Air Bags Vs Coil Overs

[firebirdzig]

Can somebody please give me the pros and cons of air bags and coil overs. Which is preferred for a pro-touring/auto cross car? Also who makes and what makes a good air bag set up for auto cross.

[67zo6Camaro]

4200742008420094201042011 Good question, should turn out to be some good opinions....So here is my 3 cents. I run strange coil-overs at all 4 corners. I have a relatively stiff frame that holds all my running gear, so the coil-overs for me are consistant to dial in ride height and performance. They are adjustable...but not on the fly like air-bags. A cool feature of the air-bags is that you can lay that thing down when ever you want. However, Im not sure how consistant the spring rate (air setting) is for the preformance side....I know ride-tech has some great proven track times and consumer ride along compliments. At some point...I think a seasoned racer or track driver will eventually talk about consistance and ability to dial in performance. For the average user...including me, the air-bags are most likely acceptable (we don't have the track experience to tell the difference) otherwise we might see more airbags on Indy cars and/or Nascar. I would love to do another pro-touring car and try the air-bags with a similar stiff frame backbone.

Brett
Fab53.com

[exwestracer]

You can get decent handling results with air springs, but they have a couple of limitations when it comes to competition. The air spring is progressive, that is; the more it's compressed, the stiffer it gets. This makes the car more difficult to tune, as the spring is acting differently at every point in it's travel. Also, you cannot change base spring rate without changing ride height. With a coilover, you have to swap springs to do that, but it is possible.

[formula]

search is your friend.

https://www.pro-touring.com/forum/showthread.php?71341-Air-Ride-Tech-%28level-2%29-v.s.-Speed-Tech-Track-Time-Suspension-Package&highlight=air+bags+coil+overs

https://www.pro-touring.com/forum/showthread.php?72222-Had-enough-of-air-ride-issues-going-to-Coilovers&highlight=air+ride

https://www.pro-touring.com/forum/showthread.php?71702-Air-Ride-Ride-Ht-vs-Spring-Rate&highlight=air+ride

https://www.pro-touring.com/forum/showthread.php?67270-Suspension-choices-and-reviews&highlight=air+ride

[LowFast]

I have read the above threads (more than once) and done a number of searches. Has anyone owned both? Or at least driven cars with both? What was your impression? The ultimate comparisons would be someone who went from one to the other on the same car. I am having the same delima choosing which way to go. I like the simplicity of the coilover but also like to on-the-fly adjustability of air. My car will be 95% cruiser with maybe an autocross or trip down the drag strip a few times a year. I wan to set it up to ride nice and low with a smooth yet responsive ride, which I know can be done with either. The subject may have been covered a few times but the technology is constantly changing as are peoples expeiences with each.

[bret]

1. With a mechanical spring you will likley need one spring that is optimized for the track and one that is optimized for ride quality.
2. A double convoluted airspring is bery progressive, meaning that the farther you compress it the stiffer it gets. Not only that, it is adjustably progressive via changes in air psressure.
3. with an airspring you can induce a bit more negative camber into your front suspension by lowering the car slightly. this can be a good fine tuning tool to optimize your car for a particular track.
4. adjusting the height of the airspring can allow you to tune the corner weights of the vehicle as well. While easy to do between laps or rounds, it is not feasible to accomplish while on the track. Way too much other stuff [like driving] going on!
5. While obviaously biased, I have had excellent success on hte track with air suspension. It has not been overwhelmingly popular simply due to the lack of understanding and education about the details. I consider this my fault and am constantly working to improve this.

[exwestracer]

2. A double convoluted airspring is bery progressive, meaning that the farther you compress it the stiffer it gets. Not only that, it is adjustably progressive via changes in air psressure.


Bret,
I'd love to be able to show my students how this works. Many of them know about air springs, but can't grasp the idea about progressive rates. Do you have any charts or graphs for common bag sizes showing system psi vs. spring rate and/or spring rate vs. travel? That would help a lot!
Thanks
Ray

[SLO_Z28]

1. With a mechanical spring you will likley need one spring that is optimized for the track and one that is optimized for ride quality.

This is the main advantage of air springs. Air springs are very capable for performance use, and offer a very comfortable ride.

