QA1 upgrade

[tfowler9]

Want to get any experience the members have on upgrading the front end stock springs and shocks to the QA1 coil over. I purchased and installed the QA1 Pro Coil Front system single adjustment 400 lbs on my 1971 351 C coup. Most of the hard work was removing the original equipment, Installing the new hardware was not very difficult............. but the tuning was.
In order to get the height I wanted ( I was not lowering the front end), I had to compress the spring by rotating the spring collar up, close to 4". Thats seem to be excessive- any thoughts on that? I adjusted the dial 8 clicks which is the top end of the comfortable ride. At that level, there was no bounce in pushing down on the front end. I reduced it to 3 clicks, which gives me about the same bounce as I had with the original springs and shocks - for street use. Considering I had no bounce at 8 clicks and the total adjustment available is 18 clicks, I am concerned the compression of the spring I needed to achieve the ride height was more than normal - again would like any input you may have.
I just completed the work so i have not driven more than a few miles to set the springs. I will follow up on my experience after driving awhile.
I follow this forum on a regular basis - thinks its the best one out there.....for any vehicle!
Tom

 

[tony-muscle]

Is this system meant to lower the car? If that's the case then yes you will have to compress it more than normal to raise the car. The counter to that is that your spring travel distance gets reduced by the same amount. I am also wondering if 400 lbs is too little.

 

[tfowler9]

Thank you for your response. They recommend the spring rate based on front end weight. Under 3000 lbs recommendation is 400. Could have done with 450?
I upgraded to improve handling not to lower the car.
Tom

 

[giantpune]

What's the distance from the center of your wheel arches to the center if your wheels?
There were different values from the factory depending on which options your car had.

 

[tony-muscle]

Thank you for your response. They recommend the spring rate based on front end weight. Under 3000 lbs recommendation is 400. Could have done with 450?
I upgraded to improve handling not to lower the car.
Tom

Was the 3,000 lbs based on overall car weight or front axle weight? Our cars are heavier than 3,000 lbs.

 

[rcadd1ct]

400 seems low to me

These are 600 1” drop for our cars

https://www.summitracing.com/parts/sdk-c7zz-5310-p/make/ford/model/mustang/year/1972

 

[tony-muscle]

The ride height will depend on stiffness (what we call "lbs") and coil height (including mounting hardware). That said we don't know the QA1 coil height but we know the lbs. Doing a quick and dirty calculation I get about 0.25" ride height for every 50 lbs of coil stiffness. Off course, we can't rely on stiffness alone to change ride height because the car will get very harsh or too soft. That said, coil height will be also important.