AirShocks for handling?

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j-c-c
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AirShocks for handling?

Post by j-c-c » Tue Sep 25, 2018 11:00 am

Can the airspring/shocks be useful for handling/cornering on track, no drag strip, I mean no springs whatsoever? I have no interest in low rider looks, but not having any ability with changing spring rate seems a big downer. I was thinking maybe making changeable mounting points on LCA to change the motion ratio might be a partial solution. It would be nice though to drop car say an inch(?) for on track use, but that seems such a compromise on alignment issues for the other suspension height.

Or just stick with typical adjustable coil over/shocks?

mk e
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Re: AirShocks for handling?

Post by mk e » Thu Oct 04, 2018 11:18 am

I've never seen a practical use for them beyond load leveling for towing.

For road racing setting the ride height and picking a spring rate are INDEPENDENT choices with different requirements, so air shocks cannot possibly do the job. Then add to the mix that damping rates want to change with spring rates but also track surface and the problems with air shocks get worse.

Dual use setups are always a compromise. The 2 mounting points is a decent idea if possible. I run normal adjustable coilovers (dpring and damping) with fairly stiff springs and usually change nothing street vs autocross...sometimes a bit more damping at the autocross it's pretty smooth. It setup I run starts to feel a bit loemse above about 120mph, which in s way above autocross speeds but would need more damping dialed in on a real road course, I'd leave the springs as is...they are stiff and already have negative preload (gap not compression)

My experience, your results may vary.
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j-c-c
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Re: AirShocks for handling?

Post by j-c-c » Fri Oct 05, 2018 2:05 pm

It seems I can vary my MR from .5 to .64, roughly in steps of .04 without too much difficulty. I spoke with air spring sales rep about my concern, and he had no clue about resolving spring rates. And they are not cheap, best to sick with CO's and tune with that tried and proven method.

Thanks.

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Re: AirShocks for handling?

Post by PackardV8 » Fri Oct 05, 2018 8:43 pm

When thinking these thoughts, look at what the fast guys are running. They always have way more experience and way more money. If it works, usually they've already got it and you can't afford it.
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Brian P
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Re: AirShocks for handling?

Post by Brian P » Mon Oct 08, 2018 7:59 pm

I know RideTech has built cars with air ride for autocross etc; there are videos on youtube showing it.

The usual headache with air springs is that the spring rate is really progressive. In cornering, you will be in the low spring rate part of its travel, Without doing anything else, that is a recipe for lots of body roll.

I am pretty sure RideTech dealt with this simply by using heavy antiroll bars. For the rear, if they used a diagonal 4 link, the roll center will be pretty high, too.

There is another common air-ride situation where this is relevant ... Transport trucks. They deal with it by using a suspension design that simply allows very little left-right difference in motion. The whole axle can go up and down with a low spring rate but it almost locks the left and right motions together.

For the most part, I don't see the purpose compared to well chosen steel springs and dampers selected to match. Those will at least perform consistently.

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Re: AirShocks for handling?

Post by j-c-c » Tue Oct 09, 2018 10:06 am

Brian P wrote:
Mon Oct 08, 2018 7:59 pm
I know RideTech has built cars with air ride for autocross etc; there are videos on youtube showing it.

The usual headache with air springs is that the spring rate is really progressive. In cornering, you will be in the low spring rate part of its travel, Without doing anything else, that is a recipe for lots of body roll.

I am pretty sure RideTech dealt with this simply by using heavy antiroll bars. For the rear, if they used a diagonal 4 link, the roll center will be pretty high, too.

There is another common air-ride situation where this is relevant ... Transport trucks. They deal with it by using a suspension design that simply allows very little left-right difference in motion. The whole axle can go up and down with a low spring rate but it almost locks the left and right motions together.

For the most part, I don't see the purpose compared to well chosen steel springs and dampers selected to match. Those will at least perform consistently.
Yes I agree, reality finally set in. :D

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Re: AirShocks for handling?

Post by mk e » Wed Oct 10, 2018 7:57 am

Brian P wrote:
Mon Oct 08, 2018 7:59 pm

The usual headache with air springs is that the spring rate is really progressive. In cornering, you will be in the low spring rate part of its travel, Without doing anything else, that is a recipe for lots of body roll.

I am pretty sure RideTech dealt with this simply by using heavy antiroll bars. For the rear, if they used a diagonal 4 link, the roll center will be pretty high, too.
Off topic a bit but spring rate and antiroll bar has been a thing for as long as I've been even aware off car stuff.

One school likes high spring rates with smallish antiroll bars to keep the suspension as independent as possible while the other school wants suspension that is soft enough keep tires settled on the track and chooses Scottish spring with nigish antiroll bars.

I've always been in the heavy spring camp and on the FSAE chassis I built I did a very progressive spring linkage with no antiroll bars at all to reduce weight. It worked but tuning it was a...hmmm...challenge. I would probably not do that again.

On my 308 which is setup for street and autocross the springs are about double factory rate, but the dampers are at the factory high speed rate but softer, more linear at low speed. Factory front antirollbar, rear bar currently removed....I need a slightly bigger front bar so I can reinstall the factory rear bar. Anyway its won a few autocrosses and honestly the street ride is smoother that stock.....these are ohlins dampers and what I difference over the koni dampers the factory used, technology matches on, just an amazing differance it ride quality on the street and traction on the track.
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Re: AirShocks for handling?

Post by lewy-d » Wed Oct 10, 2018 9:45 am

what is a "Scottish spring"? and a "nigish antiroll bar"?

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Re: AirShocks for handling?

Post by Kevin Johnson » Wed Oct 10, 2018 9:10 pm

lewy-d wrote:
Wed Oct 10, 2018 9:45 am
what is a "Scottish spring"? and a "nigish antiroll bar"?
In context, how about "softer springs and biggish anti-roll bar" after being auto-corrected and typos? A wild guess is that Mark is using his phone.

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Re: AirShocks for handling?

Post by mk e » Thu Oct 11, 2018 7:33 am

Kevin Johnson wrote:
Wed Oct 10, 2018 9:10 pm
lewy-d wrote:
Wed Oct 10, 2018 9:45 am
what is a "Scottish spring"? and a "nigish antiroll bar"?
In context, how about "softer springs and biggish anti-roll bar" after being auto-corrected and typos? A wild guess is that Mark is using his phone.
Very close "softish springs" ...which my phone just tried to change to Scottish again.....it's like being back with late 90s MS word.
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Re: AirShocks for handling?

Post by Brian P » Thu Oct 11, 2018 5:31 pm

Autocorrect = automistake more often than not. I hate it.

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Re: AirShocks for handling?

Post by pdq67 » Thu Nov 08, 2018 7:51 pm

Years ago, I rode in an early to mid '60's Cad Calais 4-Dr H/T. Talk about a BIG car!! Back about the early '70's so the big Cad. was still like new!

The sucker rode like a dream and cornered almost with NO roll!

I figure it's springs were way soft and it's sway-bars way stiff to get it to ride and corner like it did.

pdq67

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