Coil Overs are a waste of money, they offer almost no performance benefits over a properly sized performance coil spring, and are mostly bling. Spend the money you would spend on coil-overs on good shocks and you'll see way more of a benefit than you would ever see in coil overs.


If air ride has the information about bag sizes and rates, that would be amazing, I just got asked about that by an old friend.

[formula]

Coil Overs are a waste of money, they offer almost no performance benefits over a properly sized performance coil spring, and are mostly bling. Spend the money you would spend on coil-overs on good shocks and you'll see way more of a benefit than you would ever see in coil overs.


I gotta say, this is only true if you don't plan to take advantage of the benefits of a set of coilovers. It really depends on what you plan to do with the car. CAN you waste your money on coilovers? yes. But are coilovers an inherent waste of money? Absolutely not.

[marolf101x]

Attached you will find the engineering specification sheet from Firestone. This is where we start will all of our projects (there are literally thousands of air springs to choose from).

Naturally we change things to fit the Shockwaves and play around with piston designs and other things, all of which are tested and recorded in a similar style to the Firestone sheet. However, our data is not as "available" as Firestone's, if you know what I mean.
42075

[exwestracer]

Attached you will find the engineering specification sheet from Firestone. This is where we start will all of our projects (there are literally thousands of air springs to choose from).

Naturally we change things to fit the Shockwaves and play around with piston designs and other things, all of which are tested and recorded in a similar style to the Firestone sheet. However, our data is not as "available" as Firestone's, if you know what I mean.
42075

Very helpful, thanks Britt.

[parsonsj]

Coil Overs are a waste of money, they offer almost no performance benefits over a properly sized performance coil spring, and are mostly bling. I can see this argument for a mostly stock car that the owner is looking for mild upgrades. However, for custom chassis and/or major upgrades, coilover shocks from the major manufacturers are the best shocks you can get. If you are chasing the best possible suspension performance for any given scenario, coilovers are a requirement.

jp

[Bryce]

As John said, its hard to buy a really good shock that is not a coilover. It doesnt mean you have to run the spring on the shock but it does simplify everything. The springs are smaller and lighter which is a good thing. Also in the rear if you go to a link style suspension its just a lot easier to mount the coilover shock with spring rather than a shock with a seperate spring.

As for bag vs spring, both have benefits. I am kinda tired of seeing slammed cars at SEMA and other shows that you know it cant drive like that. ITs kinda fake. But air bags can give you the good performance and the ability to raise the car to clear bumps. This makes the car more street friendly and maybe funner to drive as a cruiser. The lower the height on a air bag car the softer the spring and vis-a-versa, this is compared to the same car with the same bag attach points.

Shocks have a happy middle of their range so dont think that you can raise and lower your car more than a few inches and still be in that range. To adjust height beyond that you need to have multiple mounts at different heights.

[Rhino]

3. with an airspring you can induce a bit more negative camber into your front suspension by lowering the car slightly. this can be a good fine tuning tool to optimize your car for a particular track.
4. adjusting the height of the airspring can allow you to tune the corner weights of the vehicle as well. While easy to do between laps or rounds, it is not feasible to accomplish while on the track. Way too much other stuff [like driving] going on!


Bret, I do completely understand and agree with your statements, however I do have a question. Does the pressure differential done via this tuning process cause any additional tuning changes? As it was stated previously, it's difficult to decouple ride height from spring pressure. By wedging a car by raising the ride height of that corner, you're also changing the base rate of the spring. I would think this could cause the car to act differently in left vs right turns.

[MonzaRacer]

