Friday, January 27, 2017

Tenth Gen Civic Rear Sway Bar goes to Thunderhill

We recently had the opportunity to put some miles on a Tenth Gen Civic sedan. It’s a really nice car. First I noticed the good ergonomics, quiet cabin and excellent ride quality; very refined and Honda-like in stock trim. Then I took note of the good dampers, not under-damped like so many compact cars that we often experience.

Then we pressed it a little harder, driving it more like we prefer to drive. More aggressive entry speeds, and holding a better line. The front tires complain and understeer some, then the body roll starts to creep in. And faster turn-in results in more body roll. With today’s FWD strut front suspension, any body roll means less front camber, and front grip is lost that cannot be recovered. So, one simple way to increase grip and make sport driving more comfortable is to limit body roll and improve the chassis balance. Less body roll & better balance is always more fun. It’s just that simple. But how do we limit body roll and help the balance without a complete new suspension?

If we replace the rear sway bar with a larger diameter version, the sway bar will develop more resistance to the dynamic forces that induce the body roll, so less body roll is the result. How do we help the chassis balance? If we increase the rear roll stiffness (larger diameter sway bar) and leave the front sway as is, the vehicle will have less understeer. So we did it, and it works well on this platform. It’s rare to make a chassis modification for better handling, and not have an obvious down-side show up somewhere. This mod just works! It’s not too much of a good thing, it’s just enough to polish the gem that Honda has crafted.

Although the sway bars look very similar, they perform very differently. The PROGRESS bar is 3.6mm larger in diameter, but increases the sway bar spring rate 96%. This big bump in sway bar rate is very noticeable, even within a few minutes of driving. You will feel it right away, even on moderate lane changes and highway sweepers during commuting. Of course it shines when you hammer it a bit harder on a good stretch of road. As you continue to ‘press’ the chassis harder, the body roll will initiate at first, then the chassis will ‘load up’ the sway bar, and you can feel the sway bar working to limit the roll. Cornering will be much flatter and steering inputs will be less as there is less overall understeer.

This rear sway bar installs quick and easy, just six fasteners hold it all in place. It may take longer to safely jack up the car and position the jack stands! You will need a torque wrench to tighten the fasteners and end links properly. Watch the install video here:

Product link:

We were pleased with the rate and stress calculations and ride evaluation results, so we found a production slot here and built a first run of parts. Before we finished the installation instructions and got the new kits packaged up, we got an email from one of our contacts at Honda Research West looking for an upgraded rear sway for a two-car motorsports project. 

We discussed rates and bar diameters, and the feedback was ‘that’s just what we are looking for. How soon can you ship us two units?’ Why? It turns out that HRW was race-prepping two Tenth Gen race cars for the '25 Hours of Thunderhill', an epic NASA endurance race, and PROGRESS was able to support their suspension requirement in a very  timely manner. 

So enjoy the same sway bar that Honda Research chose for their race cars, and we can say: 

“Team Honda Research West uses Progress product for 25 hour endurance racing.”

If you've been involved in any club or pro level endurance racing, you understand what it takes to race hard for 25 hours. The race cars require a high level of preparation and as many development miles as time and the budget will allow for. The crew needs to be sharp and to stay in the groove for hours on end. Problems come up on the track in seconds, and the crew needs to be ready for whatever comes their way. Drivers need stamina, patience and excellent concentration to stay on the edge and alert for the long stints through the event. Racing all night with limited vision and tired drivers is another challenge. It's rewarding and draining at the same time. Any racer that completes one of these all-night enduros has some stories to tell!