Comparison: Small -v- Large Sway bars - Coilovers -v- Strut Dampers

Comparison: Small -v- Large sway bars / Coilovers -v- Strut Dampers

Comparison: Large v Small Sway Bars - Coilovers v Struts
Aim: Comparison of large v small anti-roll bars.
Coilovers v Strut - Spring upgrade

Roadways:

Roadways consist of coarse bitumen, uphill/downhill gradients, tight and flowing corners complete with flat and undulating surfaces and minor pot holes. Some sections of roadways change texture mid corner.

The idea is to use a roadway that replicates much of what every driver is likely to encounter in day to day driving conditions.

Some routes were driven 4 times over so as each driver experiences each of the four vehicles on exactly the same portion of roadway.

The driver swaps eliminates any subjective views and exposes each VW GTI to varying driving techniques.

Conditions were overcast – dry and damp roadways.

Items description:

(1) TEIN Euro Coilover + EDFC

TEIN Euro coilover suspension is equipped with EDFC (Electronic Damping Force Controller) which makes it possible for the driver to control the damping rate via remote control from inside the vehicle with cables leading through the vehicle (under carpet & rear seat) connected to miniature motors attached to the bottom of the coil over damper tube.
All the driver has to do is operate a number of buttons from a controller inside the vehicle to alter damping rate; rather than jack up car & fiddle with the settings as in the case of a conventional coil over systems. The damping force control function is able to be calibrated for either 16 levels or 32 levels.

The TEIN Euro EDFC really is the cream of the coilover crop in suspension upgrades. These items are similar to the Porsche PASM/Bilstein B16.
Price: approx $3800.

TEIN provide a 3-year/30,000km warranty on coil over and 1-year warranty for EDFC.

(2) Koni FSD - Strut damper

Shock absorber offers a superior road-holding without compromising comfort. The frequency selective damping valve (FSD) is patented by Koni which combines the benefits of firm and comfortable suspension in a single shock absorber. Firm for sporty driving on even road surfaces. Soft for uneven surfaces.

Damper is light in weight and cost efficient. Koni-FSD adjusts automatically to road conditions as well as driving style. All in a fraction of a second.
Warranty: ‘Limited Life Time’ which means that they are warranted for the entire duration that the original purchaser owns that particular vehicle regardless of mileage.

Cost: $1200.

(3) Eibach Prokit Progressive rate springs

The Eibach ProKit are springs suited to sports suspension that can be used in conjunction with both production shocks, the Eibach Pro Damper as well as with other types of aftermarket shocks such as Bilstein Sports, Koni Sport and Koni-FSD.

The springs are aimed at a sporty road performance without sacrificing any driving comfort. Vehicles such as the new Mitsubishi Lancer EVO-X and HSV GTS have Eibach springs as factory standard equipment.
Warranty: 1 million mile warranty.

Cost: $600.

(4) H&R anti-roll bars

H&R sway bars are made from the highest tensile strength available making them strong/durable and are 100% made in Germany to exacting standards. Each bar is cold-formed. The bars are heat treated, shot-peened and powder coated. The sway bars include bushing featuring a special Urethane/Teflon composite that eliminates the need for lubrication. No squeaking.

The front bars are set on ‘soft’ and rear set on ‘hard’ to dial out under steer for a near neutral biased chassis set-up.

Cost: $890 pair.

Vehicle 1: (V1)

Red 2005 Golf GTI, Bluefin chip, aftermarket exhaust, TEIN Euro coilovers with electronic damping force control (EDFC), large 28mm/24mm H&R sway bars (f:soft/r:hard) – Gerard @ GC-Corp aka ‘gmc’.

Vehicle 2: (V2)

White 2006 Golf GTI, 18 Huff wheels, Eibach ProKit Springs, Koni FSD dampers, small H&R 26mm/22mm anti roll bars (f:soft/r:hard) – White James aka ‘fun nazi’.