Ok as for a guy who has tune both air and coil over (mostly drag racing but a few street/track cars) Ill tell you that with your coil overs, you have what you got. If its too low you raise it BUT if the adjusters get loose your tearing crap up. Coil overs for the most part for performance are going to be salty, ad multiple adjustable units and your even higher.
For daily or weekender driving, with s little or a lot of track use the air spring, be it air bags and remounted double adjustable shocks or ShockWaves DA your going to have a set up that can handle pretty much anything you throw at it.
I bought my first CoolRide rear spring in Oct 98 just before East Coast Power Tour for my 71 Monte, added in a set of Monroe Sensa Tracks as my springs were so bad the compressed ,at ride height rear spring (metal) was about 5 in total height. I had 2! coil spring lift kits welded together to keep car off my wheels/tires.
I went in to see Bret, he was still working on his wifes Bonneville at the time, picked up rear CoolRide and installed it like a week before my trip, and I only used single lines to separate fittings at rear bumper ,similar to what people used to do with air shocks, About 50-60 lbs and the car was TOTALLY different. it would not body roll like before. I had tried a set of(borrowed) aftermarket performance springs but my tires wouldnt clear, no way to adjust height to look/drive good.
I installed the CoolRide and tada, proper height, We loaded my tool box, coolers, food/supplies,clothes,etc in car, trunk and back seat was full. Then me and my buddy, trip stories are even better but still,,,,,.
My next install was in 04 into my 78 C10.
This truck has parallel 4 link from ART and CoolRide all around ART shocks up front and Truck shocks for a 67-72 Chevy Truck.
while some would say the set up wouldnt work well but it handles great.
I made the Rear 4 link bolt on as ART hadnt developed one yest and I really didnt want to mod the frame too much at time.
I even used my old A6 AC compressor for air pressure, and a 5 gallon tank.
3 paddle switches and I set the height where I want to level the truck.
Now in my 71 Monte it handled awesome, never gave a ride issue even loaded down. Heck I carried 4 350 blocks and 8 cylinder heads in trunk, never added more than 95 lbs and the car still handled well carried the load. Unloaded I dropped air pressure and tada ready to drive.
You could NEVER have done that with coil overs. If all you do is drive to track and race then drive home, I guess coil overs are ok, but if you need to load it up, and drive long distance, thne your adding height,decreasing ride quality, then readjusting again to race then readjusting again to drive home,,,,air ride is add a few lbs of air and maybe tighten or loosen a set of DA shocks to match the driving pattern.
Back in 86 , while I was in tech school I drove race car for a guy, a ladder bar equipt 86 Monte SS Aerocoupe and we drove that car to track and cruised it, much to Indy/Speedway cop chagrin. It rode like $h1t ! and the adjustments had issues as we nearly wore the stupid coil overs adjuster out to change things for dual use.
After seeing what it cost to get REAL properly tuned and valved coil overs (check out Bad Penny's new setup) I'll stick with air, and if the spring wears out , you can get replacements and they will perform pretty much like the previous ones. I have guys who break/damage coil over springs and honestly I cant see the springs as being same in specs as close as air springs.
But its all up to the owner/driver.

[MonzaRacer]

Ok as for a guy who has tune both air and coil over (mostly drag racing but a few street/track cars) Ill tell you that with your coil overs, you have what you got. If its too low you raise it BUT if the adjusters get loose your tearing crap up. Coil overs for the most part for performance are going to be salty, ad multiple adjustable units and your even higher.
For daily or weekender driving, with s little or a lot of track use the air spring, be it air bags and remounted double adjustable shocks or ShockWaves DA your going to have a set up that can handle pretty much anything you throw at it.
I bought my first CoolRide rear spring in Oct 98 just before East Coast Power Tour for my 71 Monte, added in a set of Monroe Sensa Tracks as my springs were so bad the compressed ,at ride height rear spring (metal) was about 5 in total height. I had 2! coil spring lift kits welded together to keep car off my wheels/tires.
I went in to see Bret, he was still working on his wifes Bonneville at the time, picked up rear CoolRide and installed it like a week before my trip, and I only used single lines to separate fittings at rear bumper ,similar to what people used to do with air shocks, About 50-60 lbs and the car was TOTALLY different. it would not body roll like before. I had tried a set of(borrowed) aftermarket performance springs but my tires wouldnt clear, no way to adjust height to look/drive good.
I installed the CoolRide and tada, proper height, We loaded my tool box, coolers, food/supplies,clothes,etc in car, trunk and back seat was full. Then me and my buddy, trip stories are even better but still,,,,,.
My next install was in 04 into my 78 C10.
This truck has parallel 4 link from ART and CoolRide all around ART shocks up front and Truck shocks for a 67-72 Chevy Truck.
while some would say the set up wouldnt work well but it handles great.
I made the Rear 4 link bolt on as ART hadnt developed one yest and I really didnt want to mod the frame too much at time.
I even used my old A6 AC compressor for air pressure, and a 5 gallon tank.
3 paddle switches and I set the height where I want to level the truck.
Now in my 71 Monte it handled awesome, never gave a ride issue even loaded down. Heck I carried 4 350 blocks and 8 cylinder heads in trunk, never added more than 95 lbs and the car still handled well carried the load. Unloaded I dropped air pressure and tada ready to drive.
You could NEVER have done that with coil overs. If all you do is drive to track and race then drive home, I guess coil overs are ok, but if you need to load it up, and drive long distance, thne your adding height,decreasing ride quality, then readjusting again to race then readjusting again to drive home,,,,air ride is add a few lbs of air and maybe tighten or loosen a set of DA shocks to match the driving pattern.
Back in 86 , while I was in tech school I drove race car for a guy, a ladder bar equipt 86 Monte SS Aerocoupe and we drove that car to track and cruised it, much to Indy/Speedway cop chagrin. It rode like $h1t ! and the adjustments had issues as we nearly wore the stupid coil overs adjuster out to change things for dual use.
After seeing what it cost to get REAL properly tuned and valved coil overs (check out Bad Penny's new setup) I'll stick with air, and if the spring wears out , you can get replacements and they will perform pretty much like the previous ones. I have guys who break/damage coil over springs and honestly I cant see the springs as being same in specs as close as air springs.
But its all up to the owner/driver.

