KW V3 Coilovers and Hydraulic Lift System (HLS) for the C7 Corvette Stingray

If you have been following the progress on our Project C7 Corvette Stingray, you’ve seen us work on the brakes, suspension and cosmetics. After a test session at Buttonwillow things looked to be much improved, but we really need to upgrade our wheels and tires to get the most out of our suspension and brakes upgrades. In the meantime our Chevy Performance aero kit looked great, but since it hung low it was really hard to drive around town without scraping some expensive carbon fiber. To make things more practical we decided to put a lift system on our Corvette so we could raise the front end up when going in and out of steep driveways and speed bumps. KW Suspension makes a hydraulic lift system (HLS), which we’ve used with great success on our V8 FD RX-7 project, and we wanted to look at adapting it to our C7 Corvette Stingray.

To use the KW Suspension HLS we had to switch over to KW V3 dampers. The Chevy Performance Bilsteins worked well, especially with the stock wheel and tire combination, but we really wanted to add the front lift system. This required us to convert to KW coilovers for compatibility, as the lift cylinders fit on the KW spring perches. The KW V3’s get rid of the factory transverse leaf spring and convert the suspension over to coil over springs. An additional advantage is this will allow the car to be corner weighted. Another is that the coilovers weigh less than the big leaf springs.

The KW Coilovers have a corrosion resistant stainless steel body and rustproof engineering plastic clad stainless spring seats and collars. These are coilovers are truly 4-season worthy, even in areas with road salt. You won’t need to worry about the spring collars seizing to the shock bodies. The V3’s have a lifetime corrosion guarantee.

The top mounts have hard urethane bushings to transfer as much suspension motion through the shock as possible while still absorbing some vibration. The rebound damping adjuster is located in an easy to reach location, right on the top eye of the shaft. The adjuster knob is large and easy to turn. These little details make a big difference when trying to dial in your car at the track. The V3’s have micro-cellular progressive bump stops that make bottoming out less harsh and more progressive so that handling balance won’t be too badly affected if bottoming out occurs during hard cornering. A short dust shield protects the seals.

The rear shock has a clevis style mount with a captive nut.  Note that the compression damping adjuster is also in an easy to reach location and it has a large wheel that makes adjustment easy. The canister on the shock body looks like a remote reservoir, but it’s not your typical one.  The V3 is actually a twin tube shock with the compression adjuster in the foot valve and the canister is more like an accumulator that holds a gas-filled bladder. The gas in the bladder is to make room for shock shaft displacement. By having the gas separate from the fluid the damping stays consistent with no fluid foaming, which is typical with twin tube designs that allow the gas and fluid to mix.

33 comments

  1. It would be nice to know the weights of the parts removed (not just battery) vs the replacement parts. I’m thinking some of the leaf spring is considered unsprung?
    That’s an interesting “captured” nut!

    1. This. The leaf springs may be big, but they’re a composite material and actually pretty light. It wouldn’t surprise me if a vette leaf spring is actually lighter than 2 coilovers steel springs (1 leaf spring is used for both sides of the car).

      1. the oem shock/spring setup is 40.3lb for all 4 corners, LG coilovers, which use aluminum Bilstein dampers and billet aluminum mounts, are 30.8lb. Aluminum Penske’s with remote reservoirs are 34.4lb. The steel KW’s, with their built in reservoirs, are gonna be heavier… then taking the lift cups into account, the KW with the lift system is definitely gonna be heavier than stock before even taking the pump into account. And its definitely more unsprung weight, cause with the way the leaf spring is mounted, most of its weight isn’t really sprung weight…

        That being said, if I had a Vette, it’d definitely have coilovers on it. But prolly LG’s…

        1. The LG’s are either non-adjustable or single adjustable. Double adjustable like KW is big advantage as you can really dial in the suspension for specific conditions or combinations of parts.

