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Just curious about the ride height vs. the factory springs in a small block car. As I get back to working on my car following two weeks abroad, I'm thinking about going with the F41 springs from the start so that I only have to mess with these front coils once. My initial plan was to get the car back on the road and drive it for a while....then potentially swap to the F41s later as I feel the factory base springs are a little soft for my liking. But given the aggravation of the front coil installation, I'm giving serious consideration towards doing it once and being done with it.
Any input from those running the F41 springs would be greatly appreciated.
I am. I’d go for it. They don’t seem to raise the ride height and are a perfect balance between stiff and stock. For some, they are a little harsh but I like feeling the road. I also have a 1.25” anti sway bar on the front and Koni classics adjusted half way.
Thanks for the input! I'm going to start with a 13/16" front bar off the 71-73 cars and RideTech/Fox shocks also set right in the middle. Was the static height of the front F41 springs shorter than the factory springs?
The free length of the F41 is shorter than the base spring so your short compressor rod might just work, but I'd recommend you get a little longer threaded rod so you don't have a frustrating repeat.
The free length of the F41 is shorter than the base spring so your short compressor rod might just work, but I'd recommend you get a little longer threaded rod so you don't have a frustrating repeat.
I changed on of my C2 years ago with just the rear spring and found it to be very "bouncy" and promptly removed it. I don't know if that would have gone away with the matching front springs but I doubt it.
im just running the fronts with a Vette Products composite spring. I don’t remember the spring rate on the rear. I want to say 330#. Made my rear a little high but not bad. Very smooth amd tight for me.
Bouncing would point to shocks. If adjustible, I believe you increase rebound setting. My car is stiff and very secure in handling. Mickey Thompson’s 215/70/15, 3/4” anti-sway in the rear, poly bushings (hey! I like ‘em!) I even replaced the rag joint with a hard u-joint in my quest for tightness!
Small block LT1 (iron), 64, vert, M22, power front discs/rear drums with adjustible proportioning valve, later chassis with welds redone and some bolstering on rear kick ups. ( this actually makes a difference in stiffness.) running about 370-390hp.
Only think I would change is smaller anti-sway but now I’m used to it. BTY, those mickeys are crap on wet streets. White knuckle crap your pants.
Here is the ride height with F-41 and a big block. Note the front coils are much shorter than standard, you will actually not need a spring compressor to install them. I have done it twice--I just run a chain through for safety and slowly jack up the LCA.
The ride is notably harsher than the base suspension. For normal street driving I prefer the standard suspension on my other big block and my small block cars.
Last edited by SupremeDeluxe; 10-15-2018 at 11:53 AM.
I've run the F41s on the front and rear of my 67 327 for over ten years. I like the extra stiffness and body control.
Louie, are you also running the 15/16" front sway bar? Hows the ride on the street? Obviously stiffer than factory, but do you find it "twitchy" or "bouncy" on the street? I'm very interested in your input as you're one of only a handful that I've found running the F40/41 suspension on a relatively stock small block car.
Louie, are you also running the 15/16" front sway bar? Hows the ride on the street? Obviously stiffer than factory, but do you find it "twitchy" or "bouncy" on the street? I'm very interested in your input as you're one of only a handful that I've found running the F40/41 suspension on a relatively stock small block car.
Thanks
I run the 3/4" front sway bar, no rear bar. I like the rear end to be a little looser for autocrossing. In the past I've run a 15/16" front bar and BB rear bar, but didn't like the stiffer ride on the street. I've run front bars as thick as 1-1/8" with commensurate rear bars, but the setup I have now suits me best. I like the current ride of my car, and it's not what I'd call bouncy or twitchy on the street or track. I also run Bilstein Heavy Duty (NOT Sport, which are way stiff, for track use only) shocks. Hope this helps.
I run the 3/4" front sway bar, no rear bar. I like the rear end to be a little looser for autocrossing. In the past I've run a 15/16" front bar and BB rear bar, but didn't like the stiffer ride on the street. I've run front bars as thick as 1-1/8" with commensurate rear bars, but the setup I have now suits me best. I like the current ride of my car, and it's not what I'd call bouncy or twitchy on the street or track. I also run Bilstein Heavy Duty (NOT Sport, which are way stiff, for track use only) shocks. Hope this helps.