[SLO_Z28]

I can see this argument for a mostly stock car that the owner is looking for mild upgrades. However, for custom chassis and/or major upgrades, coilover shocks from the major manufacturers are the best shocks you can get. If you are chasing the best possible suspension performance for any given scenario, coilovers are a requirement.

jp

The best shocks on the market are not coil overs, not by a long shot. There are some good shocks that are coil overs, but they are not the best. Coil Overs come from the racing world, due to limited space availability, and fine tuning corner weight. In neither case is this an issue in a street application.

For the price of a coil over, you could go to a chassis shop and get your corner weights, order custom springs for your application, and buy some of these:
https://static1.pt-content.com/images/noimg.gif
and be way ahead of the game.

[parsonsj]

That's an AFCO coilover body. Add this

https://static1.pt-content.com/images/noimg.gif

plus your springs, and away you go.

jp

[SLO_Z28]

There is no benefit for running those as a coil over in a street application, and it greatly increases failure rate.

Coil overs on a street application are bling, pure and simple. Just like all these brake kits with 6 pistons, no area to them, and small pads. Bling.

[parsonsj]

Which argument are you making? Is it

1. The best shocks aren't coilover bodies

or

2. There is no benefit to running a coilover on a street application

or

3. Coilovers greatly increases failure rate

or

4. Brakes with 6 pistons and no area are poor shocks. :)

jp

[formula]

I will agree that brakes make terrible shocks. THAT was a terrible day.

Also, never spring for crossdrilled OR slotted shocks!!

[SLO_Z28]

The point I am making is that there's no appreciable benefit to a coil over UNLESS you're building a race car, that will see only very light use, and you want to fine tune corner weights, and are very concerned about component weight(like at the point you're fine tuning your wight as a driver). Every set of coil overs I have installed has failed in street use. Then again Im way harder on my car than most are, its not a car until its been on its side :D

The point I was making with the brakes is that is a very expensive, very cool, waste of money and flat out doesn't justify the money spent on it. Bling.

[robertjra]

I'm going with air shocks i like the versatility of hight on the go and laying on the frame
https://static1.pt-content.com/images/pt/2010/11/airshock2-1.jpg

[parsonsj]

Slo, we're just gonna have to live with the fact that we disagree with each other. Every single manufacturer of aftermarket subframes (both front and rear) designs their chassis around coilovers. DSE, AME, TCI, Heidt's, Jake's, Alston, and so on. Those subframes aren't for racing (though some perform well on the track). Those subframes are for street use. Every single one.

Are they all wrong? Are all of those manufacturers having shock failures and covering it up?

If you want to have the best shocks, and the most adjustability, get coilovers. Of course, they aren't all created equal. Some are cheap (Aldan Eagles, etc.), some are mid-priced (QA1, Strange, etc.), and some are expensive (Koni, Bilstein, AFCO, etc.), and like most things in life, you get what you pay for. But to label them as "bling" as if they have no performance value is just wrong.

jp

[67zo6Camaro]

I 2nd that JP.

