle Kit. This is only needed for cars with STRUT suspensions. So, you wanna know the difference. This article will help you understand the difference between shocks and struts.

The EDFC Active GPS kit is needed in conjunction with the EDFC Active and EDFC Active Pro if you want to utilize the “Active” functions of those controllers.

A Brief History Of the EDFC

TEIN first released the EDFC in 2002 and such as system was largely unheard of in the aftermarket. The kit consisted of a two-part package. There was a controller kit and a motor kit. The motors were designed to replace the adjusting knobs at the top of each damper, and were hard wired with supplied harnesses to a central controller that could be mounted to the dash or wherever.

Original Silver EDFC in it's display-box.

This is the very first unit offered, it was silver in color and featured front and rear controls for individual adjustment. Another neat feature was that while the suspension kits were normally adjusted to 16 points with the hand adjustment, fine motor control allowed the dampers to be adjusted to 32 points, offering finer tunability.

In 2006, the EDFC got an update. The silver case was replaced with a black one…

Black gen 2 EDFC case

This more detailed image shows that the EDFC also offered up three memory settings. Our suggestion to customers was always that you could have a “Commute” setting, a “Fun” setting, and a “Mother-in-law” setting. Also, all EDFCs had been backlit with a green light.

More importantly, TEIN also changed the motors and harnesses. The motor on the left was the original motor, and the smaller one on the right was the newly released one.

Teein EDFC motors compared

These changes were hugely welcome, as the large motors made the installation in tight spaces a bit difficult. With the smaller motors, it would now be possible for the motors to be installed on the dampers before they are installed in the car. It probably would seem a lot more of a benefit if you’d done the job a few times in various cars. We definitely liked it.

Furthermore, the plugs on the harnesses were all smaller as well. Fishing EDFC wires through the interior is no harder than running stereo wires…but honestly any help in making things smaller is a definite improvement.

The most recent version of the standard EDFC is the EDFC II.

Tein EDFC II Controller

The EDFC II is functionally the same as its predecessors but it is aesthetically it is stepped up with LED lighting.

Sadly, the EDFC II was discontinued in 2020.

But the EDFC Active…Oh So Advanced

When the EDFC Active was released the whole EDFC concept seemed thrust into the 21st century.

EDFC Active from TEIN, with dimensions.

The features here are numerous, and so we are going to refer you to our EDFC Active product page for more details, but here are some bullet points:

  • Wireless Control: Instead of running wires from each motor to the controller, the front and rear motor pairs wire to shared wireless modules that communicate with the controller. So the system is not completely wireless, but installers no longer need to fish through the firewall or the interior.
  • Optional GPS kit allows active functions: With an options GPS kit, the EDFC Active can automatically adjust with speed or g-force (accelerating or decelerating). You can program the EDFC Active to vary the front/rear dampening balance as you are speeding up or¬†slowing down¬†to set positions at varying speeds. That’s awesome!
  • Variable color display: You can change it to match your interior color.

Those features are super awesome. And the EDFC Active uses the exact same motors as the EDFC II.

And then TEIN got really bonkers with the EDFC Active Pro, in which the ante is raised even further. With varying speeds and g-loads, the driver can now program the dampening force to adjust at each corner of the car., and it can do this based on lateral g-forces! So it can firm up the outside wheels in a turn, and even have the rear firm up a little more if, say, more over-steer is needed.

But then, it can be adjusted differently if the corner is a faster or slower one! OMG, there is so much capability with this unit. Truly innovative!

That’s a lot of info on the EDFC

But with a purchase like this, sometimes it’s best to chat over it. Feel free to call for a consult at any time!

Categories
Chassis Heeltoe Explains

Tech: What’s the Spring Rate of my Torsion Bars? #torsionbarhondas Content Inside!

1984-87 Honda Civic/CRX and 1986-89 Acura Integra models came with a unique torsion-bar front suspension. Because of the non-conventional nature of a torsion bar as compared to a coil spring, people at times become lost on what various bars’ diameters equate to what would be conventional spring rates. This is an important figure for determining the balance of the car and for tuning the dampers.

Between the various diameters and lengths of bars available, we were a bit lost on it ourselves, but a little poking around led us to Sway-Away’s website. As some may know, Sway-Away is one of the foremost torsion-bar producers having even produced bars for said Hondas at one point in history. We knew this convenient calculator was something we could trust!

On the page there you will find the science behind the torsion bar wheel rate calculation. You’ll also see that the effective wheel rate is the same as the spring rate taken at the end of the control arm, or what is actually the lever on which the wheel’s movement acts.

You can play with it all you like, but we have taken the liberty of making a quick chart for fast approximate reference. Some of our dimensions are approximate but the spring rates should be accurate within about 5-10% and that’s really pretty good for our purposes.

Notes:

  • LCA stands for “lower control arm.” Since people tune both Integras and Civic/CRX models, and sometimes Civic/CRX people put the longer Integra lower arms in their car to increase camber, we include both here. We approximate a 13.5″ length on the Civic/CRX and 14.5″ on the Integra, from the center of the torsion bar to the end of the ball joint.
  • All rates are in pounds per inch of travel (lb/in), but we have a lb/in to kgf/mm charge just below.
  • Not all these torsion bar diameters are actually available, but we are listing them anyway since any of them technically could be made or exist.
  • The bar length will impact the wheel rate, too. The 24.3″ bar is the length of CRX and many Civic bars. Some Civics have a bar that is about 1/3″ shorter, but the rate change is fairly minor so we have omitted it to keep the chart simpler. The Mugen bars that were made long ago were shorter than the Civic/CRX ones, with an overall length of just under 22.5″. These would give the highest rate per diameter, and being the more compact bar would have the least weight (no surprise that the Mugen bar would be the ideal for performance yielding the most rate-per-weight!).
CRX LCA CRX LCA CRX LCA ‘TEG LCA ‘TEG LCA ‘TEG LCA
Diameter/
Lengths
22.5″24.3″25.7″22.5″24.3″25.7″
19mm978480847370
20mm1201091021039589
21mm145133125126114108
22mm175159150151139130
23mm209190179181165155
24mm247225212214195184
25mm291265250252230217
26mm340310293295269253
27mm396361340343313295
28mm458417393397362341
29mm527480452457416392
30mm603550518523477449
31mm687626591596543512

We work on Japanese cars at Heeltoe here, and oftentimes it becomes necessary to work in both lbs/in and kgf/mm (that’s kilogram of force per millimeter). They are different ways of saying the same thing about a spring’s rate, but we’ve offered this handy conversion chart for you to know the equivalents. This info is pulled from Tein.com’s Standardized Spring chart.

lb/inkgf/mm
1122.0
1402.5
1683.0
1963.5
2244.0
2524.5
2805.0
3366.0
3927.0
4488.0
5049.0
56010.0
67212.0
78414.0
89616.0
100818.0
112020.0

Please feel free to leave any commentary or calls for correction below! And never forget that Heeltoe is always in your corner, aiming to provide the best and most accurate info we can to help you tune your car!