Vehicle 3: (V3)

Silver PC Geeks 2007 Golf GTI, GIAC chip, large H&R 28mm/24mm stabilizer bars (f:soft/r:hard) - Nick aka ‘Fattyboomba’.

Vehicle 4: (V4)

Silver 2006-2007 Golf GTI, Bluefin chip (revised Ed), rear only small 22mm H&R bar set on ‘soft’ setting - Eugene aka’ funny’.

Vehicle 4 (V4)

The GTI with rear only 22m H&R bar set on soft (V4) was the best riding but worst handling of the group.

The lack of front bar and rear H&R on ‘soft’ allowed ample independence giving the best ride over this treacherous route. The softer OEM sway bar ensured the springs/dampers soaked up the ridges across the tarmac mid corner, rarely unsettling the vehicle or throwing it offline. The bounciness of the OEM setup is still very apparent with the under damped shocks struggling to cope with the coil rebound.

Handling was another matter.

This vehicle is inherently under steer biased. The under steer is more attributable to the higher OEM ride height at the front, the OEM damping rate, and most importantly the OEM spring rates. The front springs are harder and the rear springs are softer - this induces more understeer than the aftermarket suspension systems, which are designed to change chassis tune to a more neutral set up.

In addition; the front end is now softer relative to the rear end. This causes the front to lean into a corner more. As the front of the GTI leans, the outer wheel has a positive camber change mid corner, causing the tyre to lean on its outer sidewall. This reduces the available contact patch of the tyre, therefore offering less grip. The tyre goes from a 225 to 155 due to positive camber change. The inside wheel also lightens up a bit as the dynamic force tends to move towards the outer front tyre, creating body roll at the front. The addition of a front bar keeps the front end tighter so there is less postive camber change. Have a look at the pictures of the GTI mid corner - look closely at the outside front wheel; you will see the wheel rolling outwards under the strain of body roll.

Adopting the slow in – fast out technique only resulted in push under steer. Trying to set up the GTI for a neutral balance through any corner was proved difficult.

Setting the rear bar to ‘hard’ would yield an improvement; but the stock OEM spring/damper settings are not suited to the application of the rear only anti roll bar. This set up does not work as a whole package. This vehicle is an improvement on full stock GTI; but only marginally. In this company, the handling of this setup was shamed. The rear only sway bar GTI had it’s ass kicked on this test.

Plus: Most independent handling of the group giving best ride over mid corner single wheel bumps. Reduced under steer from full stock GTI suspension.

Minus: Vehicle is not balanced. The front to rear sway bars and spring/damper combination felted mismatched. Push under steer. Unable to find that neutral line through corner. Too much traction control interference with added power of Bluefin (although not as bad as GIAC).

This vehicle was on Continental Contact Sport 2 tyres.

Vehicle 3 (V3)

Take a stock GTI, add GIAC with a DV on its way out and a set of big mother H&R 28mm/24mm (soft/hard) and punt it down our infamous and undulating up & down hill routes.

The big set of H&R bars as ride notably diminished over single wheel bumps mid corner. The GTI a little skittish when pushed, with weight transfer from loaded wheel shuffled across to the unloaded wheel, keeping the GTI flat but very rigid.

Refinement of ride does suffer, but it is livable for an enthusiast. The reduction in ride over single wheel bumps is not enough to throw the car completely offline mid corner. The reduction in independence in each wheel is obvious. Undulations struck simultaneously by both front and rear wheels have no effect on ride. The smoother the roadway, the better these bars work.

Adding front and rear stabilizer bars is a definite improvement in handling over the rear only sway bar GTI. The DV failing PC-Geeks GTI felt much more stable and inspired confidence to push a little harder. Driving briskly was an easier task, although you need your wits about you, as everything happens faster when approaching the limit.