Some like hot dogs and some like Hamburgers....It's just the way life is.

Brett
fab53.com

[MCB Matt]

With the major improvements bret has made with air and the amazing ride height control systems they offer if you want those advantages go ridetech, we have several customers running them and are very happy, we are about to install a system on one of our cars! Auto ride height sensors and programmable preset ride heights are VERY nice to have!

On the flip side we have sold hundreds of sets of coilovers and overall most are happy and only want them for ride height adjustment.....as well as comp/rebound adjustment being easy!

[silver69camaro]

Every set of coil overs I have installed has failed in street use.


Being in the chassis business, I like to think we sell a decent amount of coilover shocks. I don't know exactly how many thousands we've sold, but I can't think of one that came back due to a failure. A couple of leaked, but no more than a regular OE type shock. So far I've been very impressed.

Anyway, coilovers aren't bling. It's a great way to get a good quality damper combined with great packaging and light weght. We all know how much a 5" OE type spring weighs, so it's really nice to keep that weight down for a better ride quality. Also, if you have tried to engineer a suspension package, you probably know how great it can be to have small components to ease packaging headaches.

[Scott Parkhurst]

My coil over double-adjustable shocks and 6-piston 13-inch diameter brakes seem to work pretty good on the street and the track....for being bling and all.

Now as soon as I can get some Forgelines with spinners, I'll be the blingin-est SOB on the track.

[MCB Matt]

:drive:
My coil over double-adjustable shocks and 6-piston 13-inch diameter brakes seem to work pretty good on the street and the track....for being bling and all.

Now as soon as I can get some Forgelines with spinners, I'll be the blingin-est SOB on the track.

[formula]

This thread needs a theme song:


http://www.youtube.com/watch?v=LXDoxxlgNG0

[67zo6Camaro]

Nice...LMAO loud. Thanks, now I feel right at home with all my bling on my car. And Im pretty sure thats why it's so slow.

[2blownstangs]

Air Ride Technologies goes pretty hard on the track and street. I've been on their set-up for years and will never go back to a coil-over or anything else..

[yanniz]

went to Air Ride shock waves last spring with Air pod et, DA shocks front and back, cetera...prior to that I had Afco DA coil overs....95% street car now.....Air Ride is the way to go for cruising.....only thing that really disappointed me is that the system is really not functional reading air bag pressure only (not consistent at all going to the same ride height) and you are forced to buy the height sensors to get some kind of consistency....

[JRouche]

Weird, I missed this thread. Air Bags Vs Coil Overs

" Can somebody please give me the pros and cons of air bags and coil overs. Which is preferred for a pro-touring/auto cross car? Also who makes and what makes a good air bag set up for auto cross. "

Ok to answer who makes "a good air bag set up for auto cross". Not sure, but my answer would be no one. I dont know of any air spring manufactures or dealers that market their product for auto cross, havent seen the sales brochure, but they dont market race springs. And auto cross is racing right?

I have yet to see an air spring manufacture back their product for race use. But there are MANY coilover spring suppliers that are willing to say their springs are used in racing and are good to go for the racing environment.

Whats that tell you?

Air springs are great for street use. And Im a big fan of them, for the street.

But when you talk about auto crossing, racing basically, Id go with the steel springs and coil over type springs.

I have shockwave springs on my car, and to be honest, the car feels like it is ready for the track. And it may be, it might be fast, but not race car fast. Street car fast, yes. But when racing is concerned it will prolly be a lil slow, and not cause there isnt any HP. But mainly cause the suspension is tuned for the street.

Really hard to have the best of both worlds.

Race or street? Fine line some times.. JR

[wmhjr]

At the end of the day, aren't we really arguing minor degrees of differences? It's not like any of the 3 (traditional shock and coil, coil-over, and air) are either bad or are the essential component that you just can't do without. Here's my take....

1) Traditional spring and shocks: Nothing whatsoever wrong with them assuming you're going to tune to one configuration and keep a static ride height. In that case, they perform as well as or better than anything else out there. Very very consistent if done correctly. Downside is the lack of adjustability.

2) Coil-overs: Pretty much all the advantage of traditional springs and shocks, but with more flexibility in tuning the suspension more easily. Downside is cost and a little complexity in some cases.