Lou
Much appreciated Lou, that is helpful. Right now I have both the 3/4 bar and 13/16 bar in my garage, along with RideTech single adjustable shocks....I keep going back and forth on reinstalling the factory base springs or going with the F40/41. I felt the stock springs were pretty soft, it seems like opinions vary as to how "rough" the F40/41 springs are on the street.
Much appreciated Lou, that is helpful. Right now I have both the 3/4 bar and 13/16 bar in my garage, along with RideTech single adjustable shocks....I keep going back and forth on reinstalling the factory base springs or going with the F40/41. I felt the stock springs were pretty soft, it seems like opinions vary as to how "rough" the F40/41 springs are on the street.
Yeah, preferences in ride, exhaust sound, etc. are personal. If you think the base springs are too soft, you're likely a candidate for F40/41 units. The base springs seem soft to me too. Fortunately, putting in the "wrong" spring is reversible. Good luck choosing!
I run the 3/4" front sway bar, no rear bar. I like the rear end to be a little looser for autocrossing. In the past I've run a 15/16" front bar and BB rear bar, but didn't like the stiffer ride on the street. I've run front bars as thick as 1-1/8" with commensurate rear bars, but the setup I have now suits me best. I like the current ride of my car, and it's not what I'd call bouncy or twitchy on the street or track. I also run Bilstein Heavy Duty (NOT Sport, which are way stiff, for track use only) shocks. Hope this helps.
Lou
Some general comments on suspension tuning...
Optimum setups for autocross, big tracks, and canyon carving are usually quite different. For autocross you want to be able to easily kick the car into oversteer because the tight turns require very high yaw rates. For the big Willow Springs track where you enter Turn 8 in a high powered car at 120+ you definitely don't want oversteer. That's why the F-40/41 spring/bar setups are biased for more understeer than the base setup. F40/41 is tuned for big tracks.
Twisty public roads can be very fun to drive - almost as much fun as a track day if traffic is light, but they can be unpredictable. Rains can wash dirt and gravel onto blind corners, so you need a car that is forgiving and predictable. This requires more compliance, which means modest spring rates. You may give up a little response and grip, but it can save you from a crash. A stiff setup is more responsive, but response and stability are diametrically opposed. The quicker the response, the more unstable it can be, and a slower responding car is more forgiving.
Think of modern jet fighters like the F-16. In order to achieve the required responsiveness, the design ended up inherently unstable, but modern digital control technology constantly makes corrections at a much higher frequency than humans can muster, and that keeps the airplane doing what the pilot wants. Jack Northrup's flying wing design of the forties was also inherently unstable which made it difficult to fly with the conventional hydraulic control technology of the time. It was noticed that the B-35/49 were difficult to see on radar, so in the modern era of fly-by-wire computer control we were able to design the low radar cross section B-2 that is forgiving and easy to fly. The same technology is also present in modern Corvettes, which makes them forgiving of small mistakes, but you still can't beat the laws of physics, so if you go into a corner WAAAAY to fast you're probably going on an off-road excursion.
From the seventies to the nineties I spent a lot of weekends attacking Sunset Blvd, Mullholland, Angeles Crest Highway, and many other California "driver's roads" in all my cars and my 1100cc superbike. On trips to northern CA I usually spent at least half the trip on back roads rather than slogging straight up I5. The only one of my vehicles that ever got me close to serious trouble was my base suspension SWC on 225/70R15 Pirelli CN73 fabric belted radials, which were more forgiving that early steel belted radials that had "sudden breakaway" behavior. It was that C2 twitchyness at the limit. That's when I installed urethane bushings in the front anti-roll bars links, which pretty much eliminated the sudden transition to oversteer at the limit.
So when selecting springs and bars one must consider how the car it to be used, and starting with an OE setup is usually a good baseline, then you go from there making one change at a time and then testing. This can be a very time consuming task, but if you do your due diligence properly, you should end up with a very good car.
As I've said many times before if you want maximum handling you select the highest grip tires that are available and a set of adjustable rebound shocks, so you can get the damping dialed in. The you can change bars(one at a time) to achieve the best oversteer/understeer balance, and the last thing to consider increasing spring rates unless it's a dedicated track car. For a sporty handling car used primarily on public roads, the base springs are the best staring point, and on a C2 they will maintain the car's pleasant ride behavior.