A stock GTI starts telegraphing information to you at about 7/10ths; it speaks to you saying, “hey, I’m looking to lose traction. I’m going to lose traction. Losing traction’. With the added rigidity of the big H&R bars, the warning signal is more acute; they say, ‘hey buddy, you’re overstepping the limit now’. No ample warning is given. At not time did the GTI with both front and rear big H&R bars prove unnerving. The bigger bars do offer secure footed near the limit handling; without inducing any unwanted tendencies as a rear only anti-roll can do.

Despite the bounciness of the lack of damping in the OEM spring/damper combination in this vehicle, the big mother H&R bars induced a more go-cart like handling, albeit with predominately under steer approaching limit.

Initial turn in is not as good as a rear only bar GTI. But as you approach the apex and from thereon onwards, the addition of front & rears bars offers secure flat handling that inspires you to push on.

The advantage of having front and rear stabilizer bars is that you can hold your intended line for longer and stay on the power for longer from apex onwards. I found I frequently lifted off after apex with the rear only bar GTI still fighting push under steer and a softer front which causes the inside wheel to become light, making it lose drive out of corners. Front & rear bars felt more natural to drive.

Under steer near the limit was a prominent feature of this vehicle; just as it was in the other Silver rear-only sway GTI. The OEM springs/dampers are set up for an under steer bias – despite fiddling with varying stabilizer bar sizes front to rear, the spring/damping rate dictates that a GTI should push into under steer on approach to limit. Only way around this is to change the spring/damper combination.

This was also a disappointment in terms of handling as the OEM springs/dampers have trouble coping with the extra stiff front and rear stabilizers bars; albeit no where near the disappointment of the rear only sway bar GTI (V4), which didn’t inspire confidence and took some speed away on the most crucial part of the corner – the exit.

Minus: Loss of refinement in ride especially over single wheel bumps. Stock springs/dampers having difficultly containing the lateral force transfer of the extra big front & rear bars. Under steer on limit still very noticeable. Too much abrupt traction control interference trying to contain the GIAC horses; even with a failing DV. Big bars require a smooth grippy surface and very good tyres which can be expensive.

Plus: Flat go-cart handling on smooth roadways. Extra grip and sure footed handling.

This vehicle equipped with Conti CS2 & Pirelli P-Zero tyres.

Vehicle 2 (V2)

This White Golf GTI equipped with Koni FSD/Eibach ProKit/ small 26mm/22mm H&R anti-roll bars (soft/hard).

The smaller H&R anti roll bars offer the same dynamics as the larger set of H&R sway bars. There is no difference in under-steer/over-steer tendencies. Both bars are tuned to offer the same performance in relation to chassis tune.

The difference being that the smaller bars allow more independence to each individual wheel for improved rough road handling; at the detriment of a loss of rigidity and increased body roll. The smaller set of H&R bars allow the vehicle to move around a bit more; as opposed to the go-cart race sharpness of the large H&R bars.

There is an improvement in ride with the smaller H&R bars v large H&R bars. It’s not as noticeable as most would think. The larger H&R sway bars offer tighter and more secure handling up to a point. Once roadway quality begins to deteriorate, the smaller set of H&R bars allow for added compliance, causing less skittishness with wheels that follow the intended line over single wheel bumps & undulations. A bit of responsiveness is lost waiting for the weight to shift and settle with the smaller H&R anti-roll bars (I.e.bodyroll); costing some time during cornering.

On a smooth road the bigger H&R bars would make your Golf faster; on a rough road the smaller set of H&R bars would peg back some of the disadvantage in body roll through added compliance of being able to cope with single wheel bumps better than the large set of H&R sway bars.

The White James GTI felt the most fun to drive on the roadway. The car has maintained some of that stock GTI throttle/brake adjustability that puts the GTI a class above all other hot-hatches for public road driving.

The addition of Koni-FSD and Eibach ProKit springs to the H&R small bars has put this vehicle into a class of its own when compare to the vehicles with anti-roll bars & OEM springs/dampers (two silver GTI’s : V3 and V4). The difference is like a chasm.

