Getting ready to drop 1.5

[lifespeed]

On the worst one, while accelerating uphill on a right-hand sweeper, the rear end took the hit (oof) but then launched into the air (boing) and I'm pretty sure I lost contact with the road. Not a good feeling.

This sounds like you hit the bump stops.

[clmrt]

There wasn't any violence in it, just a big trampoline feeling which led me to believe otherwise but I suppose it's possible.

I'm reading up on your experiences with shock valving but I don't have the resources to drop $$ on adjustables. Maybe the HPP air spring? I think that's the spring you chose with a fairly underdamped shock?

[lifespeed]

There wasn't any violence in it, just a big trampoline feeling which led me to believe otherwise but I suppose it's possible.

I'm reading up on your experiences with shock valving but I don't have the resources to drop $$ on adjustables. Maybe the HPP air spring? I think that's the spring you chose with a fairly underdamped shock?

I have the Grand Marquis air springs, which may well be the same as HPP. Pretty sure they eventually switched to the softer air springs even for the CV sport and HPP. Only Marauder and Town Car got the stiffer ones.

One thing to keep in mind is (I believe) a thicker rear sway bar greatly reduces the correct rear spring rate in these cars. I filled up the gas tank this afternoon and the ride quality improved noticeably. I'm going to lower the rear a bit in an attempt to decrease the spring rate further, as this seems to be what the car wants with the current configuration.

Finding the right combination of ride and handling at the rear of these cars is not trivial. Rest assured a big sway bar changes the ride and calls for softer springs, while improving handling.

If adjustable shocks aren't in the cards there is very little you can do to affect the ride. Raising and lowering the rear, within reason, adjusts the spring rate. Generally, I think the Marauder might be better off with GM air springs, especially if other rear suspension upgrades are planned.

[clmrt]

"I filled up the gas tank this afternoon and the ride quality improved noticeably."

Same here - rides great with a full tank.

I think I'll look into aftermarket sways next.

If I get drunk with the credit card in my hand I might even go CVPI rear springs, 2" drop. There's always a market for them used if that doesn't work out. But that's last-ditch.

[clmrt]

Happy almost post 1000, by the way!

[lifespeed]

Just dropped the rear about 3/8", fender lip is about 1/2" above the tire now. It noticeably improved the ride with the softer spring rate. Now back to adjusting the rear shocks to match the springs . . .

I think it is much more difficult to arrive at the correct combination with air springs than it is with coils. Worth the trouble for that air ride convenience, though.