DIY Front Coilover Setup
#41
Le Mans Master
However, it's an apples:oranges comparison between front springs for an early C4 vs a late C4. My front spring is 1125lb. But as we've already discussed, the 88-96 Corvettes have a considerably lower motion ratio than the early C4s, and lower than the MR for the shock mount also. The MR on a later C4, at least with the VBP Xtreme spring I have (the pad center on it may be located in a slightly different spot than the stock springs), is 0.55:1. The shock mount's MR is 0.76:1. So a 600lb front monoleaf in my car would have a lot lower wheel rate than one in your car: only 182lb. And it would also provide a lower rate than a 600lb coilover in my car. In fact, my 1125lb front spring creates a wheel rate of only 340lb/in, slightly lower than the 347lb/in wheel rate provided by a 600lb coilover on my car. A 1125lb front leaf in your early C4 would provide a much higher wheel rate. In fact, it would ride about the same as your car with an 1125lb coilover spring.
*The above paragraph was edited to reflect actual motion ratios for my car, as measured by the previous owner. I just found that info.
Can you please provide the following info about your pre-coilover setup:
- Exactly what leaf spring was in the front of your car?
- What shocks were on the front of your car when you had the leaf spring?
- What are the differences in compressed length between the old and new shocks, including bump stops?
- How does your ride height compare before and after?
Last edited by MatthewMiller; 11-23-2018 at 08:14 PM.
#42
Team Owner
Pro Mechanic
There is some learning that can occur in this thread, Blackozvette, if you can spare the time. I'm looking/listening.....
#43
Melting Slicks
Fact - I stated it was my personal experience and opinion that a 600 lb coil was more efficient than a 600 lb leaf in the front of the C4.
(and lets not split hairs over the leaf 600 lb rate, early springs slightly less, later ones slightly more)
Fact - I stated that an upright coil was more efficient than the lateral leaf (again my opinion based on the above) I did not state the leaf was inherently inefficient due to the fact it is lateral. Matthew made a comment about a spring being a spring being a spring and its rates remain constant. My reply was if you begin to lay a coil over it loses its rate and its not the same spring anymore (I used this as an example) this then turned into an attack by Matthew and Tom who have both decided to go off on their own little tangent about how wrong I am about leaf springs.
Fact - my experience and opinions are based on converting my C4 to coilovers (both front and rear) and going racing with them. Perhaps Matthew and Tom could do the same and then get back to us with their 'experiences' on the subject.
I can happily accept that people wont always agree with anyones (including my) point of view. Quotes like this are make it quite clear that you do not value anyones opinion or experience if it differs from your own beliefs on the subject.
The tag team tactics of Matthew and Tom are nothing short of online bullying, but it has been going on in CF/C4 for quite a while now, and it does nothing to promote any healthy conversation on any topic - I have seen many people suffer from tirades against them like this thread has produced. Its a damn shame really.
(and lets not split hairs over the leaf 600 lb rate, early springs slightly less, later ones slightly more)
Fact - I stated that an upright coil was more efficient than the lateral leaf (again my opinion based on the above) I did not state the leaf was inherently inefficient due to the fact it is lateral. Matthew made a comment about a spring being a spring being a spring and its rates remain constant. My reply was if you begin to lay a coil over it loses its rate and its not the same spring anymore (I used this as an example) this then turned into an attack by Matthew and Tom who have both decided to go off on their own little tangent about how wrong I am about leaf springs.
Fact - my experience and opinions are based on converting my C4 to coilovers (both front and rear) and going racing with them. Perhaps Matthew and Tom could do the same and then get back to us with their 'experiences' on the subject.
I'm sorry, but that simply isn't a fact. And I'm not trying to split hairs with you just to win an argument. It's really important that we not propagate misinformation on this forum, and the above quote and your statements about "efficiency" and laying a spring on its side are just flat wrong.
The tag team tactics of Matthew and Tom are nothing short of online bullying, but it has been going on in CF/C4 for quite a while now, and it does nothing to promote any healthy conversation on any topic - I have seen many people suffer from tirades against them like this thread has produced. Its a damn shame really.
#44
Le Mans Master
Fact - I stated that an upright coil was more efficient than the lateral leaf (again my opinion based on the above) I did not state the leaf was inherently inefficient due to the fact it is lateral. Matthew made a comment about a spring being a spring being a spring and its rates remain constant. My reply was if you begin to lay a coil over it loses its rate and its not the same spring anymore (I used this as an example) this then turned into an attack by Matthew and Tom who have both decided to go off on their own little tangent about how wrong I am about leaf springs.
