Does anyone have any personal experience with Quantum coilovers? How is the ride quality? How do they compare to Öhlins? They have Swift springs at 10/8kg spring rates.

 

One thing to consider as well, is what sort of U.S. presence Quantum has, for service/upgrades, etc.

 

I have Quantum coilovers with 14kg Nova springs and external resovoirs.

My FD also has a full cage and a lot of bracing that forces the suspension to do a lot more work than the chassis due to how stiff it sits now. Even at 14kg the car is quite tolerable on the terrible roads where I live when street driving. There is adjustablility in them like most coilovers, but they are a lot more circut focused. Key word there is circuit, on a road course you can reach the limits of rebound on mine with severe elevation or surface condition changes. Again though, I'm in a fully caged car putting down a lot more torque than the average FD and overall they are still quite good. My car feels very neutral on track still despite how much has been altered front to back.

I am however, going to sell them to move to a more road course oriented setup that is matched better to how my FD squats and reacts corner to corner and on straights with aero assistance. I can get the Quantums serviced and upgraded, but as ptrhahn mentioned there is not a lot of options in NA.

 

Thanks for the input.

 

I have a set of T5-RS Quantums. The ride and handling is very nice for the street and back road driving. I have not had the car on the track since install. I have the same springs and rates.
My only gripe is that the ride height is verrry low in the front. At max ride height I cant even stick a finger between the tire and fender with a 255/40/17. The rear is fine though, at max height I have about 2 fingers.

I am trying to find a spacer, or different style top hat to get some extra ride height back. Only other option is air cups, but those are not cheap and I don't want to deal with the compressor an reservoir.

 

I sent a private message to atm0706 about the solution to adjusting Quantum heights, but forgot to post in here for everyone else to see.

There are several ways to fix the Quantum right height:
1) Internally, there are plastic spacers that adjust the shaft extension length. That will give you more shaft travel and height.
2) Externally, you can just put another spacer in between the upper spring perch and top hat. A simple spacer like this from McMaster does the trick. Just don't tighten down the top hat nut too much like some people do, because it creates too much tension on the shaft and breaks it at the threads. Not a Quantum specific problem - it happens with any shock shaft if not handled properly.
3) Some companies make top hat spacers that go in between the chassis shock mount and top hat. This is obviously more expensive that Option 2, but if you ran out of thread length or didn't want to send the shock back for internal adjustment like Option 1, this is certainly one way of doing it.
4) Air cups.... if you really wanted that.

https://www.mcmaster.com/92871a369