          1. oh yeah, nothing against KW… KW’s are great, just a random note on the route I’d go. Mostly cause of price and I’ve seen and experienced how well they perform first hand. If I’m spending KW Clubsport money, I’m going with MCS.

            but either way, I was more trying to make a point about the weight… the Vette’s leaf spring setup isn’t exactly heavy. Its actually pretty light considering its an OEM and the cars price point. And I wouldn’t be at all surprised if the stainless bodied KW’s are actually a little heavier.

          2. Great article,! I’d echo what the others have requested with the weight difference being published.

          3. Let’s see if I can get a weight tomorrow for the coilovers. Do you happen to know the weight of the stock shocks?

          4. I tried to post links to the pics of the shocks on the scale, but the comment just disappeared when I clicked post… I can show you pics of all this stuff on scales if there’s someway to share pics/links

  2. Remove that straight piece under de splitter. The ones in front of the wheel. It’s only there for mileage, and some minor road noise, but they create lift….

  3. Oh man… I had that exact thought a while back and was wondering why nobody made it. Leave it to KW I guess. I assume there’s some cutoff valves or something to prevent cross-talk between the corners, or is it just either all the way up or all the way down?

    1. From what i understand the HLS is usually installed on the fronts only and due to a lack of height measuring electronics it looks like an all the way up or down scenario. The valving and one line from the pump (no return lines) would lead me to believe that there is no way to prevent cross talk, meaning if one lift cup goes the other one wouldn’t work. The HLS system looks to be designed to only help raise the car for entry and exit into parking areas/driveways and not to be driven on long distances so cross-talk shouldn’t be an issue..

      1. Yes, its either up or down. It can be driven in the up position for distances. It was originally designed as an active aero/suspension element for DTM like the articles says. It’s not like a soft air spring like an air cup.

        1. OK; probably more than adequate for most purposes and having it only all the way up or down certainly simplifies things. Pretty cool still; it solves a lot of problems. I just dream about stuff with significant downforce and low-frequency active suspension all the time.

      2. Having driven this car for several weeks now on the HLS system I can say without a doubt that it completely transformed the car in terms of its comfort and practicality as a daily driver. the roads in my neighborhood aren’t the greatest and i often find myself lifting the front end as soon as leave the house and then lowering it back down once i get on the freeway. Pretty much every driveway/parking lot entry around Los Angeles was impassable without scraping the carbon fiber front lip before the HLS (one of the worst sounds ever btw). Now unless i know the roads in the area are smooth i’m in i basically use the system like a “city”/”highway” mode. It’s awesome! 🙂

        1. Just reading the other comments as I was fixated (overly?) on the weight of the dampers. And I’m going to sound like a fanboi here, but parallel with the gt3rs, if you make something much more durable without being significantly heavier, as was the exhaust system, then I consider that a win. Similarly, the ‘Vette gets an upgrade in practicality, and overall comfort, along with better handling (can’t wait to see lap times!) then if there’s a pound added, it’s worth it.

  4. Cool stuff.

    Is there any concern regarding the strength of the mounting points when going to a coilover suspension on these cars? I assume the mounting points were designed for just the damping force but now are dealing with all of the motion control. I know on E36/E46 rear suspension that if you go to true coilover then you need to do strengthening of the upper (body) mount.

  5. Did you have to make custom wiring and battery cables to mount the battery? I just want to do an RS30 or ATX30 in my c7 but Ive heard there are issues with the aux box mounting. Can you do a feature on just a lightweight battery install in a c7 with little to no changes?

  6. no we used the existing cables.. you will probably have to drill through the composite floor to mount a box in that location. we were able to secure it and the HLS pump together using the existing mounting points.

  7. Mike, any chance you guys could bring this full circle with your Suspension 101 course and show how to find the vehicle CG and Roll center for this car? I may be slightly biased/more interested since I have a C7 GrandSport of my own…

  8. Hello Mike, Jeff, I know this might be a loaded question……but how difficult was it to install the KW Coilovers? I have the V3s ready to install on my ’15 C7 here in SoCal. I may also be interested in the pump setup that you have at a later date.

    I out on headers myself, but never Coilovers. Thanks in advance!!!

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