Fact - my experience and opinions are based on converting my C4 to coilovers (both front and rear) and going racing with them. Perhaps Matthew and Tom could do the same and then get back to us with their 'experiences' on the subject.
The best way to do this would be to start with an adjustable-height front leaf, like I have. Then one could install the actual coilover dampers without the springs, and start by dialing in the damping rates. Then, and only then, one could remove the leafs and install coils that provide the same wheel rate (in my case a it looks like a 600lb coil is very close), adjust to exactly the same ride height while leaving the damping adjustments where they were with the leaf, add however much swaybar rate is lost when the leaf is removed, and check for any differences. That is the only way I can think of to eliminate the other variables. The time and money involved in such a test is considerable, but if you're willing to fund all of that, then I'm willing to try it. But we really don't need to test all of this. It's well known and established how springs and motion ratios work. And it's not like I'm dreaming this tech info up: I've learned this info from actual engineers who design suspensions and/or good coilover kits for a living, some of which are at the highest levels of motorsports.
I can happily accept that people wont always agree with anyones (including my) point of view. Quotes like this are make it quite clear that you do not value anyones opinion or experience if it differs from your own beliefs on the subject.
The tag team tactics of Matthew and Tom are nothing short of online bullying, but it has been going on in CF/C4 for quite a while now, and it does nothing to promote any healthy conversation on any topic - I have seen many people suffer from tirades against them like this thread has produced. Its a damn shame really.
#45
Team Owner
Pro Mechanic
I think I can see what is going on here. I think that this "discussion" was over before it began. Blackoz feels attacked and has moved to defensiveness. That's unfortunate...I'm all ears on this topic, but I want to discuss it using real facts, math and data...not "facts" like this...
...and this as a mind set:
^Trying to discuss this with science/math/data. Why didn't you just answer the questions Matthew asked you? I believe that he was simply exploring the reasons why you had the observations that you had. I'm interested in this too.
You've made some pretty hefty assumptions here....IDK why. *I* value opinions and experience...I value that, combined with science a whole lot more. So let's combine the two. That's where I thought this thread WAS headed. Tom and Matthew aren't "ganging up", we aren't bullying or anything like that. Tom and Matthew don't even know each other (other than that he's a member on here). I can't speak for him, but I believe that we're both exploring things until we have a full and complete understanding of it's function. That requires open, honest communication. Unfortunately, some people perceive "open/honest" as an attack. Leesvet quit the forums b/c I told him that the fuel pump runs during cranking. . That's not attacking, ganging up, or bullying...that's fact. I'm sorry that you felt accosted by my participation in this thread...that wasn't my intent at all. Happy holidays.
Quotes like this are make it quite clear that you do not value anyones opinion or experience if it differs from your own beliefs on the subject.
The tag team tactics of Matthew and Tom are nothing short of online bullying, but it has been going on in CF/C4 for quite a while now, and it does nothing to promote any healthy conversation on any topic - I have seen many people suffer from tirades against them like this thread has produced. Its a damn shame really.
The tag team tactics of Matthew and Tom are nothing short of online bullying, but it has been going on in CF/C4 for quite a while now, and it does nothing to promote any healthy conversation on any topic - I have seen many people suffer from tirades against them like this thread has produced. Its a damn shame really.
#46
Team Owner
Pro Mechanic
The best way to do this would be to start with an adjustable-height front leaf, like I have. Then one could install the actual coilover dampers without the springs, and start by dialing in the damping rates. Then, and only then, one could remove the leafs and install coils that provide the same wheel rate (in my case a it looks like a 600lb coil is very close), adjust to exactly the same ride height while leaving the damping adjustments where they were with the leaf, add however much swaybar rate is lost when the leaf is removed, and check for any differences. That is the only way I can think of to eliminate the other variables.
Over the years, and on all C4^ forums, you see thread after thread where people recommend going to coil overs to improve ride and/or handling. Repeatedly, this recommendation is backed up by the assertion that "I changed to coil overs and (ride and/or handling) was way better". Well what actually happened in that case? Did the coil spring improve the ride and/or handling? In most cases, the person posting changed old worn $89 Bilsteins with new adjustable ~$200 shocks, possibly changed their spring rate, and definitely changed their MR. Had they simply put the new, adjustable ~$200 QA1's (or whatever brand came with the coil over kit) on their car, they'd have likely realized the same or similar benefits. So misinformation is likely being passed on; "Coil overs are way better". Matthew is right that most don't change just the shock...then later, the springs and that is for time/cost reasons...and most also have no good way to measure changes. SOTP is about it.