The under-steer that was so prevalent with the OEM spring/damper GTI’s was not present with the Koni FSD/Eibach Prokit Golf.

The lower ride height and raked stance of the Koni FSD/Eibach vehicle is only one factor in improving cornering and power down. The tune of the Eibach springs and Koni-FSD allowed for a neutral chassis tune. It’s like a great leap forward with the White James GTI following the intended line through each corner, regardless if powering on or trial braking. Just point and aim. Pick your line, trail brake into the corner, clip the apex, and just ease out with moderate throttle application for best results. Abrupt throttle application will caused under steer – the car is a front wheel drive.

Traction control does interfere on this stock (no chip) GTI; but no where to the extent or abruptness of the two OEM spring/damper Volkswagen GTI’s.

Despite Nick having the bigger H&R sway bars albeit on stock suspension; seat of the pants indicates that the Koni-FSD/Eibach White James GTI is a faster car for open road driving; most probably a quicker car in all environment.

The Koni-FSD/Eibach GTI did have the outside tyre of the (18” x 7.5” x ET51) Huff wheel rub on the inner fender screw on a tight downhill 150 degree slow speed undulating hairpin corner when pushed hard. No other vehicle rubbed wheels on fenders on this corner. The tyre rubbing is a combination of the raked stance of the Eibach Prokit with the front dropping -20mm and rear -8mm lower. The advantage is that this vehicle has the best turn in of any vehicle on the test.

The Koni FSD/Eibach/small H&R Golf has the most neutral handling of any of the vehicles on this test. The chassis tune puts ‘you’ the driver back in command. Over steer or under-steer is induced at will; as opposed to the other two stock spring/damper GTI’s.

The bounciness of the OEM springs/dampers over mid corner undulations was not apparent with the Koni FSD/Eibach ProKit. The VW Golf was more upset at the front than the rear only sway GTI (V4). But this was a marginal trade off in ride for added handling.

We set up a professional photographer on a 90 degree 35kph bend with littered with patch work repairs mid corner to capture some of the roadway dynamics and chassis balance of the vehicles put to comparison.

Assessing the driving dynamics - the two GTI’s with OEM springs/dampers under-steered their way through the entire corner. The Koni FSD/Eibach Prokit had great neutral turn in, with a trace of lift off over-steer mid-corner enabling the driver to set the car up quickly for the next switchback corner.

Minus: Progressive rate springs on full compression often spring slap making them noisier than OEM springs. Dr Jekyll and Mr. Hyde handling with progressive nature of spring going from soft to hard during compression. Loss of some responsiveness of the Koni-FSD damper compared Bilstein/Koni Sport. Occasional rub of front tyres due to raked stance. Not externally adjustable for compression/rebound. Added body roll reducing some of that race car control on flat smooth roadways.

Pros: Neutral handling, comfortable ride; vehicle is composed over rough roadways, throttle adjustability, user friendly driving dynamics; confidence inspiring, more livable suspension tune that offers better ride than stock GTI in most cases. Value for money. Convenience of FSD being internally adjustable to suit roadway conditions and driving style.

This vehicle is equipped with Bridgestone Potenza Adrenalin RE001 asymmetrical tyres 18 inch diameter – tyres proved to be better than Conti CS2 and Pirelli P-Zero.

V1: The Red Golf GTI with TEIN Euro coilovers had the electronic damp force adjustment (EDFC) set to full hard position (0/16). The TEIN are coupled with the large set of H&R (28mm/24mm) anti-roll bars.

Firstly, I must state that I have followed upgrades of the chassis of this vehicle from OEM to its current tune. Installing the top of the range TEIN Euro coilver + EDFC on its own did not give this product any justice. Initially they looked overrated.

The addition of large H&R anti-roll bars made a marked improvement on handling.

The most notable improvement to date is a slight adjustment of the stabilizer bars from soft/soft to soft/hard at the rear. Wow! It become clear that the TEIN Euro were not designed for standard VW Golf GTI anti-roll bars.

