@emichel6888 Looking at the Ground Control website and it has a field for Desired Spring Rate. Do you know what the choices are? What did you choose?
His spring rate up front is 475#, not sure about the rear.@emichel6888 Looking at the Ground Control website and it has a field for Desired Spring Rate. Do you know what the choices are? What did you choose?
Could this be remedied by some helper springs?Don't get the GC kit, the springs are too short so when you lift your car or jack it up, the perch falls down from the bearing. Literally disassembles itself everytime, have to pay attention and line the bearing and strut mounts back up.
We can set the kit up for what you're looking to do. It does not have preload to it, so at full droop the spring does drop away from the perch, helpers are $74 per corner.
Typically the lowest rate we try to send with the kit is 425f/550r, we can go lower than that, but we can't guarantee that you won't have issues with coil bind or bottoming out in that situation.
There shouldn't be an issue with salt, all the aluminum parts are anodized, steel parts are either zinc plated or powdercoated.
@emichel6888 Looking at the Ground Control website and it has a field for Desired Spring Rate. Do you know what the choices are? What did you choose?
Unfortunately no, when fully compressed they add about an inch of height, so if you installed these you would not get a desirable ride height. If you try to use a shorter main spring to compensate for that added height it limits the spring travel and that can (and does) cause the spring to bottom out. There is not a lot travel in this suspension, you really don't want to do anything that lessons spring travel, and helper springs will do that. The only way to effectively use helper springs is if you could lower the bottom perch to offset the height of the helper spring when fully compressed, which is what they do with struts designed to be a coil over like the B16 kit. I found it was just easier and works just fine to live with the fact that there is a gap when the car is lifted. Like I said it slides together when lowered, so it is not even an issue. and if you are concerned that it could get out of alignment you could just do what I did above.Could this be remedied by some helper springs?
https://www.swiftsprings.com/products/assist-helper-springs/
https://eibach.com/us/c-113-products-motorsport-springs-accessories-helper-and-tender-springs.html
The problem with this car is limited suspension travel. So when you try to go with a "comfortable" spring rate, the weight of this car causes it to bottom out far to easily, and if you lower the ride height further reducing suspension travel... This car does not exactly ride great stock IMO, perhaps compared to most other sports cars it does, but not compared to typical mid tier sedan/SUV, and when you start driving fast and hitting bumps it crashes, which I really hate.I contacted GC about their kit a couple weeks ago. Here's their response.
so, they will do helper springs, but that will obviously limit drop. I was asking about somewhat softer springs (halfway between this and stock). I ran some numbers and the stock Golf R setup is somewhere around 1.4hz front, 1.7hz rear (more confident in front number than rear). This is at the high end of normal passenger cars. Sedan race cars are generally somewhere around 1.5-2. over 2 the ride can get rather harsh. (full aero cars are 3-5, because they need to support the additional aero load, unless you do something funky like the Koenigsegg 3 damper/spring setup).
the GC springs put you at 2.1 and 2.4hz. This is pushing it for DD use and bumpy tracks, and higher than I personally want for my dual use car. If I had my druthers, I'd probably aim for roughly 50% stiffer than stock, which would put spring rates around 300/375, for 1.75/2.0.
hope that helps some people out!
There are just to many variables that basic simple calculations just cannot account for, especially when it comes to something as subjective and ride comfort. The best thing anyone can do when trying to decide is to try find someone that already has the suspension components you are considering and see if you can get a ride.
I contacted GC about their kit a couple weeks ago. Here's their response.
so, they will do helper springs, but that will obviously limit drop. I was asking about somewhat softer springs (halfway between this and stock). I ran some numbers and the stock Golf R setup is somewhere around 1.4hz front, 1.7hz rear (more confident in front number than rear). This is at the high end of normal passenger cars. Sedan race cars are generally somewhere around 1.5-2. over 2 the ride can get rather harsh. (full aero cars are 3-5, because they need to support the additional aero load, unless you do something funky like the Koenigsegg 3 damper/spring setup).
the GC springs put you at 2.1 and 2.4hz. This is pushing it for DD use and bumpy tracks, and higher than I personally want for my dual use car. If I had my druthers, I'd probably aim for roughly 50% stiffer than stock, which would put spring rates around 300/375, for 1.75/2.0.
hope that helps some people out!