3) Air. Great system that can provide far more height adjustability, and ride quality adjustability. If dialed in and tuned very accurately, I'd say that history has proven that the system can perform well enough that any of us won't be able to find fault. Plus, some great flexibility in height. Downside IMHO is the far higher complexity, the inherent difficulty in truly getting consistent pressures, resulting in a likely scenario where you're not at optimal tuning parameters, and a higher potential failure rate. That is NOT a slam on air systems. When designed and installed correctly - as Bret obviously does for example - they are great systems.

Personally I just think it's pretty cool that we have those choices to begin with. It wasn't that long ago that a dropped axle was high tech.

[bret]

I won't elaborate too much here right now but only point to our success at autocross and road course tracks to demonstrate the effectiveness of a properly designed, installed, and tuned air suspension. Adjustability is the key. Every car, coil or air, must be tuned to both track and driver. With air it is a bunch easier and faster to arrive at an optimum set up
Having said that, if you are building a single purpose car with no importance given to ride quality, AND want to save some money, coil overs avoid the expense of the compressor system.

All good!

[JRouche]

I won't elaborate too much here right now but only point to our success at autocross and road course tracks to demonstrate the effectiveness of a properly designed, installed, and tuned air suspension. Adjustability is the key.
All good!

I agree, adjustability is key. But what I dont get is where is the adjustability with air springs? I dont see it. I see it for show cars, they can drop the car in the grass for a nice look and still have great ride quality when on the road when they air up.

But for performance I think Im missing the adjustability with air springs. I dont see it. Its one rate, one setting. All dependent on the weight of the car and how much air it takes to set the suspension to the correct ride height so the control arms are at the correct geometry.

I really dont see ANY way to adjust for spring rate (and I think thats the adjustability we are talking about no?) with an air spring suspension while keeping the control arms where they belong.

Solly Bret, I just dont see the adjustability with air springs for a track car, or any car for that matter. The amount of air is going to be set at a certain psi to keep the car suspended. Once thats set its a done deal. The air springs ARE progressive, but thats not adjustability.

Add any more psi and the car sits too high, remove too much and the car sets too low. Its black and white with air springs. I dont see the adjustability. JR

So I just had to add. I really enjoy my air suspension. Every day I drive the car I get used to the suspension, ok, not so much the suspension itself but the overall handling of the car. Its amazing for me to drive a 50 year old car that has the handling that it does. Its pretty much the best handling car I have driven at this point. My Carrera was actually the best, but it took much more control and learning to keep it in the lane for aggressive driving. The Carrera needed LOTS of throttle in the outside turn to keep it on the road.

But the air springs are really giving me alot of fun on the road. Almost makes me feel like dragging it out to the track up north and pushing it through a road course. I just cant afford that right now. The cost of some track tires, new brake pads (Im sure I will cook the ones I have), and really even the fluid changes for the engine. Tracking a car, not even racing gets costly. But I see all these Camaros tracking and racing and to be honest, I think I could pull up some decent numbers with my lil old Nova. Might give the heavy Camaros a run?

I have a feeling Im a lil bit lighter. I have some scales. I should break them out this weekend and scale the car as is.

Anyway. Im loving the air springs so far. Adjustability? I dont see that. Ill work on my other parts that are adjustable. Im thinking a lil more roll stiffness on the front might be in line for my car along with a lil more rear bar. But before I change the rear bar Im gonna raise the center pivot for the watts link first. I have some adjustability there without adding any money cost, and it will give a lil more stiffness for body roll in the rear, but it may kick out the rearend more than I want. I have a 700r4 auto and when it shifts its a lil hard from first to second. I dont like too much shock from the drivetrain. Thats where a manual gear box is king. Coming out of a fast corner the auto gear box is not anywhere close to controllable as a manual trans would be. I hate that heavy "kick" from 1st to 2nd. Id rather have a manual gear box for the track. For So Cal streets, I love the auto box. JR

[Hunter68]

not sure if this is the right place to put this but is the ride height really adjustable that much with the air ride? i have not seen one on a camaro or even ridden in anything with air ride, so i had a couple basic questions; does the compression rate change with the height and how does it ride at say as low as it can go to higher?