The TEIN Euro GTI has been lowered: -25mm front & -20mm rear.

The lower centre of gravity does help; especically at higher speeds. The stance of the TEIN Euro GTI is not has raked as the Koni FSD/Eibach Prokit GTI. This also has an effect on handling and turn in response.

The TEIN Euro coilover are the nemesis of the Koni-FSD. The Koni FSD operates on a hydraulic pressure mechanism to open and close the softening valve. The TEIN Euro + EDFC have a mechanical micro valve that firms up the suspension as it compresses - electronics allow you to preset the level of dampening force. They work on a similar principle; but have different mechanics.

Important point here is that the Koni FSD are set in full hard position until you strike a high frequency bumps or a pot hole; they then go soft to comfort the impact. The TEIN are in soft mode until you hit a bump or pot hole, which causes them to firm up, maintaining a better ride.

It’s a bit like owning a BMW 335i –v- BMW M3. The M3 actually rides better than the more stiffly damped 335i Coupe, as the M3 has electronic dampening adjustable suspension at a flick of a button; the 335i doesn’t.

Similar thing here; the Koni FSD are like a 335i – poor mans version. The TEIN Euro + EDFC are like the BMW M3 – the expensive electronic dampening version that can have your own 3 preset dampening rates (comfort/sport/race if you desire).

Remember these TEIN are top of the line coilovers; not your standard PSS9.

The TEIN Euro + EDFC are more refined in ride than the Koni FSD damper.

The spring/coilover damper is slightly better matched and less noisy at full compression. The Koni FSD, being a hydraulic version, is cruder in how they operate; you can feel when the valve opens and closes. With TEIN Euro the transition from soft to hard (remember Koni is hard to soft) is almost senseless.

The first run up and down our route was enough to indicate that this is a very well set up GTI. Not perfect in my opinion. It does carry a bit of under-steer compared to the White James neutral Koni FSD/Eibach/Small H&R. That’s the way the owner like its; it’s a safety margin he says. It does cost a bit of time in corner entry at lower speeds.

The levels of compression/rebound in the TEIN Euro are the likely cause of the inducement of this on-the-limit under-steer that is not present in the Koni-FSD/Eibach Prokit GTI. .

It’s one thing to stick in coilovers to upgrade handling/ride; it’s an entirely different matter in getting the turning right. Sorting out suspension tune is a tentative thing that requires trial and error. I’d be looking to soften up the compression at the front of the TEIN Euro GTI to suit my preferences for a near neutral chassis.

The TEIN Euro GTI was the only other vehicle to have lift-off over-steer induced with a slow in – fast out driving technique; apart from the Koni FSD GTI. This put the driver back in control of the handling dynamics of the vehicle; but not quite to the extent of the Koni-FSD/Eibach GTI.

The Red TEIN Euro GTI is simply a much sharper instrument. Steering transitions occur faster with added ease. Point and shoot. There less momentarily delay for the chassis to settle down as in the case of the Koni-FSD/Eibach GTI.

The rigid ride of the stock OEM sprung/damped big H&R bar (V3) GTI is still present; only with a much more controlled ride and loads more grip. Traction control interfered less than any other vehicle on this test (car has Bluefin chip).

Placing the cars back to back on a back section of roadway with narrow limits set on driving technique had the TEIN Euro GTI all over the rear of the Koni-FSD/Eibach Prokit GTI. The Koni FSD had better turn in and more neutral dynamics; the TEIN Euro GTI was simply faster due to more race car like dynamics, but lost a bit of pace due to the a slightly inherent under- steer biased chassis.

With a set of semi-slicks on a fast free-flowing race track; this TEIN Euro + EDFC will be an extremely fast car.

I have sampled a number of GTI vehicles in the past; many with modifications. Up to this point; I never felt that I would take any of them over my own GTI. The TEIN Euro + EDFC GTI is one such car that I could easily swap for mine. In fact; I didn’t want to give it back to its owner.


