talked to the qa1 engineer, we wont hit the bump stop till we hit other parts first

 

gone

 

Very interesting...

 

Sounds like a good alternative for those wanting Coil-overs, and don't want to spend $1800+ for Pfadt's or LG's etc. Depending how low I can drop the car with these and how they perform, I might pick up a set.

 

parts number:

gs402-09450 this is for the front 450# single adjustment 18 point

gs403-07450 this is for the rear 450# single adjustment 18 point

http://www.qa1.net/qa1_motorsports/new_products.html
click on Corvette C5-C6 Coil-Over Packages


based the info from qa1 engineer, we can low the car 3" from factory which is enough before our c5 become sweeping machine (air dam will be around 2")

 

How do you lower the car with these coilovers without changing the preload on the spring???

 

Yea... good question.

 

installed the QA1 coilover, has the ride height 26.5" front and 26.75" rear
the initial setup for the 18 points adjustable shock are 9/7 for front/rear
i drove 30 miles already on freeway, not hitting bump stop and when hit the pot hole my car was not all over the place


the spring rated for 450# or you can buy 550# or 650#
basicly 450# is good for overall application

all coilover system have similar setup

 

Not really, the Phadt system and others have threaded bodies that can be screwed down into the lower mounting bracket to raise or lower the car without changing the spring rate. All springs are rated are a set length that needs to be maintained to optimize the spring while not reducing the overall shock travel.

 

this one have threaded body too

 

You can't change the spring rate or the compressed spring length to raise and lower the car unless you are changing the springs. In this case, you would move the nuts on the shock body which changes the height of the lower spring perch and changes the ride height. There really is no such thing as pre-load on the spring - what, do you think you put a band around the spring to load it or something like that? The load on the springs is always the weight of the car unless you have something drastically wrong with your setup.

And the Pfadt and LG are different in that the spring is not adjusted on the shock and the shock ride height length is not changed, the lower mount is moved up or down to change the ride height. Look at the pic of this coil over and imagine the bottom mounting T-bar being moved up or down at the end, that is what the Pfadt and LG do. The disadvantage of this system is that the shock comes closer to the bump stop or closer to being fully compressed as you lower the car. But if the design is shorter than a stock shock by a few inches so you won't normally tag the bump stops then it doesn't really matter unless running the shock closer to fully compressed all the time shortens it's life or causes it not to work as well or something like that.

deetee - So the ride was better? Have you tried any cornering or bumpier roads? Is the car riding smoother or flatter?

Peter

 

 

i tried cornering, its better
i rode around 50 miles with this setup on little bit bumpy road, and it feels better than before (lowering on stock bolt and bilstein shock) because i set the shock to be smooth ride.

i thought i will hit the bump stop with this QA1 coilover, but the engineer of QA1 is right about this (you will hit any other parts 1st before you hit the bump stop)

the advantage of this QA1 coilover, they have more range of application (lower ride all the way to drag race)

i thought with pfadt and lg its more for race and low ride. but maybe im wrong

i just gonna enjoy this cheap setup for now

 

Usually there is a set distance to be maintained between the upper and lower spring perches when the shock is in an unloaded state. This is pre load. If you are simply lowering the bottom perch and allowing the weight of the car to provide the load you are effectively reducing the amount of shock travel you have. Pre load keeps the shock fully extended and in it's most effective state. If you have a threaded bottom mount you can raise and lower the car without changing the available shock travel.

 

yeah but not much, otherwise the shock travel (shock body length) will be very short.
maybe 1" of threaded bottom mount but the ride height thread about 4" long, yeah its better but not much

 

I'm more concerned with how the front pin top is mounted. Is it just a set of washers and some rubbery bushing like a regular shock?

 

Please don't compare those to pfadt or LG G2's, it doesn't look like it has spherical bushings either. Plus where's the R&D on these coilovers, and the testing report on the dampening.

 

I don't think anybody here is trying to say they are as good or better than Pfadt or LG G2's...and the price would suggest that QA1 is not looking to be comperable. They are merely trying to fill a gap between high end shocks (Koni FSD's, Pfadt inverted) and the current coilover choices that start at $1800 and go up from there. For that, I thank them.

The majority of people running Pfadt or LG G2's are doing so only because they lowered the car way too much, and now the handling has suffered dramatically with the factory leaf setup. For those just doing it for the lowered look, but want to regain some of the handling characteristics of thier car that they lost by doing so, these QA1's look to be a good compromise. Heck, if drop spindles were cheaper than coilovers, most people would be running those instead.

 

I guess you could call that pre-load but I don't. I call pre-load a load put on something in it's installed state and the spring compression due to the limited extended length of the shock has no bearing on the load when these are installed and the car is sitting on the ground. So, I guess the pre-load would be the weight of the car, which is the same load all the time. Think about a bolt, the clamped force is often referred to as the pre-load.

In any case, there is no reason that the spring needs a certain amount of compression when the shock is fully extended. You just need to keep the spring within it's working limits during operation.

Also, I hope the shocks never end up fully extended during driving. That's mean the car is lifting wheels off the ground.

You are right that the shock likely needs to be kept within certain travel limits to be most effective.

Peter

 

These look pretty exciting. I've been considering coilovers but just couldn't swallow the cost.

I'll be interested to see how the performance ends up. Especially the 550lb version and how it stacks up to the factory suspensions and the other coilovers. I don't see any reason why these couldn't beat the factory leaf spring combos. They may lack the features of the other coilovers, but for someone who does mostly street driving with a track day here and there they may be the perfect price/performance tradeoff.