Eventually, I'll be putting "coil over quality" shocks on my Kart project, but retaining the monoleaf springs. Unfortunately, I have no objective way to measure the improvement of the shock, and likely won't even continue with a change to c/o's due to cost. But I MAY, if it could be proven to me that there is an objective/actual benefit....which is why I'm "IN" on this conversation.
.
Last edited by Tom400CFI; 11-24-2018 at 01:51 PM.
#47
Le Mans Master
I find it interesting to argue against coil overs. If you have the adjustable flat front spring maybe there is advantage. Production style it's bolt it and deal with it, not really adjustable. The ride height is what it is. Adjustability is the advantage of coil overs. Spring change 20 minutes. The ability to reset ride height and corner weights quickly.
#48
Le Mans Master
I find it interesting to argue against coil overs. If you have the adjustable flat front spring maybe there is advantage. Production style it's bolt it and deal with it, not really adjustable. The ride height is what it is. Adjustability is the advantage of coil overs. Spring change 20 minutes. The ability to reset ride height and corner weights quickly.
If - big "if" - an adjustable leaf spring is available, then the big advantage to coilovers is the easy swapping of front springs for different rates, as well as the availability of a wide range of spring rates. Aftermarket stiff leafs are easier to change out than stock leafs (they have less curve in them, but the fronts are still a bit of a pain. In the rear, the leaf spring is quick and easy to swap, and it's easy to make it adjustable for ride height and preload, so they are probably a wash.
#49
Drifting
I find it interesting to argue against coil overs. If you have the adjustable flat front spring maybe there is advantage. Production style it's bolt it and deal with it, not really adjustable. The ride height is what it is. Adjustability is the advantage of coil overs. Spring change 20 minutes. The ability to reset ride height and corner weights quickly.
#50
Drifting
Yep, so with an adjustable-height leaf like my VBP Xtreme, it has easy adjustment for ride height and corner weights like any adjustable coilover. However, the real problem for now is that no such spring is currently in production. This may change in the future - I've been told someone well connected to the Corvette aftermarket that another company is tooling up to make them. But who knows?
If - big "if" - an adjustable leaf spring is available, then the big advantage to coilovers is the easy swapping of front springs for different rates, as well as the availability of a wide range of spring rates. Aftermarket stiff leafs are easier to change out than stock leafs (they have less curve in them, but the fronts are still a bit of a pain. In the rear, the leaf spring is quick and easy to swap, and it's easy to make it adjustable for ride height and preload, so they are probably a wash.
If - big "if" - an adjustable leaf spring is available, then the big advantage to coilovers is the easy swapping of front springs for different rates, as well as the availability of a wide range of spring rates. Aftermarket stiff leafs are easier to change out than stock leafs (they have less curve in them, but the fronts are still a bit of a pain. In the rear, the leaf spring is quick and easy to swap, and it's easy to make it adjustable for ride height and preload, so they are probably a wash.
#51
Drifting
Matt:
Any chance that you can talk Chris Ramey into posting a picture of his rear coil over shock mounts he fabricated to beef up the lower mounting point?
Any chance that you can talk Chris Ramey into posting a picture of his rear coil over shock mounts he fabricated to beef up the lower mounting point?
#52
Le Mans Master
Did you add adjustable bolt? I'm running FHB front with cut down pads (3/16) and small 1/8" spring tips.i cut down aluminum brackets there are no shims I think still think its a little high up front. It still required 1 lower control arm to be removed to install. Granted it was much easier than a FHA
#53
Drifting
Did you add adjustable bolt? I'm running FHB front with cut down pads (3/16) and small 1/8" spring tips.i cut down aluminum brackets there are no shims I think still think its a little high up front. It still required 1 lower control arm to be removed to install. Granted it was much easier than a FHA
This is the top of a 1222 pound spring I have as a spare:
This is the bottom of the spring.
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krackenvette (12-04-2020)
#55
Le Mans Master
#57
Team Owner
Pro Mechanic
I'd like to comment on this, because it's a great point. Why argue against coil overs? I don't think that I have done that specifically, although I can see how it would appear that way.
For me, I'm all about $$$. Coil overs cost a lot. Good shocks, combined with a monoleaf costs a lot less. If we all had so much money that money didn't matter then the case for Coil overs would be more clear.
The second thing is the actual realized benefits; What is their REAL benefit? Easy (front) spring swapping -the rear monoleaf is actually easier and faster to swap, IMO. How many of us on the CF forums are swapping front springs for events/conditions? Not many. How many forum members care about or need to care about corner weighting? Not many. Probably 99% of coil-over swappers don't change their springs, corner weights or ever touch their pre-load adjusters once they've set their desired ride height (usually driven by "looks"). So they could have accomplished the same thing with stock springs, ~the same amount of labor, and less money.
