floating feeling

[Ishmael]

I don't know if this is the right section but at about 70 mph it feels like the front of my 68 Firebird convertible is floating a little and when I start to slow down it shakes a bit. I think I need the cocktail shakers put back in and I'm putting subframe connectors in sometime soon. I'm not sure if the front is lifting and I need a chin spoiler or what it is. Any suggestions?
thanks

[F-Body International]

Start with solid body mounts and rebuilding that front suspension with quality bushings, shocks and ball joints. No need to go crazy with tubular Suspension if you’re just going for good ride quality.

It really could be a lot of things going here. Bad shocks will give you a floating feeling. Wheel balance and wheel bearings could be an issue.

[Ishmael]

Thanks for the reply. I have done the body bushings and have redone the whole front suspension with QA1s. The car isn't wandering around it just doesn't feel planted. Maybe its just me.

[UMI Tech]

How much caster is in it?

[Ishmael]

I'm not sure but I have the feeling its stock or whatever the shop sets everything at. I told them what I wanted when I got it back from body and paint and they did all kinds of stupid stuff and charged me $700 without telling me they were doing the work. Long stupid story. I will start with the alignment at a different shop. What should I set it at?

[68Formula]

Chin spoiler made a huge difference on mine.

[Ishmael]

Did you use ABS or carbon fiber? Did you have to drill your body?

[68Formula]

Did you use ABS or carbon fiber? Did you have to drill your body?

This was a while back, so it's just the simple ABS copy of the factory Camaro snowplow. I think I just had to make a couple small holes in the valance IIRC. I think some holes were already there and lined up. Very effective @ 70mph though for what it is.

[David Pozzi]

On first gens the air tends to build up on the front and raise it as you increase speed. It's made worse with soft stock springs and soft shocks. I think Camaros are a bit worse because they have a huge grille opening relative to the radiator size. Stiffer coils keep the front from rising as much, so does a front spoiler. Even with a spoiler the front has lift at speed, but less. If you have a rear spoiler it makes the front lift more & pushes the rear down.

[68Formula]

Since Mr. Pozzi brought it up; I have a '68 conv. bird as well, so no rear spoiler. Front springs are only about 400lbs/in.

[Ishmael]

My springs are soft. I have an aluminum engine and went with qa1s suggestion. I think they were 250s or something like that. I can stiffen up the shocks. I think the spoiler will help but I don't need to be driving it at 70 all that often either. Thanks guys.

[BMR Sales]

as UMI asked - what are your alignment specs?

[Ishmael]

I'm not sure but I have the feeling its stock or whatever the shop sets everything at. I went on here and searched what an ideal setting would be and they just did what they were used to.

[stab6902]

My springs are soft. I have an aluminum engine and went with qa1s suggestion. I think they were 250s or something like that. I can stiffen up the shocks. I think the spoiler will help but I don't need to be driving it at 70 all that often either. Thanks guys.

If your front spring rate is only 250 lb/in, that'll give you the old Cadillac/Buick floaty feeling at high speeds. That's quite a bit softer than even the stock front spring rates (most of which were in the 300's), which came from a time when bias plies and 55 mph speed limits were the norm.

[BMR Sales]

I'm not sure but I have the feeling its stock or whatever the shop sets everything at. I went on here and searched what an ideal setting would be and they just did what they were used to.

You really ought to know because this could be your problem

[Ishmael]

If your front spring rate is only 250 lb/in, that'll give you the old Cadillac/Buick floaty feeling at high speeds. That's quite a bit softer than even the stock front spring rates (most of which were in the 300's), which came from a time when bias plies and 55 mph speed limits were the norm.

I went with what QA1 suggested with an aluminum engine. I remember asking about 450s and was told to go with a lighter rate. I just can’t remember if it was 250 or 350.
Either way I know I have a number of things to look at. First thing I’m going to do is the subframe connectors and then check the alignment. Following that I will get in a chin spoiler and cocktail shakers. If I’m still not happy I will go with stiffer springs. I can’t change my shock settings in the meantime.

[68Formula]

If your front spring rate is only 250 lb/in, that'll give you the old Cadillac/Buick floaty feeling at high speeds. That's quite a bit softer than even the stock front spring rates (most of which were in the 300's), which came from a time when bias plies and 55 mph speed limits were the norm.

Actually the oil crisis of 1973 caused two things:

1) The feds pushed a national speed limit of 55mph to save fuel. Since they didn't have direct authority (it was up to each state, and not all complied... at least immediately), they would with withhold road funding subsidiaries from the offending states. Eventually most, if not all implemented the 55mph limit.

2) The radial tire, having a roughly 5% mpg improvement (based on EPA testing at the time), became more mainstream. They became more favored by consumers and manufactures alike. Tire manufacturers quickly re-tooled.

So by the time 55mph became the norm, so were radials.

[68Formula]

You really ought to know because this could be your problem

^^^This. The factory specs are horrible for the first generation. Made during a time that bias plys were used, and power steering was still an option. Plus they purposely calibrated it for understeer. And the tolerances for those specifications were pretty wide. If that's what the shop used, it could easily be the culprit, if not a major contributor, and you really need to get that corrected first. However, if it's still not to your liking, the front spoiler will still help even further.

[Ishmael]

So what should it be set at and I will see if I can get it into a different shop?

[ULTM8Z]

My '71 Camaro also had a "floaty" feel to it, even with the Hotchkis springs and Bilstein shocks. I didn't think it was that "bad" at the time, certainly not like when it had the factory F41 springs in there. But certainly didn't feel solidly planted like even my 4-banger daily driver does.

I then got a set of tubular upper control arms that allowed me to bump the caster up from 1.5-2 deg all the way up to 6 deg.

I'm telling you, the difference was UNBELIEVABLE. It's a totally different car now at high speed. In fact, with the way it feels now, my opinion changed about the way it was before... it was horrible before! I guess the overall suspension goemetry improved as well such that not only is the "floaty" feel gone, but the rebound is vastly improved as well. Going over bumps at high speed, the front end doesn't shoot up into the air any more.

Matter of fact, the "floaty feel" elimination and the rebound improvement were surprise benefits as I wasn't expecting those at all. The original intent just was to get more caster for better on-center feel for the steering, which the new arms did certainly provide.

Those A-arms plus the Y-braces and the Borgeson u-joint steering shaft and it feels easily as good as any late model car in terms of road manners and steering precision.