Minus: Some would say not enough compression/rebound as the Koni FSD. More taught and rigid ride due to bigger H&R anti-roll bars. Compression/rebound not individually adjustable. Cost including extra fitting cost.

Plus: adjustability of coilover in ride height & compression/rebound. Electronics provide an excellent ride. Secure handling dynamics near the limit. Direct and responsive connection with driver, car and road.

This vehicle was on Continental Contact Sport ‘3’ tyres – CS3 proved to be the best tyre on the day; unanimous decision by all drivers involved.

Summary:

The addition of a rear bar only gives you better turn in response; but that’s about it. Depending on you choice of rear sway bar, you may induce undesirable tendencies into your chassis tune. Original equipment springs/dampers are tailor made to the OEM anti-roll bars and vice versa – all are made to induce under-steer approaching limit. The owner of the rear only sway bar GTI is serious considering adding a front sway bar to improve handling.

Add front and rear anti-rolls bars is definitely an advantage despite some trade-off in ride comfort. If you’re sitting on stock springs/dampers, difference to handling with introduction of sways bars front and rear will not be as great as changing the whole package of springs/bars/dampers and possibly even bushes. In addition; if you’re looking to stay with the stock springs/dampers – the smaller set of H&R anti-roll bars may be more fitting as a compromise between ride and handling – also depends where you live and drive. The owner of this vehicle is looking at a Bilstein Sports Strut + Bilstein spring as a matched pair to compliment his big mother H&R anti-roll bars.

If you don’t have much to spend, but want a real boost in street-sports style handling and even an improvement in ride for your vehicle – conventional strut damper/spring packages with addition of a well front and rear sorted anti-roll kit will transform your vehicle. Based on this test; I am undecided on whether the large or small H&R anti-roll bars would offer the best ‘balance’ of real world handling and ride. This may be the subject of another test.

When money is no object and you want the best; or you’ve looking for a set of coilovers as a track day enthusiast; you have your pick of large or small anti-roll bars depending on your preferences and needs. Large are definitely for the racer; but livable for day to day use. If you drive on rough roads or wish to preserve some ride; the smaller bars may be for you.

Overall:
I’d say that the top of the range TEIN Euro + EDFC GTI takes out the accolades by a small margin to the Koni-FSD/Eibach ProKit GTI with smaller anti-roll bars. The TEIN Euro GTI is for the serious minded enthusiast; but is very liveable day to day.

If money was a concern; the Koni-FSD package wins - the small or large H&R anti-roll bars cost the same. It the most neutral and most fun GTI to drive.

There is a chasm of a gap from the TEIN and Koni GTI’s to the vehicles with aftermarket anti-roll bars and stock springs/dampers.

Third is the GTI with front and rear sway bars; despite the bars giving the springs & dampers a whipping on rough terrain. A good car for smooth roadways; springs & dampers feel a bit underdone in the rougher stuff. Maybe the smaller H&R bars would be more suitable.

Lastly, the GTI with the rear only aftermarket stabilizer bar. Improves turn in response; but little else. The addition of a rear bar may prove better than sticking with the stock rear bar; but a mismatched front and rear bar may introduce undesirable tendencies in the chasis. Postive camber change causing loss of tyre contact patch at fronts wheels may be an issue.

Cheers
WJ

Pictures to follow:

Some of the best action pics... More to come.

Nice shots :bow:

Brilliant write-up. Informative and strangely entertaining.

Top notch photos too. Thanks.

wow awesome information

Here are sequential pics of the up hill runs. Hit refresh/F5 to get the images moving again.


H&R 22mm rear bar with stock suspension


H&R 28mm Front, 24mm Rear bars with stock suspension


Koni FSD with Eibach springs, H&R 26mm front, 22mm rear bars


Tein Euro coilovers with H&R 28mm front, 24mm rear bars

Here are the downhill runs.

Some more pics