Eurotek Tuning's Audi S4 Slalom Test: Eurocode Swaybars

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When we decided to perform this build, our goal was to use everyday parts available to our customers and viewers, and perform real world tests to see if the gains were not hype. So when we decided to install the Eurocode front and rear swaybars and links, what a better way to test the gains of these than on a slalom course.

Slalom Course Test

We started this test by creating as close to an identical scenario as possible throughout the tests. This meant we were running the same wheels and tires, the same tire pressure, on the same road with the same spacing between the cones on the course, using the same driver (a novice grassroots motorsports racer, but somewhat experienced in amateur road racing and autocross), and lastly as close to the same ambient temperature as possible. We had already installed the Eurocode Alu Kreuz brace prior to this test as well as a brand new set of 19” Neuspeed RSe10 wheels on 255/35ZR19 Michelin Pilot Super sport tires. We set the tire pressure to factory settings and performed an inspection of the suspension components. We found that although the upper control arm bushings did show wear as expected on a car with 53k miles on the odometer, they had not torn and were still usable through this portion of the test. Everything else was in great condition.

We found an isolated patch of road near our location where we could safely perform these tests and set 4 cones at 75 feet apart. Why did we decide on 75 feet? When looking at SCCA solo autocross rules, we found they can vary from 60 feet apart up to 100 feet apart depending on the course layout and space permissions for the course. We didn’t want to have an exit speed nearing triple digits as we were testing on a public roadway and therefore felt it was only appropriate we set our course up somewhere in the lower middle of those 2 numbers.

Test 1 Results

Our first test event was a warm evening with ambient temperatures at 89 degrees and no winds. We made many passes back to back as we continued to achieve the maximum possible speed out of the slalom course. The best trap speed we had successfully recorded was 58 MPH. This was a push for the car as there was noticeable body roll and a sense of disconnection to the road. However, during our testing, we inadvertently began to experience the car pulling back power. Near the end of our attempted passes, it had become impossible to even match our fastest trap speed of 58 MPH. It had become clear the stock supercharger heat exchange unit was not up to our tests. Lucky for us, we already had an APR Coolant Performance System (CPS) on order. And with the sun beginning to set, we called it.  

Watch video below.

Audi Performance Parts included in Test 1

Installations: Eurocode Swaybars, Links, Preload & APR CPS

Now was time to install the Eurocode swaybars and links on the car. Installation is very straight forward and simple. Because we want to experience the biggest improvements on the car it was only expected that we not only install the Eurocode front and rear links with the bars, but we needed to set the preload on them as well. We could have followed the supplied instructions and set the length of the links to match that of the stock links since we had not yet lowered the car. But again, we wanted to get as much improvement with them installed as possible. That’s where the preload setting came in. We loaded the drivers seat with enough weights to match the driver, and proceeded to equalize the load/weight the bar was pushing on each side using our corner balancing scales. During this install we decided there was no better time to install the APR CPS kit that had come in just days earlier and test its worthiness on the next test event as well. The APR CPS comes with a detailing installation instruction manual and is a very straight forward install. However we don’t recommend this install be performed other than by an experienced Audi technician because there are some more specific bleeding techniques of the cooling system necessary for the CPS to perform as advertised. Lastly while we have the car in the shop, we reset the tire pressures and re-inspected the rest of the suspension system. Everything checked out the same.

Test 2 Results

We setup our slalom course once again on the same patch of road on an evening but this time ambient temps had risen to 94 degrees and there was no wind. Again, we were attempting maximum trap speed coming out of the slalom but with the new upgraded Eurocode parts. Immediately we noticed that the 58 MPH speed was easy to reach and surpass. And to our satisfaction, run after back to back run did not affect the performance of the car despite the increased ambient temperature. It was very clear the APR CPS was doing it’s job and we should be able to increase our trap speed out compared to the first test. After several attempts the fastest we recorded was 62 MPH. That’s a gain of 4 MPH. While this may not sound like much, let’s remember the rest of the suspension components are still stock and we are clearly pushing them beyond their threshold. Even when considering a component to increase horsepower, while a Dyno may show gains, in terms of 1/4 mile track times, the reduction in the run time is minimal as well. This test clearly showed that the upgraded Eurocode sway bars, tuned to the car and driver with the matching Eurocode adjustable end links, was a very useful improvement on the suspension of the car and recorded gains. Lastly, the feel of the car was dramatically improved. Why, because we could feel a better connection to the road with the car and our sense of confidence in the cars’ ability to hold to the road was stronger.

Watch video below.

Audi Performance Parts included in Test 2

To Be Continued...

Stay tuned, as we finish this test by installing and tuning a set of Bilstein B16 coilovers and SPC adjustable upper control arms.

Eurotek Tuning Audi S4 Slalom Test Video

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