Unfortunately no, when fully compressed they add about an inch of height, so if you installed these you would not get a desirable ride height. If you try to use a shorter main spring to compensate for that added height it limits the spring travel and that can (and does) cause the spring to bottom out. There is not a lot travel in this suspension, you really don't want to do anything that lessons spring travel, and helper springs will do that. The only way to effectively use helper springs is if you could lower the bottom perch to offset the height of the helper spring when fully compressed, which is what they do with struts designed to be a coil over like the B16 kit. I found it was just easier and works just fine to live with the fact that there is a gap when the car is lifted. Like I said it slides together when lowered, so it is not even an issue. and if you are concerned that it could get out of alignment you could just do what I did above.
There are definitely a bunch of calculations that I haven't done (the damping plays a big role in ride comfort), but I also don't love the idea of doubling the spring rate with the same dampers. At the end of the day suspension is a spring mass damper system, and changing only the spring rate but not the dampers can have negative effects on actual performance. The calcs I'm using are part of how suspension engineers tune a car's suspension (along with many others), and while they only get you close, they're an important part in determining overall ride and traction characteristics.
Many think that a stiff ride is "sporty" and so sports cars (especially ones without significant aero) are often oversprung compared to actual performance benefits because of marketing. Most "race" modes only actually work on glass smooth tracks. Cornering, braking, and acceleration traction is often improved by (relatively) softer spring rates and less damping in MOST real life situations. In other words... "Because race car".
That said, the R definitely has room for improvement. Either through bump stop tuning or stiffer springs. The reason you can't go softer on the coilover conversion isn't necessarily that the suspension will bottom out, but that the springs with the conversion have relatively low total travel before they hit coilbind. That's a significant problem and way worse than hitting bump stops, since there's no variable spring rate increase, it's just an immediate step function. Big fucking problems if you hit a bump mod corner and get spring bind!
Not saying the ride isn't decent with the GC kit... But it's higher than I'd want it personally based on my preferences. The fact that the minimum spring rates are determined based on the available spring travel and not the desired performance characteristics doesn't give me warm fuzzies.
I've ridden in @Cliff 's Ground Control setup prior to him switching to Ohlins, and it rode really well on track and is probably the route I'll end up taking when I can save up enough (instead of spending on track days). I know he didn't mind the ride as a daily, and has taken numerous long road trips to tracks in other states. I'm sure he'll chime in more.
Let me preface this by saying I have little to no knowledge of how to calculate hertz based off all the different numbers needed.
That being said, Karl Taht, who is a member on here, wrote an article about motion ratios, hertz, and other suspension pieces here. While this is for a GTI, his calculations end up being 8kg/9kg to keep a 1.6-1.8hz ratio. I would imagine with the increased weight of the R, the spring rates would be slightly higher? I know there's some assumptions in some numbers being used, but the end results are very different than yours. Since it seems you know more about this, maybe look into his article and see how your numbers differ from his?
This year should make it easy to save up for mods, Jeff - there aren't as many track days as a normal year. Which is good for me as I've had to replace my water heater, refrigerator, and couch this year...
I've written enough about GC's suspension kit and I don't have anything new to add. Look forward to seeing you in a few weeks at Laguna.
@Cliff One thing I'd be interested in - would you recommend doing the same path you did and use GC until the stock struts for then go Ohlins, or save up and go right to the Ohlins?
The only thing I could see making a difference there would be the DSC Sport controller but it's rather absurdly priced at $1200. If it was half that I'd almost certainly try that route first.