I've ridden in/driven enough twitchy, oversprung cars that practically rattled my dental fillings loose that I gained great respect for compliance.
Optimum setups for autocross, big tracks, and canyon carving are usually quite different. For autocross you want to be able to easily kick the car into oversteer because the tight turns require very high yaw rates. For the big Willow Springs track where you enter Turn 8 in a high powered car at 120+ you definitely don't want oversteer. That's why the F-40/41 spring/bar setups are biased for more understeer than the base setup. F40/41 is tuned for big tracks.
Twisty public roads can be very fun to drive - almost as much fun as a track day if traffic is light, but they can be unpredictable. Rains can wash dirt and gravel onto blind corners, so you need a car that is forgiving and predictable. This requires more compliance, which means modest spring rates. You may give up a little response and grip, but it can save you from a crash. A stiff setup is more responsive, but response and stability are diametrically opposed. The quicker the response, the more unstable it can be, and a slower responding car is more forgiving.
From the seventies to the nineties I spent a lot of weekends attacking Sunset Blvd, Mullholland, Angeles Crest Highway, and many other California "driver's roads" in all my cars and my 1100cc superbike. On trips to northern CA I usually spent at least half the trip on back roads rather than slogging straight up I5. The only one of my vehicles that ever got me close to serious trouble was my base suspension SWC on 225/70R15 Pirelli CN73 fabric belted radials, which were more forgiving that early steel belted radials that had "sudden breakaway" behavior. It was that C2 twitchyness at the limit. That's when I installed urethane bushings in the front anti-roll bars links, which pretty much eliminated the sudden transition to oversteer at the limit.
So when selecting springs and bars one must consider how the car it to be used, and starting with an OE setup is usually a good baseline, then you go from there making one change at a time and then testing. This can be a very time consuming task, but if you do your due diligence properly, you should end up with a very good car.
As I've said many times before if you want maximum handling you select the highest grip tires that are available and a set of adjustable rebound shocks, so you can get the damping dialed in. The you can change bars(one at a time) to achieve the best oversteer/understeer balance, and the last thing to consider increasing spring rates unless it's a dedicated track car. For a sporty handling car used primarily on public roads, the base springs are the best staring point, and on a C2 they will maintain the car's pleasant ride behavior.
I've ridden in/driven enough twitchy, oversprung cars that practically rattled my dental fillings loose that I gained great respect for compliance.
Duke
Much appreciated Duke.....for anyone thats interested, or stumbles on this thread in the future, below is some additional information from an email conversation between myself and Duke on this topic:
"As a general rule, the less compliant the suspension, the more unforgiving the car. Since your primary objective is sporty handling on mountain and canyon roads, I recommend the base springs with the 13/16" front bar with poly end link bushings, negative one degree camber on all four corners and 2 to 2.5 deg. front caster.
It's tough to get a suspension setup fully dialed in on the first try, but sticking with an OEM config. usually makes for a decent baseline. Then you work on it from there. Get the damping dialed in first, then if you need to alter the understeer/oversteer balance, do it by swapping out front bars as required.
The objective is to make the car stable at the limit of adhesion, especially on trailing throttle. The base setup can snap into oversteer at the limit, but my experience says the more tire grip you have with a specific spring/bar setup, the less likely the car is to snap into oversteer at the limit. Also, using the 13/16" front bar rather than the base C2 3/4" front bar should mitigate the twitchy limit handling of the base setup on common road tires, either bias or radial.
As a general rule you can go with a more aggressive setup if you're primary interest is race track hot lapping because closed tracks are more consistent and smoother that public roads, which can often hold surprises even if you've run them before. That's why if your primary objective is maximum performance on public roads, sacrificing a little grip for a forgiving setup can save you from a crash."
Duke, is there any middle ground between the stock small block springs and the F40/41 springs? I see that Van Steel offers a 460# spring for the front, but I imagine that would require a rear spring somewhere in the neighborhood of 220-230# in order to keep the car balanced?
10-13-2018, 09:09 AM
Who's running F41 springs?