Finally, misinformation. As I stated earlier, you see post after post where someone swapped to coil overs and fixed some ride/handling issue. The shock fixed the issue, not the spring. So now folks read that and think they need coil overs and the requisite mods to install them, for a basic maintenance problem; crappy shocks. I've been a victim of this very problem on the very forum -you don't know, someone says something and you believe 'em. You spend a bunch of money and then 1. convince yourself that something's better, or 2. your unhappy with the value of the change. I think a lot of people have it stuck in their heads that "leafs suck" and coil overs are the answer/fix. And why not? Car mags and other publications erroneously pick on the leaf spring design and frame it in the same light as the leaf springs on a pick up truck...or a horse drawn cart. This leads people to eliminate the leaf, for reasoning that doesn't exist, I believe.
For not a lot of effort and for basically $0.00, you can mod the stock front spring so that you can adjust ride height and corner weights and then the only down side compared to a coil over (that I can see) is rate tune-ability. Especially for the average forum member.
For me, I'm all about $$$. Coil overs cost a lot. Good shocks, combined with a monoleaf costs a lot less. If we all had so much money that money didn't matter then the case for Coil overs would be more clear.
The second thing is the actual realized benefits; What is their REAL benefit? Easy (front) spring swapping -the rear monoleaf is actually easier and faster to swap, IMO. How many of us on the CF forums are swapping front springs for events/conditions? Not many. How many forum members care about or need to care about corner weighting? Not many. Probably 99% of coil-over swappers don't change their springs, corner weights or ever touch their pre-load adjusters once they've set their desired ride height (usually driven by "looks"). So they could have accomplished the same thing with stock springs, ~the same amount of labor, and less money.
Finally, misinformation. As I stated earlier, you see post after post where someone swapped to coil overs and fixed some ride/handling issue. The shock fixed the issue, not the spring. So now folks read that and think they need coil overs and the requisite mods to install them, for a basic maintenance problem; crappy shocks. I've been a victim of this very problem on the very forum -you don't know, someone says something and you believe 'em. You spend a bunch of money and then 1. convince yourself that something's better, or 2. your unhappy with the value of the change. I think a lot of people have it stuck in their heads that "leafs suck" and coil overs are the answer/fix. And why not? Car mags and other publications erroneously pick on the leaf spring design and frame it in the same light as the leaf springs on a pick up truck...or a horse drawn cart. This leads people to eliminate the leaf, for reasoning that doesn't exist, I believe.
For not a lot of effort and for basically $0.00, you can mod the stock front spring so that you can adjust ride height and corner weights and then the only down side compared to a coil over (that I can see) is rate tune-ability. Especially for the average forum member.
#58
Le Mans Master
Coil overs arn't IMO for the average C4 Corvette owner. The benefit of coil overs is in the front, not so much the rear. If you track your car at the same track week in an week out once set up is set you are just tweaking. If you run multiple tracks you may different springs and shocks or settings. Most owners aren't opting for high rate springs or even adjustable shocks. The beginning of the thread related to the high cost of aftermarket performance springs made coil overs comparable in cost. Notice he didn't price a kit but the pieces to build his own.
#59
Instructor
Thread Starter
Coil overs arn't IMO for the average C4 Corvette owner. The benefit of coil overs is in the front, not so much the rear. If you track your car at the same track week in an week out once set up is set you are just tweaking. If you run multiple tracks you may different springs and shocks or settings. Most owners aren't opting for high rate springs or even adjustable shocks. The beginning of the thread related to the high cost of aftermarket performance springs made coil overs comparable in cost. Notice he didn't price a kit but the pieces to build his own.
This thread has turned into quite the debate! I'm all for a good discussion but it is difficult for any readers of this thread to distinguish between the objective and the subjective information. There are a ton of different person experiences from different setup but generally they are never narrowed down to one variable. Most of the time when a major suspension change like coilovers occurs the vehicle now has new shocks, a new alignment, possible different ride height, etc... If anyone would like a very technical textbook on these topics, I highly recommend "Fundamentals of Vehicle Dynamics" by Thomas Gillespie. You can pick it up pretty cheap used on Amazon or Barnes and Noble. Vehicle Dynamics theory in the book is reality. It's a very physics based environment. It becomes difficult to represent every single variable in a system to completely estimate how it reacts (think ball joint stiffness, bushing stiffness, wheel stiffness, etc... some of which aren't exactly linear) but estimations are extremely close. This is how modern vehicle suspensions are designed, around proven theories and principles. Just remember that it is very rare for only one variable in a system to change for us to truly understand what made the difference that we feel/experience.
#60